media: adv7180: Add optional reset GPIO

There is a reset input that can be controlled by GPIO. Let's add it
to let the driver control it if required.

[hverkuil: fix a small checkpatch alignment warning]
Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/i2c/adv7180.c

@@ -205,6 +205,7 @@ struct adv7180_state {
 	struct mutex		mutex; /* mutual excl. when accessing chip */
 	int			irq;
 	struct gpio_desc	*pwdn_gpio;
+	struct gpio_desc	*rst_gpio;
 	v4l2_std_id		curr_norm;
 	bool			powered;
 	bool			streaming;
@@ -484,6 +485,19 @@ static void adv7180_set_power_pin(struct adv7180_state *state, bool on)
 	}
 }
 
+static void adv7180_set_reset_pin(struct adv7180_state *state, bool on)
+{
+	if (!state->rst_gpio)
+		return;
+
+	if (on) {
+		gpiod_set_value_cansleep(state->rst_gpio, 1);
+	} else {
+		gpiod_set_value_cansleep(state->rst_gpio, 0);
+		usleep_range(5000, 10000);
+	}
+}
+
 static int adv7180_set_power(struct adv7180_state *state, bool on)
 {
 	u8 val;
@@ -1263,6 +1277,7 @@ static int init_device(struct adv7180_state *state)
 	mutex_lock(&state->mutex);
 
 	adv7180_set_power_pin(state, true);
+	adv7180_set_reset_pin(state, false);
 
 	adv7180_write(state, ADV7180_REG_PWR_MAN, ADV7180_PWR_MAN_RES);
 	usleep_range(5000, 10000);
@@ -1338,6 +1353,14 @@ static int adv7180_probe(struct i2c_client *client,
 		return ret;
 	}
 
+	state->rst_gpio = devm_gpiod_get_optional(&client->dev, "reset",
+						  GPIOD_OUT_HIGH);
+	if (IS_ERR(state->rst_gpio)) {
+		ret = PTR_ERR(state->rst_gpio);
+		v4l_err(client, "request for reset pin failed: %d\n", ret);
+		return ret;
+	}
+
 	if (state->chip_info->flags & ADV7180_FLAG_MIPI_CSI2) {
 		state->csi_client = i2c_new_dummy_device(client->adapter,
 				ADV7180_DEFAULT_CSI_I2C_ADDR);
@@ -1428,6 +1451,7 @@ static int adv7180_remove(struct i2c_client *client)
 	i2c_unregister_device(state->vpp_client);
 	i2c_unregister_device(state->csi_client);
 
+	adv7180_set_reset_pin(state, true);
 	adv7180_set_power_pin(state, false);
 
 	mutex_destroy(&state->mutex);