linux-kernel - Re: [PATCH v5 3/3] media: ov7670: Add the s

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Message-ID: <20170919073643.szwwdmff6cp2v2fn@valkosipuli.retiisi.org.uk>
Date:   Tue, 19 Sep 2017 10:36:43 +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 v5 3/3] media: ov7670: Add the s_power operation

Hi Wenyou,

On Tue, Sep 19, 2017 at 08:45:09AM +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.

This is still broken: accessing controls through the sub-device node won't
work when the device is powered off. The options are what I suggested the
previous time: keep it powered at all times, fix it or convert to runtime
PM.

> 
> Signed-off-by: Wenyou Yang <wenyou.yang@...rochip.com>
> ---
> 
> Changes in v5: None
> Changes in v4: None
> Changes in v3: None
> Changes in v2:
>  - Add the patch to support the get_fmt ops.
>  - Remove the redundant invoking ov7670_init_gpio().
> 
>  drivers/media/i2c/ov7670.c | 32 +++++++++++++++++++++++++++-----
>  1 file changed, 27 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/media/i2c/ov7670.c b/drivers/media/i2c/ov7670.c
> index 73ceec63a8ca..8e86479d8a24 100644
> --- a/drivers/media/i2c/ov7670.c
> +++ b/drivers/media/i2c/ov7670.c
> @@ -1544,6 +1544,22 @@ 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);
> +	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 void ov7670_get_default_format(struct v4l2_subdev *sd,
>  				      struct v4l2_mbus_framefmt *format)
>  {
> @@ -1577,6 +1593,7 @@ 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 = {
> @@ -1694,23 +1711,25 @@ static int ov7670_probe(struct i2c_client *client,
>  	if (ret)
>  		return ret;
>  
> -	ret = ov7670_init_gpio(client, info);
> -	if (ret)
> -		goto clk_disable;
> -
>  	info->clock_speed = clk_get_rate(info->clk) / 1000000;
>  	if (info->clock_speed < 10 || info->clock_speed > 48) {
>  		ret = -EINVAL;
>  		goto clk_disable;
>  	}
>  
> +	ret = ov7670_init_gpio(client, info);
> +	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);
> @@ -1789,6 +1808,8 @@ static int ov7670_probe(struct i2c_client *client,
>  #endif
>  hdl_free:
>  	v4l2_ctrl_handler_free(&info->hdl);
> +power_off:
> +	ov7670_s_power(sd, 0);
>  clk_disable:
>  	clk_disable_unprepare(info->clk);
>  	return ret;
> @@ -1806,6 +1827,7 @@ static int ov7670_remove(struct i2c_client *client)
>  #if defined(CONFIG_MEDIA_CONTROLLER)
>  	media_entity_cleanup(&info->sd.entity);
>  #endif
> +	ov7670_s_power(sd, 0);
>  	return 0;
>  }
>  
> -- 
> 2.13.0
> 

-- 
Regards,

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