drm/amd/display: Added documentation for some DC interface functions

Signed-off-by: Yasir Al Shekerchi <YasirAl.Shekerchi@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/core/dc.c

@@ -169,6 +169,22 @@ static bool create_links(
 	return false;
 }
 
+/**
+ *****************************************************************************
+ *  Function: dc_stream_adjust_vmin_vmax
+ *
+ *  @brief
+ *     Looks up the pipe context of dc_stream_state and updates the
+ *     vertical_total_min and vertical_total_max of the DRR, Dynamic Refresh
+ *     Rate, which is a power-saving feature that targets reducing panel
+ *     refresh rate while the screen is static
+ *
+ *  @param [in] dc: dc reference
+ *  @param [in] stream: Initial dc stream state
+ *  @param [in] adjust: Updated parameters for vertical_total_min and
+ *  vertical_total_max
+ *****************************************************************************
+ */
 bool dc_stream_adjust_vmin_vmax(struct dc *dc,
 		struct dc_stream_state **streams, int num_streams,
 		int vmin, int vmax)

drivers/gpu/drm/amd/display/dc/core/dc_link.c

@@ -2433,6 +2433,22 @@ void core_link_set_avmute(struct pipe_ctx *pipe_ctx, bool enable)
 	core_dc->hwss.set_avmute(pipe_ctx, enable);
 }
 
+/**
+ *****************************************************************************
+ *  Function: dc_link_enable_hpd_filter
+ *
+ *  @brief
+ *     If enable is true, programs HPD filter on associated HPD line using
+ *     delay_on_disconnect/delay_on_connect values dependent on
+ *     link->connector_signal
+ *
+ *     If enable is false, programs HPD filter on associated HPD line with no
+ *     delays on connect or disconnect
+ *
+ *  @param [in] link: pointer to the dc link
+ *  @param [in] enable: boolean specifying whether to enable hbd
+ *****************************************************************************
+ */
 void dc_link_enable_hpd_filter(struct dc_link *link, bool enable)
 {
 	struct gpio *hpd;

drivers/gpu/drm/amd/display/dc/core/dc_surface.c

@@ -84,6 +84,17 @@ struct dc_plane_state *dc_create_plane_state(struct dc *dc)
 	return plane_state;
 }
 
+/**
+ *****************************************************************************
+ *  Function: dc_plane_get_status
+ *
+ *  @brief
+ *     Looks up the pipe context of plane_state and updates the pending status
+ *     of the pipe context. Then returns plane_state->status
+ *
+ *  @param [in] plane_state: pointer to the plane_state to get the status of
+ *****************************************************************************
+ */
 const struct dc_plane_status *dc_plane_get_status(
 		const struct dc_plane_state *plane_state)
 {