drm/amdgpu: utilize subconnector property for DP through atombios

Since DP-specific information is stored in driver's structures, every
driver needs to implement subconnector property by itself.

v2: rebase

v3: renamed a function call

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: David (ChunMing) Zhou <David1.Zhou@amd.com>
Cc: amd-gfx@lists.freedesktop.org
Signed-off-by: Jeevan B <jeevan.b@intel.com>
Signed-off-by: Oleg Vasilev <oleg.vasilev@intel.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1587732655-17544-4-git-send-email-jeevan.b@intel.com

drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c

@@ -26,6 +26,7 @@
 
 #include <drm/drm_edid.h>
 #include <drm/drm_fb_helper.h>
+#include <drm/drm_dp_helper.h>
 #include <drm/drm_probe_helper.h>
 #include <drm/amdgpu_drm.h>
 #include "amdgpu.h"
@@ -1405,6 +1406,10 @@ amdgpu_connector_dp_detect(struct drm_connector *connector, bool force)
 		pm_runtime_put_autosuspend(connector->dev->dev);
 	}
 
+	drm_dp_set_subconnector_property(&amdgpu_connector->base,
+					 ret,
+					 amdgpu_dig_connector->dpcd,
+					 amdgpu_dig_connector->downstream_ports);
 	return ret;
 }
 
@@ -1951,6 +1956,11 @@ amdgpu_connector_add(struct amdgpu_device *adev,
 	if (has_aux)
 		amdgpu_atombios_dp_aux_init(amdgpu_connector);
 
+	if (connector_type == DRM_MODE_CONNECTOR_DisplayPort ||
+	    connector_type == DRM_MODE_CONNECTOR_eDP) {
+		drm_connector_attach_dp_subconnector_property(&amdgpu_connector->base);
+	}
+
 	return;
 
 failed:

drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h

@@ -469,6 +469,7 @@ struct amdgpu_encoder {
 struct amdgpu_connector_atom_dig {
 	/* displayport */
 	u8 dpcd[DP_RECEIVER_CAP_SIZE];
+	u8 downstream_ports[DP_MAX_DOWNSTREAM_PORTS];
 	u8 dp_sink_type;
 	int dp_clock;
 	int dp_lane_count;

drivers/gpu/drm/amd/amdgpu/atombios_dp.c

@@ -328,6 +328,22 @@ static void amdgpu_atombios_dp_probe_oui(struct amdgpu_connector *amdgpu_connect
 			      buf[0], buf[1], buf[2]);
 }
 
+static void amdgpu_atombios_dp_ds_ports(struct amdgpu_connector *amdgpu_connector)
+{
+	struct amdgpu_connector_atom_dig *dig_connector = amdgpu_connector->con_priv;
+	int ret;
+
+	if (dig_connector->dpcd[DP_DPCD_REV] > 0x10) {
+		ret = drm_dp_dpcd_read(&amdgpu_connector->ddc_bus->aux,
+				       DP_DOWNSTREAM_PORT_0,
+				       dig_connector->downstream_ports,
+				       DP_MAX_DOWNSTREAM_PORTS);
+		if (ret)
+			memset(dig_connector->downstream_ports, 0,
+			       DP_MAX_DOWNSTREAM_PORTS);
+	}
+}
+
 int amdgpu_atombios_dp_get_dpcd(struct amdgpu_connector *amdgpu_connector)
 {
 	struct amdgpu_connector_atom_dig *dig_connector = amdgpu_connector->con_priv;
@@ -343,7 +359,7 @@ int amdgpu_atombios_dp_get_dpcd(struct amdgpu_connector *amdgpu_connector)
 			      dig_connector->dpcd);
 
 		amdgpu_atombios_dp_probe_oui(amdgpu_connector);
-
+		amdgpu_atombios_dp_ds_ports(amdgpu_connector);
 		return 0;
 	}