Hi,

On Monday 14 December 2015 21:26:25 Laurent Pinchart wrote:

Hi Markus,

Thank you for the patch.

On Monday 14 December 2015 15:41:51 Markus Pargmann wrote:

quoted

Add optional reset and standby gpios. The reset gpio is used to reset
the chip in power_on().

The standby gpio is not used currently. It is just unset, so the chip is
not in standby.

Signed-off-by: Markus Pargmann <redacted>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Rob Herring <robh@kernel.org>
---
 .../devicetree/bindings/media/i2c/mt9v032.txt      |  2 ++
 drivers/media/i2c/mt9v032.c                        | 28 +++++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/Documentation/devicetree/bindings/media/i2c/mt9v032.txt

b/Documentation/devicetree/bindings/media/i2c/mt9v032.txt index
202565313e82..100f0ae43269 100644

--- a/Documentation/devicetree/bindings/media/i2c/mt9v032.txt
+++ b/Documentation/devicetree/bindings/media/i2c/mt9v032.txt

@@ -20,6 +20,8 @@ Optional Properties:

 - link-frequencies: List of allowed link frequencies in Hz. Each frequency

is expressed as a 64-bit big-endian integer.
+- reset-gpios: GPIO handle which is connected to the reset pin of the chip.
+- standby-gpios: GPIO handle which is connected to the standby pin of the
chip.

 For further reading on port node refer to
 Documentation/devicetree/bindings/media/video-interfaces.txt.

diff --git a/drivers/media/i2c/mt9v032.c b/drivers/media/i2c/mt9v032.c
index a68ce94ee097..c1bc564a0979 100644
--- a/drivers/media/i2c/mt9v032.c
+++ b/drivers/media/i2c/mt9v032.c

@@ -14,6 +14,7 @@

 #include <linux/clk.h>
 #include <linux/delay.h>
+#include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
 #include <linux/log2.h>
 #include <linux/mutex.h>

@@ -251,6 +252,8 @@ struct mt9v032 {

 	struct regmap *regmap;
 	struct clk *clk;
+	struct gpio_desc *reset_gpio;
+	struct gpio_desc *standby_gpio;

 	struct mt9v032_platform_data *pdata;
 	const struct mt9v032_model_info *model;

@@ -312,16 +315,31 @@ static int mt9v032_power_on(struct mt9v032 *mt9v032)
 	struct regmap *map = mt9v032->regmap;
 	int ret;

+	if (mt9v032->reset_gpio)
+		gpiod_set_value_cansleep(mt9v032->reset_gpio, 1);
+

gpiod_set_value_cansleep() already checks whether the gpiod is NULL, you don't 
need to duplicate the check here.

Apart from that,

Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

No need to resubmit I'll fix this when applying.

Ok, thank you.

Best Regards,

Markus

quoted

 	ret = clk_set_rate(mt9v032->clk, mt9v032->sysclk);
 	if (ret < 0)
 		return ret;

+	/* System clock has to be enabled before releasing the reset */
 	ret = clk_prepare_enable(mt9v032->clk);
 	if (ret)
 		return ret;

 	udelay(1);

+	if (mt9v032->reset_gpio) {
+		gpiod_set_value_cansleep(mt9v032->reset_gpio, 0);
+
+		/* After releasing reset we need to wait 10 clock cycles
+		 * before accessing the sensor over I2C. As the minimum SYSCLK
+		 * frequency is 13MHz, waiting 1µs will be enough in the worst
+		 * case.
+		 */
+		udelay(1);
+	}
+
 	/* Reset the chip and stop data read out */
 	ret = regmap_write(map, MT9V032_RESET, 1);
 	if (ret < 0)

@@ -954,6 +972,16 @@ static int mt9v032_probe(struct i2c_client *client,
 	if (IS_ERR(mt9v032->clk))
 		return PTR_ERR(mt9v032->clk);

+	mt9v032->reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
+						      GPIOD_OUT_HIGH);
+	if (IS_ERR(mt9v032->reset_gpio))
+		return PTR_ERR(mt9v032->reset_gpio);
+
+	mt9v032->standby_gpio = devm_gpiod_get_optional(&client->dev, "standby",
+							GPIOD_OUT_LOW);
+	if (IS_ERR(mt9v032->standby_gpio))
+		return PTR_ERR(mt9v032->standby_gpio);
+
 	mutex_init(&mt9v032->power_lock);
 	mt9v032->pdata = pdata;
 	mt9v032->model = (const void *)did->driver_data;

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