[PATCH 2/3] media: i2c: adv7180: Allow the control of the reset pin

[Fabio Estevam <festevam@gmail.com>]

On a design where the ADV7180 pin is pulled down, it is not possible
to make it functional unless the GPIO connected to this pin goes
high.

Add support for the reset GPIO by introducing an optional property
called 'reset-gpios'.

Note: the reset operation is still performed via software as recommended
by the Analog Devices, but the reset GPIO still needs to go high to make
the chip operational.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
---
 drivers/media/i2c/adv7180.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/media/i2c/adv7180.c b/drivers/media/i2c/adv7180.c
index 44bb6fe85644..2811f2c337fa 100644
--- a/drivers/media/i2c/adv7180.c
+++ b/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	*reset_gpio;
 	v4l2_std_id		curr_norm;
 	bool			powered;
 	bool			streaming;
@@ -473,13 +474,15 @@ static int adv7180_g_frame_interval(struct v4l2_subdev *sd,
 
 static void adv7180_set_power_pin(struct adv7180_state *state, bool on)
 {
-	if (!state->pwdn_gpio)
+	if (!state->pwdn_gpio && !state->reset_gpio)
 		return;
 
 	if (on) {
+		gpiod_set_value_cansleep(state->reset_gpio, 0);
 		gpiod_set_value_cansleep(state->pwdn_gpio, 0);
 		usleep_range(5000, 10000);
 	} else {
+		gpiod_set_value_cansleep(state->reset_gpio, 1);
 		gpiod_set_value_cansleep(state->pwdn_gpio, 1);
 	}
 }
@@ -1338,6 +1341,15 @@ static int adv7180_probe(struct i2c_client *client,
 		return ret;
 	}
 
+	state->reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
+						     GPIOD_OUT_HIGH);
+	if (IS_ERR(state->reset_gpio)) {
+		ret = PTR_ERR(state->reset_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);
-- 
2.25.1