usb: gadget: f_uac2: allow changing terminal types through configfs

Add "c_terminal_type" and "p_terminal_type" configfs entries
in order to allow the user to change the capture and playback terminal
type codes.

These fields affect the type of audio device that Windows detects, so
being able to modify this is useful when it would be advantageous for
a gadget to be detected as something other than a generic
speaker/microphone.

The fields default to microphone for the capture type field and speaker
for the playback type field as was the case before.

Signed-off-by: James Gruber <jimmyjgruber@gmail.com>
Link: https://lore.kernel.org/r/20230914222746.155126-1-jimmyjgruber@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/Documentation/ABI/testing/configfs-usb-gadget-uac2 b/Documentation/ABI/testing/configfs-usb-gadget-uac2
index 3371c39..a2bf4fd 100644 (file)
--- a/Documentation/ABI/testing/configfs-usb-gadget-uac2
+++ b/Documentation/ABI/testing/configfs-usb-gadget-uac2
@@ -35,4 +35,6 @@ Description:
                req_number              the number of pre-allocated requests
                                        for both capture and playback
                function_name           name of the interface
+               c_terminal_type         code of the capture terminal type
+               p_terminal_type         code of the playback terminal type
                =====================   =======================================

diff --git a/Documentation/usb/gadget-testing.rst b/Documentation/usb/gadget-testing.rst
index 394cd22..29072c1 100644 (file)
--- a/Documentation/usb/gadget-testing.rst
+++ b/Documentation/usb/gadget-testing.rst
@@ -755,6 +755,8 @@ The uac2 function provides these attributes in its function directory:
        req_number       the number of pre-allocated request for both capture
                         and playback
        function_name    name of the interface
+       c_terminal_type  code of the capture terminal type
+       p_terminal_type  code of the playback terminal type
        ================ ====================================================
 
 The attributes have sane default values.

diff --git a/drivers/usb/gadget/function/f_uac2.c b/drivers/usb/gadget/function/f_uac2.c
index 0219cd7..f9a0f07 100644 (file)
--- a/drivers/usb/gadget/function/f_uac2.c
+++ b/drivers/usb/gadget/function/f_uac2.c
@@ -212,7 +212,7 @@ static struct uac2_input_terminal_descriptor io_in_it_desc = {
 
        .bDescriptorSubtype = UAC_INPUT_TERMINAL,
        /* .bTerminalID = DYNAMIC */
-       .wTerminalType = cpu_to_le16(UAC_INPUT_TERMINAL_MICROPHONE),
+       /* .wTerminalType = DYNAMIC */
        .bAssocTerminal = 0,
        /* .bCSourceID = DYNAMIC */
        .iChannelNames = 0,
@@ -240,7 +240,7 @@ static struct uac2_output_terminal_descriptor io_out_ot_desc = {
 
        .bDescriptorSubtype = UAC_OUTPUT_TERMINAL,
        /* .bTerminalID = DYNAMIC */
-       .wTerminalType = cpu_to_le16(UAC_OUTPUT_TERMINAL_SPEAKER),
+       /* .wTerminalType = DYNAMIC */
        .bAssocTerminal = 0,
        /* .bSourceID = DYNAMIC */
        /* .bCSourceID = DYNAMIC */
@@ -977,6 +977,9 @@ static void setup_descriptor(struct f_uac2_opts *opts)
                iad_desc.bInterfaceCount++;
        }
 
+       io_in_it_desc.wTerminalType = cpu_to_le16(opts->c_terminal_type);
+       io_out_ot_desc.wTerminalType = cpu_to_le16(opts->p_terminal_type);
+
        setup_headers(opts, fs_audio_desc, USB_SPEED_FULL);
        setup_headers(opts, hs_audio_desc, USB_SPEED_HIGH);
        setup_headers(opts, ss_audio_desc, USB_SPEED_SUPER);
@@ -2095,6 +2098,9 @@ UAC2_ATTRIBUTE(s16, c_volume_res);
 UAC2_ATTRIBUTE(u32, fb_max);
 UAC2_ATTRIBUTE_STRING(function_name);
 
+UAC2_ATTRIBUTE(s16, p_terminal_type);
+UAC2_ATTRIBUTE(s16, c_terminal_type);
+
 static struct configfs_attribute *f_uac2_attrs[] = {
        &f_uac2_opts_attr_p_chmask,
        &f_uac2_opts_attr_p_srate,
@@ -2122,6 +2128,9 @@ static struct configfs_attribute *f_uac2_attrs[] = {
 
        &f_uac2_opts_attr_function_name,
 
+       &f_uac2_opts_attr_p_terminal_type,
+       &f_uac2_opts_attr_c_terminal_type,
+
        NULL,
 };
 
@@ -2180,6 +2189,9 @@ static struct usb_function_instance *afunc_alloc_inst(void)
 
        snprintf(opts->function_name, sizeof(opts->function_name), "Source/Sink");
 
+       opts->p_terminal_type = UAC2_DEF_P_TERM_TYPE;
+       opts->c_terminal_type = UAC2_DEF_C_TERM_TYPE;
+
        return &opts->func_inst;
 }
 

diff --git a/drivers/usb/gadget/function/u_uac2.h b/drivers/usb/gadget/function/u_uac2.h
index 0510c9b..5e81bdd 100644 (file)
--- a/drivers/usb/gadget/function/u_uac2.h
+++ b/drivers/usb/gadget/function/u_uac2.h
@@ -35,6 +35,11 @@
 #define UAC2_DEF_REQ_NUM 2
 #define UAC2_DEF_INT_REQ_NUM   10
 
+#define UAC2_DEF_P_TERM_TYPE 0x301
+       /* UAC_OUTPUT_TERMINAL_SPEAKER */
+#define UAC2_DEF_C_TERM_TYPE 0x201
+       /* UAC_INPUT_TERMINAL_MICROPHONE*/
+
 struct f_uac2_opts {
        struct usb_function_instance    func_inst;
        int                             p_chmask;
@@ -65,6 +70,9 @@ struct f_uac2_opts {
 
        char                    function_name[32];
 
+       s16                             p_terminal_type;
+       s16                             c_terminal_type;
+
        struct mutex                    lock;
        int                             refcnt;
 };