drm: bridge: dw_hdmi: Enable GCP only for Deep Color

HDMI1.4b specification section 6.5.3:
Source shall only send GCPs with non-zero CD to sinks
that indicate support for Deep Color.

DW HDMI GCP default enabled, but only transmit CD
and do not handle AVMUTE, PP norDefault_Phase (yet).
Disable Auto GCP when 24-bit color for sinks that not support Deep Color.

Signed-off-by: Sandor Yu <Sandor.yu@nxp.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/78fa41e4fb3d3d53354034bc221fcf870dbac617.1649989179.git.Sandor.yu@nxp.com

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
index c11782fc15016fd05fc510c8fdc396626b9ddcee..81f4c39fab8535d28a8414e138dbb54f45ea3f91 100644 (file)
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
@@ -1108,6 +1108,8 @@ static void hdmi_video_packetize(struct dw_hdmi *hdmi)
        unsigned int output_select = HDMI_VP_CONF_OUTPUT_SELECTOR_PP;
        struct hdmi_data_info *hdmi_data = &hdmi->hdmi_data;
        u8 val, vp_conf;
+       u8 clear_gcp_auto = 0;
+
 
        if (hdmi_bus_fmt_is_rgb(hdmi->hdmi_data.enc_out_bus_format) ||
            hdmi_bus_fmt_is_yuv444(hdmi->hdmi_data.enc_out_bus_format) ||
@@ -1117,6 +1119,7 @@ static void hdmi_video_packetize(struct dw_hdmi *hdmi)
                case 8:
                        color_depth = 4;
                        output_select = HDMI_VP_CONF_OUTPUT_SELECTOR_BYPASS;
+                       clear_gcp_auto = 1;
                        break;
                case 10:
                        color_depth = 5;
@@ -1136,6 +1139,7 @@ static void hdmi_video_packetize(struct dw_hdmi *hdmi)
                case 0:
                case 8:
                        remap_size = HDMI_VP_REMAP_YCC422_16bit;
+                       clear_gcp_auto = 1;
                        break;
                case 10:
                        remap_size = HDMI_VP_REMAP_YCC422_20bit;
@@ -1160,6 +1164,19 @@ static void hdmi_video_packetize(struct dw_hdmi *hdmi)
                HDMI_VP_PR_CD_DESIRED_PR_FACTOR_MASK);
        hdmi_writeb(hdmi, val, HDMI_VP_PR_CD);
 
+       /* HDMI1.4b specification section 6.5.3:
+        * Source shall only send GCPs with non-zero CD to sinks
+        * that indicate support for Deep Color.
+        * GCP only transmit CD and do not handle AVMUTE, PP norDefault_Phase (yet).
+        * Disable Auto GCP when 24-bit color for sinks that not support Deep Color.
+        */
+       val = hdmi_readb(hdmi, HDMI_FC_DATAUTO3);
+       if (clear_gcp_auto == 1)
+               val &= ~HDMI_FC_DATAUTO3_GCP_AUTO;
+       else
+               val |= HDMI_FC_DATAUTO3_GCP_AUTO;
+       hdmi_writeb(hdmi, val, HDMI_FC_DATAUTO3);
+
        hdmi_modb(hdmi, HDMI_VP_STUFF_PR_STUFFING_STUFFING_MODE,
                  HDMI_VP_STUFF_PR_STUFFING_MASK, HDMI_VP_STUFF);
 

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.h b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.h
index 1999db05bc3b267b10934fb24a9ffd7830fd88dc..18df3e11955308636f45df88a57cb4d0a56fc973 100644 (file)
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.h
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.h
@@ -850,6 +850,9 @@ enum {
        HDMI_FC_DATAUTO0_VSD_MASK = 0x08,
        HDMI_FC_DATAUTO0_VSD_OFFSET = 3,
 
+/* FC_DATAUTO3 field values */
+       HDMI_FC_DATAUTO3_GCP_AUTO = 0x04,
+
 /* PHY_CONF0 field values */
        HDMI_PHY_CONF0_PDZ_MASK = 0x80,
        HDMI_PHY_CONF0_PDZ_OFFSET = 7,