[1/8] drm/display/dp: Add helper function to get DSC bpp prescision

[Sui Jingfeng]

Hi,


The word 'prescision' in the commit title is a typo,
perhaps it's more better correct it as 'precision' when merge.


On 2023/9/13 14:05, Mitul Golani wrote:
> From: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
>
> Add helper to get the DSC bits_per_pixel precision for the DP sink.
>
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
> Reviewed-by: Suraj Kandpal <suraj.kandpal at intel.com>
> ---
>   drivers/gpu/drm/display/drm_dp_helper.c | 27 +++++++++++++++++++++++++
>   include/drm/display/drm_dp_helper.h     |  1 +
>   2 files changed, 28 insertions(+)
>
> diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c
> index 8a1b64c57dfd..5c23d5b8fc50 100644
> --- a/drivers/gpu/drm/display/drm_dp_helper.c
> +++ b/drivers/gpu/drm/display/drm_dp_helper.c
> @@ -2323,6 +2323,33 @@ int drm_dp_read_desc(struct drm_dp_aux *aux, struct drm_dp_desc *desc,
>   }
>   EXPORT_SYMBOL(drm_dp_read_desc);
>   
> +/**
> + * drm_dp_dsc_sink_bpp_incr() - Get bits per pixel increment
> + * @dsc_dpcd: DSC capabilities from DPCD
> + *
> + * Returns the bpp precision supported by the DP sink.
> + */
> +u8 drm_dp_dsc_sink_bpp_incr(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE])
> +{
> +	u8 bpp_increment_dpcd = dsc_dpcd[DP_DSC_BITS_PER_PIXEL_INC - DP_DSC_SUPPORT];
> +
> +	switch (bpp_increment_dpcd) {
> +	case DP_DSC_BITS_PER_PIXEL_1_16:
> +		return 16;
> +	case DP_DSC_BITS_PER_PIXEL_1_8:
> +		return 8;
> +	case DP_DSC_BITS_PER_PIXEL_1_4:
> +		return 4;
> +	case DP_DSC_BITS_PER_PIXEL_1_2:
> +		return 2;
> +	case DP_DSC_BITS_PER_PIXEL_1_1:
> +		return 1;
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(drm_dp_dsc_sink_bpp_incr);
> +
>   /**
>    * drm_dp_dsc_sink_max_slice_count() - Get the max slice count
>    * supported by the DSC sink.
> diff --git a/include/drm/display/drm_dp_helper.h b/include/drm/display/drm_dp_helper.h
> index 3369104e2d25..6968d4d87931 100644
> --- a/include/drm/display/drm_dp_helper.h
> +++ b/include/drm/display/drm_dp_helper.h
> @@ -164,6 +164,7 @@ drm_dp_is_branch(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
>   }
>   
>   /* DP/eDP DSC support */
> +u8 drm_dp_dsc_sink_bpp_incr(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE]);
>   u8 drm_dp_dsc_sink_max_slice_count(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE],
>   				   bool is_edp);
>   u8 drm_dp_dsc_sink_line_buf_depth(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE]);