[PATCH v3 03/12] drm: Read DPCD receiver capability for DP to DVI converter

[Mika Kahola]

Read from DPCD receiver capability field for the following
features:
 - max TMDS clock rate
 - max bits per component
 - single or dual link support
 - high color depth support

Signed-off-by: Mika Kahola <mika.kahola at intel.com>
---
 drivers/gpu/drm/drm_dp_helper.c |  5 +++++
 include/drm/drm_dp_helper.h     | 14 ++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index c5bec6f..f5cf706 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -451,6 +451,11 @@ int drm_dp_bd(struct drm_dp_aux *aux, struct drm_dp_bd *bd)
 		if (bd->type & DP_DS_PORT_TYPE_VGA) {
 			bd->dfp.vga.dot_clk = info[1] * 8 * 1000;
 			bd->dfp.vga.bpc = info[2] & DP_DS_VGA_MAX_BPC_MASK;
+		} else if (bd->type & DP_DS_PORT_TYPE_DVI) {
+			bd->dfp.dvi.tmds_clk = info[1] * 2500;
+			bd->dfp.dvi.bpc = info[2] & DP_DS_VGA_MAX_BPC_MASK;
+			bd->dfp.dvi.dual_link = info[3] & DP_DS_DVI_DUAL_LINK;
+			bd->dfp.dvi.hi_color_depth = info[3] & DP_DS_DVI_HI_COLOR_DEPTH;
 		}
 	}
 
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index d3e78a5..1a4e131 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -221,6 +221,9 @@
 # define DP_DS_VGA_10BPC		    1
 # define DP_DS_VGA_12BPC		    2
 # define DP_DS_VGA_16BPC		    3
+/* offset 3 for DVI dual link and high color depth */
+# define DP_DS_DVI_DUAL_LINK                (1<<1)
+# define DP_DS_DVI_HI_COLOR_DEPTH           (1<<2)
 
 /* link configuration */
 #define	DP_LINK_BW_SET		            0x100
@@ -811,6 +814,16 @@ struct drm_dp_vga {
 };
 
 /*
+ * DP to DVI
+ */
+struct drm_dp_dvi {
+	int tmds_clk;
+	uint8_t bpc;
+	bool dual_link;
+	bool hi_color_depth;
+};
+
+/*
  * Branch device
  */
 struct drm_dp_bd {
@@ -819,6 +832,7 @@ struct drm_dp_bd {
 	bool hpd;
 	union {
 		struct drm_dp_vga vga;
+		struct drm_dp_dvi dvi;
 	} dfp;
 };
 
-- 
1.9.1