[v1 1/6] drm/i915/display: Add HDR Capability detection for LSPCON

[Uma Shankar <uma.shankar@intel.com>]

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.

Signed-off-by: Uma Shankar <uma.shankar@intel.com>
---
 .../drm/i915/display/intel_display_types.h    |  1 +
 drivers/gpu/drm/i915/display/intel_lspcon.c   | 32 +++++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index 40390d855815..560af086259a 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1268,6 +1268,7 @@ 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 f8f1308643a9..a1d0127b7f57 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 +106,31 @@ static bool lspcon_detect_vendor(struct intel_lspcon *lspcon)
 	return true;
 }
 
+static bool lspcon_detect_hdr_capability(struct intel_lspcon *lspcon)
+{
+	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 false;
+
+	if (ret < 0) {
+		DRM_DEBUG_KMS("hdr capability detection failed\n");
+		lspcon->hdr_supported = false;
+		return false;
+	} else if (hdr_caps & 0x1) {
+		DRM_DEBUG_KMS("lspcon capable of HDR\n");
+		lspcon->hdr_supported = true;
+	}
+
+	return true;
+}
+
 static enum drm_lspcon_mode lspcon_get_current_mode(struct intel_lspcon *lspcon)
 {
 	enum drm_lspcon_mode current_mode;
@@ -581,6 +608,11 @@ bool lspcon_init(struct intel_digital_port *intel_dig_port)
 		return false;
 	}
 
+	if (!lspcon_detect_hdr_capability(lspcon)) {
+		DRM_ERROR("LSPCON hdr detection failed\n");
+		return false;
+	}
+
 	connector->ycbcr_420_allowed = true;
 	lspcon->active = true;
 	DRM_DEBUG_KMS("Success: LSPCON init\n");
-- 
2.22.0

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