diff options
Diffstat (limited to 'include/media/videobuf2-v4l2.h')
| -rw-r--r-- | include/media/videobuf2-v4l2.h | 112 |
1 files changed, 59 insertions, 53 deletions
diff --git a/include/media/videobuf2-v4l2.h b/include/media/videobuf2-v4l2.h index c2fa55657440..3d5e2d739f05 100644 --- a/include/media/videobuf2-v4l2.h +++ b/include/media/videobuf2-v4l2.h @@ -24,16 +24,17 @@ #endif /** - * struct vb2_v4l2_buffer - video buffer information for v4l2 + * struct vb2_v4l2_buffer - video buffer information for v4l2. * - * @vb2_buf: video buffer 2 - * @flags: buffer informational flags - * @field: enum v4l2_field; field order of the image in the buffer - * @timecode: frame timecode - * @sequence: sequence count of this frame + * @vb2_buf: embedded struct &vb2_buffer. + * @flags: buffer informational flags. + * @field: field order of the image in the buffer, as defined by + * &enum v4l2_field. + * @timecode: frame timecode. + * @sequence: sequence count of this frame. * * Should contain enough information to be able to cover all the fields - * of struct v4l2_buffer at videodev2.h + * of &struct v4l2_buffer at ``videodev2.h``. */ struct vb2_v4l2_buffer { struct vb2_buffer vb2_buf; @@ -56,9 +57,9 @@ int vb2_querybuf(struct vb2_queue *q, struct v4l2_buffer *b); * vb2_reqbufs() - Wrapper for vb2_core_reqbufs() that also verifies * the memory and type values. * - * @q: videobuf2 queue - * @req: struct passed from userspace to vidioc_reqbufs handler - * in driver + * @q: pointer to &struct vb2_queue with videobuf2 queue. + * @req: &struct v4l2_requestbuffers passed from userspace to + * &v4l2_ioctl_ops->vidioc_reqbufs handler in driver. */ int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req); @@ -66,94 +67,99 @@ int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req); * vb2_create_bufs() - Wrapper for vb2_core_create_bufs() that also verifies * the memory and type values. * - * @q: videobuf2 queue - * @create: creation parameters, passed from userspace to vidioc_create_bufs - * handler in driver + * @q: pointer to &struct vb2_queue with videobuf2 queue. + * @create: creation parameters, passed from userspace to + * &v4l2_ioctl_ops->vidioc_create_bufs handler in driver */ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create); /** * vb2_prepare_buf() - Pass ownership of a buffer from userspace to the kernel * - * @q: videobuf2 queue - * @b: buffer structure passed from userspace to vidioc_prepare_buf - * handler in driver + * @q: pointer to &struct vb2_queue with videobuf2 queue. + * @b: buffer structure passed from userspace to + * &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver + * + * Should be called from &v4l2_ioctl_ops->vidioc_prepare_buf ioctl handler + * of a driver. * - * Should be called from vidioc_prepare_buf ioctl handler of a driver. * This function: * * #) verifies the passed buffer, - * #) calls buf_prepare callback in the driver (if provided), in which - * driver-specific buffer initialization can be performed. + * #) calls &vb2_ops->buf_prepare callback in the driver (if provided), + * in which driver-specific buffer initialization can be performed. * * The return values from this function are intended to be directly returned - * from vidioc_prepare_buf handler in driver. + * from &v4l2_ioctl_ops->vidioc_prepare_buf handler in driver. */ int vb2_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b); /** * vb2_qbuf() - Queue a buffer from userspace - * @q: videobuf2 queue - * @b: buffer structure passed from userspace to VIDIOC_QBUF() handler - * in driver + * @q: pointer to &struct vb2_queue with videobuf2 queue. + * @b: buffer structure passed from userspace to + * &v4l2_ioctl_ops->vidioc_qbuf handler in driver * - * Should be called from VIDIOC_QBUF() ioctl handler of a driver. + * Should be called from &v4l2_ioctl_ops->vidioc_qbuf handler of a driver. * * This function: * - * #) verifies the passed buffer, - * #) if necessary, calls buf_prepare callback in the driver (if provided), in - * which driver-specific buffer initialization can be performed, - * #) if streaming is on, queues the buffer in driver by the means of buf_queue - * callback for processing. + * #) verifies the passed buffer; + * #) if necessary, calls &vb2_ops->buf_prepare callback in the driver + * (if provided), in which driver-specific buffer initialization can + * be performed; + * #) if streaming is on, queues the buffer in driver by the means of + * &vb2_ops->buf_queue callback for processing. * * The return values from this function are intended to be directly returned - * from VIDIOC_QBUF() handler in driver. + * from &v4l2_ioctl_ops->vidioc_qbuf handler in driver. */ int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b); /** * vb2_expbuf() - Export a buffer as a file descriptor - * @q: videobuf2 queue - * @eb: export buffer structure passed from userspace to VIDIOC_EXPBUF() - * handler in driver + * @q: pointer to &struct vb2_queue with videobuf2 queue. + * @eb: export buffer structure passed from userspace to + * &v4l2_ioctl_ops->vidioc_expbuf handler in driver * * The return values from this function are intended to be directly returned - * from VIDIOC_EXPBUF() handler in driver. + * from &v4l2_ioctl_ops->vidioc_expbuf handler in driver. */ int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb); /** * vb2_dqbuf() - Dequeue a buffer to the userspace - * @q: videobuf2 queue - * @b: buffer structure passed from userspace to VIDIOC_DQBUF() handler - * in driver + * @q: pointer to &struct vb2_queue with videobuf2 queue. + * @b: buffer structure passed from userspace to + * &v4l2_ioctl_ops->vidioc_dqbuf handler in driver * @nonblocking: if true, this call will not sleep waiting for a buffer if no * buffers ready for dequeuing are present. Normally the driver - * would be passing (file->f_flags & O_NONBLOCK) here + * would be passing (&file->f_flags & %O_NONBLOCK) here * - * Should be called from VIDIOC_DQBUF() ioctl handler of a driver. + * Should be called from &v4l2_ioctl_ops->vidioc_dqbuf ioctl handler + * of a driver. * * This function: * - * #) verifies the passed buffer, - * #) calls buf_finish callback in the driver (if provided), in which + * #) verifies the passed buffer; + * #) calls &vb2_ops->buf_finish callback in the driver (if provided), in which * driver can perform any additional operations that may be required before - * returning the buffer to userspace, such as cache sync, + * returning the buffer to userspace, such as cache sync; * #) the buffer struct members are filled with relevant information for * the userspace. * * The return values from this function are intended to be directly returned - * from VIDIOC_DQBUF() handler in driver. + * from &v4l2_ioctl_ops->vidioc_dqbuf handler in driver. */ int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking); /** * vb2_streamon - start streaming - * @q: videobuf2 queue - * @type: type argument passed from userspace to vidioc_streamon handler + * @q: pointer to &struct vb2_queue with videobuf2 queue. + * @type: type argument passed from userspace to vidioc_streamon handler, + * as defined by &enum v4l2_buf_type. * - * Should be called from vidioc_streamon handler of a driver. + * Should be called from &v4l2_ioctl_ops->vidioc_streamon handler of a driver. * * This function: * @@ -161,13 +167,13 @@ int vb2_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool nonblocking); * 2) passes any previously queued buffers to the driver and starts streaming * * The return values from this function are intended to be directly returned - * from vidioc_streamon handler in the driver. + * from &v4l2_ioctl_ops->vidioc_streamon handler in the driver. */ int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type); /** * vb2_streamoff - stop streaming - * @q: videobuf2 queue + * @q: pointer to &struct vb2_queue with videobuf2 queue. * @type: type argument passed from userspace to vidioc_streamoff handler * * Should be called from vidioc_streamoff handler of a driver. @@ -186,7 +192,7 @@ int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type); /** * vb2_queue_init() - initialize a videobuf2 queue - * @q: videobuf2 queue; this structure should be allocated in driver + * @q: pointer to &struct vb2_queue with videobuf2 queue. * * The vb2_queue structure should be allocated by the driver. The driver is * responsible of clearing it's content and setting initial values for some @@ -199,7 +205,7 @@ int __must_check vb2_queue_init(struct vb2_queue *q); /** * vb2_queue_release() - stop streaming, release the queue and free memory - * @q: videobuf2 queue + * @q: pointer to &struct vb2_queue with videobuf2 queue. * * This function stops streaming and performs necessary clean ups, including * freeing video buffer memory. The driver is responsible for freeing @@ -209,7 +215,7 @@ void vb2_queue_release(struct vb2_queue *q); /** * vb2_poll() - implements poll userspace operation - * @q: videobuf2 queue + * @q: pointer to &struct vb2_queue with videobuf2 queue. * @file: file argument passed to the poll file operation handler * @wait: wait argument passed to the poll file operation handler * @@ -270,7 +276,7 @@ unsigned long vb2_fop_get_unmapped_area(struct file *file, unsigned long addr, /** * vb2_ops_wait_prepare - helper function to lock a struct &vb2_queue * - * @vq: pointer to struct vb2_queue + * @vq: pointer to &struct vb2_queue * * ..note:: only use if vq->lock is non-NULL. */ @@ -279,7 +285,7 @@ void vb2_ops_wait_prepare(struct vb2_queue *vq); /** * vb2_ops_wait_finish - helper function to unlock a struct &vb2_queue * - * @vq: pointer to struct vb2_queue + * @vq: pointer to &struct vb2_queue * * ..note:: only use if vq->lock is non-NULL. */ |