Commit 07c9b863 authored by Ankit Nautiyal's avatar Ankit Nautiyal Committed by Jani Nikula
Browse files

drm/dp_helper: Add helpers to configure PCONs RGB-YCbCr Conversion 

DP Specification for DP2.0 to HDMI2.1 Pcon specifies support for conversion
of colorspace from RGB to YCbCr.
https://groups.vesa.org/wg/DP/document/previewpdf/15651



This patch adds the relavant registers and helper functions to
get the capability and set the color conversion bits for rgb->ycbcr
conversion through PCON.

v2: As suggested in review comments:
-Fixed bug in the check condition in a drm_helper as reported by
 Dan Carpenter and Kernel test robot. (Dan Carepenter)
-Modified the color-conversion cap helper function, to accommodate
 BT709 and BT2020 colorspace. (Uma Shankar)
-Added spec details for the new cap for color conversion. (Uma Shankar)

Signed-off-by: default avatarAnkit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: default avatarUma Shankar <uma.shankar@intel.com>
Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201218103723.30844-8-ankit.k.nautiyal@intel.com
parent e2e16da3

drivers/gpu/drm/drm_dp_helper.c

+61 −0
Original line number Diff line number Diff line
@@ -949,6 +949,38 @@ bool drm_dp_downstream_444_to_420_conversion(const u8 dpcd[DP_RECEIVER_CAP_SIZE] 
}

EXPORT_SYMBOL(drm_dp_downstream_444_to_420_conversion);



/**

 * drm_dp_downstream_rgb_to_ycbcr_conversion() - determine downstream facing port

 *                                               RGB->YCbCr conversion capability

 * @dpcd: DisplayPort configuration data

 * @port_cap: downstream facing port capabilities

 * @colorspc: Colorspace for which conversion cap is sought

 *

 * Returns: whether the downstream facing port can convert RGB->YCbCr for a given

 * colorspace.

 */

bool drm_dp_downstream_rgb_to_ycbcr_conversion(const u8 dpcd[DP_RECEIVER_CAP_SIZE],

					       const u8 port_cap[4],

					       u8 color_spc)

{

	if (!drm_dp_is_branch(dpcd))

		return false;



	if (dpcd[DP_DPCD_REV] < 0x13)

		return false;



	switch (port_cap[0] & DP_DS_PORT_TYPE_MASK) {

	case DP_DS_PORT_TYPE_HDMI:

		if ((dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DETAILED_CAP_INFO_AVAILABLE) == 0)

			return false;



		return port_cap[3] & color_spc;

	default:

		return false;

	}

}

EXPORT_SYMBOL(drm_dp_downstream_rgb_to_ycbcr_conversion);



/**

 * drm_dp_downstream_mode() - return a mode for downstream facing port

 * @dev: DRM device
@@ -3101,3 +3133,32 @@ int drm_dp_pcon_pps_override_param(struct drm_dp_aux *aux, u8 pps_param[6]) 
	return 0;

}

EXPORT_SYMBOL(drm_dp_pcon_pps_override_param);



/*

 * drm_dp_pcon_convert_rgb_to_ycbcr() - Configure the PCon to convert RGB to Ycbcr

 * @aux: displayPort AUX channel

 * @color_spc: Color-space/s for which conversion is to be enabled, 0 for disable.

 *

 * Returns 0 on success, else returns negative error code.

 */

int drm_dp_pcon_convert_rgb_to_ycbcr(struct drm_dp_aux *aux, u8 color_spc)

{

	int ret;

	u8 buf;



	ret = drm_dp_dpcd_readb(aux, DP_PROTOCOL_CONVERTER_CONTROL_2, &buf);

	if (ret < 0)

		return ret;



	if (color_spc & DP_CONVERSION_RGB_YCBCR_MASK)

		buf |= (color_spc & DP_CONVERSION_RGB_YCBCR_MASK);

	else

		buf &= ~DP_CONVERSION_RGB_YCBCR_MASK;



	ret = drm_dp_dpcd_writeb(aux, DP_PROTOCOL_CONVERTER_CONTROL_2, buf);

	if (ret < 0)

		return ret;



	return 0;

}

EXPORT_SYMBOL(drm_dp_pcon_convert_rgb_to_ycbcr);

include/drm/drm_dp_helper.h

+18 −1
Original line number Diff line number Diff line
@@ -432,6 +432,17 @@ struct drm_device; 
# define DP_DS_HDMI_YCBCR444_TO_422_CONV    (1 << 3)

# define DP_DS_HDMI_YCBCR444_TO_420_CONV    (1 << 4)



/*

 * VESA DP-to-HDMI PCON Specification adds caps for colorspace

 * conversion in DFP cap DPCD 83h. Sec6.1 Table-3.

 * Based on the available support the source can enable

 * color conversion by writing into PROTOCOL_COVERTER_CONTROL_2

 * DPCD 3052h.

 */

# define DP_DS_HDMI_BT601_RGB_YCBCR_CONV    (1 << 5)

# define DP_DS_HDMI_BT709_RGB_YCBCR_CONV    (1 << 6)

# define DP_DS_HDMI_BT2020_RGB_YCBCR_CONV   (1 << 7)



#define DP_MAX_DOWNSTREAM_PORTS		    0x10



/* DP Forward error Correction Registers */
@@ -1207,7 +1218,10 @@ struct drm_device; 
# define DP_PCON_ENC_PPS_OVERRIDE_DISABLED      0

# define DP_PCON_ENC_PPS_OVERRIDE_EN_PARAMS     1

# define DP_PCON_ENC_PPS_OVERRIDE_EN_BUFFER     2



# define DP_CONVERSION_RGB_YCBCR_MASK	       (7 << 4)

# define DP_CONVERSION_BT601_RGB_YCBCR_ENABLE  (1 << 4)

# define DP_CONVERSION_BT709_RGB_YCBCR_ENABLE  (1 << 5)

# define DP_CONVERSION_BT2020_RGB_YCBCR_ENABLE (1 << 6)



/* PCON Downstream HDMI ERROR Status per Lane */

#define DP_PCON_HDMI_ERROR_STATUS_LN0          0x3037
@@ -2167,5 +2181,8 @@ int drm_dp_pcon_dsc_bpp_incr(const u8 pcon_dsc_dpcd[DP_PCON_DSC_ENCODER_CAP_SIZE 
int drm_dp_pcon_pps_default(struct drm_dp_aux *aux);

int drm_dp_pcon_pps_override_buf(struct drm_dp_aux *aux, u8 pps_buf[128]);

int drm_dp_pcon_pps_override_param(struct drm_dp_aux *aux, u8 pps_param[6]);

bool drm_dp_downstream_rgb_to_ycbcr_conversion(const u8 dpcd[DP_RECEIVER_CAP_SIZE],

					       const u8 port_cap[4], u8 color_spc);

int drm_dp_pcon_convert_rgb_to_ycbcr(struct drm_dp_aux *aux, u8 color_spc);



#endif /* _DRM_DP_HELPER_H_ */