@@ -438,6 +438,12 @@ enum v4l2_buf_type
* - ``V4L2_BUF_TYPE_META_OUTPUT``
- 14
- Buffer for metadata output, see :ref:`metadata`.
+ * - ``V4L2_BUF_TYPE_AUDIO_CAPTURE``
+ - 15
+ - Buffer for audio capture, see :ref:`audio`.
+ * - ``V4L2_BUF_TYPE_AUDIO_OUTPUT``
+ - 16
+ - Buffer for audio output, see :ref:`audio`.
.. _buffer-flags:
new file mode 100644
@@ -0,0 +1,71 @@
+.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
+
+.. _audiomem2mem:
+
+********************************
+Audio Memory-To-Memory Interface
+********************************
+
+A audio memory-to-memory device can compress, decompress, transform, or
+otherwise convert audio data from one format into another format, in memory.
+Such memory-to-memory devices set the ``V4L2_CAP_AUDIO_M2M`` capability.
+Examples of memory-to-memory devices are codecs, audio preprocessing,
+audio postprocessing.
+
+A memory-to-memory audio node supports both output (sending frames from
+memory to the hardware) and capture (receiving the processed frames
+from the hardware into memory) stream I/O. An application will have to
+setup the stream I/O for both sides and finally call
+:ref:`VIDIOC_STREAMON <VIDIOC_STREAMON>` for both capture and output to
+start the hardware.
+
+Memory-to-memory devices function as a shared resource: you can
+open the audio node multiple times, each application setting up their
+own properties that are local to the file handle, and each can use
+it independently from the others. The driver will arbitrate access to
+the hardware and reprogram it whenever another file handler gets access.
+
+Audio memory-to-memory devices are accessed through character device
+special files named ``/dev/v4l-audio``
+
+Querying Capabilities
+=====================
+
+Device nodes supporting the audio memory-to-memory interface set the
+``V4L2_CAP_AUDIO_M2M`` flag in the ``device_caps`` field of the
+:c:type:`v4l2_capability` structure returned by the :c:func:`VIDIOC_QUERYCAP`
+ioctl.
+
+Data Format Negotiation
+=======================
+
+The audio device uses the :ref:`format` ioctls to select the capture format.
+The audio buffer content format is bound to that selected format. In addition
+to the basic :ref:`format` ioctls, the :c:func:`VIDIOC_ENUM_FMT` ioctl must be
+supported as well.
+
+To use the :ref:`format` ioctls applications set the ``type`` field of the
+:c:type:`v4l2_format` structure to ``V4L2_BUF_TYPE_AUDIO_CAPTURE`` or to
+``V4L2_BUF_TYPE_AUDIO_OUTPUT``. Both drivers and applications must set the
+remainder of the :c:type:`v4l2_format` structure to 0.
+
+.. c:type:: v4l2_audio_format
+
+.. tabularcolumns:: |p{1.4cm}|p{2.4cm}|p{13.5cm}|
+
+.. flat-table:: struct v4l2_audio_format
+ :header-rows: 0
+ :stub-columns: 0
+ :widths: 1 1 2
+
+ * - __u32
+ - ``pixelformat``
+ - The sample format, set by the application. see :ref:`pixfmt-audio`
+ * - __u32
+ - ``channels``
+ - The channel number, set by the application. channel number range is
+ [1, 32].
+ * - __u32
+ - ``buffersize``
+ - Maximum buffer size in bytes required for data. The value is set by the
+ driver.
@@ -24,3 +24,4 @@ Interfaces
dev-event
dev-subdev
dev-meta
+ dev-audio-mem2mem
@@ -96,6 +96,8 @@ the ``mbus_code`` field is handled differently:
``V4L2_BUF_TYPE_VIDEO_OVERLAY``,
``V4L2_BUF_TYPE_SDR_CAPTURE``,
``V4L2_BUF_TYPE_SDR_OUTPUT``,
+ ``V4L2_BUF_TYPE_AUDIO_CAPTURE``,
+ ``V4L2_BUF_TYPE_AUDIO_OUTPUT``,
``V4L2_BUF_TYPE_META_CAPTURE`` and
``V4L2_BUF_TYPE_META_OUTPUT``.
See :c:type:`v4l2_buf_type`.
@@ -130,6 +130,10 @@ The format as returned by :ref:`VIDIOC_TRY_FMT <VIDIOC_G_FMT>` must be identical
- ``meta``
- Definition of a metadata format, see :ref:`meta-formats`, used by
metadata capture devices.
+ * - struct :c:type:`v4l2_audio_format`
+ - ``audio``
+ - Definition of a audio data format, see :ref:`audiomem2mem`, used by
+ audio memory-to-memory devices
* - __u8
- ``raw_data``\ [200]
- Place holder for future extensions.
@@ -29,6 +29,8 @@ replace symbol V4L2_FIELD_SEQ_TB :c:type:`v4l2_field`
replace symbol V4L2_FIELD_TOP :c:type:`v4l2_field`
# Documented enum v4l2_buf_type
+replace symbol V4L2_BUF_TYPE_AUDIO_CAPTURE :c:type:`v4l2_buf_type`
+replace symbol V4L2_BUF_TYPE_AUDIO_OUTPUT :c:type:`v4l2_buf_type`
replace symbol V4L2_BUF_TYPE_META_CAPTURE :c:type:`v4l2_buf_type`
replace symbol V4L2_BUF_TYPE_META_OUTPUT :c:type:`v4l2_buf_type`
replace symbol V4L2_BUF_TYPE_SDR_CAPTURE :c:type:`v4l2_buf_type`
@@ -785,6 +785,10 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
case V4L2_BUF_TYPE_META_OUTPUT:
requested_sizes[0] = f->fmt.meta.buffersize;
break;
+ case V4L2_BUF_TYPE_AUDIO_CAPTURE:
+ case V4L2_BUF_TYPE_AUDIO_OUTPUT:
+ requested_sizes[0] = f->fmt.audio.buffersize;
+ break;
default:
return -EINVAL;
}
@@ -553,6 +553,7 @@ static void determine_valid_ioctls(struct video_device *vdev)
bool is_tch = vdev->vfl_type == VFL_TYPE_TOUCH;
bool is_meta = vdev->vfl_type == VFL_TYPE_VIDEO &&
(vdev->device_caps & meta_caps);
+ bool is_audio = vdev->vfl_type == VFL_TYPE_AUDIO;
bool is_rx = vdev->vfl_dir != VFL_DIR_TX;
bool is_tx = vdev->vfl_dir != VFL_DIR_RX;
bool is_io_mc = vdev->device_caps & V4L2_CAP_IO_MC;
@@ -664,6 +665,19 @@ static void determine_valid_ioctls(struct video_device *vdev)
SET_VALID_IOCTL(ops, VIDIOC_S_FMT, vidioc_s_fmt_meta_out);
SET_VALID_IOCTL(ops, VIDIOC_TRY_FMT, vidioc_try_fmt_meta_out);
}
+ if (is_audio && is_rx) {
+ /* audio capture specific ioctls */
+ SET_VALID_IOCTL(ops, VIDIOC_ENUM_FMT, vidioc_enum_fmt_audio_cap);
+ SET_VALID_IOCTL(ops, VIDIOC_G_FMT, vidioc_g_fmt_audio_cap);
+ SET_VALID_IOCTL(ops, VIDIOC_S_FMT, vidioc_s_fmt_audio_cap);
+ SET_VALID_IOCTL(ops, VIDIOC_TRY_FMT, vidioc_try_fmt_audio_cap);
+ } else if (is_audio && is_tx) {
+ /* audio output specific ioctls */
+ SET_VALID_IOCTL(ops, VIDIOC_ENUM_FMT, vidioc_enum_fmt_audio_out);
+ SET_VALID_IOCTL(ops, VIDIOC_G_FMT, vidioc_g_fmt_audio_out);
+ SET_VALID_IOCTL(ops, VIDIOC_S_FMT, vidioc_s_fmt_audio_out);
+ SET_VALID_IOCTL(ops, VIDIOC_TRY_FMT, vidioc_try_fmt_audio_out);
+ }
if (is_vbi) {
/* vbi specific ioctls */
if ((is_rx && (ops->vidioc_g_fmt_vbi_cap ||
@@ -927,6 +941,9 @@ int __video_register_device(struct video_device *vdev,
case VFL_TYPE_TOUCH:
name_base = "v4l-touch";
break;
+ case VFL_TYPE_AUDIO:
+ name_base = "v4l-audio";
+ break;
default:
pr_err("%s called with unknown type: %d\n",
__func__, type);
@@ -188,6 +188,8 @@ const char *v4l2_type_names[] = {
[V4L2_BUF_TYPE_SDR_OUTPUT] = "sdr-out",
[V4L2_BUF_TYPE_META_CAPTURE] = "meta-cap",
[V4L2_BUF_TYPE_META_OUTPUT] = "meta-out",
+ [V4L2_BUF_TYPE_AUDIO_CAPTURE] = "audio-cap",
+ [V4L2_BUF_TYPE_AUDIO_OUTPUT] = "audio-out",
};
EXPORT_SYMBOL(v4l2_type_names);
@@ -276,6 +278,7 @@ static void v4l_print_format(const void *arg, bool write_only)
const struct v4l2_sliced_vbi_format *sliced;
const struct v4l2_window *win;
const struct v4l2_meta_format *meta;
+ const struct v4l2_audio_format *audio;
u32 pixelformat;
u32 planes;
unsigned i;
@@ -346,6 +349,13 @@ static void v4l_print_format(const void *arg, bool write_only)
pr_cont(", dataformat=%p4cc, buffersize=%u\n",
&pixelformat, meta->buffersize);
break;
+ case V4L2_BUF_TYPE_AUDIO_CAPTURE:
+ case V4L2_BUF_TYPE_AUDIO_OUTPUT:
+ audio = &p->fmt.audio;
+ pixelformat = audio->audioformat;
+ pr_cont(", format=%p4cc, channels=%u, buffersize=%u\n",
+ &pixelformat, audio->channels, audio->buffersize);
+ break;
}
}
@@ -927,6 +937,7 @@ static int check_fmt(struct file *file, enum v4l2_buf_type type)
bool is_tch = vfd->vfl_type == VFL_TYPE_TOUCH;
bool is_meta = vfd->vfl_type == VFL_TYPE_VIDEO &&
(vfd->device_caps & meta_caps);
+ bool is_audio = vfd->vfl_type == VFL_TYPE_AUDIO;
bool is_rx = vfd->vfl_dir != VFL_DIR_TX;
bool is_tx = vfd->vfl_dir != VFL_DIR_RX;
@@ -992,6 +1003,14 @@ static int check_fmt(struct file *file, enum v4l2_buf_type type)
if (is_meta && is_tx && ops->vidioc_g_fmt_meta_out)
return 0;
break;
+ case V4L2_BUF_TYPE_AUDIO_CAPTURE:
+ if (is_audio && is_rx && ops->vidioc_g_fmt_audio_cap)
+ return 0;
+ break;
+ case V4L2_BUF_TYPE_AUDIO_OUTPUT:
+ if (is_audio && is_tx && ops->vidioc_g_fmt_audio_out)
+ return 0;
+ break;
default:
break;
}
@@ -1596,6 +1615,16 @@ static int v4l_enum_fmt(const struct v4l2_ioctl_ops *ops,
break;
ret = ops->vidioc_enum_fmt_meta_out(file, fh, arg);
break;
+ case V4L2_BUF_TYPE_AUDIO_CAPTURE:
+ if (unlikely(!ops->vidioc_enum_fmt_audio_cap))
+ break;
+ ret = ops->vidioc_enum_fmt_audio_cap(file, fh, arg);
+ break;
+ case V4L2_BUF_TYPE_AUDIO_OUTPUT:
+ if (unlikely(!ops->vidioc_enum_fmt_audio_out))
+ break;
+ ret = ops->vidioc_enum_fmt_audio_out(file, fh, arg);
+ break;
}
if (ret == 0)
v4l_fill_fmtdesc(p);
@@ -1672,6 +1701,10 @@ static int v4l_g_fmt(const struct v4l2_ioctl_ops *ops,
return ops->vidioc_g_fmt_meta_cap(file, fh, arg);
case V4L2_BUF_TYPE_META_OUTPUT:
return ops->vidioc_g_fmt_meta_out(file, fh, arg);
+ case V4L2_BUF_TYPE_AUDIO_CAPTURE:
+ return ops->vidioc_g_fmt_audio_cap(file, fh, arg);
+ case V4L2_BUF_TYPE_AUDIO_OUTPUT:
+ return ops->vidioc_g_fmt_audio_out(file, fh, arg);
}
return -EINVAL;
}
@@ -1783,6 +1816,16 @@ static int v4l_s_fmt(const struct v4l2_ioctl_ops *ops,
break;
memset_after(p, 0, fmt.meta);
return ops->vidioc_s_fmt_meta_out(file, fh, arg);
+ case V4L2_BUF_TYPE_AUDIO_CAPTURE:
+ if (unlikely(!ops->vidioc_s_fmt_audio_cap))
+ break;
+ memset_after(p, 0, fmt.audio);
+ return ops->vidioc_s_fmt_audio_cap(file, fh, arg);
+ case V4L2_BUF_TYPE_AUDIO_OUTPUT:
+ if (unlikely(!ops->vidioc_s_fmt_audio_out))
+ break;
+ memset_after(p, 0, fmt.audio);
+ return ops->vidioc_s_fmt_audio_out(file, fh, arg);
}
return -EINVAL;
}
@@ -1891,6 +1934,16 @@ static int v4l_try_fmt(const struct v4l2_ioctl_ops *ops,
break;
memset_after(p, 0, fmt.meta);
return ops->vidioc_try_fmt_meta_out(file, fh, arg);
+ case V4L2_BUF_TYPE_AUDIO_CAPTURE:
+ if (unlikely(!ops->vidioc_try_fmt_audio_cap))
+ break;
+ memset_after(p, 0, fmt.audio);
+ return ops->vidioc_try_fmt_audio_cap(file, fh, arg);
+ case V4L2_BUF_TYPE_AUDIO_OUTPUT:
+ if (unlikely(!ops->vidioc_try_fmt_audio_out))
+ break;
+ memset_after(p, 0, fmt.audio);
+ return ops->vidioc_try_fmt_audio_out(file, fh, arg);
}
return -EINVAL;
}
@@ -30,6 +30,7 @@
* @VFL_TYPE_SUBDEV: for V4L2 subdevices
* @VFL_TYPE_SDR: for Software Defined Radio tuners
* @VFL_TYPE_TOUCH: for touch sensors
+ * @VFL_TYPE_AUDIO: for audio memory-to-memory devices
* @VFL_TYPE_MAX: number of VFL types, must always be last in the enum
*/
enum vfl_devnode_type {
@@ -39,6 +40,7 @@ enum vfl_devnode_type {
VFL_TYPE_SUBDEV,
VFL_TYPE_SDR,
VFL_TYPE_TOUCH,
+ VFL_TYPE_AUDIO,
VFL_TYPE_MAX /* Shall be the last one */
};
@@ -45,6 +45,12 @@ struct v4l2_fh;
* @vidioc_enum_fmt_meta_out: pointer to the function that implements
* :ref:`VIDIOC_ENUM_FMT <vidioc_enum_fmt>` ioctl logic
* for metadata output
+ * @vidioc_enum_fmt_audio_cap: pointer to the function that implements
+ * :ref:`VIDIOC_ENUM_FMT <vidioc_enum_fmt>` ioctl logic
+ * for audio capture
+ * @vidioc_enum_fmt_audio_out: pointer to the function that implements
+ * :ref:`VIDIOC_ENUM_FMT <vidioc_enum_fmt>` ioctl logic
+ * for audio output
* @vidioc_g_fmt_vid_cap: pointer to the function that implements
* :ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for video capture
* in single plane mode
@@ -79,6 +85,10 @@ struct v4l2_fh;
* :ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for metadata capture
* @vidioc_g_fmt_meta_out: pointer to the function that implements
* :ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for metadata output
+ * @vidioc_g_fmt_audio_cap: pointer to the function that implements
+ * :ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for audio capture
+ * @vidioc_g_fmt_audio_out: pointer to the function that implements
+ * :ref:`VIDIOC_G_FMT <vidioc_g_fmt>` ioctl logic for audio output
* @vidioc_s_fmt_vid_cap: pointer to the function that implements
* :ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for video capture
* in single plane mode
@@ -113,6 +123,10 @@ struct v4l2_fh;
* :ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for metadata capture
* @vidioc_s_fmt_meta_out: pointer to the function that implements
* :ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for metadata output
+ * @vidioc_s_fmt_audio_cap: pointer to the function that implements
+ * :ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for audio capture
+ * @vidioc_s_fmt_audio_out: pointer to the function that implements
+ * :ref:`VIDIOC_S_FMT <vidioc_g_fmt>` ioctl logic for audio output
* @vidioc_try_fmt_vid_cap: pointer to the function that implements
* :ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for video capture
* in single plane mode
@@ -149,6 +163,10 @@ struct v4l2_fh;
* :ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for metadata capture
* @vidioc_try_fmt_meta_out: pointer to the function that implements
* :ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for metadata output
+ * @vidioc_try_fmt_audio_cap: pointer to the function that implements
+ * :ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for audio capture
+ * @vidioc_try_fmt_audio_out: pointer to the function that implements
+ * :ref:`VIDIOC_TRY_FMT <vidioc_g_fmt>` ioctl logic for audio output
* @vidioc_reqbufs: pointer to the function that implements
* :ref:`VIDIOC_REQBUFS <vidioc_reqbufs>` ioctl
* @vidioc_querybuf: pointer to the function that implements
@@ -315,6 +333,10 @@ struct v4l2_ioctl_ops {
struct v4l2_fmtdesc *f);
int (*vidioc_enum_fmt_meta_out)(struct file *file, void *fh,
struct v4l2_fmtdesc *f);
+ int (*vidioc_enum_fmt_audio_cap)(struct file *file, void *fh,
+ struct v4l2_fmtdesc *f);
+ int (*vidioc_enum_fmt_audio_out)(struct file *file, void *fh,
+ struct v4l2_fmtdesc *f);
/* VIDIOC_G_FMT handlers */
int (*vidioc_g_fmt_vid_cap)(struct file *file, void *fh,
@@ -345,6 +367,10 @@ struct v4l2_ioctl_ops {
struct v4l2_format *f);
int (*vidioc_g_fmt_meta_out)(struct file *file, void *fh,
struct v4l2_format *f);
+ int (*vidioc_g_fmt_audio_cap)(struct file *file, void *fh,
+ struct v4l2_format *f);
+ int (*vidioc_g_fmt_audio_out)(struct file *file, void *fh,
+ struct v4l2_format *f);
/* VIDIOC_S_FMT handlers */
int (*vidioc_s_fmt_vid_cap)(struct file *file, void *fh,
@@ -375,6 +401,10 @@ struct v4l2_ioctl_ops {
struct v4l2_format *f);
int (*vidioc_s_fmt_meta_out)(struct file *file, void *fh,
struct v4l2_format *f);
+ int (*vidioc_s_fmt_audio_cap)(struct file *file, void *fh,
+ struct v4l2_format *f);
+ int (*vidioc_s_fmt_audio_out)(struct file *file, void *fh,
+ struct v4l2_format *f);
/* VIDIOC_TRY_FMT handlers */
int (*vidioc_try_fmt_vid_cap)(struct file *file, void *fh,
@@ -405,6 +435,10 @@ struct v4l2_ioctl_ops {
struct v4l2_format *f);
int (*vidioc_try_fmt_meta_out)(struct file *file, void *fh,
struct v4l2_format *f);
+ int (*vidioc_try_fmt_audio_cap)(struct file *file, void *fh,
+ struct v4l2_format *f);
+ int (*vidioc_try_fmt_audio_out)(struct file *file, void *fh,
+ struct v4l2_format *f);
/* Buffer handlers */
int (*vidioc_reqbufs)(struct file *file, void *fh,
@@ -153,6 +153,8 @@ enum v4l2_buf_type {
V4L2_BUF_TYPE_SDR_OUTPUT = 12,
V4L2_BUF_TYPE_META_CAPTURE = 13,
V4L2_BUF_TYPE_META_OUTPUT = 14,
+ V4L2_BUF_TYPE_AUDIO_CAPTURE = 15,
+ V4L2_BUF_TYPE_AUDIO_OUTPUT = 16,
/* Deprecated, do not use */
V4L2_BUF_TYPE_PRIVATE = 0x80,
};
@@ -169,6 +171,7 @@ enum v4l2_buf_type {
|| (type) == V4L2_BUF_TYPE_VBI_OUTPUT \
|| (type) == V4L2_BUF_TYPE_SLICED_VBI_OUTPUT \
|| (type) == V4L2_BUF_TYPE_SDR_OUTPUT \
+ || (type) == V4L2_BUF_TYPE_AUDIO_OUTPUT \
|| (type) == V4L2_BUF_TYPE_META_OUTPUT)
#define V4L2_TYPE_IS_CAPTURE(type) (!V4L2_TYPE_IS_OUTPUT(type))
@@ -2418,6 +2421,18 @@ struct v4l2_meta_format {
__u32 buffersize;
} __attribute__ ((packed));
+/**
+ * struct v4l2_audio_format - audio data format definition
+ * @audioformat: little endian four character code (fourcc)
+ * @channels: channel numbers
+ * @buffersize: maximum size in bytes required for data
+ */
+struct v4l2_audio_format {
+ __u32 audioformat;
+ __u32 channels;
+ __u32 buffersize;
+} __attribute__ ((packed));
+
/**
* struct v4l2_format - stream data format
* @type: enum v4l2_buf_type; type of the data stream
@@ -2426,6 +2441,7 @@ struct v4l2_meta_format {
* @win: definition of an overlaid image
* @vbi: raw VBI capture or output parameters
* @sliced: sliced VBI capture or output parameters
+ * @audio: definition of an audio format
* @raw_data: placeholder for future extensions and custom formats
* @fmt: union of @pix, @pix_mp, @win, @vbi, @sliced, @sdr, @meta
* and @raw_data
@@ -2440,6 +2456,7 @@ struct v4l2_format {
struct v4l2_sliced_vbi_format sliced; /* V4L2_BUF_TYPE_SLICED_VBI_CAPTURE */
struct v4l2_sdr_format sdr; /* V4L2_BUF_TYPE_SDR_CAPTURE */
struct v4l2_meta_format meta; /* V4L2_BUF_TYPE_META_CAPTURE */
+ struct v4l2_audio_format audio; /* V4L2_BUF_TYPE_AUDIO_CAPTURE */
__u8 raw_data[200]; /* user-defined */
} fmt;
};
Audio signal processing has the requirement for memory to memory similar as Video. This patch is to add this support in v4l2 framework, defined new buffer type V4L2_BUF_TYPE_AUDIO_CAPTURE and V4L2_BUF_TYPE_AUDIO_OUTPUT, defined new format v4l2_audio_format for audio case usage. The created audio device is named "/dev/v4l-audioX". Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com> --- .../userspace-api/media/v4l/buffer.rst | 6 ++ .../media/v4l/dev-audio-mem2mem.rst | 71 +++++++++++++++++++ .../userspace-api/media/v4l/devices.rst | 1 + .../media/v4l/vidioc-enum-fmt.rst | 2 + .../userspace-api/media/v4l/vidioc-g-fmt.rst | 4 ++ .../media/videodev2.h.rst.exceptions | 2 + .../media/common/videobuf2/videobuf2-v4l2.c | 4 ++ drivers/media/v4l2-core/v4l2-dev.c | 17 +++++ drivers/media/v4l2-core/v4l2-ioctl.c | 53 ++++++++++++++ include/media/v4l2-dev.h | 2 + include/media/v4l2-ioctl.h | 34 +++++++++ include/uapi/linux/videodev2.h | 17 +++++ 12 files changed, 213 insertions(+) create mode 100644 Documentation/userspace-api/media/v4l/dev-audio-mem2mem.rst