Documentation/gpu: Add entry for OPP in the kernel doc

Introduce OPP as part of the kernel documentation.

Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Harry Wentland <Harry.Wentland@amd.com>
Cc: Hamza Mahfooz <hamza.mahfooz@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Aurabindo Pillai <aurabindo.pillai@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Documentation/gpu/amdgpu/display/dcn-blocks.rst

@@ -52,3 +52,15 @@ MPC
 
 .. kernel-doc:: drivers/gpu/drm/amd/display/dc/inc/hw/mpc.h
    :internal:
+
+OPP
+---
+
+.. kernel-doc:: drivers/gpu/drm/amd/display/dc/inc/hw/opp.h
+   :doc: overview
+
+.. kernel-doc:: drivers/gpu/drm/amd/display/dc/inc/hw/opp.h
+   :export:
+
+.. kernel-doc:: drivers/gpu/drm/amd/display/dc/inc/hw/opp.h
+   :internal:

drivers/gpu/drm/amd/display/dc/inc/hw/opp.h

@@ -23,6 +23,22 @@
  *
  */
 
+/**
+ * DOC: overview
+ *
+ * The Output Plane Processor (OPP) block groups have functions that format
+ * pixel streams such that they are suitable for display at the display device.
+ * The key functions contained in the OPP are:
+ *
+ * - Adaptive Backlight Modulation (ABM)
+ * - Formatter (FMT) which provide pixel-by-pixel operations for format the
+ *   incoming pixel stream.
+ * - Output Buffer that provide pixel replication, and overlapping.
+ * - Interface between MPC and OPTC.
+ * - Clock and reset generation.
+ * - CRC generation.
+ */
+
 #ifndef __DAL_OPP_H__
 #define __DAL_OPP_H__