Re: [PATCH v2 5/6] media: i2c: adv748x: Implement get_mbus_config

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

Hi Jacopo,

Thank you for the patch.

On Wed, Apr 15, 2020 at 12:50:02PM +0200, Jacopo Mondi wrote:
> Implement the newly introduced get_mbus_config operation to report the
> number of currently used data lanes on the MIPI CSI-2 interface.
> 
> Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
> Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> ---
>  drivers/media/i2c/adv748x/adv748x-csi2.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/drivers/media/i2c/adv748x/adv748x-csi2.c b/drivers/media/i2c/adv748x/adv748x-csi2.c
> index 2091cda50935..f13563da3ff3 100644
> --- a/drivers/media/i2c/adv748x/adv748x-csi2.c
> +++ b/drivers/media/i2c/adv748x/adv748x-csi2.c
> @@ -214,9 +214,24 @@ static int adv748x_csi2_set_format(struct v4l2_subdev *sd,
>  	return ret;
>  }
>  
> +static int adv748x_csi2_get_mbus_config(struct v4l2_subdev *sd, unsigned int pad,
> +					struct v4l2_mbus_pad_config *config)
> +{
> +	struct adv748x_csi2 *tx = adv748x_sd_to_csi2(sd);
> +
> +	if (pad != ADV748X_CSI2_SOURCE)
> +		return -EINVAL;
> +
> +	config->type = V4L2_MBUS_CSI2_DPHY;
> +	config->csi2_dphy.data_lanes = tx->active_lanes;
> +
> +	return 0;

This looks fine, but raises a few questions whose answers need to be
documented in 1/6 I think.

- Is the caller expected to zero the config struct ?
- What are the allowed returned values for this operation, and under
  what circumstances ?

These are generic questions for the API. For this patch,

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> +}
> +
>  static const struct v4l2_subdev_pad_ops adv748x_csi2_pad_ops = {
>  	.get_fmt = adv748x_csi2_get_format,
>  	.set_fmt = adv748x_csi2_set_format,
> +	.get_mbus_config = adv748x_csi2_get_mbus_config,
>  };
>  
>  /* -----------------------------------------------------------------------------

-- 
Regards,

Laurent Pinchart