drm/bridge: dw-hdmi: set mtmdsclock for deep color

Configure the correct mtmdsclock for deep colors to prepare support
for 10, 12 & 16bit output.
Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Jernej Škrabec <jernej.skrabec@siol.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20200304104052.17196-2-narmstrong@baylibre.com

drivers/gpu/drm/bridge/synopsys/dw-hdmi.c

@@ -1814,13 +1814,32 @@ static void hdmi_av_composer(struct dw_hdmi *hdmi,
 	int hblank, vblank, h_de_hs, v_de_vs, hsync_len, vsync_len;
 	unsigned int vdisplay, hdisplay;
 
-	vmode->mtmdsclock = vmode->mpixelclock = mode->clock * 1000;
+	vmode->mpixelclock = mode->clock * 1000;
 
 	dev_dbg(hdmi->dev, "final pixclk = %d\n", vmode->mpixelclock);
 
+	vmode->mtmdsclock = vmode->mpixelclock;
+
+	if (!hdmi_bus_fmt_is_yuv422(hdmi->hdmi_data.enc_out_bus_format)) {
+		switch (hdmi_bus_fmt_color_depth(
+				hdmi->hdmi_data.enc_out_bus_format)) {
+		case 16:
+			vmode->mtmdsclock = vmode->mpixelclock * 2;
+			break;
+		case 12:
+			vmode->mtmdsclock = vmode->mpixelclock * 3 / 2;
+			break;
+		case 10:
+			vmode->mtmdsclock = vmode->mpixelclock * 5 / 4;
+			break;
+		}
+	}
+
 	if (hdmi_bus_fmt_is_yuv420(hdmi->hdmi_data.enc_out_bus_format))
 		vmode->mtmdsclock /= 2;
 
+	dev_dbg(hdmi->dev, "final tmdsclock = %d\n", vmode->mtmdsclock);
+
 	/* Set up HDMI_FC_INVIDCONF */
 	inv_val = (hdmi->hdmi_data.hdcp_enable ||
 		   (dw_hdmi_support_scdc(hdmi) &&