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 accomodate BT709 and BT2020 colorspace. (Uma Shankar) -Added spec details for the new cap for color conversion. (Uma Shankar)
Signed-off-by: Ankit Nautiyal ankit.k.nautiyal@intel.com Reviewed-by: Uma Shankar uma.shankar@intel.com --- drivers/gpu/drm/drm_dp_helper.c | 61 +++++++++++++++++++++++++++++++++ include/drm/drm_dp_helper.h | 19 +++++++++- 2 files changed, 79 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index 689fd0d5f6c5..9abd65c694ab 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -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); diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index baad87fe6b0a..e096ee98842b 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -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_ */