media: i2c: og01a1b: Add management of optional reset GPIO

Omnivision OG01A1B camera sensor may have a connected active low GPIO
to XSHUTDOWN pad, and if so, include it into sensor power up sequence.

Signed-off-by: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

Author: Vladimir Zapolskiy

drivers/media/i2c/og01a1b.c

@@ -5,6 +5,7 @@
 #include <linux/acpi.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
+#include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
 #include <linux/pm_runtime.h>
@@ -420,6 +421,7 @@ static const struct og01a1b_mode supported_modes[] = {
 
 struct og01a1b {
 	struct clk *xvclk;
+	struct gpio_desc *reset_gpio;
 
 	struct v4l2_subdev sd;
 	struct media_pad pad;
@@ -987,7 +989,11 @@ static int og01a1b_power_on(struct device *dev)
 	if (ret)
 		return ret;
 
-	if (og01a1b->xvclk)
+	gpiod_set_value_cansleep(og01a1b->reset_gpio, 0);
+
+	if (og01a1b->reset_gpio)
+		usleep_range(5 * USEC_PER_MSEC, 6 * USEC_PER_MSEC);
+	else if (og01a1b->xvclk)
 		usleep_range(delay, 2 * delay);
 
 	return 0;
@@ -1004,6 +1010,8 @@ static int og01a1b_power_off(struct device *dev)
 
 	clk_disable_unprepare(og01a1b->xvclk);
 
+	gpiod_set_value_cansleep(og01a1b->reset_gpio, 1);
+
 	return 0;
 }
 
@@ -1044,6 +1052,13 @@ static int og01a1b_probe(struct i2c_client *client)
 		return ret;
 	}
 
+	og01a1b->reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
+						      GPIOD_OUT_LOW);
+	if (IS_ERR(og01a1b->reset_gpio)) {
+		dev_err(&client->dev, "cannot get reset GPIO\n");
+		return PTR_ERR(og01a1b->reset_gpio);
+	}
+
 	/* The sensor must be powered on to read the CHIP_ID register */
 	ret = og01a1b_power_on(&client->dev);
 	if (ret)