drm/amd/display: Add some extra kernel doc to amdgpu_dm

Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -9321,6 +9321,7 @@ static int add_affected_mst_dsc_crtcs(struct drm_atomic_state *state, struct drm
 
 /**
  * amdgpu_dm_atomic_check() - Atomic check implementation for AMDgpu DM.
+ *
  * @dev: The DRM device
  * @state: The atomic state to commit
  *
@@ -9935,6 +9936,16 @@ static int parse_hdmi_amd_vsdb(struct amdgpu_dm_connector *aconnector,
 	return valid_vsdb_found ? i : -ENODEV;
 }
 
+/**
+ * amdgpu_dm_update_freesync_caps - Update Freesync capabilities
+ *
+ * @aconnector: Connector to query.
+ *
+ * Amdgpu supports Freesync in DP and HDMI displays, and it is required to keep
+ * track of some of the display information in the internal data struct used by
+ * amdgpu_dm. This function checks which type of connector we need to set the
+ * FreeSync parameters.
+ */
 void amdgpu_dm_update_freesync_caps(struct drm_connector *connector,
 				    struct edid *edid)
 {
@@ -9949,8 +9960,8 @@ void amdgpu_dm_update_freesync_caps(struct drm_connector *connector,
 
 	struct drm_device *dev = connector->dev;
 	struct amdgpu_device *adev = drm_to_adev(dev);
-	bool freesync_capable = false;
 	struct amdgpu_hdmi_vsdb_info vsdb_info = {0};
+	bool freesync_capable = false;
 
 	if (!connector->state) {
 		DRM_ERROR("%s - Connector has no state", __func__);
@@ -9979,7 +9990,6 @@ void amdgpu_dm_update_freesync_caps(struct drm_connector *connector,
 	if (!adev->dm.freesync_module)
 		goto update;
 
-
 	if (sink->sink_signal == SIGNAL_TYPE_DISPLAY_PORT
 		|| sink->sink_signal == SIGNAL_TYPE_EDP) {
 		bool edid_check_required = false;

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h

@@ -598,6 +598,10 @@ struct amdgpu_dm_connector {
 	 * The 'current' sink is in dc_link->sink. */
 	struct dc_sink *dc_sink;
 	struct dc_link *dc_link;
+
+	/**
+	 * @dc_em_sink: Reference to the emulated (virtual) sink.
+	 */
 	struct dc_sink *dc_em_sink;
 
 	/* DM only */
@@ -610,7 +614,16 @@ struct amdgpu_dm_connector {
 	struct amdgpu_i2c_adapter *i2c;
 
 	/* Monitor range limits */
-	int min_vfreq ;
+	/**
+	 * @min_vfreq: Minimal frequency supported by the display in Hz. This
+	 * value is set to zero when there is no FreeSync support.
+	 */
+	int min_vfreq;
+
+	/**
+	 * @max_vfreq: Maximum frequency supported by the display in Hz. This
+	 * value is set to zero when there is no FreeSync support.
+	 */
 	int max_vfreq ;
 	int pixel_clock_mhz;
 
@@ -705,11 +718,34 @@ struct dm_connector_state {
 	uint64_t pbn;
 };
 
+/**
+ * struct amdgpu_hdmi_vsdb_info - Keep track of the VSDB info
+ *
+ * AMDGPU supports FreeSync over HDMI by using the VSDB section, and this
+ * struct is useful to keep track of the display-specific information about
+ * FreeSync.
+ */
 struct amdgpu_hdmi_vsdb_info {
-	unsigned int amd_vsdb_version;		/* VSDB version, should be used to determine which VSIF to send */
-	bool freesync_supported;		/* FreeSync Supported */
-	unsigned int min_refresh_rate_hz;	/* FreeSync Minimum Refresh Rate in Hz */
-	unsigned int max_refresh_rate_hz;	/* FreeSync Maximum Refresh Rate in Hz */
+	/**
+	 * @amd_vsdb_version: Vendor Specific Data Block Version, should be
+	 * used to determine which Vendor Specific InfoFrame (VSIF) to send.
+	 */
+	unsigned int amd_vsdb_version;
+
+	/**
+	 * @freesync_supported: FreeSync Supported.
+	 */
+	bool freesync_supported;
+
+	/**
+	 * @min_refresh_rate_hz: FreeSync Minimum Refresh Rate in Hz.
+	 */
+	unsigned int min_refresh_rate_hz;
+
+	/**
+	 * @max_refresh_rate_hz: FreeSync Maximum Refresh Rate in Hz
+	 */
+	unsigned int max_refresh_rate_hz;
 };