media: uapi: HEVC: Add documentation to uAPI structure

Add kernel-doc documentation for all the HEVC structures.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
Reviewed-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Acked-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Tested-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

2 files changed, 313 insertions, 76 deletions

diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
index 8ba16e8742f3..e88b5e6944a6 100644
--- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
+++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
@@ -2695,70 +2695,76 @@ enum v4l2_mpeg_video_hevc_size_of_length_field -
         of H.265 specifications.
     * - __u16
       - ``pic_width_in_luma_samples``
-      -
+      - Specifies the width of each decoded picture in units of luma samples.
     * - __u16
       - ``pic_height_in_luma_samples``
-      -
+      - Specifies the height of each decoded picture in units of luma samples.
     * - __u8
       - ``bit_depth_luma_minus8``
-      -
+      - This value plus 8 specifies the bit depth of the samples of the luma array.
     * - __u8
       - ``bit_depth_chroma_minus8``
-      -
+      - This value plus 8 specifies the bit depth of the samples of the chroma arrays.
     * - __u8
       - ``log2_max_pic_order_cnt_lsb_minus4``
-      -
+      - This value plus 4 specifies the value of the variable MaxPicOrderCntLsb.
     * - __u8
       - ``sps_max_dec_pic_buffering_minus1``
-      -
+      - This value plus 1 specifies the maximum required size of the decoded picture buffer for
+        the codec video sequence.
     * - __u8
       - ``sps_max_num_reorder_pics``
-      -
+      - Indicates the maximum allowed number of pictures.
     * - __u8
       - ``sps_max_latency_increase_plus1``
-      -
+      - Not equal to 0 is used to compute the value of SpsMaxLatencyPictures array.
     * - __u8
       - ``log2_min_luma_coding_block_size_minus3``
-      -
+      - This value plus 3 specifies the minimum luma coding block size.
     * - __u8
       - ``log2_diff_max_min_luma_coding_block_size``
-      -
+      - Specifies the difference between the maximum and minimum luma coding block size.
     * - __u8
       - ``log2_min_luma_transform_block_size_minus2``
-      -
+      - This value plus 2 specifies the minimum luma transform block size.
     * - __u8
       - ``log2_diff_max_min_luma_transform_block_size``
-      -
+      - Specifies the difference between the maximum and minimum luma transform block size.
     * - __u8
       - ``max_transform_hierarchy_depth_inter``
-      -
+      - Specifies the maximum hierarchy depth for transform units of coding units coded
+        in inter prediction mode.
     * - __u8
       - ``max_transform_hierarchy_depth_intra``
-      -
+      - Specifies the maximum hierarchy depth for transform units of coding units coded in
+        intra prediction mode.
     * - __u8
       - ``pcm_sample_bit_depth_luma_minus1``
-      -
+      - This value plus 1 specifies the number of bits used to represent each of PCM sample
+        values of the luma component.
     * - __u8
       - ``pcm_sample_bit_depth_chroma_minus1``
-      -
+      - This value plus 1 specifies the number of bits used to represent each of PCM sample
+        values of the chroma components.
     * - __u8
       - ``log2_min_pcm_luma_coding_block_size_minus3``
-      -
+      - This value plus 3 specifies the minimum size of coding blocks.
     * - __u8
       - ``log2_diff_max_min_pcm_luma_coding_block_size``
-      -
+      - Specifies the difference between the maximum and minimum size of coding blocks.
     * - __u8
       - ``num_short_term_ref_pic_sets``
-      -
+      - Specifies the number of st_ref_pic_set() syntax structures included in the SPS.
     * - __u8
       - ``num_long_term_ref_pics_sps``
-      -
+      - Specifies the number of candidate long-term reference pictures that are
+        specified in the SPS.
     * - __u8
       - ``chroma_format_idc``
-      -
+      - Specifies the chroma sampling.
     * - __u8
       - ``sps_max_sub_layers_minus1``
-      -
+      - This value plus 1 specifies the maximum number of temporal sub-layers.
     * - __u64
       - ``flags``
       - See :ref:`Sequence Parameter Set Flags <hevc_sps_flags>`
@@ -2837,46 +2843,52 @@ enum v4l2_mpeg_video_hevc_size_of_length_field -
       - Identifies the PPS for reference by other syntax elements.
     * - __u8
       - ``num_extra_slice_header_bits``
-      -
+      - Specifies the number of extra slice header bits that are present
+        in the slice header RBSP for coded pictures referring to the PPS.
     * - __u8
       - ``num_ref_idx_l0_default_active_minus1``
-      - Specifies the inferred value of num_ref_idx_l0_active_minus1
+      - This value plus 1 specifies the inferred value of num_ref_idx_l0_active_minus1.
     * - __u8
       - ``num_ref_idx_l1_default_active_minus1``
-      - Specifies the inferred value of num_ref_idx_l1_active_minus1
+      - This value plus 1 specifies the inferred value of num_ref_idx_l1_active_minus1.
     * - __s8
       - ``init_qp_minus26``
-      -
+      - This value plus 26 specifies the initial value of SliceQp Y for each slice
+        referring to the PPS.
     * - __u8
       - ``diff_cu_qp_delta_depth``
-      -
+      - Specifies the difference between the luma coding tree block size
+        and the minimum luma coding block size of coding units that
+        convey cu_qp_delta_abs and cu_qp_delta_sign_flag.
     * - __s8
       - ``pps_cb_qp_offset``
-      -
+      - Specifies the offsets to the luma quantization parameter Cb.
     * - __s8
       - ``pps_cr_qp_offset``
-      -
+      - Specifies the offsets to the luma quantization parameter Cr.
     * - __u8
       - ``num_tile_columns_minus1``
-      -
+      - This value plus 1 specifies the number of tile columns partitioning the picture.
     * - __u8
       - ``num_tile_rows_minus1``
-      -
+      - This value plus 1 specifies the number of tile rows partitioning the picture.
     * - __u8
       - ``column_width_minus1[20]``
-      -
+      - Plus 1 specifies the width of each tile column in units of
+        coding tree blocks.
     * - __u8
       - ``row_height_minus1[22]``
-      -
+      - This value plus 1 specifies the height of each tile row in units of coding
+        tree blocks.
     * - __s8
       - ``pps_beta_offset_div2``
-      -
+      - Specifies the default deblocking parameter offsets for beta divided by 2.
     * - __s8
       - ``pps_tc_offset_div2``
-      -
+      - Specifies the default deblocking parameter offsets for tC divided by 2.
     * - __u8
       - ``log2_parallel_merge_level_minus2``
-      -
+      - Plus 2 specifies the value of the variable Log2ParMrgLevel.
     * - __u8
       - ``padding[4]``
       - Applications and drivers must set this to zero.
@@ -2998,10 +3010,10 @@ enum v4l2_mpeg_video_hevc_size_of_length_field -
       - Offset (in bits) to the video data in the current slice data.
     * - __u8
       - ``nal_unit_type``
-      -
+      - Specifies the coding type of the slice (B, P or I).
     * - __u8
       - ``nuh_temporal_id_plus1``
-      -
+      - This value minus 1 specifies a temporal identifier for the NAL unit.
     * - __u8
       - ``slice_type``
       -
@@ -3009,52 +3021,56 @@ enum v4l2_mpeg_video_hevc_size_of_length_field -
 	V4L2_HEVC_SLICE_TYPE_B).
     * - __u8
       - ``colour_plane_id``
-      -
+      - Specifies the colour plane associated with the current slice.
     * - __s32
       - ``slice_pic_order_cnt``
-      -
+      - Specifies the picture order count.
     * - __u8
       - ``num_ref_idx_l0_active_minus1``
-      -
+      - This value plus 1 specifies the maximum reference index for
+        reference picture list 0 that may be used to decode the slice.
     * - __u8
       - ``num_ref_idx_l1_active_minus1``
-      -
+      - This value plus 1 specifies the maximum reference index for
+        reference picture list 1 that may be used to decode the slice.
     * - __u8
       - ``collocated_ref_idx``
-      -
+      - Specifies the reference index of the collocated picture used for
+        temporal motion vector prediction.
     * - __u8
       - ``five_minus_max_num_merge_cand``
-      -
+      - Specifies the maximum number of merging motion vector prediction
+        candidates supported in the slice subtracted from 5.
     * - __s8
       - ``slice_qp_delta``
-      -
+      - Specifies the initial value of QpY to be used for the coding blocks in the slice.
     * - __s8
       - ``slice_cb_qp_offset``
-      -
+      - Specifies a difference to be added to the value of pps_cb_qp_offset.
     * - __s8
       - ``slice_cr_qp_offset``
-      -
+      - Specifies a difference to be added to the value of pps_cr_qp_offset.
     * - __s8
       - ``slice_act_y_qp_offset``
-      -
+      - Screen content extension parameters.
     * - __s8
       - ``slice_act_cb_qp_offset``
-      -
+      - Screen content extension parameters.
     * - __s8
       - ``slice_act_cr_qp_offset``
-      -
+      - Screen content extension parameters.
     * - __s8
       - ``slice_beta_offset_div2``
-      -
+      - Specifies the deblocking parameter offsets for beta divided by 2.
     * - __s8
       - ``slice_tc_offset_div2``
-      -
+      - Specifies the deblocking parameter offsets for tC divided by 2.
     * - __u8
       - ``pic_struct``
-      -
+      - Indicates whether a picture should be displayed as a frame or as one or more fields.
     * - __u32
       - ``slice_segment_addr``
-      -
+      - Specifies the address of the first coding tree block in the slice segment.
     * - __u8
       - ``ref_idx_l0[V4L2_HEVC_DPB_ENTRIES_NUM_MAX]``
       - The list of L0 reference elements as indices in the DPB.
@@ -3219,11 +3235,9 @@ enum v4l2_mpeg_video_hevc_size_of_length_field -
       - ``field_pic``
       - Whether the reference is a field picture or a frame.
         See :ref:`HEVC dpb field pic Flags <hevc_dpb_field_pic_flags>`
-    * - __u16
-      - ``pic_order_cnt[2]``
-      - The picture order count of the reference. Only the first element of the
-        array is used for frame pictures, while the first element identifies the
-        top field and the second the bottom field in field-coded pictures.
+    * - __s32
+      - ``pic_order_cnt_val``
+      - The picture order count of the current picture.
     * - __u8
       - ``padding[2]``
       - Applications and drivers must set this to zero.
@@ -3298,36 +3312,44 @@ enum v4l2_mpeg_video_hevc_size_of_length_field -
     :stub-columns: 0
     :widths:       1 1 2
 
-    * - __u8
-      - ``luma_log2_weight_denom``
-      -
-    * - __s8
-      - ``delta_chroma_log2_weight_denom``
-      -
     * - __s8
       - ``delta_luma_weight_l0[V4L2_HEVC_DPB_ENTRIES_NUM_MAX]``
-      -
+      - The difference of the weighting factor applied to the luma
+        prediction value for list 0.
     * - __s8
       - ``luma_offset_l0[V4L2_HEVC_DPB_ENTRIES_NUM_MAX]``
-      -
+      - The additive offset applied to the luma prediction value for list 0.
     * - __s8
       - ``delta_chroma_weight_l0[V4L2_HEVC_DPB_ENTRIES_NUM_MAX][2]``
-      -
+      - The difference of the weighting factor applied to the chroma
+        prediction value for list 0.
     * - __s8
       - ``chroma_offset_l0[V4L2_HEVC_DPB_ENTRIES_NUM_MAX][2]``
-      -
+      - The difference of the additive offset applied to the chroma
+        prediction values for list 0.
     * - __s8
       - ``delta_luma_weight_l1[V4L2_HEVC_DPB_ENTRIES_NUM_MAX]``
-      -
+      - The difference of the weighting factor applied to the luma
+        prediction value for list 1.
     * - __s8
       - ``luma_offset_l1[V4L2_HEVC_DPB_ENTRIES_NUM_MAX]``
-      -
+      - The additive offset applied to the luma prediction value for list 1.
     * - __s8
       - ``delta_chroma_weight_l1[V4L2_HEVC_DPB_ENTRIES_NUM_MAX][2]``
-      -
+      - The difference of the weighting factor applied to the chroma
+        prediction value for list 1.
     * - __s8
       - ``chroma_offset_l1[V4L2_HEVC_DPB_ENTRIES_NUM_MAX][2]``
-      -
+      - The difference of the additive offset applied to the chroma
+        prediction values for list 1.
+    * - __u8
+      - ``luma_log2_weight_denom``
+      - The base 2 logarithm of the denominator for all luma weighting
+        factors.
+    * - __s8
+      - ``delta_chroma_log2_weight_denom``
+      - The difference of the base 2 logarithm of the denominator for
+        all chroma weighting factors.
     * - __u8
       - ``padding[6]``
       - Applications and drivers must set this to zero.
diff --git a/include/media/hevc-ctrls.h b/include/media/hevc-ctrls.h
index f3695ab44389..57053cfa099b 100644
--- a/include/media/hevc-ctrls.h
+++ b/include/media/hevc-ctrls.h
@@ -55,9 +55,68 @@ enum v4l2_stateless_hevc_start_code {
 #define V4L2_HEVC_SPS_FLAG_SPS_TEMPORAL_MVP_ENABLED		(1ULL << 7)
 #define V4L2_HEVC_SPS_FLAG_STRONG_INTRA_SMOOTHING_ENABLED	(1ULL << 8)
 
-/* The controls are not stable at the moment and will likely be reworked. */
+/**
+ * struct v4l2_ctrl_hevc_sps - ITU-T Rec. H.265: Sequence parameter set
+ *
+ * @video_parameter_set_id: specifies the value of the
+ *			    vps_video_parameter_set_id of the active VPS
+ * @seq_parameter_set_id: provides an identifier for the SPS for
+ *			  reference by other syntax elements
+ * @pic_width_in_luma_samples: specifies the width of each decoded picture
+ *			       in units of luma samples
+ * @pic_height_in_luma_samples: specifies the height of each decoded picture
+ *				in units of luma samples
+ * @bit_depth_luma_minus8: this value plus 8 specifies the bit depth of the
+ *                         samples of the luma array
+ * @bit_depth_chroma_minus8: this value plus 8 specifies the bit depth of the
+ *                           samples of the chroma arrays
+ * @log2_max_pic_order_cnt_lsb_minus4: this value plus 4 specifies the value
+ *                                     of the variable MaxPicOrderCntLsb
+ * @sps_max_dec_pic_buffering_minus1: this value plus 1 specifies the maximum
+ *                                    required size of the decoded picture
+ *                                    buffer for the codec video sequence
+ * @sps_max_num_reorder_pics: indicates the maximum allowed number of pictures
+ * @sps_max_latency_increase_plus1: not equal to 0 is used to compute the
+ *				    value of SpsMaxLatencyPictures array
+ * @log2_min_luma_coding_block_size_minus3: this value plus 3 specifies the
+ *                                          minimum luma coding block size
+ * @log2_diff_max_min_luma_coding_block_size: specifies the difference between
+ *					      the maximum and minimum luma
+ *					      coding block size
+ * @log2_min_luma_transform_block_size_minus2: this value plus 2 specifies the
+ *                                             minimum luma transform block size
+ * @log2_diff_max_min_luma_transform_block_size: specifies the difference between
+ *						 the maximum and minimum luma
+ *						 transform block size
+ * @max_transform_hierarchy_depth_inter: specifies the maximum hierarchy
+ *					 depth for transform units of
+ *					 coding units coded in inter
+ *					 prediction mode
+ * @max_transform_hierarchy_depth_intra: specifies the maximum hierarchy
+ *					 depth for transform units of
+ *					 coding units coded in intra
+ *					 prediction mode
+ * @pcm_sample_bit_depth_luma_minus1: this value plus 1 specifies the number of
+ *                                    bits used to represent each of PCM sample
+ *                                    values of the luma component
+ * @pcm_sample_bit_depth_chroma_minus1: this value plus 1 specifies the number
+ *                                      of bits used to represent each of PCM
+ *                                      sample values of the chroma components
+ * @log2_min_pcm_luma_coding_block_size_minus3: this value plus 3 specifies the
+ *                                              minimum size of coding blocks
+ * @log2_diff_max_min_pcm_luma_coding_block_size: specifies the difference between
+ *						  the maximum and minimum size of
+ *						  coding blocks
+ * @num_short_term_ref_pic_sets: specifies the number of st_ref_pic_set()
+ *				 syntax structures included in the SPS
+ * @num_long_term_ref_pics_sps:	specifies the number of candidate long-term
+ *				reference pictures that are specified in the SPS
+ * @chroma_format_idc: specifies the chroma sampling
+ * @sps_max_sub_layers_minus1: this value plus 1 specifies the maximum number
+ *                             of temporal sub-layers
+ * @flags: see V4L2_HEVC_SPS_FLAG_{}
+ */
 struct v4l2_ctrl_hevc_sps {
-	/* ISO/IEC 23008-2, ITU-T Rec. H.265: Sequence parameter set */
 	__u8	video_parameter_set_id;
 	__u8	seq_parameter_set_id;
 	__u16	pic_width_in_luma_samples;
@@ -108,8 +167,43 @@ struct v4l2_ctrl_hevc_sps {
 #define V4L2_HEVC_PPS_FLAG_DEBLOCKING_FILTER_CONTROL_PRESENT	(1ULL << 19)
 #define V4L2_HEVC_PPS_FLAG_UNIFORM_SPACING			(1ULL << 20)
 
+/**
+ * struct v4l2_ctrl_hevc_pps - ITU-T Rec. H.265: Picture parameter set
+ *
+ * @pic_parameter_set_id: identifies the PPS for reference by other
+ *			  syntax elements
+ * @num_extra_slice_header_bits: specifies the number of extra slice header
+ *				 bits that are present in the slice header RBSP
+ *				 for coded pictures referring to the PPS.
+ * @num_ref_idx_l0_default_active_minus1: this value plus 1 specifies the inferred
+ *                                        value of num_ref_idx_l0_active_minus1
+ * @num_ref_idx_l1_default_active_minus1: this value plus 1 specifies the inferred
+ *                                        value of num_ref_idx_l1_active_minus1
+ * @init_qp_minus26: this value plus 26 specifies the initial value of SliceQp Y
+ *                   for each slice referring to the PPS
+ * @diff_cu_qp_delta_depth: specifies the difference between the luma coding
+ *			    tree block size and the minimum luma coding block
+ *			    size of coding units that convey cu_qp_delta_abs
+ *			    and cu_qp_delta_sign_flag
+ * @pps_cb_qp_offset: specify the offsets to the luma quantization parameter Cb
+ * @pps_cr_qp_offset: specify the offsets to the luma quantization parameter Cr
+ * @num_tile_columns_minus1: this value plus 1 specifies the number of tile columns
+ *			     partitioning the picture
+ * @num_tile_rows_minus1: this value plus 1 specifies the number of tile rows
+ *                        partitioning the picture
+ * @column_width_minus1: this value plus 1 specifies the width of each tile column
+ *                       in units of coding tree blocks
+ * @row_height_minus1: this value plus 1 specifies the height of each tile row in
+ *		       units of coding tree blocks
+ * @pps_beta_offset_div2: specify the default deblocking parameter offsets for
+ *			  beta divided by 2
+ * @pps_tc_offset_div2: specify the default deblocking parameter offsets for tC
+ *			divided by 2
+ * @log2_parallel_merge_level_minus2: this value plus 2 specifies the value of
+ *                                    the variable Log2ParMrgLevel
+ * @flags: see V4L2_HEVC_PPS_FLAG_{}
+ */
 struct v4l2_ctrl_hevc_pps {
-	/* ISO/IEC 23008-2, ITU-T Rec. H.265: Picture parameter set */
 	__u8	pic_parameter_set_id;
 	__u8	num_extra_slice_header_bits;
 	__u8	num_ref_idx_l0_default_active_minus1;
@@ -148,6 +242,14 @@ struct v4l2_ctrl_hevc_pps {
 
 #define V4L2_HEVC_DPB_ENTRIES_NUM_MAX		16
 
+/**
+ * struct v4l2_hevc_dpb_entry - HEVC decoded picture buffer entry
+ *
+ * @timestamp: timestamp of the V4L2 capture buffer to use as reference.
+ * @flags: long term flag for the reference frame
+ * @field_pic: whether the reference is a field picture or a frame.
+ * @pic_order_cnt_val: the picture order count of the reference.
+ */
 struct v4l2_hevc_dpb_entry {
 	__u64	timestamp;
 	__u8	flags;
@@ -156,6 +258,31 @@ struct v4l2_hevc_dpb_entry {
 	__u8	padding[2];
 };
 
+/**
+ * struct v4l2_hevc_pred_weight_table - HEVC weighted prediction parameters
+ *
+ * @delta_luma_weight_l0: the difference of the weighting factor applied
+ *			  to the luma prediction value for list 0
+ * @luma_offset_l0: the additive offset applied to the luma prediction value
+ *		    for list 0
+ * @delta_chroma_weight_l0: the difference of the weighting factor applied
+ *			    to the chroma prediction values for list 0
+ * @chroma_offset_l0: the difference of the additive offset applied to
+ *		      the chroma prediction values for list 0
+ * @delta_luma_weight_l1: the difference of the weighting factor applied
+ *			  to the luma prediction value for list 1
+ * @luma_offset_l1: the additive offset applied to the luma prediction value
+ *		    for list 1
+ * @delta_chroma_weight_l1: the difference of the weighting factor applied
+ *			    to the chroma prediction values for list 1
+ * @chroma_offset_l1: the difference of the additive offset applied to
+ *		      the chroma prediction values for list 1
+ * @luma_log2_weight_denom: the base 2 logarithm of the denominator for
+ *			    all luma weighting factors
+ * @delta_chroma_log2_weight_denom: the difference of the base 2 logarithm
+ *				    of the denominator for all chroma
+ *				    weighting factors
+ */
 struct v4l2_hevc_pred_weight_table {
 	__s8	delta_luma_weight_l0[V4L2_HEVC_DPB_ENTRIES_NUM_MAX];
 	__s8	luma_offset_l0[V4L2_HEVC_DPB_ENTRIES_NUM_MAX];
@@ -184,6 +311,50 @@ struct v4l2_hevc_pred_weight_table {
 #define V4L2_HEVC_SLICE_PARAMS_FLAG_SLICE_LOOP_FILTER_ACROSS_SLICES_ENABLED (1ULL << 8)
 #define V4L2_HEVC_SLICE_PARAMS_FLAG_DEPENDENT_SLICE_SEGMENT	(1ULL << 9)
 
+/**
+ * struct v4l2_ctrl_hevc_slice_params - HEVC slice parameters
+ *
+ * @bit_size: size (in bits) of the current slice data
+ * @data_bit_offset: offset (in bits) to the video data in the current slice data
+ * @nal_unit_type: specifies the coding type of the slice (B, P or I)
+ * @nuh_temporal_id_plus1: minus 1 specifies a temporal identifier for the NAL unit
+ * @slice_type: see V4L2_HEVC_SLICE_TYPE_{}
+ * @colour_plane_id: specifies the colour plane associated with the current slice
+ * @slice_pic_order_cnt: specifies the picture order count
+ * @num_ref_idx_l0_active_minus1: this value plus 1 specifies the maximum reference
+ *                                index for reference picture list 0 that may be
+ *                                used to decode the slice
+ * @num_ref_idx_l1_active_minus1: this value plus 1 specifies the maximum reference
+ *                                index for reference picture list 1 that may be
+ *                                used to decode the slice
+ * @collocated_ref_idx: specifies the reference index of the collocated picture used
+ *			for temporal motion vector prediction
+ * @five_minus_max_num_merge_cand: specifies the maximum number of merging
+ *				   motion vector prediction candidates supported in
+ *				   the slice subtracted from 5
+ * @slice_qp_delta: specifies the initial value of QpY to be used for the coding
+ *		    blocks in the slice
+ * @slice_cb_qp_offset: specifies a difference to be added to the value of pps_cb_qp_offset
+ * @slice_cr_qp_offset: specifies a difference to be added to the value of pps_cr_qp_offset
+ * @slice_act_y_qp_offset: screen content extension parameters
+ * @slice_act_cb_qp_offset: screen content extension parameters
+ * @slice_act_cr_qp_offset: screen content extension parameters
+ * @slice_beta_offset_div2: specify the deblocking parameter offsets for beta divided by 2
+ * @slice_tc_offset_div2: specify the deblocking parameter offsets for tC divided by 2
+ * @pic_struct: indicates whether a picture should be displayed as a frame or as one or
+ *		more fields
+ * @slice_segment_addr: specifies the address of the first coding tree block in
+ *			the slice segment
+ * @ref_idx_l0: the list of L0 reference elements as indices in the DPB
+ * @ref_idx_l1: the list of L1 reference elements as indices in the DPB
+ * @short_term_ref_pic_set_size: specifies the size of short-term reference
+ *				 pictures included in the SPS
+ * @long_term_ref_pic_set_size: specifies the size of long-term reference
+ *				picture include in the SPS
+ * @pred_weight_table: the prediction weight coefficients for inter-picture
+ *		       prediction
+ * @flags: see V4L2_HEVC_SLICE_PARAMS_FLAG_{}
+ */
 struct v4l2_ctrl_hevc_slice_params {
 	__u32	bit_size;
 	__u32	data_bit_offset;
@@ -230,6 +401,28 @@ struct v4l2_ctrl_hevc_slice_params {
 #define V4L2_HEVC_DECODE_PARAM_FLAG_IDR_PIC		0x2
 #define V4L2_HEVC_DECODE_PARAM_FLAG_NO_OUTPUT_OF_PRIOR  0x4
 
+/**
+ * struct v4l2_ctrl_hevc_decode_params - HEVC decode parameters
+ *
+ * @pic_order_cnt_val: picture order count
+ * @short_term_ref_pic_set_size: specifies the size of short-term reference
+ *				 pictures set included in the SPS of the first slice
+ * @long_term_ref_pic_set_size: specifies the size of long-term reference
+ *				pictures set include in the SPS of the first slice
+ * @num_active_dpb_entries: the number of entries in dpb
+ * @dpb: the decoded picture buffer, for meta-data about reference frames
+ * @num_poc_st_curr_before: the number of reference pictures in the short-term
+ *			    set that come before the current frame
+ * @num_poc_st_curr_after: the number of reference pictures in the short-term
+ *			   set that come after the current frame
+ * @num_poc_lt_curr: the number of reference pictures in the long-term set
+ * @poc_st_curr_before: provides the index of the short term before references
+ *			in DPB array
+ * @poc_st_curr_after: provides the index of the short term after references
+ *		       in DPB array
+ * @poc_lt_curr: provides the index of the long term references in DPB array
+ * @flags: see V4L2_HEVC_DECODE_PARAM_FLAG_{}
+ */
 struct v4l2_ctrl_hevc_decode_params {
 	__s32	pic_order_cnt_val;
 	__u16	short_term_ref_pic_set_size;
@@ -245,6 +438,28 @@ struct v4l2_ctrl_hevc_decode_params {
 	__u64	flags;
 };
 
+/**
+ * struct v4l2_ctrl_hevc_scaling_matrix - HEVC scaling lists parameters
+ *
+ * @scaling_list_4x4: scaling list is used for the scaling process for
+ *		      transform coefficients. The values on each scaling
+ *		      list are expected in raster scan order
+ * @scaling_list_8x8: scaling list is used for the scaling process for
+ *		      transform coefficients. The values on each scaling
+ *		      list are expected in raster scan order
+ * @scaling_list_16x16: scaling list is used for the scaling process for
+ *			transform coefficients. The values on each scaling
+ *			list are expected in raster scan order
+ * @scaling_list_32x32:	scaling list is used for the scaling process for
+ *			transform coefficients. The values on each scaling
+ *			list are expected in raster scan order
+ * @scaling_list_dc_coef_16x16: scaling list is used for the scaling process
+ *				for transform coefficients. The values on each
+ *				scaling list are expected in raster scan order.
+ * @scaling_list_dc_coef_32x32:	scaling list is used for the scaling process
+ *				for transform coefficients. The values on each
+ *				scaling list are expected in raster scan order.
+ */
 struct v4l2_ctrl_hevc_scaling_matrix {
 	__u8	scaling_list_4x4[6][16];
 	__u8	scaling_list_8x8[6][64];