Re: [PATCH 1/1] mt9v032: Provide pixel rate control

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Sakari,

Thanks for the patch.

On Thursday 15 March 2012 23:01:39 Sakari Ailus wrote:
> Provide pixel rate control calculated from external clock and horizontal
> binning factor.
> 
> Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
> ---
>  drivers/media/video/mt9v032.c |   35 ++++++++++++++++++++++++++++++++++-
>  1 files changed, 34 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/media/video/mt9v032.c b/drivers/media/video/mt9v032.c
> index 75e253a..e530e8d 100644
> --- a/drivers/media/video/mt9v032.c
> +++ b/drivers/media/video/mt9v032.c
> @@ -122,6 +122,7 @@ struct mt9v032 {
>  	struct v4l2_mbus_framefmt format;
>  	struct v4l2_rect crop;
> 
> +	struct v4l2_ctrl *pixel_rate;
>  	struct v4l2_ctrl_handler ctrls;
> 
>  	struct mutex power_lock;
> @@ -187,13 +188,15 @@ mt9v032_update_aec_agc(struct mt9v032 *mt9v032, u16
> which, int enable) return 0;
>  }
> 
> +#define EXT_CLK		25000000
> +
>  static int mt9v032_power_on(struct mt9v032 *mt9v032)
>  {
>  	struct i2c_client *client = v4l2_get_subdevdata(&mt9v032->subdev);
>  	int ret;
> 
>  	if (mt9v032->pdata->set_clock) {
> -		mt9v032->pdata->set_clock(&mt9v032->subdev, 25000000);
> +		mt9v032->pdata->set_clock(&mt9v032->subdev, EXT_CLK);
>  		udelay(1);
>  	}
> 
> @@ -365,6 +368,27 @@ static int mt9v032_get_format(struct v4l2_subdev
> *subdev, return 0;
>  }
> 
> +static void mt9v032_configure_pixel_rate(struct v4l2_subdev *subdev,
> +					 unsigned int hratio)
> +{
> +	struct i2c_client *client = v4l2_get_subdevdata(subdev);
> +	struct mt9v032 *mt9v032 = to_mt9v032(subdev);
> +	struct v4l2_ext_controls ctrls;
> +	struct v4l2_ext_control ctrl;
> +
> +	memset(&ctrls, 0, sizeof(ctrls));
> +	memset(&ctrl, 0, sizeof(ctrl));
> +
> +	ctrls.count = 1;
> +	ctrls.controls = &ctrl;
> +
> +	ctrl.id = V4L2_CID_PIXEL_RATE;
> +	ctrl.value64 = EXT_CLK / hratio;
> +
> +	if (v4l2_s_ext_ctrls(mt9v032->pixel_rate->ctrl_handler, &ctrls) < 0)
> +		dev_warn(&client->dev, "bug: failed to set pixel rate\n");

What about just calling v4l2_ctrl_s_ctrl() ?

> +}
> +
>  static int mt9v032_set_format(struct v4l2_subdev *subdev,
>  			      struct v4l2_subdev_fh *fh,
>  			      struct v4l2_subdev_format *format)
> @@ -395,6 +419,8 @@ static int mt9v032_set_format(struct v4l2_subdev
> *subdev, format->which);
>  	__format->width = __crop->width / hratio;
>  	__format->height = __crop->height / vratio;
> +	if (format->which == V4L2_SUBDEV_FORMAT_ACTIVE)
> +		mt9v032_configure_pixel_rate(subdev, hratio);
> 
>  	format->format = *__format;
> 
> @@ -450,6 +476,8 @@ static int mt9v032_set_crop(struct v4l2_subdev *subdev,
>  						    crop->which);
>  		__format->width = rect.width;
>  		__format->height = rect.height;
> +		if (format->which == V4L2_SUBDEV_FORMAT_ACTIVE)
> +			mt9v032_configure_pixel_rate(subdev, 1);
>  	}
> 
>  	*__crop = rect;
> @@ -695,6 +723,9 @@ static int mt9v032_probe(struct i2c_client *client,
>  			  V4L2_CID_EXPOSURE, MT9V032_TOTAL_SHUTTER_WIDTH_MIN,
>  			  MT9V032_TOTAL_SHUTTER_WIDTH_MAX, 1,
>  			  MT9V032_TOTAL_SHUTTER_WIDTH_DEF);
> +	mt9v032->pixel_rate =
> +		v4l2_ctrl_new_std(&mt9v032->ctrls, &mt9v032_ctrl_ops,
> +				  V4L2_CID_PIXEL_RATE, 0, 0, 1, 0);

Shouldn't you set the bounds to [EXT_CLK/4..EXT_CLK] ? Otherwise the set 
control call will likely fail. We probably need a new control framework 
function to modify the bounds.

> 
>  	for (i = 0; i < ARRAY_SIZE(mt9v032_ctrls); ++i)
>  		v4l2_ctrl_new_custom(&mt9v032->ctrls, &mt9v032_ctrls[i], NULL);
> @@ -716,6 +747,8 @@ static int mt9v032_probe(struct i2c_client *client,
>  	mt9v032->format.field = V4L2_FIELD_NONE;
>  	mt9v032->format.colorspace = V4L2_COLORSPACE_SRGB;
> 
> +	mt9v032_configure_pixel_rate(subdev, 1);
> +

You could just initialize the control value to EXT_CLK when creating the 
control.

>  	mt9v032->aec_agc = MT9V032_AEC_ENABLE | MT9V032_AGC_ENABLE;
> 
>  	v4l2_i2c_subdev_init(&mt9v032->subdev, client, &mt9v032_subdev_ops);

-- 
Regards,

Laurent Pinchart