[Intel-gfx] [PATCH 5/9] drm/display/dp: Add helper function to get DSC bpp prescision

[Kandpal, Suraj]

> 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>
> ---
>  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 e6a78fd32380..aa8ea36211de 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;

Shouldn't there be a default MISSING_CASE to throw a warning if its none of the above case
Occurs in case a addition bit for step is added in dpcd going forward

Regards,
Suraj Kandpal

> +	}
> +
> +	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 86f24a759268..ba0514f0b032 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]);
> --
> 2.40.1