[Intel-gfx] [v3 1/8] drm/i915/display: Add HDR Capability detection for LSPCON

[Uma Shankar]

LSPCON firmware exposes HDR capability through LPCON_CAPABILITIES
DPCD register. LSPCON implementations capable of supporting
HDR set HDR_CAPABILITY bit in LSPCON_CAPABILITIES to 1. This patch
reads the same, detects the HDR capability and adds this to
intel_lspcon struct.

v2: Addressed Jani Nikula's review comment and fixed the HDR
    capability detection logic

Signed-off-by: Uma Shankar <uma.shankar at intel.com>
---
 .../drm/i915/display/intel_display_types.h    |  1 +
 drivers/gpu/drm/i915/display/intel_lspcon.c   | 30 +++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index 4b0aaa3081c9..ca99a05f52da 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1386,6 +1386,7 @@ struct intel_lspcon {
 	bool active;
 	enum drm_lspcon_mode mode;
 	enum lspcon_vendor vendor;
+	bool hdr_supported;
 };
 
 struct intel_digital_port {
diff --git a/drivers/gpu/drm/i915/display/intel_lspcon.c b/drivers/gpu/drm/i915/display/intel_lspcon.c
index 6ff7b226f0a1..70bd564cae46 100644
--- a/drivers/gpu/drm/i915/display/intel_lspcon.c
+++ b/drivers/gpu/drm/i915/display/intel_lspcon.c
@@ -35,6 +35,8 @@
 #define LSPCON_VENDOR_PARADE_OUI 0x001CF8
 #define LSPCON_VENDOR_MCA_OUI 0x0060AD
 
+#define DPCD_MCA_LSPCON_HDR_STATUS	0x70003
+
 /* AUX addresses to write MCA AVI IF */
 #define LSPCON_MCA_AVI_IF_WRITE_OFFSET 0x5C0
 #define LSPCON_MCA_AVI_IF_CTRL 0x5DF
@@ -104,6 +106,32 @@ static bool lspcon_detect_vendor(struct intel_lspcon *lspcon)
 	return true;
 }
 
+static void lspcon_detect_hdr_capability(struct intel_lspcon *lspcon)
+{
+	struct intel_digital_port *intel_dig_port =
+		container_of(lspcon, struct intel_digital_port, lspcon);
+	struct drm_device *dev = intel_dig_port->base.base.dev;
+	struct intel_dp *dp = lspcon_to_intel_dp(lspcon);
+	u8 hdr_caps;
+	int ret;
+
+	/* Enable HDR for MCA based LSPCON devices */
+	if (lspcon->vendor == LSPCON_VENDOR_MCA)
+		ret = drm_dp_dpcd_read(&dp->aux, DPCD_MCA_LSPCON_HDR_STATUS,
+				       &hdr_caps, 1);
+	else
+		return;
+
+	if (ret < 0) {
+		drm_dbg_kms(dev, "hdr capability detection failed\n");
+		lspcon->hdr_supported = false;
+		return;
+	} else if (hdr_caps & 0x1) {
+		drm_dbg_kms(dev, "lspcon capable of HDR\n");
+		lspcon->hdr_supported = true;
+	}
+}
+
 static enum drm_lspcon_mode lspcon_get_current_mode(struct intel_lspcon *lspcon)
 {
 	enum drm_lspcon_mode current_mode;
@@ -581,6 +609,8 @@ bool lspcon_init(struct intel_digital_port *intel_dig_port)
 		return false;
 	}
 
+	lspcon_detect_hdr_capability(lspcon);
+
 	connector->ycbcr_420_allowed = true;
 	lspcon->active = true;
 	DRM_DEBUG_KMS("Success: LSPCON init\n");
-- 
2.22.0