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 <m...@pengutronix.de>
Reviewed-by: Philipp Zabel <p.za...@pengutronix.de>
---
 .../devicetree/bindings/media/i2c/mt9v032.txt      |  2 ++
 drivers/media/i2c/mt9v032.c                        | 23 ++++++++++++++++++++++
 2 files changed, 25 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..4aefde9634f5 100644
--- a/drivers/media/i2c/mt9v032.c
+++ b/drivers/media/i2c/mt9v032.c
@@ -24,6 +24,7 @@
 #include <linux/videodev2.h>
 #include <linux/v4l2-mediabus.h>
 #include <linux/module.h>
+#include <linux/gpio/consumer.h>
 
 #include <media/mt9v032.h>
 #include <media/v4l2-ctrls.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 +315,26 @@ static int mt9v032_power_on(struct mt9v032 *mt9v032)
        struct regmap *map = mt9v032->regmap;
        int ret;
 
+       gpiod_set_value_cansleep(mt9v032->reset_gpio, 1);
+
        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);
 
+       gpiod_set_value_cansleep(mt9v032->reset_gpio, 0);
+
+       /*
+        * After releasing reset, it can take up to 1us until the chip is done
+        */
+       udelay(1);
+
        /* Reset the chip and stop data read out */
        ret = regmap_write(map, MT9V032_RESET, 1);
        if (ret < 0)
@@ -954,6 +967,16 @@ 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;
-- 
2.6.1

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