USB: serial: cp210x: add GPIO support for CP2104

The CP2104 chips feature 4 controllable GPIO pins, which are similar to
the ones on CP2102N chip (output-only when push-pull, output or
simulated input mode when open-drain).

Add support for the GPIO pins for cp210x driver. The pin get/set routine
is shared with CP2102N, but the pinconf initialization code is not
shared because the acquisition of GPIO configuration in OTP ROM is
similar to CP2105, not CP2102N.

Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Signed-off-by: Johan Hovold <johan@kernel.org>

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index 336a3c0..260c875 100644 (file)
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -443,10 +443,10 @@ struct cp210x_pin_mode {
 #define CP210X_PIN_MODE_GPIO           BIT(0)
 
 /*
- * CP210X_VENDOR_SPECIFIC, CP210X_GET_PORTCONFIG call reads these 0xf bytes.
- * Structure needs padding due to unused/unspecified bytes.
+ * CP210X_VENDOR_SPECIFIC, CP210X_GET_PORTCONFIG call reads these 0xf bytes
+ * on a CP2105 chip. Structure needs padding due to unused/unspecified bytes.
  */
-struct cp210x_config {
+struct cp210x_dual_port_config {
        __le16  gpio_mode;
        u8      __pad0[2];
        __le16  reset_state;
@@ -457,6 +457,19 @@ struct cp210x_config {
        u8      device_cfg;
 } __packed;
 
+/*
+ * CP210X_VENDOR_SPECIFIC, CP210X_GET_PORTCONFIG call reads these 0xd bytes
+ * on a CP2104 chip. Structure needs padding due to unused/unspecified bytes.
+ */
+struct cp210x_single_port_config {
+       __le16  gpio_mode;
+       u8      __pad0[2];
+       __le16  reset_state;
+       u8      __pad1[4];
+       __le16  suspend_state;
+       u8      device_cfg;
+} __packed;
+
 /* GPIO modes */
 #define CP210X_SCI_GPIO_MODE_OFFSET    9
 #define CP210X_SCI_GPIO_MODE_MASK      GENMASK(11, 9)
@@ -464,11 +477,19 @@ struct cp210x_config {
 #define CP210X_ECI_GPIO_MODE_OFFSET    2
 #define CP210X_ECI_GPIO_MODE_MASK      GENMASK(3, 2)
 
+#define CP210X_GPIO_MODE_OFFSET                8
+#define CP210X_GPIO_MODE_MASK          GENMASK(11, 8)
+
 /* CP2105 port configuration values */
 #define CP2105_GPIO0_TXLED_MODE                BIT(0)
 #define CP2105_GPIO1_RXLED_MODE                BIT(1)
 #define CP2105_GPIO1_RS485_MODE                BIT(2)
 
+/* CP2104 port configuration values */
+#define CP2104_GPIO0_TXLED_MODE                BIT(0)
+#define CP2104_GPIO1_RXLED_MODE                BIT(1)
+#define CP2104_GPIO2_RS485_MODE                BIT(2)
+
 /* CP2102N configuration array indices */
 #define CP210X_2NCONFIG_CONFIG_VERSION_IDX     2
 #define CP210X_2NCONFIG_GPIO_MODE_IDX          581
@@ -1470,7 +1491,7 @@ static int cp2105_gpioconf_init(struct usb_serial *serial)
 {
        struct cp210x_serial_private *priv = usb_get_serial_data(serial);
        struct cp210x_pin_mode mode;
-       struct cp210x_config config;
+       struct cp210x_dual_port_config config;
        u8 intf_num = cp210x_interface_num(serial);
        u8 iface_config;
        int result;
@@ -1529,6 +1550,56 @@ static int cp2105_gpioconf_init(struct usb_serial *serial)
        return 0;
 }
 
+static int cp2104_gpioconf_init(struct usb_serial *serial)
+{
+       struct cp210x_serial_private *priv = usb_get_serial_data(serial);
+       struct cp210x_single_port_config config;
+       u8 iface_config;
+       u8 gpio_latch;
+       int result;
+       u8 i;
+
+       result = cp210x_read_vendor_block(serial, REQTYPE_DEVICE_TO_HOST,
+                                         CP210X_GET_PORTCONFIG, &config,
+                                         sizeof(config));
+       if (result < 0)
+               return result;
+
+       priv->gc.ngpio = 4;
+
+       iface_config = config.device_cfg;
+       priv->gpio_pushpull = (u8)((le16_to_cpu(config.gpio_mode) &
+                                       CP210X_GPIO_MODE_MASK) >>
+                                       CP210X_GPIO_MODE_OFFSET);
+       gpio_latch = (u8)((le16_to_cpu(config.reset_state) &
+                                       CP210X_GPIO_MODE_MASK) >>
+                                       CP210X_GPIO_MODE_OFFSET);
+
+       /* mark all pins which are not in GPIO mode */
+       if (iface_config & CP2104_GPIO0_TXLED_MODE)     /* GPIO 0 */
+               priv->gpio_altfunc |= BIT(0);
+       if (iface_config & CP2104_GPIO1_RXLED_MODE)     /* GPIO 1 */
+               priv->gpio_altfunc |= BIT(1);
+       if (iface_config & CP2104_GPIO2_RS485_MODE)     /* GPIO 2 */
+               priv->gpio_altfunc |= BIT(2);
+
+       /*
+        * Like CP2102N, CP2104 has also no strict input and output pin
+        * modes.
+        * Do the same input mode emulation as CP2102N.
+        */
+       for (i = 0; i < priv->gc.ngpio; ++i) {
+               /*
+                * Set direction to "input" iff pin is open-drain and reset
+                * value is 1.
+                */
+               if (!(priv->gpio_pushpull & BIT(i)) && (gpio_latch & BIT(i)))
+                       priv->gpio_input |= BIT(i);
+       }
+
+       return 0;
+}
+
 static int cp2102n_gpioconf_init(struct usb_serial *serial)
 {
        struct cp210x_serial_private *priv = usb_get_serial_data(serial);
@@ -1627,6 +1698,9 @@ static int cp210x_gpio_init(struct usb_serial *serial)
        int result;
 
        switch (priv->partnum) {
+       case CP210X_PARTNUM_CP2104:
+               result = cp2104_gpioconf_init(serial);
+               break;
        case CP210X_PARTNUM_CP2105:
                result = cp2105_gpioconf_init(serial);
                break;