[RFC PATCH v2 4/7] media: v4l2: Add audio capture and output support

Shengjiu Wang
2023-07-25T06:46:36Z

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/audioX".

Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
---
.../media/common/videobuf2/videobuf2-v4l2.c | 4 ++
drivers/media/v4l2-core/v4l2-dev.c | 17 ++++++
drivers/media/v4l2-core/v4l2-ioctl.c | 52 +++++++++++++++++++
include/media/v4l2-dev.h | 2 +
include/media/v4l2-ioctl.h | 34 ++++++++++++
include/uapi/linux/videodev2.h | 19 +++++++
6 files changed, 128 insertions(+)

diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
index c7a54d82a55e..12f2be2773a2 100644
--- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
+++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
@@ -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;
}
diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
index f81279492682..67484f4c6eaf 100644
--- a/drivers/media/v4l2-core/v4l2-dev.c
+++ b/drivers/media/v4l2-core/v4l2-dev.c
@@ -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 = "audio";
+ break;
default:
pr_err("%s called with unknown type: %d\n",
__func__, type);
diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index 01ba27f2ef87..aa9d872bba8d 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -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 +349,12 @@ 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;
+ pr_cont(", rate=%u, format=%u, channels=%u, buffersize=%u\n",
+ audio->rate, audio->format, audio->channels, audio->buffersize);
+ break;
}
}

@@ -927,6 +936,7 @@ 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 +1002,14 @@ 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;
}
@@ -1594,6 +1612,16 @@ 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);
@@ -1670,6 +1698,10 @@ 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;
}
@@ -1781,6 +1813,16 @@ 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;
}
@@ -1889,6 +1931,16 @@ 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;
}
diff --git a/include/media/v4l2-dev.h b/include/media/v4l2-dev.h
index e0a13505f88d..0924e6d1dab1 100644
--- a/include/media/v4l2-dev.h
+++ b/include/media/v4l2-dev.h
@@ -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 input/output 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 */
};

diff --git a/include/media/v4l2-ioctl.h b/include/media/v4l2-ioctl.h
index edb733f21604..f840cf740ce1 100644
--- a/include/media/v4l2-ioctl.h
+++ b/include/media/v4l2-ioctl.h
@@ -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,
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 3af6a82d0cad..e5051410928a 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -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))
@@ -2415,6 +2418,20 @@ struct v4l2_meta_format {
__u32 buffersize;
} __attribute__ ((packed));

+/**
+ * struct v4l2_audio_format - audio data format definition
+ * @rate: sample rate
+ * @format: sample format
+ * @channels: channel numbers
+ * @buffersize: maximum size in bytes required for data
+ */
+struct v4l2_audio_format {
+ __u32 rate;
+ __u32 format;
+ __u32 channels;
+ __u32 buffersize;
+} __attribute__ ((packed));
+
/**
* struct v4l2_format - stream data format
* @type: enum v4l2_buf_type; type of the data stream
@@ -2423,6 +2440,7 @@ 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
@@ -2437,6 +2455,7 @@ 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;
};
--
2.34.1