linux-kernel - Re: [PATCH 2/2] media: ov7670: Add the s

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Date:   Tue, 15 Aug 2017 19:36:39 +0300
From:   Sakari Ailus <sakari.ailus@....fi>
To:     Wenyou Yang <wenyou.yang@...rochip.com>
Cc:     Jonathan Corbet <corbet@....net>,
        Nicolas Ferre <nicolas.ferre@...rochip.com>,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        Linux Media Mailing List <linux-media@...r.kernel.org>,
        Mauro Carvalho Chehab <mchehab@...pensource.com>
Subject: Re: [PATCH 2/2] media: ov7670: Add the s_power operation

Hi Wenyou,

On Thu, Aug 10, 2017 at 05:06:45PM +0800, Wenyou Yang wrote:
> Add the s_power operation which is responsible for manipulating the
> power dowm mode through the PWDN pin and the reset operation through
> the RESET pin.
> 
> Signed-off-by: Wenyou Yang <wenyou.yang@...rochip.com>
> ---
> 
>  drivers/media/i2c/ov7670.c | 30 +++++++++++++++++++++++++++---
>  1 file changed, 27 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/media/i2c/ov7670.c b/drivers/media/i2c/ov7670.c
> index 5c8460ee65c3..5ed79ccfaf91 100644
> --- a/drivers/media/i2c/ov7670.c
> +++ b/drivers/media/i2c/ov7670.c
> @@ -1506,6 +1506,22 @@ static int ov7670_s_register(struct v4l2_subdev *sd, const struct v4l2_dbg_regis
>  }
>  #endif
>  
> +static int ov7670_s_power(struct v4l2_subdev *sd, int on)
> +{
> +	struct ov7670_info *info = to_state(sd);
> +
> +	if (info->pwdn_gpio)
> +		gpiod_direction_output(info->pwdn_gpio, !on);

gpiod_direction_output() can cope with NULL gpio_desc.

> +	if (on && info->resetb_gpio) {
> +		gpiod_set_value(info->resetb_gpio, 1);
> +		usleep_range(500, 1000);
> +		gpiod_set_value(info->resetb_gpio, 0);
> +		usleep_range(3000, 5000);
> +	}
> +
> +	return 0;
> +}
> +
>  /* ----------------------------------------------------------------------- */
>  
>  static const struct v4l2_subdev_core_ops ov7670_core_ops = {
> @@ -1515,6 +1531,7 @@ static const struct v4l2_subdev_core_ops ov7670_core_ops = {
>  	.g_register = ov7670_g_register,
>  	.s_register = ov7670_s_register,
>  #endif
> +	.s_power = ov7670_s_power,
>  };
>  
>  static const struct v4l2_subdev_video_ops ov7670_video_ops = {
> @@ -1568,8 +1585,6 @@ static int ov7670_init_gpio(struct i2c_client *client, struct ov7670_info *info)
>  		return PTR_ERR(info->resetb_gpio);
>  	}
>  
> -	usleep_range(3000, 5000);
> -
>  	return 0;
>  }
>  
> @@ -1630,13 +1645,19 @@ static int ov7670_probe(struct i2c_client *client,
>  		goto clk_disable;
>  	}
>  
> +	ret = ov7670_init_gpio(client, info);

ov7670_init_gpio() is already called a few lines above this. Was this
intended?

> +	if (ret)
> +		goto clk_disable;
> +
> +	ov7670_s_power(sd, 1);
> +
>  	/* Make sure it's an ov7670 */
>  	ret = ov7670_detect(sd);
>  	if (ret) {
>  		v4l_dbg(1, debug, client,
>  			"chip found @ 0x%x (%s) is not an ov7670 chip.\n",
>  			client->addr << 1, client->adapter->name);
> -		goto clk_disable;
> +		goto power_off;
>  	}
>  	v4l_info(client, "chip found @ 0x%02x (%s)\n",
>  			client->addr << 1, client->adapter->name);
> @@ -1708,6 +1729,8 @@ static int ov7670_probe(struct i2c_client *client,
>  	media_entity_cleanup(&info->sd.entity);
>  hdl_free:
>  	v4l2_ctrl_handler_free(&info->hdl);
> +power_off:
> +	ov7670_s_power(sd, 0);
>  clk_disable:
>  	clk_disable_unprepare(info->clk);
>  	return ret;
> @@ -1723,6 +1746,7 @@ static int ov7670_remove(struct i2c_client *client)
>  	v4l2_ctrl_handler_free(&info->hdl);
>  	clk_disable_unprepare(info->clk);
>  	media_entity_cleanup(&info->sd.entity);
> +	ov7670_s_power(sd, 0);
>  	return 0;
>  }
>  

-- 
Sakari Ailus
e-mail: sakari.ailus@....fi