[media] adv7604: Add support for hardware reset

The part can be reset by a low pulse on the RESET pin (i.e. a hardware
reset) with a minimum width of 5 ms. It is recommended to wait 5 ms
after the low pulse before an I2C write is performed to the part.
For safety reasons, the delays will be between 5 and 10 ms.

The RESET pin can be tied high, so the GPIO is optional.

Signed-off-by: Dragos Bogdan <dragos.bogdan@analog.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

diff --git a/drivers/media/i2c/adv7604.c b/drivers/media/i2c/adv7604.c
index 3ffb3231be3fd517cc04e93ee50df56513a0ede6..0b362eeb55c7815d0b93a2125c44f595390184ca 100644 (file)
--- a/drivers/media/i2c/adv7604.c
+++ b/drivers/media/i2c/adv7604.c
@@ -164,6 +164,7 @@ struct adv76xx_state {
        struct adv76xx_platform_data pdata;
 
        struct gpio_desc *hpd_gpio[4];
+       struct gpio_desc *reset_gpio;
 
        struct v4l2_subdev sd;
        struct media_pad pads[ADV76XX_PAD_MAX];
@@ -3018,6 +3019,19 @@ static int configure_regmaps(struct adv76xx_state *state)
        return 0;
 }
 
+static void adv76xx_reset(struct adv76xx_state *state)
+{
+       if (state->reset_gpio) {
+               /* ADV76XX can be reset by a low reset pulse of minimum 5 ms. */
+               gpiod_set_value_cansleep(state->reset_gpio, 0);
+               usleep_range(5000, 10000);
+               gpiod_set_value_cansleep(state->reset_gpio, 1);
+               /* It is recommended to wait 5 ms after the low pulse before */
+               /* an I2C write is performed to the ADV76XX. */
+               usleep_range(5000, 10000);
+       }
+}
+
 static int adv76xx_probe(struct i2c_client *client,
                         const struct i2c_device_id *id)
 {
@@ -3081,6 +3095,12 @@ static int adv76xx_probe(struct i2c_client *client,
                if (state->hpd_gpio[i])
                        v4l_info(client, "Handling HPD %u GPIO\n", i);
        }
+       state->reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
+                                                               GPIOD_OUT_HIGH);
+       if (IS_ERR(state->reset_gpio))
+               return PTR_ERR(state->reset_gpio);
+
+       adv76xx_reset(state);
 
        state->timings = cea640x480;
        state->format = adv76xx_format_info(state, MEDIA_BUS_FMT_YUYV8_2X8);