Re: [PATCH 7/9] drm/vc4: hdmi: Add a function to retrieve the CSC matrix

[Thomas Zimmermann]

Hi

Am 07.12.22 um 17:07 schrieb Maxime Ripard:
> From: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
>
> The CSC matrix to use depends on the output format, its range and the
> colorspace.
>
> Since we're going to add more colorspaces, let's move the CSC matrix
> retrieval to a function.
>
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> Signed-off-by: Maxime Ripard <maxime@xxxxxxxxxx>

Reviewed-by: Thomas Zimmermann <tzimmermann@xxxxxxx>

> ---
>   drivers/gpu/drm/vc4/vc4_hdmi.c | 26 +++++++++++++++++++++++---
>   1 file changed, 23 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
> index cb92d07680f0..cd6775429b5e 100644
> --- a/drivers/gpu/drm/vc4/vc4_hdmi.c
> +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
> @@ -1273,6 +1273,20 @@ static void vc5_hdmi_set_csc_coeffs_swap(struct vc4_hdmi *vc4_hdmi,
>   	HDMI_WRITE(HDMI_CSC_34_33, (coeffs[1][3] << 16) | coeffs[1][2]);
>   }
>   
> +static const u16
> +(*vc5_hdmi_get_yuv_csc_coeffs(struct vc4_hdmi *vc4_hdmi, u32 colorspace, bool limited))[4]

I don't like the function name here. The helper 
vc5_hdmi_set_csc_coeffs() programs hardware, but this similarly named 
helper looks up static data.

Best regards
Thomas

> +{
> +	switch (colorspace) {
> +	default:
> +	case DRM_MODE_COLORIMETRY_NO_DATA:
> +	case DRM_MODE_COLORIMETRY_BT709_YCC:
> +	case DRM_MODE_COLORIMETRY_XVYCC_709:
> +	case DRM_MODE_COLORIMETRY_RGB_WIDE_FIXED:
> +	case DRM_MODE_COLORIMETRY_RGB_WIDE_FLOAT:
> +		return vc5_hdmi_csc_full_rgb_to_yuv_bt709[limited];
> +	}
> +}
> +
>   static void vc5_hdmi_csc_setup(struct vc4_hdmi *vc4_hdmi,
>   			       struct drm_connector_state *state,
>   			       const struct drm_display_mode *mode)
> @@ -1282,6 +1296,7 @@ static void vc5_hdmi_csc_setup(struct vc4_hdmi *vc4_hdmi,
>   		conn_state_to_vc4_hdmi_conn_state(state);
>   	unsigned int lim_range = vc4_hdmi_is_full_range(vc4_hdmi, mode) ? 0 : 1;
>   	unsigned long flags;
> +	const u16 (*csc)[4];
>   	u32 if_cfg = 0;
>   	u32 if_xbar = 0x543210;
>   	u32 csc_chan_ctl = 0;
> @@ -1296,11 +1311,16 @@ static void vc5_hdmi_csc_setup(struct vc4_hdmi *vc4_hdmi,
>   
>   	switch (vc4_state->output_format) {
>   	case VC4_HDMI_OUTPUT_YUV444:
> -		vc5_hdmi_set_csc_coeffs_swap(vc4_hdmi,
> -					     vc5_hdmi_csc_full_rgb_to_yuv_bt709[lim_range]);
> +		csc = vc5_hdmi_get_yuv_csc_coeffs(vc4_hdmi, state->colorspace,
> +						  vc4_hdmi_is_full_range(vc4_hdmi, mode));
> +
> +		vc5_hdmi_set_csc_coeffs_swap(vc4_hdmi, csc);
>   		break;
>   
>   	case VC4_HDMI_OUTPUT_YUV422:
> +		csc = vc5_hdmi_get_yuv_csc_coeffs(vc4_hdmi, state->colorspace,
> +						  vc4_hdmi_is_full_range(vc4_hdmi, mode));
> +
>   		csc_ctl |= VC4_SET_FIELD(VC5_MT_CP_CSC_CTL_FILTER_MODE_444_TO_422_STANDARD,
>   					 VC5_MT_CP_CSC_CTL_FILTER_MODE_444_TO_422) |
>   			VC5_MT_CP_CSC_CTL_USE_444_TO_422 |
> @@ -1312,7 +1332,7 @@ static void vc5_hdmi_csc_setup(struct vc4_hdmi *vc4_hdmi,
>   		if_cfg |= VC4_SET_FIELD(VC5_DVP_HT_VEC_INTERFACE_CFG_SEL_422_FORMAT_422_LEGACY,
>   					VC5_DVP_HT_VEC_INTERFACE_CFG_SEL_422);
>   
> -		vc5_hdmi_set_csc_coeffs(vc4_hdmi, vc5_hdmi_csc_full_rgb_to_yuv_bt709[lim_range]);
> +		vc5_hdmi_set_csc_coeffs(vc4_hdmi, csc);
>   		break;
>   
>   	case VC4_HDMI_OUTPUT_RGB:

--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev

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