media: i2c: ov5670: Probe GPIOs

The OV5670 has a powerdown and reset pin, named respectively "PWDN" and
"XSHUTDOWN".

Optionally probe the gpios connected to the pins during the driver probe
routine.
Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Luca Weiss <luca@z3ntu.xyz>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

drivers/media/i2c/ov5670.c

@@ -3,6 +3,7 @@
 
 #include <linux/acpi.h>
 #include <linux/clk.h>
+#include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
@@ -1848,6 +1849,10 @@ struct ov5670 {
 	/* Regulators */
 	struct regulator_bulk_data supplies[OV5670_NUM_SUPPLIES];
 
+	/* Power-down and reset gpios. */
+	struct gpio_desc *pwdn_gpio; /* PWDNB pin. */
+	struct gpio_desc *reset_gpio; /* XSHUTDOWN pin. */
+
 	/* To serialize asynchronus callbacks */
 	struct mutex mutex;
 
@@ -2500,6 +2505,23 @@ static int ov5670_regulators_probe(struct ov5670 *ov5670)
 				       ov5670->supplies);
 }
 
+static int ov5670_gpio_probe(struct ov5670 *ov5670)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&ov5670->sd);
+
+	ov5670->pwdn_gpio = devm_gpiod_get_optional(&client->dev, "powerdown",
+						    GPIOD_OUT_LOW);
+	if (IS_ERR(ov5670->pwdn_gpio))
+		return PTR_ERR(ov5670->pwdn_gpio);
+
+	ov5670->reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
+						     GPIOD_OUT_LOW);
+	if (IS_ERR(ov5670->reset_gpio))
+		return PTR_ERR(ov5670->reset_gpio);
+
+	return 0;
+}
+
 static int ov5670_probe(struct i2c_client *client)
 {
 	struct ov5670 *ov5670;
@@ -2540,6 +2562,12 @@ static int ov5670_probe(struct i2c_client *client)
 		goto error_print;
 	}
 
+	ret = ov5670_gpio_probe(ov5670);
+	if (ret) {
+		err_msg = "GPIO probe failed";
+		goto error_print;
+	}
+
 	full_power = acpi_dev_state_d0(&client->dev);
 	if (full_power) {
 		/* Check module identity */