ALSA: usb-audio: scarlett2: Move get config above set config
[linux-2.6-microblaze.git] / sound / usb / mixer_scarlett_gen2.c
index 49c4662..7a5346c 100644 (file)
@@ -1,8 +1,12 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- *   Focusrite Scarlett 6i6/18i8/18i20 Gen 2 Driver for ALSA
+ *   Focusrite Scarlett Gen 2/3 Driver for ALSA
  *
- *   Copyright (c) 2018-2019 by Geoffrey D. Bennett <g at b4.vu>
+ *   Supported models:
+ *   - 6i6/18i8/18i20 Gen 2
+ *   - 4i4/8i6/18i8/18i20 Gen 3
+ *
+ *   Copyright (c) 2018-2021 by Geoffrey D. Bennett <g at b4.vu>
  *
  *   Based on the Scarlett (Gen 1) Driver for ALSA:
  *
  *   David Henningsson <david.henningsson at canonical.com>
  */
 
-/* Mixer Interface for the Focusrite Scarlett 6i6/18i8/18i20 Gen 2 audio
- * interface. Based on the Gen 1 driver and rewritten.
- */
-
 /* The protocol was reverse engineered by looking at the communication
  * between Focusrite Control 2.3.4 and the Focusrite(R) Scarlett 18i20
  * (firmware 1083) using usbmon in July-August 2018.
  * Scarlett 6i6 support added in June 2019 (thanks to Martin Wittmann
  * for providing usbmon output and testing).
  *
+ * Scarlett 4i4/8i6 Gen 3 support added in May 2020 (thanks to Laurent
+ * Debricon for donating a 4i4 and to Fredrik Unger for providing 8i6
+ * usbmon output and testing).
+ *
+ * Scarlett 18i8/18i20 Gen 3 support added in June 2020 (thanks to
+ * Darren Jaeckel, Alex Sedlack, and Clovis Lunel for providing usbmon
+ * output, protocol traces and testing).
+ *
  * Support for loading mixer volume and mux configuration from the
  * interface during driver initialisation added in May 2021 (thanks to
  * Vladimir Sadovnikov for figuring out how).
  *
- * This ALSA mixer gives access to:
+ * This ALSA mixer gives access to (model-dependent):
  *  - input, output, mixer-matrix muxes
- *  - 18x10 mixer-matrix gain stages
- *  - gain/volume controls
+ *  - mixer-matrix gain stages
+ *  - gain/volume/mute controls
  *  - level meters
  *  - line/inst level and pad controls
+ *  - disable/enable MSD mode
  *
  * <ditaa>
  *    /--------------\    18chn            20chn     /--------------\
  *  \--------------/
  * </ditaa>
  *
+ * Gen 3 devices have a Mass Storage Device (MSD) mode where a small
+ * disk with registration and driver download information is presented
+ * to the host. To access the full functionality of the device without
+ * proprietary software, MSD mode can be disabled by:
+ * - holding down the 48V button for five seconds while powering on
+ *   the device, or
+ * - using this driver and alsamixer to change the "MSD Mode" setting
+ *   to Off and power-cycling the device
  */
 
 #include <linux/slab.h>
 /* device_setup value to enable */
 #define SCARLETT2_ENABLE 0x01
 
+/* device_setup value to allow turning MSD mode back on */
+#define SCARLETT2_MSD_ENABLE 0x02
+
 /* some gui mixers can't handle negative ctl values */
 #define SCARLETT2_VOLUME_BIAS 127
 
@@ -148,23 +168,21 @@ static const u16 scarlett2_mixer_values[SCARLETT2_MIXER_VALUE_COUNT] = {
 
 /* Maximum number of level and pad switches */
 #define SCARLETT2_LEVEL_SWITCH_MAX 2
-#define SCARLETT2_PAD_SWITCH_MAX 4
+#define SCARLETT2_PAD_SWITCH_MAX 8
 
 /* Maximum number of inputs to the mixer */
-#define SCARLETT2_INPUT_MIX_MAX 18
+#define SCARLETT2_INPUT_MIX_MAX 25
 
 /* Maximum number of outputs from the mixer */
-#define SCARLETT2_OUTPUT_MIX_MAX 10
+#define SCARLETT2_OUTPUT_MIX_MAX 12
 
 /* Maximum size of the data in the USB mux assignment message:
- * 18 inputs, 20 outputs, 18 matrix inputs, 8 spare
+ * 20 inputs, 20 outputs, 25 matrix inputs, 12 spare
  */
-#define SCARLETT2_MUX_MAX 64
+#define SCARLETT2_MUX_MAX 77
 
-/* Number of meters:
- * 18 inputs, 20 outputs, 18 matrix inputs
- */
-#define SCARLETT2_NUM_METERS 56
+/* Maximum number of meters (sum of output port counts) */
+#define SCARLETT2_MAX_METERS 65
 
 /* Hardware port types:
  * - None (no input to mux)
@@ -184,44 +202,123 @@ enum {
        SCARLETT2_PORT_TYPE_COUNT    = 6,
 };
 
-/* Count of total I/O and number available at each sample rate */
+/* I/O count of each port type kept in struct scarlett2_ports */
 enum {
-       SCARLETT2_PORT_IN      = 0,
-       SCARLETT2_PORT_OUT     = 1,
-       SCARLETT2_PORT_OUT_44  = 2,
-       SCARLETT2_PORT_OUT_88  = 3,
-       SCARLETT2_PORT_OUT_176 = 4,
-       SCARLETT2_PORT_DIRNS   = 5,
+       SCARLETT2_PORT_IN    = 0,
+       SCARLETT2_PORT_OUT   = 1,
+       SCARLETT2_PORT_DIRNS = 2,
 };
 
 /* Dim/Mute buttons on the 18i20 */
-#define SCARLETT2_DIM_MUTE_COUNT 2
+enum {
+       SCARLETT2_BUTTON_MUTE    = 0,
+       SCARLETT2_BUTTON_DIM     = 1,
+       SCARLETT2_DIM_MUTE_COUNT = 2,
+};
 
 static const char *const scarlett2_dim_mute_names[SCARLETT2_DIM_MUTE_COUNT] = {
        "Mute", "Dim"
 };
 
 /* Description of each hardware port type:
- * - id: hardware ID for this port type
- * - num: number of sources/destinations of this port type
+ * - id: hardware ID of this port type
  * - src_descr: printf format string for mux input selections
  * - src_num_offset: added to channel number for the fprintf
  * - dst_descr: printf format string for mixer controls
  */
-struct scarlett2_ports {
+struct scarlett2_port {
        u16 id;
-       int num[SCARLETT2_PORT_DIRNS];
        const char * const src_descr;
        int src_num_offset;
        const char * const dst_descr;
 };
 
+static const struct scarlett2_port scarlett2_ports[SCARLETT2_PORT_TYPE_COUNT] = {
+       [SCARLETT2_PORT_TYPE_NONE] = {
+               .id = 0x000,
+               .src_descr = "Off"
+       },
+       [SCARLETT2_PORT_TYPE_ANALOGUE] = {
+               .id = 0x080,
+               .src_descr = "Analogue %d",
+               .src_num_offset = 1,
+               .dst_descr = "Analogue Output %02d Playback"
+       },
+       [SCARLETT2_PORT_TYPE_SPDIF] = {
+               .id = 0x180,
+               .src_descr = "S/PDIF %d",
+               .src_num_offset = 1,
+               .dst_descr = "S/PDIF Output %d Playback"
+       },
+       [SCARLETT2_PORT_TYPE_ADAT] = {
+               .id = 0x200,
+               .src_descr = "ADAT %d",
+               .src_num_offset = 1,
+               .dst_descr = "ADAT Output %d Playback"
+       },
+       [SCARLETT2_PORT_TYPE_MIX] = {
+               .id = 0x300,
+               .src_descr = "Mix %c",
+               .src_num_offset = 'A',
+               .dst_descr = "Mixer Input %02d Capture"
+       },
+       [SCARLETT2_PORT_TYPE_PCM] = {
+               .id = 0x600,
+               .src_descr = "PCM %d",
+               .src_num_offset = 1,
+               .dst_descr = "PCM %02d Capture"
+       },
+};
+
+/* Number of mux tables: one for each band of sample rates
+ * (44.1/48kHz, 88.2/96kHz, and 176.4/176kHz)
+ */
+#define SCARLETT2_MUX_TABLES 3
+
+/* Maximum number of entries in a mux table */
+#define SCARLETT2_MAX_MUX_ENTRIES 10
+
+/* One entry within mux_assignment defines the port type and range of
+ * ports to add to the set_mux message. The end of the list is marked
+ * with count == 0.
+ */
+struct scarlett2_mux_entry {
+       u8 port_type;
+       u8 start;
+       u8 count;
+};
+
 struct scarlett2_device_info {
-       u8 line_out_hw_vol; /* line out hw volume is sw controlled */
-       u8 level_input_count; /* inputs with level selectable */
-       u8 pad_input_count; /* inputs with pad selectable */
+       u32 usb_id; /* USB device identifier */
+
+       /* Gen 3 devices have an internal MSD mode switch that needs
+        * to be disabled in order to access the full functionality of
+        * the device.
+        */
+       u8 has_msd_mode;
+
+       /* line out hw volume is sw controlled */
+       u8 line_out_hw_vol;
+
+       /* the number of analogue inputs with a software switchable
+        * level control that can be set to line or instrument
+        */
+       u8 level_input_count;
+
+       /* the number of analogue inputs with a software switchable
+        * 10dB pad control
+        */
+       u8 pad_input_count;
+
+       /* additional description for the line out volume controls */
        const char * const line_out_descrs[SCARLETT2_ANALOGUE_MAX];
-       struct scarlett2_ports ports[SCARLETT2_PORT_TYPE_COUNT];
+
+       /* number of sources/destinations of each port type */
+       const int port_count[SCARLETT2_PORT_TYPE_COUNT][SCARLETT2_PORT_DIRNS];
+
+       /* layout/order of the entries in the set_mux message */
+       struct scarlett2_mux_entry mux_assignment[SCARLETT2_MUX_TABLES]
+                                                [SCARLETT2_MAX_MUX_ENTRIES];
 };
 
 struct scarlett2_data {
@@ -230,19 +327,32 @@ struct scarlett2_data {
        struct mutex data_mutex; /* lock access to this data */
        struct delayed_work work;
        const struct scarlett2_device_info *info;
+       __u8 bInterfaceNumber;
+       __u8 bEndpointAddress;
+       __u16 wMaxPacketSize;
+       __u8 bInterval;
        int num_mux_srcs;
        int num_mux_dsts;
        u16 scarlett2_seq;
+       u8 sync_updated;
        u8 vol_updated;
+       u8 input_other_updated;
+       u8 sync;
        u8 master_vol;
        u8 vol[SCARLETT2_ANALOGUE_MAX];
        u8 vol_sw_hw_switch[SCARLETT2_ANALOGUE_MAX];
+       u8 mute_switch[SCARLETT2_ANALOGUE_MAX];
        u8 level_switch[SCARLETT2_LEVEL_SWITCH_MAX];
        u8 pad_switch[SCARLETT2_PAD_SWITCH_MAX];
        u8 dim_mute[SCARLETT2_DIM_MUTE_COUNT];
+       u8 msd_switch;
+       struct snd_kcontrol *sync_ctl;
        struct snd_kcontrol *master_vol_ctl;
        struct snd_kcontrol *vol_ctls[SCARLETT2_ANALOGUE_MAX];
+       struct snd_kcontrol *mute_ctls[SCARLETT2_ANALOGUE_MAX];
        struct snd_kcontrol *dim_mute_ctls[SCARLETT2_DIM_MUTE_COUNT];
+       struct snd_kcontrol *level_ctls[SCARLETT2_LEVEL_SWITCH_MAX];
+       struct snd_kcontrol *pad_ctls[SCARLETT2_PAD_SWITCH_MAX];
        u8 mux[SCARLETT2_MUX_MAX];
        u8 mix[SCARLETT2_INPUT_MIX_MAX * SCARLETT2_OUTPUT_MIX_MAX];
 };
@@ -250,65 +360,54 @@ struct scarlett2_data {
 /*** Model-specific data ***/
 
 static const struct scarlett2_device_info s6i6_gen2_info = {
-       /* The first two analogue inputs can be switched between line
-        * and instrument levels.
-        */
-       .level_input_count = 2,
+       .usb_id = USB_ID(0x1235, 0x8203),
 
-       /* The first two analogue inputs have an optional pad. */
+       .level_input_count = 2,
        .pad_input_count = 2,
 
        .line_out_descrs = {
-               "Monitor L",
-               "Monitor R",
-               "Headphones L",
-               "Headphones R",
+               "Headphones 1 L",
+               "Headphones 1 R",
+               "Headphones L",
+               "Headphones R",
        },
 
-       .ports = {
-               [SCARLETT2_PORT_TYPE_NONE] = {
-                       .id = 0x000,
-                       .num = { 1, 0, 8, 8, 8 },
-                       .src_descr = "Off",
-               },
-               [SCARLETT2_PORT_TYPE_ANALOGUE] = {
-                       .id = 0x080,
-                       .num = { 4, 4, 4, 4, 4 },
-                       .src_descr = "Analogue %d",
-                       .src_num_offset = 1,
-                       .dst_descr = "Analogue Output %02d Playback"
-               },
-               [SCARLETT2_PORT_TYPE_SPDIF] = {
-                       .id = 0x180,
-                       .num = { 2, 2, 2, 2, 2 },
-                       .src_descr = "S/PDIF %d",
-                       .src_num_offset = 1,
-                       .dst_descr = "S/PDIF Output %d Playback"
-               },
-               [SCARLETT2_PORT_TYPE_MIX] = {
-                       .id = 0x300,
-                       .num = { 10, 18, 18, 18, 18 },
-                       .src_descr = "Mix %c",
-                       .src_num_offset = 65,
-                       .dst_descr = "Mixer Input %02d Capture"
-               },
-               [SCARLETT2_PORT_TYPE_PCM] = {
-                       .id = 0x600,
-                       .num = { 6, 6, 6, 6, 6 },
-                       .src_descr = "PCM %d",
-                       .src_num_offset = 1,
-                       .dst_descr = "PCM %02d Capture"
-               },
+       .port_count = {
+               [SCARLETT2_PORT_TYPE_NONE]     = {  1,  0 },
+               [SCARLETT2_PORT_TYPE_ANALOGUE] = {  4,  4 },
+               [SCARLETT2_PORT_TYPE_SPDIF]    = {  2,  2 },
+               [SCARLETT2_PORT_TYPE_MIX]      = { 10, 18 },
+               [SCARLETT2_PORT_TYPE_PCM]      = {  6,  6 },
        },
+
+       .mux_assignment = { {
+               { SCARLETT2_PORT_TYPE_PCM,      0,  6 },
+               { SCARLETT2_PORT_TYPE_ANALOGUE, 0,  4 },
+               { SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+               { SCARLETT2_PORT_TYPE_MIX,      0, 18 },
+               { SCARLETT2_PORT_TYPE_NONE,     0,  8 },
+               { 0,                            0,  0 },
+       }, {
+               { SCARLETT2_PORT_TYPE_PCM,      0,  6 },
+               { SCARLETT2_PORT_TYPE_ANALOGUE, 0,  4 },
+               { SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+               { SCARLETT2_PORT_TYPE_MIX,      0, 18 },
+               { SCARLETT2_PORT_TYPE_NONE,     0,  8 },
+               { 0,                            0,  0 },
+       }, {
+               { SCARLETT2_PORT_TYPE_PCM,      0,  6 },
+               { SCARLETT2_PORT_TYPE_ANALOGUE, 0,  4 },
+               { SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+               { SCARLETT2_PORT_TYPE_MIX,      0, 18 },
+               { SCARLETT2_PORT_TYPE_NONE,     0,  8 },
+               { 0,                            0,  0 },
+       } },
 };
 
 static const struct scarlett2_device_info s18i8_gen2_info = {
-       /* The first two analogue inputs can be switched between line
-        * and instrument levels.
-        */
-       .level_input_count = 2,
+       .usb_id = USB_ID(0x1235, 0x8204),
 
-       /* The first four analogue inputs have an optional pad. */
+       .level_input_count = 2,
        .pad_input_count = 4,
 
        .line_out_descrs = {
@@ -320,53 +419,42 @@ static const struct scarlett2_device_info s18i8_gen2_info = {
                "Headphones 2 R",
        },
 
-       .ports = {
-               [SCARLETT2_PORT_TYPE_NONE] = {
-                       .id = 0x000,
-                       .num = { 1, 0, 8, 8, 4 },
-                       .src_descr = "Off",
-               },
-               [SCARLETT2_PORT_TYPE_ANALOGUE] = {
-                       .id = 0x080,
-                       .num = { 8, 6, 6, 6, 6 },
-                       .src_descr = "Analogue %d",
-                       .src_num_offset = 1,
-                       .dst_descr = "Analogue Output %02d Playback"
-               },
-               [SCARLETT2_PORT_TYPE_SPDIF] = {
-                       .id = 0x180,
-                       .num = { 2, 2, 2, 2, 2 },
-                       .src_descr = "S/PDIF %d",
-                       .src_num_offset = 1,
-                       .dst_descr = "S/PDIF Output %d Playback"
-               },
-               [SCARLETT2_PORT_TYPE_ADAT] = {
-                       .id = 0x200,
-                       .num = { 8, 0, 0, 0, 0 },
-                       .src_descr = "ADAT %d",
-                       .src_num_offset = 1,
-               },
-               [SCARLETT2_PORT_TYPE_MIX] = {
-                       .id = 0x300,
-                       .num = { 10, 18, 18, 18, 18 },
-                       .src_descr = "Mix %c",
-                       .src_num_offset = 65,
-                       .dst_descr = "Mixer Input %02d Capture"
-               },
-               [SCARLETT2_PORT_TYPE_PCM] = {
-                       .id = 0x600,
-                       .num = { 8, 18, 18, 14, 10 },
-                       .src_descr = "PCM %d",
-                       .src_num_offset = 1,
-                       .dst_descr = "PCM %02d Capture"
-               },
+       .port_count = {
+               [SCARLETT2_PORT_TYPE_NONE]     = {  1,  0 },
+               [SCARLETT2_PORT_TYPE_ANALOGUE] = {  8,  6 },
+               [SCARLETT2_PORT_TYPE_SPDIF]    = {  2,  2 },
+               [SCARLETT2_PORT_TYPE_ADAT]     = {  8,  0 },
+               [SCARLETT2_PORT_TYPE_MIX]      = { 10, 18 },
+               [SCARLETT2_PORT_TYPE_PCM]      = {  8, 18 },
        },
+
+       .mux_assignment = { {
+               { SCARLETT2_PORT_TYPE_PCM,      0, 18 },
+               { SCARLETT2_PORT_TYPE_ANALOGUE, 0,  6 },
+               { SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+               { SCARLETT2_PORT_TYPE_MIX,      0, 18 },
+               { SCARLETT2_PORT_TYPE_NONE,     0,  8 },
+               { 0,                            0,  0 },
+       }, {
+               { SCARLETT2_PORT_TYPE_PCM,      0, 14 },
+               { SCARLETT2_PORT_TYPE_ANALOGUE, 0,  6 },
+               { SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+               { SCARLETT2_PORT_TYPE_MIX,      0, 18 },
+               { SCARLETT2_PORT_TYPE_NONE,     0,  8 },
+               { 0,                            0,  0 },
+       }, {
+               { SCARLETT2_PORT_TYPE_PCM,      0, 10 },
+               { SCARLETT2_PORT_TYPE_ANALOGUE, 0,  6 },
+               { SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+               { SCARLETT2_PORT_TYPE_MIX,      0, 18 },
+               { SCARLETT2_PORT_TYPE_NONE,     0,  4 },
+               { 0,                            0,  0 },
+       } },
 };
 
 static const struct scarlett2_device_info s18i20_gen2_info = {
-       /* The analogue line outputs on the 18i20 can be switched
-        * between software and hardware volume control
-        */
+       .usb_id = USB_ID(0x1235, 0x8201),
+
        .line_out_hw_vol = 1,
 
        .line_out_descrs = {
@@ -382,88 +470,303 @@ static const struct scarlett2_device_info s18i20_gen2_info = {
                "Headphones 2 R",
        },
 
-       .ports = {
-               [SCARLETT2_PORT_TYPE_NONE] = {
-                       .id = 0x000,
-                       .num = { 1, 0, 8, 8, 6 },
-                       .src_descr = "Off",
-               },
-               [SCARLETT2_PORT_TYPE_ANALOGUE] = {
-                       .id = 0x080,
-                       .num = { 8, 10, 10, 10, 10 },
-                       .src_descr = "Analogue %d",
-                       .src_num_offset = 1,
-                       .dst_descr = "Analogue Output %02d Playback"
-               },
-               [SCARLETT2_PORT_TYPE_SPDIF] = {
-                       /* S/PDIF outputs aren't available at 192kHz
-                        * but are included in the USB mux I/O
-                        * assignment message anyway
-                        */
-                       .id = 0x180,
-                       .num = { 2, 2, 2, 2, 2 },
-                       .src_descr = "S/PDIF %d",
-                       .src_num_offset = 1,
-                       .dst_descr = "S/PDIF Output %d Playback"
-               },
-               [SCARLETT2_PORT_TYPE_ADAT] = {
-                       .id = 0x200,
-                       .num = { 8, 8, 8, 4, 0 },
-                       .src_descr = "ADAT %d",
-                       .src_num_offset = 1,
-                       .dst_descr = "ADAT Output %d Playback"
-               },
-               [SCARLETT2_PORT_TYPE_MIX] = {
-                       .id = 0x300,
-                       .num = { 10, 18, 18, 18, 18 },
-                       .src_descr = "Mix %c",
-                       .src_num_offset = 65,
-                       .dst_descr = "Mixer Input %02d Capture"
-               },
-               [SCARLETT2_PORT_TYPE_PCM] = {
-                       .id = 0x600,
-                       .num = { 20, 18, 18, 14, 10 },
-                       .src_descr = "PCM %d",
-                       .src_num_offset = 1,
-                       .dst_descr = "PCM %02d Capture"
-               },
+       .port_count = {
+               [SCARLETT2_PORT_TYPE_NONE]     = {  1,  0 },
+               [SCARLETT2_PORT_TYPE_ANALOGUE] = {  8, 10 },
+               [SCARLETT2_PORT_TYPE_SPDIF]    = {  2,  2 },
+               [SCARLETT2_PORT_TYPE_ADAT]     = {  8,  8 },
+               [SCARLETT2_PORT_TYPE_MIX]      = { 10, 18 },
+               [SCARLETT2_PORT_TYPE_PCM]      = { 20, 18 },
        },
+
+       .mux_assignment = { {
+               { SCARLETT2_PORT_TYPE_PCM,      0, 18 },
+               { SCARLETT2_PORT_TYPE_ANALOGUE, 0, 10 },
+               { SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+               { SCARLETT2_PORT_TYPE_ADAT,     0,  8 },
+               { SCARLETT2_PORT_TYPE_MIX,      0, 18 },
+               { SCARLETT2_PORT_TYPE_NONE,     0,  8 },
+               { 0,                            0,  0 },
+       }, {
+               { SCARLETT2_PORT_TYPE_PCM,      0, 14 },
+               { SCARLETT2_PORT_TYPE_ANALOGUE, 0, 10 },
+               { SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+               { SCARLETT2_PORT_TYPE_ADAT,     0,  4 },
+               { SCARLETT2_PORT_TYPE_MIX,      0, 18 },
+               { SCARLETT2_PORT_TYPE_NONE,     0,  8 },
+               { 0,                            0,  0 },
+       }, {
+               { SCARLETT2_PORT_TYPE_PCM,      0, 10 },
+               { SCARLETT2_PORT_TYPE_ANALOGUE, 0, 10 },
+               { SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+               { SCARLETT2_PORT_TYPE_MIX,      0, 18 },
+               { SCARLETT2_PORT_TYPE_NONE,     0,  6 },
+               { 0,                            0,  0 },
+       } },
+};
+
+static const struct scarlett2_device_info s4i4_gen3_info = {
+       .usb_id = USB_ID(0x1235, 0x8212),
+
+       .has_msd_mode = 1,
+       .level_input_count = 2,
+       .pad_input_count = 2,
+
+       .line_out_descrs = {
+               "Monitor L",
+               "Monitor R",
+               "Headphones L",
+               "Headphones R",
+       },
+
+       .port_count = {
+               [SCARLETT2_PORT_TYPE_NONE]     = { 1, 0 },
+               [SCARLETT2_PORT_TYPE_ANALOGUE] = { 4, 4 },
+               [SCARLETT2_PORT_TYPE_MIX]      = { 6, 8 },
+               [SCARLETT2_PORT_TYPE_PCM]      = { 4, 6 },
+       },
+
+       .mux_assignment = { {
+               { SCARLETT2_PORT_TYPE_PCM,      0,  6 },
+               { SCARLETT2_PORT_TYPE_ANALOGUE, 0,  4 },
+               { SCARLETT2_PORT_TYPE_MIX,      0,  8 },
+               { SCARLETT2_PORT_TYPE_NONE,     0, 16 },
+               { 0,                            0,  0 },
+       }, {
+               { SCARLETT2_PORT_TYPE_PCM,      0,  6 },
+               { SCARLETT2_PORT_TYPE_ANALOGUE, 0,  4 },
+               { SCARLETT2_PORT_TYPE_MIX,      0,  8 },
+               { SCARLETT2_PORT_TYPE_NONE,     0, 16 },
+               { 0,                            0,  0 },
+       }, {
+               { SCARLETT2_PORT_TYPE_PCM,      0,  6 },
+               { SCARLETT2_PORT_TYPE_ANALOGUE, 0,  4 },
+               { SCARLETT2_PORT_TYPE_MIX,      0,  8 },
+               { SCARLETT2_PORT_TYPE_NONE,     0, 16 },
+               { 0,                            0,  0 },
+       } },
+};
+
+static const struct scarlett2_device_info s8i6_gen3_info = {
+       .usb_id = USB_ID(0x1235, 0x8213),
+
+       .has_msd_mode = 1,
+       .level_input_count = 2,
+       .pad_input_count = 2,
+
+       .line_out_descrs = {
+               "Headphones 1 L",
+               "Headphones 1 R",
+               "Headphones 2 L",
+               "Headphones 2 R",
+       },
+
+       .port_count = {
+               [SCARLETT2_PORT_TYPE_NONE]     = { 1,  0 },
+               [SCARLETT2_PORT_TYPE_ANALOGUE] = { 6,  4 },
+               [SCARLETT2_PORT_TYPE_SPDIF]    = { 2,  2 },
+               [SCARLETT2_PORT_TYPE_MIX]      = { 8,  8 },
+               [SCARLETT2_PORT_TYPE_PCM]      = { 6, 10 },
+       },
+
+       .mux_assignment = { {
+               { SCARLETT2_PORT_TYPE_PCM,      0,  8 },
+               { SCARLETT2_PORT_TYPE_ANALOGUE, 0,  4 },
+               { SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+               { SCARLETT2_PORT_TYPE_PCM,      8,  2 },
+               { SCARLETT2_PORT_TYPE_MIX,      0,  8 },
+               { SCARLETT2_PORT_TYPE_NONE,     0, 18 },
+               { 0,                            0,  0 },
+       }, {
+               { SCARLETT2_PORT_TYPE_PCM,      0,  8 },
+               { SCARLETT2_PORT_TYPE_ANALOGUE, 0,  4 },
+               { SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+               { SCARLETT2_PORT_TYPE_PCM,      8,  2 },
+               { SCARLETT2_PORT_TYPE_MIX,      0,  8 },
+               { SCARLETT2_PORT_TYPE_NONE,     0, 18 },
+               { 0,                            0,  0 },
+       }, {
+               { SCARLETT2_PORT_TYPE_PCM,      0,  8 },
+               { SCARLETT2_PORT_TYPE_ANALOGUE, 0,  4 },
+               { SCARLETT2_PORT_TYPE_SPDIF,    0,  2 },
+               { SCARLETT2_PORT_TYPE_PCM,      8,  2 },
+               { SCARLETT2_PORT_TYPE_MIX,      0,  8 },
+               { SCARLETT2_PORT_TYPE_NONE,     0, 18 },
+               { 0,                            0,  0 },
+       } },
+};
+
+static const struct scarlett2_device_info s18i8_gen3_info = {
+       .usb_id = USB_ID(0x1235, 0x8214),
+
+       .has_msd_mode = 1,
+       .line_out_hw_vol = 1,
+       .level_input_count = 2,
+       .pad_input_count = 2,
+
+       .line_out_descrs = {
+               "Monitor L",
+               "Monitor R",
+               "Headphones 1 L",
+               "Headphones 1 R",
+               "Headphones 2 L",
+               "Headphones 2 R",
+               "Alt Monitor L",
+               "Alt Monitor R",
+       },
+
+       .port_count = {
+               [SCARLETT2_PORT_TYPE_NONE]     = {  1,  0 },
+               [SCARLETT2_PORT_TYPE_ANALOGUE] = {  8,  8 },
+               [SCARLETT2_PORT_TYPE_SPDIF]    = {  2,  2 },
+               [SCARLETT2_PORT_TYPE_ADAT]     = {  8,  0 },
+               [SCARLETT2_PORT_TYPE_MIX]      = { 10, 20 },
+               [SCARLETT2_PORT_TYPE_PCM]      = {  8, 20 },
+       },
+
+       .mux_assignment = { {
+               { SCARLETT2_PORT_TYPE_PCM,       0, 10 },
+               { SCARLETT2_PORT_TYPE_PCM,      12,  8 },
+               { SCARLETT2_PORT_TYPE_ANALOGUE,  0,  2 },
+               { SCARLETT2_PORT_TYPE_ANALOGUE,  6,  2 },
+               { SCARLETT2_PORT_TYPE_ANALOGUE,  2,  4 },
+               { SCARLETT2_PORT_TYPE_SPDIF,     0,  2 },
+               { SCARLETT2_PORT_TYPE_PCM,      10,  2 },
+               { SCARLETT2_PORT_TYPE_MIX,       0, 20 },
+               { SCARLETT2_PORT_TYPE_NONE,      0, 10 },
+               { 0,                             0,  0 },
+       }, {
+               { SCARLETT2_PORT_TYPE_PCM,       0, 10 },
+               { SCARLETT2_PORT_TYPE_PCM,      12,  4 },
+               { SCARLETT2_PORT_TYPE_ANALOGUE,  0,  2 },
+               { SCARLETT2_PORT_TYPE_ANALOGUE,  6,  2 },
+               { SCARLETT2_PORT_TYPE_ANALOGUE,  2,  4 },
+               { SCARLETT2_PORT_TYPE_SPDIF,     0,  2 },
+               { SCARLETT2_PORT_TYPE_PCM,      10,  2 },
+               { SCARLETT2_PORT_TYPE_MIX,       0, 20 },
+               { SCARLETT2_PORT_TYPE_NONE,      0, 10 },
+               { 0,                             0,  0 },
+       }, {
+               { SCARLETT2_PORT_TYPE_PCM,       0, 10 },
+               { SCARLETT2_PORT_TYPE_ANALOGUE,  0,  2 },
+               { SCARLETT2_PORT_TYPE_ANALOGUE,  6,  2 },
+               { SCARLETT2_PORT_TYPE_ANALOGUE,  2,  4 },
+               { SCARLETT2_PORT_TYPE_SPDIF,     0,  2 },
+               { SCARLETT2_PORT_TYPE_MIX,       0, 20 },
+               { SCARLETT2_PORT_TYPE_NONE,      0, 10 },
+               { 0,                             0,  0 },
+       } },
+};
+
+static const struct scarlett2_device_info s18i20_gen3_info = {
+       .usb_id = USB_ID(0x1235, 0x8215),
+
+       .has_msd_mode = 1,
+       .line_out_hw_vol = 1,
+       .level_input_count = 2,
+       .pad_input_count = 8,
+
+       .line_out_descrs = {
+               "Monitor 1 L",
+               "Monitor 1 R",
+               "Monitor 2 L",
+               "Monitor 2 R",
+               NULL,
+               NULL,
+               "Headphones 1 L",
+               "Headphones 1 R",
+               "Headphones 2 L",
+               "Headphones 2 R",
+       },
+
+       .port_count = {
+               [SCARLETT2_PORT_TYPE_NONE]     = {  1,  0 },
+               [SCARLETT2_PORT_TYPE_ANALOGUE] = {  9, 10 },
+               [SCARLETT2_PORT_TYPE_SPDIF]    = {  2,  2 },
+               [SCARLETT2_PORT_TYPE_ADAT]     = {  8,  8 },
+               [SCARLETT2_PORT_TYPE_MIX]      = { 12, 25 },
+               [SCARLETT2_PORT_TYPE_PCM]      = { 20, 20 },
+       },
+
+       .mux_assignment = { {
+               { SCARLETT2_PORT_TYPE_PCM,       0,  8 },
+               { SCARLETT2_PORT_TYPE_PCM,      10, 10 },
+               { SCARLETT2_PORT_TYPE_ANALOGUE,  0, 10 },
+               { SCARLETT2_PORT_TYPE_SPDIF,     0,  2 },
+               { SCARLETT2_PORT_TYPE_ADAT,      0,  8 },
+               { SCARLETT2_PORT_TYPE_PCM,       8,  2 },
+               { SCARLETT2_PORT_TYPE_MIX,       0, 25 },
+               { SCARLETT2_PORT_TYPE_NONE,      0, 12 },
+               { 0,                             0,  0 },
+       }, {
+               { SCARLETT2_PORT_TYPE_PCM,       0,  8 },
+               { SCARLETT2_PORT_TYPE_PCM,      10,  8 },
+               { SCARLETT2_PORT_TYPE_ANALOGUE,  0, 10 },
+               { SCARLETT2_PORT_TYPE_SPDIF,     0,  2 },
+               { SCARLETT2_PORT_TYPE_ADAT,      0,  8 },
+               { SCARLETT2_PORT_TYPE_PCM,       8,  2 },
+               { SCARLETT2_PORT_TYPE_MIX,       0, 25 },
+               { SCARLETT2_PORT_TYPE_NONE,      0, 10 },
+               { 0,                             0,  0 },
+       }, {
+               { SCARLETT2_PORT_TYPE_PCM,       0, 10 },
+               { SCARLETT2_PORT_TYPE_ANALOGUE,  0, 10 },
+               { SCARLETT2_PORT_TYPE_SPDIF,     0,  2 },
+               { SCARLETT2_PORT_TYPE_NONE,      0, 24 },
+               { 0,                             0,  0 },
+       } },
+};
+
+static const struct scarlett2_device_info *scarlett2_devices[] = {
+       /* Supported Gen 2 devices */
+       &s6i6_gen2_info,
+       &s18i8_gen2_info,
+       &s18i20_gen2_info,
+
+       /* Supported Gen 3 devices */
+       &s4i4_gen3_info,
+       &s8i6_gen3_info,
+       &s18i8_gen3_info,
+       &s18i20_gen3_info,
+
+       /* End of list */
+       NULL
 };
 
 /* get the starting port index number for a given port type/direction */
-static int scarlett2_get_port_start_num(const struct scarlett2_ports *ports,
-                                       int direction, int port_type)
+static int scarlett2_get_port_start_num(
+       const int port_count[][SCARLETT2_PORT_DIRNS],
+       int direction, int port_type)
 {
        int i, num = 0;
 
        for (i = 0; i < port_type; i++)
-               num += ports[i].num[direction];
+               num += port_count[i][direction];
 
        return num;
 }
 
 /*** USB Interactions ***/
 
-/* Vendor-Specific Interface, Endpoint, MaxPacketSize, Interval */
-#define SCARLETT2_USB_VENDOR_SPECIFIC_INTERFACE 5
-#define SCARLETT2_USB_INTERRUPT_ENDPOINT 4
-#define SCARLETT2_USB_INTERRUPT_MAX_DATA 64
-#define SCARLETT2_USB_INTERRUPT_INTERVAL 3
-
-/* Interrupt flags for dim/mute button and monitor changes */
-#define SCARLETT2_USB_NOTIFY_DIM_MUTE 0x00200000
-#define SCARLETT2_USB_NOTIFY_MONITOR  0x00400000
+/* Notifications from the interface */
+#define SCARLETT2_USB_NOTIFY_SYNC        0x00000008
+#define SCARLETT2_USB_NOTIFY_DIM_MUTE    0x00200000
+#define SCARLETT2_USB_NOTIFY_MONITOR     0x00400000
+#define SCARLETT2_USB_NOTIFY_INPUT_OTHER 0x00800000
 
 /* Commands for sending/receiving requests/responses */
-#define SCARLETT2_USB_VENDOR_SPECIFIC_CMD_REQ  2
-#define SCARLETT2_USB_VENDOR_SPECIFIC_CMD_RESP 3
+#define SCARLETT2_USB_CMD_INIT 0
+#define SCARLETT2_USB_CMD_REQ  2
+#define SCARLETT2_USB_CMD_RESP 3
 
-#define SCARLETT2_USB_INIT_SEQ  0x00000000
+#define SCARLETT2_USB_INIT_1    0x00000000
+#define SCARLETT2_USB_INIT_2    0x00000002
 #define SCARLETT2_USB_GET_METER 0x00001001
 #define SCARLETT2_USB_GET_MIX   0x00002001
 #define SCARLETT2_USB_SET_MIX   0x00002002
 #define SCARLETT2_USB_GET_MUX   0x00003001
 #define SCARLETT2_USB_SET_MUX   0x00003002
+#define SCARLETT2_USB_GET_SYNC  0x00006004
 #define SCARLETT2_USB_GET_DATA  0x00800000
 #define SCARLETT2_USB_SET_DATA  0x00800001
 #define SCARLETT2_USB_DATA_CMD  0x00800002
@@ -486,7 +789,8 @@ struct scarlett2_usb_volume_status {
        /* actual volume of output inc. dim (-18dB) */
        s16 hw_vol[SCARLETT2_ANALOGUE_MAX];
 
-       u8 pad2[SCARLETT2_ANALOGUE_MAX];
+       /* internal mute buttons */
+       u8 mute_switch[SCARLETT2_ANALOGUE_MAX];
 
        /* sw (0) or hw (1) controlled */
        u8 sw_hw_switch[SCARLETT2_ANALOGUE_MAX];
@@ -501,10 +805,12 @@ struct scarlett2_usb_volume_status {
 enum {
        SCARLETT2_CONFIG_DIM_MUTE = 0,
        SCARLETT2_CONFIG_LINE_OUT_VOLUME = 1,
-       SCARLETT2_CONFIG_SW_HW_SWITCH = 2,
-       SCARLETT2_CONFIG_LEVEL_SWITCH = 3,
-       SCARLETT2_CONFIG_PAD_SWITCH = 4,
-       SCARLETT2_CONFIG_COUNT = 5
+       SCARLETT2_CONFIG_MUTE_SWITCH = 2,
+       SCARLETT2_CONFIG_SW_HW_SWITCH = 3,
+       SCARLETT2_CONFIG_LEVEL_SWITCH = 4,
+       SCARLETT2_CONFIG_PAD_SWITCH = 5,
+       SCARLETT2_CONFIG_MSD_SWITCH = 6,
+       SCARLETT2_CONFIG_COUNT = 7
 };
 
 /* Location, size, and activation command number for the configuration
@@ -518,40 +824,26 @@ struct scarlett2_config {
 
 static const struct scarlett2_config
                scarlett2_config_items[SCARLETT2_CONFIG_COUNT] = {
-       /* Dim/Mute Buttons */
-       {
-               .offset = 0x31,
-               .size = 1,
-               .activate = 2
-       },
+       [SCARLETT2_CONFIG_DIM_MUTE] = {
+               .offset = 0x31, .size = 1, .activate = 2 },
 
-       /* Line Out Volume */
-       {
-               .offset = 0x34,
-               .size = 2,
-               .activate = 1
-       },
+       [SCARLETT2_CONFIG_LINE_OUT_VOLUME] = {
+               .offset = 0x34, .size = 2, .activate = 1 },
 
-       /* SW/HW Volume Switch */
-       {
-               .offset = 0x66,
-               .size = 1,
-               .activate = 3
-       },
+       [SCARLETT2_CONFIG_MUTE_SWITCH] = {
+               .offset = 0x5c, .size = 1, .activate = 1 },
 
-       /* Level Switch */
-       {
-               .offset = 0x7c,
-               .size = 1,
-               .activate = 7
-       },
+       [SCARLETT2_CONFIG_SW_HW_SWITCH] = {
+               .offset = 0x66, .size = 1, .activate = 3 },
 
-       /* Pad Switch */
-       {
-               .offset = 0x84,
-               .size = 1,
-               .activate = 8
-       }
+       [SCARLETT2_CONFIG_LEVEL_SWITCH] = {
+               .offset = 0x7c, .size = 1, .activate = 7 },
+
+       [SCARLETT2_CONFIG_PAD_SWITCH] = {
+               .offset = 0x84, .size = 1, .activate = 8 },
+
+       [SCARLETT2_CONFIG_MSD_SWITCH] = {
+               .offset = 0x9d, .size = 1, .activate = 6 },
 };
 
 /* proprietary request/response format */
@@ -578,12 +870,31 @@ static void scarlett2_fill_request_header(struct scarlett2_data *private,
        req->pad = 0;
 }
 
+static int scarlett2_usb_tx(struct usb_device *dev, int interface,
+                           void *buf, u16 size)
+{
+       return snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
+                       SCARLETT2_USB_CMD_REQ,
+                       USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
+                       0, interface, buf, size);
+}
+
+static int scarlett2_usb_rx(struct usb_device *dev, int interface,
+                           u32 usb_req, void *buf, u16 size)
+{
+       return snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0),
+                       usb_req,
+                       USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
+                       0, interface, buf, size);
+}
+
 /* Send a proprietary format request to the Scarlett interface */
 static int scarlett2_usb(
        struct usb_mixer_interface *mixer, u32 cmd,
        void *req_data, u16 req_size, void *resp_data, u16 resp_size)
 {
        struct scarlett2_data *private = mixer->private_data;
+       struct usb_device *dev = mixer->chip->dev;
        u16 req_buf_size = sizeof(struct scarlett2_usb_packet) + req_size;
        u16 resp_buf_size = sizeof(struct scarlett2_usb_packet) + resp_size;
        struct scarlett2_usb_packet *req, *resp = NULL;
@@ -610,19 +921,13 @@ static int scarlett2_usb(
        if (req_size)
                memcpy(req->data, req_data, req_size);
 
-       err = snd_usb_ctl_msg(mixer->chip->dev,
-                       usb_sndctrlpipe(mixer->chip->dev, 0),
-                       SCARLETT2_USB_VENDOR_SPECIFIC_CMD_REQ,
-                       USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
-                       0,
-                       SCARLETT2_USB_VENDOR_SPECIFIC_INTERFACE,
-                       req,
-                       req_buf_size);
+       err = scarlett2_usb_tx(dev, private->bInterfaceNumber,
+                              req, req_buf_size);
 
        if (err != req_buf_size) {
                usb_audio_err(
                        mixer->chip,
-                       "Scarlett Gen 2 USB request result cmd %x was %d\n",
+                       "Scarlett Gen 2/3 USB request result cmd %x was %d\n",
                        cmd, err);
                err = -EINVAL;
                goto unlock;
@@ -630,34 +935,34 @@ static int scarlett2_usb(
 
        /* send a second message to get the response */
 
-       err = snd_usb_ctl_msg(mixer->chip->dev,
-                       usb_rcvctrlpipe(mixer->chip->dev, 0),
-                       SCARLETT2_USB_VENDOR_SPECIFIC_CMD_RESP,
-                       USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
-                       0,
-                       SCARLETT2_USB_VENDOR_SPECIFIC_INTERFACE,
-                       resp,
-                       resp_buf_size);
+       err = scarlett2_usb_rx(dev, private->bInterfaceNumber,
+                              SCARLETT2_USB_CMD_RESP,
+                              resp, resp_buf_size);
 
        /* validate the response */
 
        if (err != resp_buf_size) {
                usb_audio_err(
                        mixer->chip,
-                       "Scarlett Gen 2 USB response result cmd %x was %d\n",
-                       cmd, err);
+                       "Scarlett Gen 2/3 USB response result cmd %x was %d "
+                       "expected %d\n",
+                       cmd, err, resp_buf_size);
                err = -EINVAL;
                goto unlock;
        }
 
+       /* cmd/seq/size should match except when initialising
+        * seq sent = 1, response = 0
+        */
        if (resp->cmd != req->cmd ||
-           resp->seq != req->seq ||
+           (resp->seq != req->seq &&
+               (le16_to_cpu(req->seq) != 1 || resp->seq != 0)) ||
            resp_size != le16_to_cpu(resp->size) ||
            resp->error ||
            resp->pad) {
                usb_audio_err(
                        mixer->chip,
-                       "Scarlett Gen 2 USB invalid response; "
+                       "Scarlett Gen 2/3 USB invalid response; "
                           "cmd tx/rx %d/%d seq %d/%d size %d/%d "
                           "error %d pad %d\n",
                        le32_to_cpu(req->cmd), le32_to_cpu(resp->cmd),
@@ -669,7 +974,7 @@ static int scarlett2_usb(
                goto unlock;
        }
 
-       if (resp_size > 0)
+       if (resp_data && resp_size > 0)
                memcpy(resp_data, resp->data, resp_size);
 
 unlock:
@@ -680,6 +985,34 @@ error:
        return err;
 }
 
+/* Send a USB message to get data; result placed in *buf */
+static int scarlett2_usb_get(
+       struct usb_mixer_interface *mixer,
+       int offset, void *buf, int size)
+{
+       struct {
+               __le32 offset;
+               __le32 size;
+       } __packed req;
+
+       req.offset = cpu_to_le32(offset);
+       req.size = cpu_to_le32(size);
+       return scarlett2_usb(mixer, SCARLETT2_USB_GET_DATA,
+                            &req, sizeof(req), buf, size);
+}
+
+/* Send a USB message to get configuration parameters; result placed in *buf */
+static int scarlett2_usb_get_config(
+       struct usb_mixer_interface *mixer,
+       int config_item_num, int count, void *buf)
+{
+       const struct scarlett2_config *config_item =
+               &scarlett2_config_items[config_item_num];
+       int size = config_item->size * count;
+
+       return scarlett2_usb_get(mixer, config_item->offset, buf, size);
+}
+
 /* Send SCARLETT2_USB_DATA_CMD SCARLETT2_USB_CONFIG_SAVE */
 static void scarlett2_config_save(struct usb_mixer_interface *mixer)
 {
@@ -706,8 +1039,8 @@ static int scarlett2_usb_set_config(
        struct usb_mixer_interface *mixer,
        int config_item_num, int index, int value)
 {
-       const struct scarlett2_config config_item =
-              scarlett2_config_items[config_item_num];
+       const struct scarlett2_config *config_item =
+              &scarlett2_config_items[config_item_num];
        struct {
                __le32 offset;
                __le32 bytes;
@@ -721,54 +1054,44 @@ static int scarlett2_usb_set_config(
        cancel_delayed_work_sync(&private->work);
 
        /* Send the configuration parameter data */
-       req.offset = cpu_to_le32(config_item.offset + index * config_item.size);
-       req.bytes = cpu_to_le32(config_item.size);
+       req.offset = cpu_to_le32(config_item->offset + index * config_item->size);
+       req.bytes = cpu_to_le32(config_item->size);
        req.value = cpu_to_le32(value);
        err = scarlett2_usb(mixer, SCARLETT2_USB_SET_DATA,
-                           &req, sizeof(u32) * 2 + config_item.size,
+                           &req, sizeof(u32) * 2 + config_item->size,
                            NULL, 0);
        if (err < 0)
                return err;
 
        /* Activate the change */
-       req2 = cpu_to_le32(config_item.activate);
+       req2 = cpu_to_le32(config_item->activate);
        err = scarlett2_usb(mixer, SCARLETT2_USB_DATA_CMD,
                            &req2, sizeof(req2), NULL, 0);
        if (err < 0)
                return err;
 
        /* Schedule the change to be written to NVRAM */
-       schedule_delayed_work(&private->work, msecs_to_jiffies(2000));
+       if (config_item->activate != SCARLETT2_USB_CONFIG_SAVE)
+               schedule_delayed_work(&private->work, msecs_to_jiffies(2000));
 
        return 0;
 }
 
-/* Send a USB message to get data; result placed in *buf */
-static int scarlett2_usb_get(
+/* Send a USB message to get sync status; result placed in *sync */
+static int scarlett2_usb_get_sync_status(
        struct usb_mixer_interface *mixer,
-       int offset, void *buf, int size)
+       u8 *sync)
 {
-       struct {
-               __le32 offset;
-               __le32 size;
-       } __packed req;
-
-       req.offset = cpu_to_le32(offset);
-       req.size = cpu_to_le32(size);
-       return scarlett2_usb(mixer, SCARLETT2_USB_GET_DATA,
-                            &req, sizeof(req), buf, size);
-}
+       __le32 data;
+       int err;
 
-/* Send a USB message to get configuration parameters; result placed in *buf */
-static int scarlett2_usb_get_config(
-       struct usb_mixer_interface *mixer,
-       int config_item_num, int count, void *buf)
-{
-       const struct scarlett2_config config_item =
-              scarlett2_config_items[config_item_num];
-       int size = config_item.size * count;
+       err = scarlett2_usb(mixer, SCARLETT2_USB_GET_SYNC,
+                           NULL, 0, &data, sizeof(data));
+       if (err < 0)
+               return err;
 
-       return scarlett2_usb_get(mixer, config_item.offset, buf, size);
+       *sync = !!data;
+       return 0;
 }
 
 /* Send a USB message to get volume status; result placed in *buf */
@@ -790,7 +1113,7 @@ static int scarlett2_usb_get_mix(struct usb_mixer_interface *mixer,
        const struct scarlett2_device_info *info = private->info;
 
        int num_mixer_in =
-               info->ports[SCARLETT2_PORT_TYPE_MIX].num[SCARLETT2_PORT_OUT];
+               info->port_count[SCARLETT2_PORT_TYPE_MIX][SCARLETT2_PORT_OUT];
        int err, i, j, k;
 
        struct {
@@ -839,7 +1162,7 @@ static int scarlett2_usb_set_mix(struct usb_mixer_interface *mixer,
 
        int i, j;
        int num_mixer_in =
-               info->ports[SCARLETT2_PORT_TYPE_MIX].num[SCARLETT2_PORT_OUT];
+               info->port_count[SCARLETT2_PORT_TYPE_MIX][SCARLETT2_PORT_OUT];
 
        req.mix_num = cpu_to_le16(mix_num);
 
@@ -853,18 +1176,18 @@ static int scarlett2_usb_set_mix(struct usb_mixer_interface *mixer,
                             NULL, 0);
 }
 
-/* Convert a port number index (per info->ports) to a hardware ID */
-static u32 scarlett2_mux_src_num_to_id(const struct scarlett2_ports *ports,
-                                      int num)
+/* Convert a port number index (per info->port_count) to a hardware ID */
+static u32 scarlett2_mux_src_num_to_id(
+       const int port_count[][SCARLETT2_PORT_DIRNS], int num)
 {
        int port_type;
 
        for (port_type = 0;
             port_type < SCARLETT2_PORT_TYPE_COUNT;
             port_type++) {
-               if (num < ports[port_type].num[SCARLETT2_PORT_IN])
-                       return ports[port_type].id | num;
-               num -= ports[port_type].num[SCARLETT2_PORT_IN];
+               if (num < port_count[port_type][SCARLETT2_PORT_IN])
+                       return scarlett2_ports[port_type].id | num;
+               num -= port_count[port_type][SCARLETT2_PORT_IN];
        }
 
        /* Oops */
@@ -872,9 +1195,8 @@ static u32 scarlett2_mux_src_num_to_id(const struct scarlett2_ports *ports,
 }
 
 /* Convert a hardware ID to a port number index */
-static u32 scarlett2_mux_id_to_num(const struct scarlett2_ports *ports,
-                                  int direction,
-                                  u32 id)
+static u32 scarlett2_mux_id_to_num(
+       const int port_count[][SCARLETT2_PORT_DIRNS], int direction, u32 id)
 {
        int port_type;
        int port_num = 0;
@@ -882,11 +1204,11 @@ static u32 scarlett2_mux_id_to_num(const struct scarlett2_ports *ports,
        for (port_type = 0;
             port_type < SCARLETT2_PORT_TYPE_COUNT;
             port_type++) {
-               struct scarlett2_ports port = ports[port_type];
-               int count = port.num[direction];
+               int base = scarlett2_ports[port_type].id;
+               int count = port_count[port_type][direction];
 
-               if (id >= port.id && id < port.id + count)
-                       return port_num + id - port.id;
+               if (id >= base && id < base + count)
+                       return port_num + id - base;
                port_num += count;
        }
 
@@ -899,11 +1221,11 @@ static void scarlett2_usb_populate_mux(struct scarlett2_data *private,
                                       u32 mux_entry)
 {
        const struct scarlett2_device_info *info = private->info;
-       const struct scarlett2_ports *ports = info->ports;
+       const int (*port_count)[SCARLETT2_PORT_DIRNS] = info->port_count;
 
        int dst_idx, src_idx;
 
-       dst_idx = scarlett2_mux_id_to_num(ports, SCARLETT2_PORT_OUT,
+       dst_idx = scarlett2_mux_id_to_num(port_count, SCARLETT2_PORT_OUT,
                                          mux_entry & 0xFFF);
        if (dst_idx < 0)
                return;
@@ -915,7 +1237,7 @@ static void scarlett2_usb_populate_mux(struct scarlett2_data *private,
                return;
        }
 
-       src_idx = scarlett2_mux_id_to_num(ports, SCARLETT2_PORT_IN,
+       src_idx = scarlett2_mux_id_to_num(port_count, SCARLETT2_PORT_IN,
                                          mux_entry >> 12);
        if (src_idx < 0)
                return;
@@ -964,17 +1286,8 @@ static int scarlett2_usb_set_mux(struct usb_mixer_interface *mixer)
 {
        struct scarlett2_data *private = mixer->private_data;
        const struct scarlett2_device_info *info = private->info;
-       const struct scarlett2_ports *ports = info->ports;
-       int rate, port_dir_rate;
-
-       static const int assignment_order[SCARLETT2_PORT_TYPE_COUNT] = {
-               SCARLETT2_PORT_TYPE_PCM,
-               SCARLETT2_PORT_TYPE_ANALOGUE,
-               SCARLETT2_PORT_TYPE_SPDIF,
-               SCARLETT2_PORT_TYPE_ADAT,
-               SCARLETT2_PORT_TYPE_MIX,
-               SCARLETT2_PORT_TYPE_NONE,
-       };
+       const int (*port_count)[SCARLETT2_PORT_DIRNS] = info->port_count;
+       int table;
 
        struct {
                __le16 pad;
@@ -984,39 +1297,44 @@ static int scarlett2_usb_set_mux(struct usb_mixer_interface *mixer)
 
        req.pad = 0;
 
-       /* mux settings for each rate */
-       for (rate = 0, port_dir_rate = SCARLETT2_PORT_OUT_44;
-            port_dir_rate <= SCARLETT2_PORT_OUT_176;
-            rate++, port_dir_rate++) {
-               int order_num, i, err;
-
-               req.num = cpu_to_le16(rate);
-
-               for (order_num = 0, i = 0;
-                    order_num < SCARLETT2_PORT_TYPE_COUNT;
-                    order_num++) {
-                       int port_type = assignment_order[order_num];
-                       int j = scarlett2_get_port_start_num(ports,
-                                                            SCARLETT2_PORT_OUT,
-                                                            port_type);
-                       int port_id = ports[port_type].id;
-                       int channel;
-
-                       for (channel = 0;
-                            channel < ports[port_type].num[port_dir_rate];
-                            channel++, i++, j++)
-                               /* lower 12 bits for the destination and
-                                * next 12 bits for the source
-                                */
-                               req.data[i] = !port_id
-                                       ? 0
-                                       : cpu_to_le32(
-                                               port_id |
-                                               channel |
-                                               scarlett2_mux_src_num_to_id(
-                                                       ports, private->mux[j]
-                                               ) << 12
-                                         );
+       /* set mux settings for each rate */
+       for (table = 0; table < SCARLETT2_MUX_TABLES; table++) {
+               const struct scarlett2_mux_entry *entry;
+
+               /* i counts over the output array */
+               int i = 0, err;
+
+               req.num = cpu_to_le16(table);
+
+               /* loop through each entry */
+               for (entry = info->mux_assignment[table];
+                    entry->count;
+                    entry++) {
+                       int j;
+                       int port_type = entry->port_type;
+                       int port_idx = entry->start;
+                       int mux_idx = scarlett2_get_port_start_num(port_count,
+                               SCARLETT2_PORT_OUT, port_type) + port_idx;
+                       int dst_id = scarlett2_ports[port_type].id + port_idx;
+
+                       /* Empty slots */
+                       if (!dst_id) {
+                               for (j = 0; j < entry->count; j++)
+                                       req.data[i++] = 0;
+                               continue;
+                       }
+
+                       /* Non-empty mux slots use the lower 12 bits
+                        * for the destination and next 12 bits for
+                        * the source
+                        */
+                       for (j = 0; j < entry->count; j++) {
+                               int src_id = scarlett2_mux_src_num_to_id(
+                                       port_count, private->mux[mux_idx++]);
+                               req.data[i++] = cpu_to_le32(dst_id |
+                                                           src_id << 12);
+                               dst_id++;
+                       }
                }
 
                err = scarlett2_usb(mixer, SCARLETT2_USB_SET_MUX,
@@ -1031,26 +1349,26 @@ static int scarlett2_usb_set_mux(struct usb_mixer_interface *mixer)
 
 /* Send USB message to get meter levels */
 static int scarlett2_usb_get_meter_levels(struct usb_mixer_interface *mixer,
-                                         u16 *levels)
+                                         u16 num_meters, u16 *levels)
 {
        struct {
                __le16 pad;
                __le16 num_meters;
                __le32 magic;
        } __packed req;
-       u32 resp[SCARLETT2_NUM_METERS];
+       u32 resp[SCARLETT2_MAX_METERS];
        int i, err;
 
        req.pad = 0;
-       req.num_meters = cpu_to_le16(SCARLETT2_NUM_METERS);
+       req.num_meters = cpu_to_le16(num_meters);
        req.magic = cpu_to_le32(SCARLETT2_USB_METER_LEVELS_GET_MAGIC);
        err = scarlett2_usb(mixer, SCARLETT2_USB_GET_METER,
-                           &req, sizeof(req), resp, sizeof(resp));
+                           &req, sizeof(req), resp, num_meters * sizeof(u32));
        if (err < 0)
                return err;
 
        /* copy, convert to u16 */
-       for (i = 0; i < SCARLETT2_NUM_METERS; i++)
+       for (i = 0; i < num_meters; i++)
                levels[i] = resp[i];
 
        return 0;
@@ -1072,10 +1390,15 @@ static int scarlett2_add_new_ctl(struct usb_mixer_interface *mixer,
        if (!elem)
                return -ENOMEM;
 
+       /* We set USB_MIXER_BESPOKEN type, so that the core USB mixer code
+        * ignores them for resume and other operations.
+        * Also, the head.id field is set to 0, as we don't use this field.
+        */
        elem->head.mixer = mixer;
        elem->control = index;
-       elem->head.id = index;
+       elem->head.id = 0;
        elem->channels = channels;
+       elem->val_type = USB_MIXER_BESPOKEN;
 
        kctl = snd_ctl_new1(ncontrol, elem);
        if (!kctl) {
@@ -1096,6 +1419,60 @@ static int scarlett2_add_new_ctl(struct usb_mixer_interface *mixer,
        return 0;
 }
 
+/*** Sync Control ***/
+
+/* Update sync control after receiving notification that the status
+ * has changed
+ */
+static int scarlett2_update_sync(struct usb_mixer_interface *mixer)
+{
+       struct scarlett2_data *private = mixer->private_data;
+
+       private->sync_updated = 0;
+       return scarlett2_usb_get_sync_status(mixer, &private->sync);
+}
+
+static int scarlett2_sync_ctl_info(struct snd_kcontrol *kctl,
+                                  struct snd_ctl_elem_info *uinfo)
+{
+       static const char *texts[2] = {
+               "Unlocked", "Locked"
+       };
+       return snd_ctl_enum_info(uinfo, 1, 2, texts);
+}
+
+static int scarlett2_sync_ctl_get(struct snd_kcontrol *kctl,
+                                 struct snd_ctl_elem_value *ucontrol)
+{
+       struct usb_mixer_elem_info *elem = kctl->private_data;
+       struct usb_mixer_interface *mixer = elem->head.mixer;
+       struct scarlett2_data *private = mixer->private_data;
+
+       mutex_lock(&private->data_mutex);
+       if (private->sync_updated)
+               scarlett2_update_sync(mixer);
+       ucontrol->value.enumerated.item[0] = private->sync;
+       mutex_unlock(&private->data_mutex);
+
+       return 0;
+}
+
+static const struct snd_kcontrol_new scarlett2_sync_ctl = {
+       .iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+       .access = SNDRV_CTL_ELEM_ACCESS_READ,
+       .name = "",
+       .info = scarlett2_sync_ctl_info,
+       .get  = scarlett2_sync_ctl_get
+};
+
+static int scarlett2_add_sync_ctl(struct usb_mixer_interface *mixer)
+{
+       struct scarlett2_data *private = mixer->private_data;
+
+       return scarlett2_add_new_ctl(mixer, &scarlett2_sync_ctl,
+                                    0, 1, "Sync Status", &private->sync_ctl);
+}
+
 /*** Analogue Line Out Volume Controls ***/
 
 /* Update hardware volume controls after receiving notification that
@@ -1105,11 +1482,12 @@ static int scarlett2_update_volumes(struct usb_mixer_interface *mixer)
 {
        struct scarlett2_data *private = mixer->private_data;
        const struct scarlett2_device_info *info = private->info;
-       const struct scarlett2_ports *ports = info->ports;
+       const int (*port_count)[SCARLETT2_PORT_DIRNS] = info->port_count;
        struct scarlett2_usb_volume_status volume_status;
        int num_line_out =
-               ports[SCARLETT2_PORT_TYPE_ANALOGUE].num[SCARLETT2_PORT_OUT];
+               port_count[SCARLETT2_PORT_TYPE_ANALOGUE][SCARLETT2_PORT_OUT];
        int err, i;
+       int mute;
 
        private->vol_updated = 0;
 
@@ -1121,15 +1499,18 @@ static int scarlett2_update_volumes(struct usb_mixer_interface *mixer)
                volume_status.master_vol + SCARLETT2_VOLUME_BIAS,
                0, SCARLETT2_VOLUME_BIAS);
 
-       for (i = 0; i < num_line_out; i++) {
-               if (private->vol_sw_hw_switch[i])
-                       private->vol[i] = private->master_vol;
-       }
-
        if (info->line_out_hw_vol)
                for (i = 0; i < SCARLETT2_DIM_MUTE_COUNT; i++)
                        private->dim_mute[i] = !!volume_status.dim_mute[i];
 
+       mute = private->dim_mute[SCARLETT2_BUTTON_MUTE];
+
+       for (i = 0; i < num_line_out; i++)
+               if (private->vol_sw_hw_switch[i]) {
+                       private->vol[i] = private->master_vol;
+                       private->mute_switch[i] = mute;
+               }
+
        return 0;
 }
 
@@ -1234,6 +1615,55 @@ static const struct snd_kcontrol_new scarlett2_line_out_volume_ctl = {
        .tlv = { .p = db_scale_scarlett2_gain }
 };
 
+/*** Mute Switch Controls ***/
+
+static int scarlett2_mute_ctl_get(struct snd_kcontrol *kctl,
+                                       struct snd_ctl_elem_value *ucontrol)
+{
+       struct usb_mixer_elem_info *elem = kctl->private_data;
+       struct scarlett2_data *private = elem->head.mixer->private_data;
+       int index = elem->control;
+
+       ucontrol->value.integer.value[0] = private->mute_switch[index];
+       return 0;
+}
+
+static int scarlett2_mute_ctl_put(struct snd_kcontrol *kctl,
+                                       struct snd_ctl_elem_value *ucontrol)
+{
+       struct usb_mixer_elem_info *elem = kctl->private_data;
+       struct usb_mixer_interface *mixer = elem->head.mixer;
+       struct scarlett2_data *private = mixer->private_data;
+       int index = elem->control;
+       int oval, val, err = 0;
+
+       mutex_lock(&private->data_mutex);
+
+       oval = private->mute_switch[index];
+       val = !!ucontrol->value.integer.value[0];
+
+       if (oval == val)
+               goto unlock;
+
+       private->mute_switch[index] = val;
+
+       /* Send mute change to the device */
+       err = scarlett2_usb_set_config(mixer, SCARLETT2_CONFIG_MUTE_SWITCH,
+                                      index, val);
+
+unlock:
+       mutex_unlock(&private->data_mutex);
+       return err;
+}
+
+static const struct snd_kcontrol_new scarlett2_mute_ctl = {
+       .iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+       .name = "",
+       .info = snd_ctl_boolean_mono_info,
+       .get  = scarlett2_mute_ctl_get,
+       .put  = scarlett2_mute_ctl_put,
+};
+
 /*** HW/SW Volume Switch Controls ***/
 
 static int scarlett2_sw_hw_enum_ctl_info(struct snd_kcontrol *kctl,
@@ -1257,6 +1687,32 @@ static int scarlett2_sw_hw_enum_ctl_get(struct snd_kcontrol *kctl,
        return 0;
 }
 
+static void scarlett2_vol_ctl_set_writable(struct usb_mixer_interface *mixer,
+                                          int index, int value)
+{
+       struct scarlett2_data *private = mixer->private_data;
+       struct snd_card *card = mixer->chip->card;
+
+       /* Set/Clear write bits */
+       if (value) {
+               private->vol_ctls[index]->vd[0].access |=
+                       SNDRV_CTL_ELEM_ACCESS_WRITE;
+               private->mute_ctls[index]->vd[0].access |=
+                       SNDRV_CTL_ELEM_ACCESS_WRITE;
+       } else {
+               private->vol_ctls[index]->vd[0].access &=
+                       ~SNDRV_CTL_ELEM_ACCESS_WRITE;
+               private->mute_ctls[index]->vd[0].access &=
+                       ~SNDRV_CTL_ELEM_ACCESS_WRITE;
+       }
+
+       /* Notify of write bit change */
+       snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO,
+                      &private->vol_ctls[index]->id);
+       snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO,
+                      &private->mute_ctls[index]->id);
+}
+
 static int scarlett2_sw_hw_enum_ctl_put(struct snd_kcontrol *kctl,
                                        struct snd_ctl_elem_value *ucontrol)
 {
@@ -1280,15 +1736,11 @@ static int scarlett2_sw_hw_enum_ctl_put(struct snd_kcontrol *kctl,
        /* Change access mode to RO (hardware controlled volume)
         * or RW (software controlled volume)
         */
-       if (val)
-               private->vol_ctls[index]->vd[0].access &=
-                       ~SNDRV_CTL_ELEM_ACCESS_WRITE;
-       else
-               private->vol_ctls[index]->vd[0].access |=
-                       SNDRV_CTL_ELEM_ACCESS_WRITE;
+       scarlett2_vol_ctl_set_writable(mixer, index, !val);
 
-       /* Reset volume to master volume */
+       /* Reset volume/mute to master volume/mute */
        private->vol[index] = private->master_vol;
+       private->mute_switch[index] = private->dim_mute[SCARLETT2_BUTTON_MUTE];
 
        /* Set SW volume to current HW volume */
        err = scarlett2_usb_set_config(
@@ -1297,9 +1749,12 @@ static int scarlett2_sw_hw_enum_ctl_put(struct snd_kcontrol *kctl,
        if (err < 0)
                goto unlock;
 
-       /* Notify of RO/RW change */
-       snd_ctl_notify(mixer->chip->card, SNDRV_CTL_EVENT_MASK_INFO,
-                      &private->vol_ctls[index]->id);
+       /* Set SW mute to current HW mute */
+       err = scarlett2_usb_set_config(
+               mixer, SCARLETT2_CONFIG_MUTE_SWITCH,
+               index, private->dim_mute[SCARLETT2_BUTTON_MUTE]);
+       if (err < 0)
+               goto unlock;
 
        /* Send SW/HW switch change to the device */
        err = scarlett2_usb_set_config(mixer, SCARLETT2_CONFIG_SW_HW_SWITCH,
@@ -1322,6 +1777,32 @@ static const struct snd_kcontrol_new scarlett2_sw_hw_enum_ctl = {
 
 /*** Line Level/Instrument Level Switch Controls ***/
 
+static int scarlett2_update_input_other(struct usb_mixer_interface *mixer)
+{
+       struct scarlett2_data *private = mixer->private_data;
+       const struct scarlett2_device_info *info = private->info;
+
+       private->input_other_updated = 0;
+
+       if (info->level_input_count) {
+               int err = scarlett2_usb_get_config(
+                       mixer, SCARLETT2_CONFIG_LEVEL_SWITCH,
+                       info->level_input_count, private->level_switch);
+               if (err < 0)
+                       return err;
+       }
+
+       if (info->pad_input_count) {
+               int err = scarlett2_usb_get_config(
+                       mixer, SCARLETT2_CONFIG_PAD_SWITCH,
+                       info->pad_input_count, private->pad_switch);
+               if (err < 0)
+                       return err;
+       }
+
+       return 0;
+}
+
 static int scarlett2_level_enum_ctl_info(struct snd_kcontrol *kctl,
                                         struct snd_ctl_elem_info *uinfo)
 {
@@ -1336,10 +1817,16 @@ static int scarlett2_level_enum_ctl_get(struct snd_kcontrol *kctl,
                                        struct snd_ctl_elem_value *ucontrol)
 {
        struct usb_mixer_elem_info *elem = kctl->private_data;
-       struct scarlett2_data *private = elem->head.mixer->private_data;
+       struct usb_mixer_interface *mixer = elem->head.mixer;
+       struct scarlett2_data *private = mixer->private_data;
 
+       mutex_lock(&private->data_mutex);
+       if (private->input_other_updated)
+               scarlett2_update_input_other(mixer);
        ucontrol->value.enumerated.item[0] =
                private->level_switch[elem->control];
+       mutex_unlock(&private->data_mutex);
+
        return 0;
 }
 
@@ -1388,10 +1875,16 @@ static int scarlett2_pad_ctl_get(struct snd_kcontrol *kctl,
                                 struct snd_ctl_elem_value *ucontrol)
 {
        struct usb_mixer_elem_info *elem = kctl->private_data;
-       struct scarlett2_data *private = elem->head.mixer->private_data;
+       struct usb_mixer_interface *mixer = elem->head.mixer;
+       struct scarlett2_data *private = mixer->private_data;
 
+       mutex_lock(&private->data_mutex);
+       if (private->input_other_updated)
+               scarlett2_update_input_other(mixer);
        ucontrol->value.integer.value[0] =
                private->pad_switch[elem->control];
+       mutex_unlock(&private->data_mutex);
+
        return 0;
 }
 
@@ -1458,9 +1951,13 @@ static int scarlett2_dim_mute_ctl_put(struct snd_kcontrol *kctl,
        struct usb_mixer_elem_info *elem = kctl->private_data;
        struct usb_mixer_interface *mixer = elem->head.mixer;
        struct scarlett2_data *private = mixer->private_data;
+       const struct scarlett2_device_info *info = private->info;
+       const int (*port_count)[SCARLETT2_PORT_DIRNS] = info->port_count;
+       int num_line_out =
+               port_count[SCARLETT2_PORT_TYPE_ANALOGUE][SCARLETT2_PORT_OUT];
 
        int index = elem->control;
-       int oval, val, err = 0;
+       int oval, val, err = 0, i;
 
        mutex_lock(&private->data_mutex);
 
@@ -1478,6 +1975,15 @@ static int scarlett2_dim_mute_ctl_put(struct snd_kcontrol *kctl,
        if (err == 0)
                err = 1;
 
+       if (index == SCARLETT2_BUTTON_MUTE)
+               for (i = 0; i < num_line_out; i++)
+                       if (private->vol_sw_hw_switch[i]) {
+                               private->mute_switch[i] = val;
+                               snd_ctl_notify(mixer->chip->card,
+                                              SNDRV_CTL_EVENT_MASK_INFO,
+                                              &private->mute_ctls[i]->id);
+                       }
+
 unlock:
        mutex_unlock(&private->data_mutex);
        return err;
@@ -1497,9 +2003,9 @@ static int scarlett2_add_line_out_ctls(struct usb_mixer_interface *mixer)
 {
        struct scarlett2_data *private = mixer->private_data;
        const struct scarlett2_device_info *info = private->info;
-       const struct scarlett2_ports *ports = info->ports;
+       const int (*port_count)[SCARLETT2_PORT_DIRNS] = info->port_count;
        int num_line_out =
-               ports[SCARLETT2_PORT_TYPE_ANALOGUE].num[SCARLETT2_PORT_OUT];
+               port_count[SCARLETT2_PORT_TYPE_ANALOGUE][SCARLETT2_PORT_OUT];
        int err, i;
        char s[SNDRV_CTL_ELEM_ID_NAME_MAXLEN];
 
@@ -1531,10 +2037,22 @@ static int scarlett2_add_line_out_ctls(struct usb_mixer_interface *mixer)
                if (err < 0)
                        return err;
 
-               /* Make the fader read-only if the SW/HW switch is set to HW */
+               /* Mute Switch */
+               snprintf(s, sizeof(s),
+                        "Line %02d Mute Playback Switch",
+                        i + 1);
+               err = scarlett2_add_new_ctl(mixer,
+                                           &scarlett2_mute_ctl,
+                                           i, 1, s,
+                                           &private->mute_ctls[i]);
+               if (err < 0)
+                       return err;
+
+               /* Make the fader and mute controls read-only if the
+                * SW/HW switch is set to HW
+                */
                if (private->vol_sw_hw_switch[i])
-                       private->vol_ctls[i]->vd[0].access &=
-                               ~SNDRV_CTL_ELEM_ACCESS_WRITE;
+                       scarlett2_vol_ctl_set_writable(mixer, i, 0);
 
                /* SW/HW Switch */
                if (info->line_out_hw_vol) {
@@ -1571,21 +2089,22 @@ static int scarlett2_add_line_in_ctls(struct usb_mixer_interface *mixer)
        const struct scarlett2_device_info *info = private->info;
        int err, i;
        char s[SNDRV_CTL_ELEM_ID_NAME_MAXLEN];
+       const char *fmt = "Line In %d %s Capture %s";
 
        /* Add input level (line/inst) controls */
        for (i = 0; i < info->level_input_count; i++) {
-               snprintf(s, sizeof(s), "Line In %d Level Capture Enum", i + 1);
+               snprintf(s, sizeof(s), fmt, i + 1, "Level", "Enum");
                err = scarlett2_add_new_ctl(mixer, &scarlett2_level_enum_ctl,
-                                           i, 1, s, NULL);
+                                           i, 1, s, &private->level_ctls[i]);
                if (err < 0)
                        return err;
        }
 
        /* Add input pad controls */
        for (i = 0; i < info->pad_input_count; i++) {
-               snprintf(s, sizeof(s), "Line In %d Pad Capture Switch", i + 1);
+               snprintf(s, sizeof(s), fmt, i + 1, "Pad", "Switch");
                err = scarlett2_add_new_ctl(mixer, &scarlett2_pad_ctl,
-                                           i, 1, s, NULL);
+                                           i, 1, s, &private->pad_ctls[i]);
                if (err < 0)
                        return err;
        }
@@ -1625,7 +2144,7 @@ static int scarlett2_mixer_ctl_put(struct snd_kcontrol *kctl,
        struct usb_mixer_interface *mixer = elem->head.mixer;
        struct scarlett2_data *private = mixer->private_data;
        const struct scarlett2_device_info *info = private->info;
-       const struct scarlett2_ports *ports = info->ports;
+       const int (*port_count)[SCARLETT2_PORT_DIRNS] = info->port_count;
        int oval, val, num_mixer_in, mix_num, err = 0;
        int index = elem->control;
 
@@ -1633,7 +2152,7 @@ static int scarlett2_mixer_ctl_put(struct snd_kcontrol *kctl,
 
        oval = private->mix[index];
        val = ucontrol->value.integer.value[0];
-       num_mixer_in = ports[SCARLETT2_PORT_TYPE_MIX].num[SCARLETT2_PORT_OUT];
+       num_mixer_in = port_count[SCARLETT2_PORT_TYPE_MIX][SCARLETT2_PORT_OUT];
        mix_num = index / num_mixer_in;
 
        if (oval == val)
@@ -1670,13 +2189,16 @@ static const struct snd_kcontrol_new scarlett2_mixer_ctl = {
 static int scarlett2_add_mixer_ctls(struct usb_mixer_interface *mixer)
 {
        struct scarlett2_data *private = mixer->private_data;
-       const struct scarlett2_ports *ports = private->info->ports;
+       const struct scarlett2_device_info *info = private->info;
+       const int (*port_count)[SCARLETT2_PORT_DIRNS] = info->port_count;
        int err, i, j;
        int index;
        char s[SNDRV_CTL_ELEM_ID_NAME_MAXLEN];
 
-       int num_inputs = ports[SCARLETT2_PORT_TYPE_MIX].num[SCARLETT2_PORT_OUT];
-       int num_outputs = ports[SCARLETT2_PORT_TYPE_MIX].num[SCARLETT2_PORT_IN];
+       int num_inputs =
+               port_count[SCARLETT2_PORT_TYPE_MIX][SCARLETT2_PORT_OUT];
+       int num_outputs =
+               port_count[SCARLETT2_PORT_TYPE_MIX][SCARLETT2_PORT_IN];
 
        for (i = 0, index = 0; i < num_outputs; i++)
                for (j = 0; j < num_inputs; j++, index++) {
@@ -1699,7 +2221,8 @@ static int scarlett2_mux_src_enum_ctl_info(struct snd_kcontrol *kctl,
 {
        struct usb_mixer_elem_info *elem = kctl->private_data;
        struct scarlett2_data *private = elem->head.mixer->private_data;
-       const struct scarlett2_ports *ports = private->info->ports;
+       const struct scarlett2_device_info *info = private->info;
+       const int (*port_count)[SCARLETT2_PORT_DIRNS] = info->port_count;
        unsigned int item = uinfo->value.enumerated.item;
        int items = private->num_mux_srcs;
        int port_type;
@@ -1714,13 +2237,15 @@ static int scarlett2_mux_src_enum_ctl_info(struct snd_kcontrol *kctl,
        for (port_type = 0;
             port_type < SCARLETT2_PORT_TYPE_COUNT;
             port_type++) {
-               if (item < ports[port_type].num[SCARLETT2_PORT_IN]) {
+               if (item < port_count[port_type][SCARLETT2_PORT_IN]) {
+                       const struct scarlett2_port *port =
+                               &scarlett2_ports[port_type];
+
                        sprintf(uinfo->value.enumerated.name,
-                               ports[port_type].src_descr,
-                               item + ports[port_type].src_num_offset);
+                               port->src_descr, item + port->src_num_offset);
                        return 0;
                }
-               item -= ports[port_type].num[SCARLETT2_PORT_IN];
+               item -= port_count[port_type][SCARLETT2_PORT_IN];
        }
 
        return -EINVAL;
@@ -1775,18 +2300,20 @@ static const struct snd_kcontrol_new scarlett2_mux_src_enum_ctl = {
 static int scarlett2_add_mux_enums(struct usb_mixer_interface *mixer)
 {
        struct scarlett2_data *private = mixer->private_data;
-       const struct scarlett2_ports *ports = private->info->ports;
+       const struct scarlett2_device_info *info = private->info;
+       const int (*port_count)[SCARLETT2_PORT_DIRNS] = info->port_count;
        int port_type, channel, i;
 
        for (i = 0, port_type = 0;
             port_type < SCARLETT2_PORT_TYPE_COUNT;
             port_type++) {
                for (channel = 0;
-                    channel < ports[port_type].num[SCARLETT2_PORT_OUT];
+                    channel < port_count[port_type][SCARLETT2_PORT_OUT];
                     channel++, i++) {
                        int err;
                        char s[SNDRV_CTL_ELEM_ID_NAME_MAXLEN];
-                       const char *const descr = ports[port_type].dst_descr;
+                       const char *const descr =
+                               scarlett2_ports[port_type].dst_descr;
 
                        snprintf(s, sizeof(s) - 5, descr, channel + 1);
                        strcat(s, " Enum");
@@ -1821,10 +2348,11 @@ static int scarlett2_meter_ctl_get(struct snd_kcontrol *kctl,
                                   struct snd_ctl_elem_value *ucontrol)
 {
        struct usb_mixer_elem_info *elem = kctl->private_data;
-       u16 meter_levels[SCARLETT2_NUM_METERS];
+       u16 meter_levels[SCARLETT2_MAX_METERS];
        int i, err;
 
-       err = scarlett2_usb_get_meter_levels(elem->head.mixer, meter_levels);
+       err = scarlett2_usb_get_meter_levels(elem->head.mixer, elem->channels,
+                                            meter_levels);
        if (err < 0)
                return err;
 
@@ -1844,11 +2372,78 @@ static const struct snd_kcontrol_new scarlett2_meter_ctl = {
 
 static int scarlett2_add_meter_ctl(struct usb_mixer_interface *mixer)
 {
+       struct scarlett2_data *private = mixer->private_data;
+
        return scarlett2_add_new_ctl(mixer, &scarlett2_meter_ctl,
-                                    0, SCARLETT2_NUM_METERS,
+                                    0, private->num_mux_dsts,
                                     "Level Meter", NULL);
 }
 
+/*** MSD Controls ***/
+
+static int scarlett2_msd_ctl_get(struct snd_kcontrol *kctl,
+                                struct snd_ctl_elem_value *ucontrol)
+{
+       struct usb_mixer_elem_info *elem = kctl->private_data;
+       struct scarlett2_data *private = elem->head.mixer->private_data;
+
+       ucontrol->value.integer.value[0] = private->msd_switch;
+       return 0;
+}
+
+static int scarlett2_msd_ctl_put(struct snd_kcontrol *kctl,
+                                struct snd_ctl_elem_value *ucontrol)
+{
+       struct usb_mixer_elem_info *elem = kctl->private_data;
+       struct usb_mixer_interface *mixer = elem->head.mixer;
+       struct scarlett2_data *private = mixer->private_data;
+
+       int oval, val, err = 0;
+
+       mutex_lock(&private->data_mutex);
+
+       oval = private->msd_switch;
+       val = !!ucontrol->value.integer.value[0];
+
+       if (oval == val)
+               goto unlock;
+
+       private->msd_switch = val;
+
+       /* Send switch change to the device */
+       err = scarlett2_usb_set_config(mixer, SCARLETT2_CONFIG_MSD_SWITCH,
+                                      0, val);
+
+unlock:
+       mutex_unlock(&private->data_mutex);
+       return err;
+}
+
+static const struct snd_kcontrol_new scarlett2_msd_ctl = {
+       .iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+       .name = "",
+       .info = snd_ctl_boolean_mono_info,
+       .get  = scarlett2_msd_ctl_get,
+       .put  = scarlett2_msd_ctl_put,
+};
+
+static int scarlett2_add_msd_ctl(struct usb_mixer_interface *mixer)
+{
+       struct scarlett2_data *private = mixer->private_data;
+       const struct scarlett2_device_info *info = private->info;
+
+       if (!info->has_msd_mode)
+               return 0;
+
+       /* If MSD mode is off, hide the switch by default */
+       if (!private->msd_switch && !(mixer->chip->setup & SCARLETT2_MSD_ENABLE))
+               return 0;
+
+       /* Add MSD control */
+       return scarlett2_add_new_ctl(mixer, &scarlett2_msd_ctl,
+                                    0, 1, "MSD Mode", NULL);
+}
+
 /*** Cleanup/Suspend Callbacks ***/
 
 static void scarlett2_private_free(struct usb_mixer_interface *mixer)
@@ -1872,21 +2467,54 @@ static void scarlett2_private_suspend(struct usb_mixer_interface *mixer)
 
 static void scarlett2_count_mux_io(struct scarlett2_data *private)
 {
-       const struct scarlett2_ports *ports = private->info->ports;
+       const struct scarlett2_device_info *info = private->info;
+       const int (*port_count)[SCARLETT2_PORT_DIRNS] = info->port_count;
        int port_type, srcs = 0, dsts = 0;
 
        for (port_type = 0;
             port_type < SCARLETT2_PORT_TYPE_COUNT;
             port_type++) {
-               srcs += ports[port_type].num[SCARLETT2_PORT_IN];
-               dsts += ports[port_type].num[SCARLETT2_PORT_OUT_44];
+               srcs += port_count[port_type][SCARLETT2_PORT_IN];
+               dsts += port_count[port_type][SCARLETT2_PORT_OUT];
        }
 
        private->num_mux_srcs = srcs;
        private->num_mux_dsts = dsts;
 }
 
-/* Initialise private data and sequence number */
+/* Look through the interface descriptors for the Focusrite Control
+ * interface (bInterfaceClass = 255 Vendor Specific Class) and set
+ * bInterfaceNumber, bEndpointAddress, wMaxPacketSize, and bInterval
+ * in private
+ */
+static int scarlett2_find_fc_interface(struct usb_device *dev,
+                                      struct scarlett2_data *private)
+{
+       struct usb_host_config *config = dev->actconfig;
+       int i;
+
+       for (i = 0; i < config->desc.bNumInterfaces; i++) {
+               struct usb_interface *intf = config->interface[i];
+               struct usb_interface_descriptor *desc =
+                       &intf->altsetting[0].desc;
+               struct usb_endpoint_descriptor *epd;
+
+               if (desc->bInterfaceClass != 255)
+                       continue;
+
+               epd = get_endpoint(intf->altsetting, 0);
+               private->bInterfaceNumber = desc->bInterfaceNumber;
+               private->bEndpointAddress = epd->bEndpointAddress &
+                       USB_ENDPOINT_NUMBER_MASK;
+               private->wMaxPacketSize = le16_to_cpu(epd->wMaxPacketSize);
+               private->bInterval = epd->bInterval;
+               return 0;
+       }
+
+       return -EINVAL;
+}
+
+/* Initialise private data */
 static int scarlett2_init_private(struct usb_mixer_interface *mixer,
                                  const struct scarlett2_device_info *info)
 {
@@ -1899,16 +2527,45 @@ static int scarlett2_init_private(struct usb_mixer_interface *mixer,
        mutex_init(&private->usb_mutex);
        mutex_init(&private->data_mutex);
        INIT_DELAYED_WORK(&private->work, scarlett2_config_save_work);
+
+       mixer->private_data = private;
+       mixer->private_free = scarlett2_private_free;
+       mixer->private_suspend = scarlett2_private_suspend;
+
        private->info = info;
        scarlett2_count_mux_io(private);
        private->scarlett2_seq = 0;
        private->mixer = mixer;
-       mixer->private_data = private;
-       mixer->private_free = scarlett2_private_free;
-       mixer->private_suspend = scarlett2_private_suspend;
 
-       /* Initialise the sequence number used for the proprietary commands */
-       return scarlett2_usb(mixer, SCARLETT2_USB_INIT_SEQ, NULL, 0, NULL, 0);
+       return scarlett2_find_fc_interface(mixer->chip->dev, private);
+}
+
+/* Cargo cult proprietary initialisation sequence */
+static int scarlett2_usb_init(struct usb_mixer_interface *mixer)
+{
+       struct usb_device *dev = mixer->chip->dev;
+       struct scarlett2_data *private = mixer->private_data;
+       u8 buf[24];
+       int err;
+
+       if (usb_pipe_type_check(dev, usb_sndctrlpipe(dev, 0)))
+               return -EINVAL;
+
+       /* step 0 */
+       err = scarlett2_usb_rx(dev, private->bInterfaceNumber,
+                              SCARLETT2_USB_CMD_INIT, buf, sizeof(buf));
+       if (err < 0)
+               return err;
+
+       /* step 1 */
+       private->scarlett2_seq = 1;
+       err = scarlett2_usb(mixer, SCARLETT2_USB_INIT_1, NULL, 0, NULL, 0);
+       if (err < 0)
+               return err;
+
+       /* step 2 */
+       private->scarlett2_seq = 1;
+       return scarlett2_usb(mixer, SCARLETT2_USB_INIT_2, NULL, 0, NULL, 84);
 }
 
 /* Read configuration from the interface on start */
@@ -1916,44 +2573,48 @@ static int scarlett2_read_configs(struct usb_mixer_interface *mixer)
 {
        struct scarlett2_data *private = mixer->private_data;
        const struct scarlett2_device_info *info = private->info;
-       const struct scarlett2_ports *ports = info->ports;
+       const int (*port_count)[SCARLETT2_PORT_DIRNS] = info->port_count;
        int num_line_out =
-               ports[SCARLETT2_PORT_TYPE_ANALOGUE].num[SCARLETT2_PORT_OUT];
+               port_count[SCARLETT2_PORT_TYPE_ANALOGUE][SCARLETT2_PORT_OUT];
        int num_mixer_out =
-               ports[SCARLETT2_PORT_TYPE_MIX].num[SCARLETT2_PORT_IN];
+               port_count[SCARLETT2_PORT_TYPE_MIX][SCARLETT2_PORT_IN];
        struct scarlett2_usb_volume_status volume_status;
        int err, i;
 
-       if (info->level_input_count) {
+       if (info->has_msd_mode) {
                err = scarlett2_usb_get_config(
-                       mixer,
-                       SCARLETT2_CONFIG_LEVEL_SWITCH,
-                       info->level_input_count,
-                       private->level_switch);
+                       mixer, SCARLETT2_CONFIG_MSD_SWITCH,
+                       1, &private->msd_switch);
                if (err < 0)
                        return err;
-       }
 
-       if (info->pad_input_count) {
-               err = scarlett2_usb_get_config(
-                       mixer,
-                       SCARLETT2_CONFIG_PAD_SWITCH,
-                       info->pad_input_count,
-                       private->pad_switch);
-               if (err < 0)
-                       return err;
+               /* no other controls are created if MSD mode is on */
+               if (private->msd_switch)
+                       return 0;
        }
 
+       err = scarlett2_update_input_other(mixer);
+       if (err < 0)
+               return err;
+
+       err = scarlett2_update_sync(mixer);
+       if (err < 0)
+               return err;
+
        err = scarlett2_usb_get_volume_status(mixer, &volume_status);
        if (err < 0)
                return err;
 
+       if (info->line_out_hw_vol)
+               for (i = 0; i < SCARLETT2_DIM_MUTE_COUNT; i++)
+                       private->dim_mute[i] = !!volume_status.dim_mute[i];
+
        private->master_vol = clamp(
                volume_status.master_vol + SCARLETT2_VOLUME_BIAS,
                0, SCARLETT2_VOLUME_BIAS);
 
        for (i = 0; i < num_line_out; i++) {
-               int volume;
+               int volume, mute;
 
                private->vol_sw_hw_switch[i] =
                        info->line_out_hw_vol
@@ -1965,11 +2626,12 @@ static int scarlett2_read_configs(struct usb_mixer_interface *mixer)
                volume = clamp(volume + SCARLETT2_VOLUME_BIAS,
                               0, SCARLETT2_VOLUME_BIAS);
                private->vol[i] = volume;
-       }
 
-       if (info->line_out_hw_vol)
-               for (i = 0; i < SCARLETT2_DIM_MUTE_COUNT; i++)
-                       private->dim_mute[i] = !!volume_status.dim_mute[i];
+               mute = private->vol_sw_hw_switch[i]
+                        ? private->dim_mute[SCARLETT2_BUTTON_MUTE]
+                        : volume_status.mute_switch[i];
+               private->mute_switch[i] = mute;
+       }
 
        for (i = 0; i < num_mixer_out; i++) {
                err = scarlett2_usb_get_mix(mixer, i);
@@ -1980,16 +2642,33 @@ static int scarlett2_read_configs(struct usb_mixer_interface *mixer)
        return scarlett2_usb_get_mux(mixer);
 }
 
+/* Notify on sync change */
+static void scarlett2_notify_sync(
+       struct usb_mixer_interface *mixer)
+{
+       struct scarlett2_data *private = mixer->private_data;
+
+       private->sync_updated = 1;
+
+       snd_ctl_notify(mixer->chip->card, SNDRV_CTL_EVENT_MASK_VALUE,
+                      &private->sync_ctl->id);
+}
+
 /* Notify on monitor change */
 static void scarlett2_notify_monitor(
        struct usb_mixer_interface *mixer)
 {
        struct scarlett2_data *private = mixer->private_data;
-       const struct scarlett2_ports *ports = private->info->ports;
+       const struct scarlett2_device_info *info = private->info;
+       const int (*port_count)[SCARLETT2_PORT_DIRNS] = info->port_count;
        int num_line_out =
-               ports[SCARLETT2_PORT_TYPE_ANALOGUE].num[SCARLETT2_PORT_OUT];
+               port_count[SCARLETT2_PORT_TYPE_ANALOGUE][SCARLETT2_PORT_OUT];
        int i;
 
+       /* if line_out_hw_vol is 0, there are no controls to update */
+       if (!info->line_out_hw_vol)
+               return;
+
        private->vol_updated = 1;
 
        snd_ctl_notify(mixer->chip->card, SNDRV_CTL_EVENT_MASK_VALUE,
@@ -2007,8 +2686,12 @@ static void scarlett2_notify_monitor(
 static void scarlett2_notify_dim_mute(
        struct usb_mixer_interface *mixer)
 {
+       struct snd_card *card = mixer->chip->card;
        struct scarlett2_data *private = mixer->private_data;
        const struct scarlett2_device_info *info = private->info;
+       const int (*port_count)[SCARLETT2_PORT_DIRNS] = info->port_count;
+       int num_line_out =
+               port_count[SCARLETT2_PORT_TYPE_ANALOGUE][SCARLETT2_PORT_OUT];
        int i;
 
        private->vol_updated = 1;
@@ -2017,8 +2700,32 @@ static void scarlett2_notify_dim_mute(
                return;
 
        for (i = 0; i < SCARLETT2_DIM_MUTE_COUNT; i++)
-               snd_ctl_notify(mixer->chip->card, SNDRV_CTL_EVENT_MASK_VALUE,
+               snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
                               &private->dim_mute_ctls[i]->id);
+
+       for (i = 0; i < num_line_out; i++)
+               if (private->vol_sw_hw_switch[i])
+                       snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+                                      &private->mute_ctls[i]->id);
+}
+
+/* Notify on "input other" change (level/pad) */
+static void scarlett2_notify_input_other(
+       struct usb_mixer_interface *mixer)
+{
+       struct snd_card *card = mixer->chip->card;
+       struct scarlett2_data *private = mixer->private_data;
+       const struct scarlett2_device_info *info = private->info;
+       int i;
+
+       private->input_other_updated = 1;
+
+       for (i = 0; i < info->level_input_count; i++)
+               snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+                              &private->level_ctls[i]->id);
+       for (i = 0; i < info->pad_input_count; i++)
+               snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+                              &private->pad_ctls[i]->id);
 }
 
 /* Interrupt callback */
@@ -2033,10 +2740,14 @@ static void scarlett2_notify(struct urb *urb)
                goto requeue;
 
        data = le32_to_cpu(*(__le32 *)urb->transfer_buffer);
+       if (data & SCARLETT2_USB_NOTIFY_SYNC)
+               scarlett2_notify_sync(mixer);
        if (data & SCARLETT2_USB_NOTIFY_MONITOR)
                scarlett2_notify_monitor(mixer);
        if (data & SCARLETT2_USB_NOTIFY_DIM_MUTE)
                scarlett2_notify_dim_mute(mixer);
+       if (data & SCARLETT2_USB_NOTIFY_INPUT_OTHER)
+               scarlett2_notify_input_other(mixer);
 
 requeue:
        if (ustatus != -ENOENT &&
@@ -2050,8 +2761,8 @@ requeue:
 static int scarlett2_init_notify(struct usb_mixer_interface *mixer)
 {
        struct usb_device *dev = mixer->chip->dev;
-       unsigned int pipe = usb_rcvintpipe(dev,
-                                          SCARLETT2_USB_INTERRUPT_ENDPOINT);
+       struct scarlett2_data *private = mixer->private_data;
+       unsigned int pipe = usb_rcvintpipe(dev, private->bEndpointAddress);
        void *transfer_buffer;
 
        if (mixer->urb) {
@@ -2067,25 +2778,35 @@ static int scarlett2_init_notify(struct usb_mixer_interface *mixer)
        if (!mixer->urb)
                return -ENOMEM;
 
-       transfer_buffer = kmalloc(SCARLETT2_USB_INTERRUPT_MAX_DATA, GFP_KERNEL);
+       transfer_buffer = kmalloc(private->wMaxPacketSize, GFP_KERNEL);
        if (!transfer_buffer)
                return -ENOMEM;
 
        usb_fill_int_urb(mixer->urb, dev, pipe,
-                        transfer_buffer, SCARLETT2_USB_INTERRUPT_MAX_DATA,
-                        scarlett2_notify, mixer,
-                        SCARLETT2_USB_INTERRUPT_INTERVAL);
+                        transfer_buffer, private->wMaxPacketSize,
+                        scarlett2_notify, mixer, private->bInterval);
 
        return usb_submit_urb(mixer->urb, GFP_KERNEL);
 }
 
-static int snd_scarlett_gen2_controls_create(struct usb_mixer_interface *mixer,
-                                            const struct scarlett2_device_info *info)
+static int snd_scarlett_gen2_controls_create(struct usb_mixer_interface *mixer)
 {
+       const struct scarlett2_device_info **info = scarlett2_devices;
        int err;
 
-       /* Initialise private data and sequence number */
-       err = scarlett2_init_private(mixer, info);
+       /* Find device in scarlett2_devices */
+       while (*info && (*info)->usb_id != mixer->chip->usb_id)
+               info++;
+       if (!*info)
+               return -EINVAL;
+
+       /* Initialise private data */
+       err = scarlett2_init_private(mixer, *info);
+       if (err < 0)
+               return err;
+
+       /* Send proprietary USB initialisation sequence */
+       err = scarlett2_usb_init(mixer);
        if (err < 0)
                return err;
 
@@ -2094,6 +2815,15 @@ static int snd_scarlett_gen2_controls_create(struct usb_mixer_interface *mixer,
        if (err < 0)
                return err;
 
+       /* Create the MSD control */
+       err = scarlett2_add_msd_ctl(mixer);
+       if (err < 0)
+               return err;
+
+       /* If MSD mode is enabled, don't create any other controls */
+       if (((struct scarlett2_data *)mixer->private_data)->msd_switch)
+               return 0;
+
        /* Create the analogue output controls */
        err = scarlett2_add_line_out_ctls(mixer);
        if (err < 0)
@@ -2119,12 +2849,15 @@ static int snd_scarlett_gen2_controls_create(struct usb_mixer_interface *mixer,
        if (err < 0)
                return err;
 
-       /* Set up the interrupt polling if there are hardware buttons */
-       if (info->line_out_hw_vol) {
-               err = scarlett2_init_notify(mixer);
-               if (err < 0)
-                       return err;
-       }
+       /* Create the sync control */
+       err = scarlett2_add_sync_ctl(mixer);
+       if (err < 0)
+               return err;
+
+       /* Set up the interrupt polling */
+       err = scarlett2_init_notify(mixer);
+       if (err < 0)
+               return err;
 
        return 0;
 }
@@ -2132,30 +2865,15 @@ static int snd_scarlett_gen2_controls_create(struct usb_mixer_interface *mixer,
 int snd_scarlett_gen2_init(struct usb_mixer_interface *mixer)
 {
        struct snd_usb_audio *chip = mixer->chip;
-       const struct scarlett2_device_info *info;
        int err;
 
        /* only use UAC_VERSION_2 */
        if (!mixer->protocol)
                return 0;
 
-       switch (chip->usb_id) {
-       case USB_ID(0x1235, 0x8203):
-               info = &s6i6_gen2_info;
-               break;
-       case USB_ID(0x1235, 0x8204):
-               info = &s18i8_gen2_info;
-               break;
-       case USB_ID(0x1235, 0x8201):
-               info = &s18i20_gen2_info;
-               break;
-       default: /* device not (yet) supported */
-               return -EINVAL;
-       }
-
        if (!(chip->setup & SCARLETT2_ENABLE)) {
                usb_audio_info(chip,
-                       "Focusrite Scarlett Gen 2 Mixer Driver disabled; "
+                       "Focusrite Scarlett Gen 2/3 Mixer Driver disabled; "
                        "use options snd_usb_audio vid=0x%04x pid=0x%04x "
                        "device_setup=1 to enable and report any issues "
                        "to g@b4.vu",
@@ -2165,10 +2883,10 @@ int snd_scarlett_gen2_init(struct usb_mixer_interface *mixer)
        }
 
        usb_audio_info(chip,
-               "Focusrite Scarlett Gen 2 Mixer Driver enabled pid=0x%04x",
+               "Focusrite Scarlett Gen 2/3 Mixer Driver enabled pid=0x%04x",
                USB_ID_PRODUCT(chip->usb_id));
 
-       err = snd_scarlett_gen2_controls_create(mixer, info);
+       err = snd_scarlett_gen2_controls_create(mixer);
        if (err < 0)
                usb_audio_err(mixer->chip,
                              "Error initialising Scarlett Mixer Driver: %d",