Re: [PATCH v2 1/3] [media] mt9v032: Add reset and standby gpios

[Markus Pargmann <mpa@pengutronix.de>]

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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:
> > 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 <mpa@pengutronix.de>
> > 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

> 
> >  	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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