media: aspeed: add comments and macro

Add comments to describe video-stat and 'struct aspeed_video'.
Add macro, ASPEED_VIDEO_V4L2_MIN_BUF_REQ, to describe the buffers
needed.
Signed-off-by: Jammy Huang <jammy_huang@aspeedtech.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
[hverkuil: drop docbook tags, not needed]

drivers/media/platform/aspeed-video.c

@@ -34,6 +34,8 @@
 #include <media/videobuf2-dma-contig.h>
 #include <linux/videodev2.h>
 
+#define ASPEED_VIDEO_V4L2_MIN_BUF_REQ 3
+
 #define DEVICE_NAME			"aspeed-video"
 
 #define ASPEED_VIDEO_JPEG_NUM_QUALITIES	12
@@ -181,6 +183,15 @@
 #define VE_MEM_RESTRICT_START		0x310
 #define VE_MEM_RESTRICT_END		0x314
 
+/*
+ * VIDEO_MODE_DETECT_DONE:	a flag raised if signal lock
+ * VIDEO_RES_CHANGE:		a flag raised if res_change work on-going
+ * VIDEO_RES_DETECT:		a flag raised if res. detection on-going
+ * VIDEO_STREAMING:		a flag raised if user requires stream-on
+ * VIDEO_FRAME_INPRG:		a flag raised if hw working on a frame
+ * VIDEO_STOPPED:		a flag raised if device release
+ * VIDEO_CLOCKS_ON:		a flag raised if clk is on
+ */
 enum {
 	VIDEO_MODE_DETECT_DONE,
 	VIDEO_RES_CHANGE,
@@ -213,6 +224,25 @@ struct aspeed_video_perf {
 #define to_aspeed_video_buffer(x) \
 	container_of((x), struct aspeed_video_buffer, vb)
 
+/*
+ * struct aspeed_video - driver data
+ *
+ * res_work:           holds the delayed_work for res-detection if unlock
+ * buffers:            holds the list of buffer queued from user
+ * flags:		holds the state of video
+ * sequence:		holds the last number of frame completed
+ * max_compressed_size:	holds max compressed stream's size
+ * srcs:		holds the buffer information for srcs
+ * jpeg:		holds the buffer information for jpeg header
+ * yuv420:		a flag raised if JPEG subsampling is 420
+ * frame_rate:		holds the frame_rate
+ * jpeg_quality:	holds jpeq's quality (0~11)
+ * frame_bottom:	end position of video data in vertical direction
+ * frame_left:		start position of video data in horizontal direction
+ * frame_right:		end position of video data in horizontal direction
+ * frame_top:		start position of video data in vertical direction
+ * perf:		holds the statistics primary for debugfs
+ */
 struct aspeed_video {
 	void __iomem *base;
 	struct clk *eclk;
@@ -1212,7 +1242,7 @@ static int aspeed_video_get_parm(struct file *file, void *fh,
 	struct aspeed_video *video = video_drvdata(file);
 
 	a->parm.capture.capability = V4L2_CAP_TIMEPERFRAME;
-	a->parm.capture.readbuffers = 3;
+	a->parm.capture.readbuffers = ASPEED_VIDEO_V4L2_MIN_BUF_REQ;
 	a->parm.capture.timeperframe.numerator = 1;
 	if (!video->frame_rate)
 		a->parm.capture.timeperframe.denominator = MAX_FRAME_RATE;
@@ -1229,7 +1259,7 @@ static int aspeed_video_set_parm(struct file *file, void *fh,
 	struct aspeed_video *video = video_drvdata(file);
 
 	a->parm.capture.capability = V4L2_CAP_TIMEPERFRAME;
-	a->parm.capture.readbuffers = 3;
+	a->parm.capture.readbuffers = ASPEED_VIDEO_V4L2_MIN_BUF_REQ;
 
 	if (a->parm.capture.timeperframe.numerator)
 		frame_rate = a->parm.capture.timeperframe.denominator /
@@ -1781,7 +1811,7 @@ static int aspeed_video_setup_video(struct aspeed_video *video)
 	vbq->drv_priv = video;
 	vbq->buf_struct_size = sizeof(struct aspeed_video_buffer);
 	vbq->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
-	vbq->min_buffers_needed = 3;
+	vbq->min_buffers_needed = ASPEED_VIDEO_V4L2_MIN_BUF_REQ;
 
 	rc = vb2_queue_init(vbq);
 	if (rc) {