2.27. V4L2 common functions and data structures¶

int v4l2_ctrl_query_fill(struct v4l2_queryctrl *qctrl, s32 min, s32 max, s32 step, s32 def)¶: Fill in a struct v4l2_queryctrl

Parameters

struct v4l2_queryctrl *qctrl: pointer to the struct v4l2_queryctrl to be filled
s32 min: minimum value for the control
s32 max: maximum value for the control
s32 step: control step
s32 def: default value for the control

Description

Fills the struct v4l2_queryctrl fields for the query control.

Note

This function assumes that the qctrl->id field is filled.

Returns -EINVAL if the control is not known by the V4L2 core, 0 on success.

enum v4l2_i2c_tuner_type¶: specifies the range of tuner address that should be used when seeking for I2C devices.

Constants

ADDRS_RADIO: Radio tuner addresses. Represent the following I2C addresses: 0x10 (if compiled with tea5761 support) and 0x60.
ADDRS_DEMOD: Demod tuner addresses. Represent the following I2C addresses: 0x42, 0x43, 0x4a and 0x4b.
ADDRS_TV: TV tuner addresses. Represent the following I2C addresses: 0x42, 0x43, 0x4a, 0x4b, 0x60, 0x61, 0x62, 0x63 and 0x64.
ADDRS_TV_WITH_DEMOD: TV tuner addresses if demod is present, this excludes addresses used by the demodulator from the list of candidates. Represent the following I2C addresses: 0x60, 0x61, 0x62, 0x63 and 0x64.

NOTE

All I2C addresses above use the 7-bit notation.

struct v4l2_subdev *v4l2_i2c_new_subdev(struct v4l2_device *v4l2_dev, struct i2c_adapter *adapter, const char *client_type, u8 addr, const unsigned short *probe_addrs)¶: Load an i2c module and return an initialized struct v4l2_subdev.

Parameters

struct v4l2_device *v4l2_dev: pointer to struct v4l2_device
struct i2c_adapter *adapter: pointer to struct i2c_adapter
const char *client_type: name of the chip that’s on the adapter.
u8 addr: I2C address. If zero, it will use probe_addrs
const unsigned short *probe_addrs: array with a list of address. The last entry at such array should be I2C_CLIENT_END.

Description

returns a struct v4l2_subdev pointer.

struct v4l2_subdev *v4l2_i2c_new_subdev_board(struct v4l2_device *v4l2_dev, struct i2c_adapter *adapter, struct i2c_board_info *info, const unsigned short *probe_addrs)¶: Load an i2c module and return an initialized struct v4l2_subdev.

Parameters

struct v4l2_device *v4l2_dev: pointer to struct v4l2_device
struct i2c_adapter *adapter: pointer to struct i2c_adapter
struct i2c_board_info *info: pointer to struct i2c_board_info used to replace the irq, platform_data and addr arguments.
const unsigned short *probe_addrs: array with a list of address. The last entry at such array should be I2C_CLIENT_END.

Description

returns a struct v4l2_subdev pointer.

void v4l2_i2c_subdev_set_name(struct v4l2_subdev *sd, struct i2c_client *client, const char *devname, const char *postfix)¶: Set name for an I²C sub-device

Parameters

struct v4l2_subdev *sd: pointer to struct v4l2_subdev
struct i2c_client *client: pointer to struct i2c_client
const char *devname: the name of the device; if NULL, the I²C device drivers’s name will be used
const char *postfix: sub-device specific string to put right after the I²C device name; may be NULL

void v4l2_i2c_subdev_init(struct v4l2_subdev *sd, struct i2c_client *client, const struct v4l2_subdev_ops *ops)¶: Initializes a struct v4l2_subdev with data from an i2c_client struct.

Parameters

struct v4l2_subdev *sd: pointer to struct v4l2_subdev
struct i2c_client *client: pointer to struct i2c_client
const struct v4l2_subdev_ops *ops: pointer to struct v4l2_subdev_ops

unsigned short v4l2_i2c_subdev_addr(struct v4l2_subdev *sd)¶: returns i2c client address of struct v4l2_subdev.

Parameters

struct v4l2_subdev *sd: pointer to struct v4l2_subdev

Description

Returns the address of an I2C sub-device

const unsigned short *v4l2_i2c_tuner_addrs(enum v4l2_i2c_tuner_type type)¶: Return a list of I2C tuner addresses to probe.

Parameters

enum v4l2_i2c_tuner_type type: type of the tuner to seek, as defined by enum v4l2_i2c_tuner_type.

NOTE

Use only if the tuner addresses are unknown.

void v4l2_i2c_subdev_unregister(struct v4l2_subdev *sd)¶: Unregister a v4l2_subdev

Parameters

struct v4l2_subdev *sd: pointer to struct v4l2_subdev

struct v4l2_subdev *v4l2_spi_new_subdev(struct v4l2_device *v4l2_dev, struct spi_controller *ctlr, struct spi_board_info *info)¶: Load an spi module and return an initialized struct v4l2_subdev.

Parameters

struct v4l2_device *v4l2_dev: pointer to struct v4l2_device.
struct spi_controller *ctlr: pointer to struct spi_controller.
struct spi_board_info *info: pointer to struct spi_board_info.

Description

returns a struct v4l2_subdev pointer.

void v4l2_spi_subdev_init(struct v4l2_subdev *sd, struct spi_device *spi, const struct v4l2_subdev_ops *ops)¶: Initialize a v4l2_subdev with data from an spi_device struct.

Parameters

struct v4l2_subdev *sd: pointer to struct v4l2_subdev
struct spi_device *spi: pointer to struct spi_device.
const struct v4l2_subdev_ops *ops: pointer to struct v4l2_subdev_ops

void v4l2_spi_subdev_unregister(struct v4l2_subdev *sd)¶: Unregister a v4l2_subdev

Parameters

struct v4l2_subdev *sd: pointer to struct v4l2_subdev

void v4l_bound_align_image(unsigned int *width, unsigned int wmin, unsigned int wmax, unsigned int walign, unsigned int *height, unsigned int hmin, unsigned int hmax, unsigned int halign, unsigned int salign)¶: adjust video dimensions according to a given constraints.

Parameters

unsigned int *width: pointer to width that will be adjusted if needed.
unsigned int wmin: minimum width.
unsigned int wmax: maximum width.
unsigned int walign: least significant bit on width.
unsigned int *height: pointer to height that will be adjusted if needed.
unsigned int hmin: minimum height.
unsigned int hmax: maximum height.
unsigned int halign: least significant bit on height.
unsigned int salign: least significant bit for the image size (e. g. $width * height$ ).

Description

Clip an image to have width between wmin and wmax, and height between hmin and hmax, inclusive.

Additionally, the width will be a multiple of $2^{walign}$ , the height will be a multiple of $2^{halign}$ , and the overall size $width * height$ will be a multiple of $2^{salign}$ .

Note

The clipping rectangle may be shrunk or enlarged to fit the alignment constraints.
wmax must not be smaller than wmin.
hmax must not be smaller than hmin.
The alignments must not be so high there are no possible image sizes within the allowed bounds.
wmin and hmin must be at least 1 (don’t use 0).
For walign, halign and salign, if you don’t care about a certain alignment, specify 0, as $2^0 = 1$ and one byte alignment is equivalent to no alignment.
If you only want to adjust downward, specify a maximum that’s the same as the initial value.

v4l2_find_nearest_size¶

v4l2_find_nearest_size (array, array_size, width_field, height_field, width, height)

Find the nearest size among a discrete set of resolutions contained in an array of a driver specific struct.

Parameters

array: a driver specific array of image sizes
array_size: the length of the driver specific array of image sizes
width_field: the name of the width field in the driver specific struct
height_field: the name of the height field in the driver specific struct
width: desired width.
height: desired height.

Description

Finds the closest resolution to minimize the width and height differences between what requested and the supported resolutions. The size of the width and height fields in the driver specific must equal to that of u32, i.e. four bytes.

Returns the best match or NULL if the length of the array is zero.

int v4l2_g_parm_cap(struct video_device *vdev, struct v4l2_subdev *sd, struct v4l2_streamparm *a)¶: helper routine for vidioc_g_parm to fill this in by calling the get_frame_interval op of the given subdev. It only works for V4L2_BUF_TYPE_VIDEO_CAPTURE(_MPLANE), hence the _cap in the function name.

Parameters

struct video_device *vdev: the struct video_device pointer. Used to determine the device caps.
struct v4l2_subdev *sd: the sub-device pointer.
struct v4l2_streamparm *a: the VIDIOC_G_PARM argument.

int v4l2_s_parm_cap(struct video_device *vdev, struct v4l2_subdev *sd, struct v4l2_streamparm *a)¶: helper routine for vidioc_s_parm to fill this in by calling the set_frame_interval op of the given subdev. It only works for V4L2_BUF_TYPE_VIDEO_CAPTURE(_MPLANE), hence the _cap in the function name.

Parameters

struct video_device *vdev: the struct video_device pointer. Used to determine the device caps.
struct v4l2_subdev *sd: the sub-device pointer.
struct v4l2_streamparm *a: the VIDIOC_S_PARM argument.

enum v4l2_pixel_encoding¶: specifies the pixel encoding value

Constants

V4L2_PIXEL_ENC_UNKNOWN: Pixel encoding is unknown/un-initialized
V4L2_PIXEL_ENC_YUV: Pixel encoding is YUV
V4L2_PIXEL_ENC_RGB: Pixel encoding is RGB
V4L2_PIXEL_ENC_BAYER: Pixel encoding is Bayer

struct v4l2_format_info¶: information about a V4L2 format

Definition:

struct v4l2_format_info {
    u32 format;
    u8 pixel_enc;
    u8 mem_planes;
    u8 comp_planes;
    u8 bpp[4];
    u8 bpp_div[4];
    u8 hdiv;
    u8 vdiv;
    u8 block_w[4];
    u8 block_h[4];
};

Members

format: 4CC format identifier (V4L2_PIX_FMT_*)
pixel_enc: Pixel encoding (see enum v4l2_pixel_encoding above)
mem_planes: Number of memory planes, which includes the alpha plane (1 to 4).
comp_planes: Number of component planes, which includes the alpha plane (1 to 4).
bpp: Array of per-plane bytes per pixel
bpp_div: Array of per-plane bytes per pixel divisors to support fractional pixel sizes.
hdiv: Horizontal chroma subsampling factor
vdiv: Vertical chroma subsampling factor
block_w: Per-plane macroblock pixel width (optional)
block_h: Per-plane macroblock pixel height (optional)

s64 v4l2_get_link_freq(struct v4l2_ctrl_handler *handler, unsigned int mul, unsigned int div)¶: Get link rate from transmitter

Parameters

struct v4l2_ctrl_handler *handler: The transmitter’s control handler
unsigned int mul: The multiplier between pixel rate and link frequency. Bits per pixel on D-PHY, samples per clock on parallel. 0 otherwise.
unsigned int div: The divisor between pixel rate and link frequency. Number of data lanes times two on D-PHY, 1 on parallel. 0 otherwise.

Description

This function is intended for obtaining the link frequency from the transmitter sub-devices. It returns the link rate, either from the V4L2_CID_LINK_FREQ control implemented by the transmitter, or value calculated based on the V4L2_CID_PIXEL_RATE implemented by the transmitter.

Return

>0: Link frequency
-ENOENT: Link frequency or pixel rate control not found
-EINVAL: Invalid link frequency value

int v4l2_link_freq_to_bitmap(struct device *dev, const u64 *fw_link_freqs, unsigned int num_of_fw_link_freqs, const s64 *driver_link_freqs, unsigned int num_of_driver_link_freqs, unsigned long *bitmap)¶: Figure out platform-supported link frequencies

Parameters

struct device *dev: The struct device
const u64 *fw_link_freqs: Array of link frequencies from firmware
unsigned int num_of_fw_link_freqs: Number of entries in fw_link_freqs
const s64 *driver_link_freqs: Array of link frequencies supported by the driver
unsigned int num_of_driver_link_freqs: Number of entries in driver_link_freqs
unsigned long *bitmap: Bitmap of driver-supported link frequencies found in fw_link_freqs

Description

This function checks which driver-supported link frequencies are enabled in system firmware and sets the corresponding bits in bitmap (after first zeroing it).

Return

0: Success
-ENOENT: No match found between driver-supported link frequencies and those available in firmware.
-ENODATA: No link frequencies were specified in firmware.

struct v4l2_ioctl_ops¶: describe operations for each V4L2 ioctl

Definition:

struct v4l2_ioctl_ops {
    int (*vidioc_querycap)(struct file *file, void *fh, struct v4l2_capability *cap);
    int (*vidioc_enum_fmt_vid_cap)(struct file *file, void *fh, struct v4l2_fmtdesc *f);
    int (*vidioc_enum_fmt_vid_overlay)(struct file *file, void *fh, struct v4l2_fmtdesc *f);
    int (*vidioc_enum_fmt_vid_out)(struct file *file, void *fh, struct v4l2_fmtdesc *f);
    int (*vidioc_enum_fmt_sdr_cap)(struct file *file, void *fh, struct v4l2_fmtdesc *f);
    int (*vidioc_enum_fmt_sdr_out)(struct file *file, void *fh, struct v4l2_fmtdesc *f);
    int (*vidioc_enum_fmt_meta_cap)(struct file *file, void *fh, struct v4l2_fmtdesc *f);
    int (*vidioc_enum_fmt_meta_out)(struct file *file, void *fh, struct v4l2_fmtdesc *f);
    int (*vidioc_g_fmt_vid_cap)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_g_fmt_vid_overlay)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_g_fmt_vid_out)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_g_fmt_vid_out_overlay)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_g_fmt_vbi_cap)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_g_fmt_vbi_out)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_g_fmt_sliced_vbi_cap)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_g_fmt_sliced_vbi_out)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_g_fmt_vid_cap_mplane)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_g_fmt_vid_out_mplane)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_g_fmt_sdr_cap)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_g_fmt_sdr_out)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_g_fmt_meta_cap)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_g_fmt_meta_out)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_s_fmt_vid_cap)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_s_fmt_vid_overlay)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_s_fmt_vid_out)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_s_fmt_vid_out_overlay)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_s_fmt_vbi_cap)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_s_fmt_vbi_out)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_s_fmt_sliced_vbi_cap)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_s_fmt_sliced_vbi_out)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_s_fmt_vid_cap_mplane)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_s_fmt_vid_out_mplane)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_s_fmt_sdr_cap)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_s_fmt_sdr_out)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_s_fmt_meta_cap)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_s_fmt_meta_out)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_try_fmt_vid_cap)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_try_fmt_vid_overlay)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_try_fmt_vid_out)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_try_fmt_vid_out_overlay)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_try_fmt_vbi_cap)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_try_fmt_vbi_out)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_try_fmt_sliced_vbi_cap)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_try_fmt_sliced_vbi_out)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_try_fmt_vid_cap_mplane)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_try_fmt_vid_out_mplane)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_try_fmt_sdr_cap)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_try_fmt_sdr_out)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_try_fmt_meta_cap)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_try_fmt_meta_out)(struct file *file, void *fh, struct v4l2_format *f);
    int (*vidioc_reqbufs)(struct file *file, void *fh, struct v4l2_requestbuffers *b);
    int (*vidioc_querybuf)(struct file *file, void *fh, struct v4l2_buffer *b);
    int (*vidioc_qbuf)(struct file *file, void *fh, struct v4l2_buffer *b);
    int (*vidioc_expbuf)(struct file *file, void *fh, struct v4l2_exportbuffer *e);
    int (*vidioc_dqbuf)(struct file *file, void *fh, struct v4l2_buffer *b);
    int (*vidioc_create_bufs)(struct file *file, void *fh, struct v4l2_create_buffers *b);
    int (*vidioc_prepare_buf)(struct file *file, void *fh, struct v4l2_buffer *b);
    int (*vidioc_remove_bufs)(struct file *file, void *fh, struct v4l2_remove_buffers *d);
    int (*vidioc_overlay)(struct file *file, void *fh, unsigned int i);
    int (*vidioc_g_fbuf)(struct file *file, void *fh, struct v4l2_framebuffer *a);
    int (*vidioc_s_fbuf)(struct file *file, void *fh, const struct v4l2_framebuffer *a);
    int (*vidioc_streamon)(struct file *file, void *fh, enum v4l2_buf_type i);
    int (*vidioc_streamoff)(struct file *file, void *fh, enum v4l2_buf_type i);
    int (*vidioc_g_std)(struct file *file, void *fh, v4l2_std_id *norm);
    int (*vidioc_s_std)(struct file *file, void *fh, v4l2_std_id norm);
    int (*vidioc_querystd)(struct file *file, void *fh, v4l2_std_id *a);
    int (*vidioc_enum_input)(struct file *file, void *fh, struct v4l2_input *inp);
    int (*vidioc_g_input)(struct file *file, void *fh, unsigned int *i);
    int (*vidioc_s_input)(struct file *file, void *fh, unsigned int i);
    int (*vidioc_enum_output)(struct file *file, void *fh, struct v4l2_output *a);
    int (*vidioc_g_output)(struct file *file, void *fh, unsigned int *i);
    int (*vidioc_s_output)(struct file *file, void *fh, unsigned int i);
    int (*vidioc_queryctrl)(struct file *file, void *fh, struct v4l2_queryctrl *a);
    int (*vidioc_query_ext_ctrl)(struct file *file, void *fh, struct v4l2_query_ext_ctrl *a);
    int (*vidioc_g_ctrl)(struct file *file, void *fh, struct v4l2_control *a);
    int (*vidioc_s_ctrl)(struct file *file, void *fh, struct v4l2_control *a);
    int (*vidioc_g_ext_ctrls)(struct file *file, void *fh, struct v4l2_ext_controls *a);
    int (*vidioc_s_ext_ctrls)(struct file *file, void *fh, struct v4l2_ext_controls *a);
    int (*vidioc_try_ext_ctrls)(struct file *file, void *fh, struct v4l2_ext_controls *a);
    int (*vidioc_querymenu)(struct file *file, void *fh, struct v4l2_querymenu *a);
    int (*vidioc_enumaudio)(struct file *file, void *fh, struct v4l2_audio *a);
    int (*vidioc_g_audio)(struct file *file, void *fh, struct v4l2_audio *a);
    int (*vidioc_s_audio)(struct file *file, void *fh, const struct v4l2_audio *a);
    int (*vidioc_enumaudout)(struct file *file, void *fh, struct v4l2_audioout *a);
    int (*vidioc_g_audout)(struct file *file, void *fh, struct v4l2_audioout *a);
    int (*vidioc_s_audout)(struct file *file, void *fh, const struct v4l2_audioout *a);
    int (*vidioc_g_modulator)(struct file *file, void *fh, struct v4l2_modulator *a);
    int (*vidioc_s_modulator)(struct file *file, void *fh, const struct v4l2_modulator *a);
    int (*vidioc_g_pixelaspect)(struct file *file, void *fh, int buf_type, struct v4l2_fract *aspect);
    int (*vidioc_g_selection)(struct file *file, void *fh, struct v4l2_selection *s);
    int (*vidioc_s_selection)(struct file *file, void *fh, struct v4l2_selection *s);
    int (*vidioc_g_jpegcomp)(struct file *file, void *fh, struct v4l2_jpegcompression *a);
    int (*vidioc_s_jpegcomp)(struct file *file, void *fh, const struct v4l2_jpegcompression *a);
    int (*vidioc_g_enc_index)(struct file *file, void *fh, struct v4l2_enc_idx *a);
    int (*vidioc_encoder_cmd)(struct file *file, void *fh, struct v4l2_encoder_cmd *a);
    int (*vidioc_try_encoder_cmd)(struct file *file, void *fh, struct v4l2_encoder_cmd *a);
    int (*vidioc_decoder_cmd)(struct file *file, void *fh, struct v4l2_decoder_cmd *a);
    int (*vidioc_try_decoder_cmd)(struct file *file, void *fh, struct v4l2_decoder_cmd *a);
    int (*vidioc_g_parm)(struct file *file, void *fh, struct v4l2_streamparm *a);
    int (*vidioc_s_parm)(struct file *file, void *fh, struct v4l2_streamparm *a);
    int (*vidioc_g_tuner)(struct file *file, void *fh, struct v4l2_tuner *a);
    int (*vidioc_s_tuner)(struct file *file, void *fh, const struct v4l2_tuner *a);
    int (*vidioc_g_frequency)(struct file *file, void *fh, struct v4l2_frequency *a);
    int (*vidioc_s_frequency)(struct file *file, void *fh, const struct v4l2_frequency *a);
    int (*vidioc_enum_freq_bands)(struct file *file, void *fh, struct v4l2_frequency_band *band);
    int (*vidioc_g_sliced_vbi_cap)(struct file *file, void *fh, struct v4l2_sliced_vbi_cap *a);
    int (*vidioc_log_status)(struct file *file, void *fh);
    int (*vidioc_s_hw_freq_seek)(struct file *file, void *fh, const struct v4l2_hw_freq_seek *a);
#ifdef CONFIG_VIDEO_ADV_DEBUG;
    int (*vidioc_g_register)(struct file *file, void *fh, struct v4l2_dbg_register *reg);
    int (*vidioc_s_register)(struct file *file, void *fh, const struct v4l2_dbg_register *reg);
    int (*vidioc_g_chip_info)(struct file *file, void *fh, struct v4l2_dbg_chip_info *chip);
#endif;
    int (*vidioc_enum_framesizes)(struct file *file, void *fh, struct v4l2_frmsizeenum *fsize);
    int (*vidioc_enum_frameintervals)(struct file *file, void *fh, struct v4l2_frmivalenum *fival);
    int (*vidioc_s_dv_timings)(struct file *file, void *fh, struct v4l2_dv_timings *timings);
    int (*vidioc_g_dv_timings)(struct file *file, void *fh, struct v4l2_dv_timings *timings);
    int (*vidioc_query_dv_timings)(struct file *file, void *fh, struct v4l2_dv_timings *timings);
    int (*vidioc_enum_dv_timings)(struct file *file, void *fh, struct v4l2_enum_dv_timings *timings);
    int (*vidioc_dv_timings_cap)(struct file *file, void *fh, struct v4l2_dv_timings_cap *cap);
    int (*vidioc_g_edid)(struct file *file, void *fh, struct v4l2_edid *edid);
    int (*vidioc_s_edid)(struct file *file, void *fh, struct v4l2_edid *edid);
    int (*vidioc_subscribe_event)(struct v4l2_fh *fh, const struct v4l2_event_subscription *sub);
    int (*vidioc_unsubscribe_event)(struct v4l2_fh *fh, const struct v4l2_event_subscription *sub);
    long (*vidioc_default)(struct file *file, void *fh, bool valid_prio, unsigned int cmd, void *arg);
};

Members

vidioc_querycap: pointer to the function that implements VIDIOC_QUERYCAP ioctl
vidioc_enum_fmt_vid_cap: pointer to the function that implements VIDIOC_ENUM_FMT ioctl logic for video capture in single and multi plane mode
vidioc_enum_fmt_vid_overlay: pointer to the function that implements VIDIOC_ENUM_FMT ioctl logic for video overlay
vidioc_enum_fmt_vid_out: pointer to the function that implements VIDIOC_ENUM_FMT ioctl logic for video output in single and multi plane mode
vidioc_enum_fmt_sdr_cap: pointer to the function that implements VIDIOC_ENUM_FMT ioctl logic for Software Defined Radio capture
vidioc_enum_fmt_sdr_out: pointer to the function that implements VIDIOC_ENUM_FMT ioctl logic for Software Defined Radio output
vidioc_enum_fmt_meta_cap: pointer to the function that implements VIDIOC_ENUM_FMT ioctl logic for metadata capture
vidioc_enum_fmt_meta_out: pointer to the function that implements VIDIOC_ENUM_FMT ioctl logic for metadata output
vidioc_g_fmt_vid_cap: pointer to the function that implements VIDIOC_G_FMT ioctl logic for video capture in single plane mode
vidioc_g_fmt_vid_overlay: pointer to the function that implements VIDIOC_G_FMT ioctl logic for video overlay
vidioc_g_fmt_vid_out: pointer to the function that implements VIDIOC_G_FMT ioctl logic for video out in single plane mode
vidioc_g_fmt_vid_out_overlay: pointer to the function that implements VIDIOC_G_FMT ioctl logic for video overlay output
vidioc_g_fmt_vbi_cap: pointer to the function that implements VIDIOC_G_FMT ioctl logic for raw VBI capture
vidioc_g_fmt_vbi_out: pointer to the function that implements VIDIOC_G_FMT ioctl logic for raw VBI output
vidioc_g_fmt_sliced_vbi_cap: pointer to the function that implements VIDIOC_G_FMT ioctl logic for sliced VBI capture
vidioc_g_fmt_sliced_vbi_out: pointer to the function that implements VIDIOC_G_FMT ioctl logic for sliced VBI output
vidioc_g_fmt_vid_cap_mplane: pointer to the function that implements VIDIOC_G_FMT ioctl logic for video capture in multiple plane mode
vidioc_g_fmt_vid_out_mplane: pointer to the function that implements VIDIOC_G_FMT ioctl logic for video out in multiplane plane mode
vidioc_g_fmt_sdr_cap: pointer to the function that implements VIDIOC_G_FMT ioctl logic for Software Defined Radio capture
vidioc_g_fmt_sdr_out: pointer to the function that implements VIDIOC_G_FMT ioctl logic for Software Defined Radio output
vidioc_g_fmt_meta_cap: pointer to the function that implements VIDIOC_G_FMT ioctl logic for metadata capture
vidioc_g_fmt_meta_out: pointer to the function that implements VIDIOC_G_FMT ioctl logic for metadata output
vidioc_s_fmt_vid_cap: pointer to the function that implements VIDIOC_S_FMT ioctl logic for video capture in single plane mode
vidioc_s_fmt_vid_overlay: pointer to the function that implements VIDIOC_S_FMT ioctl logic for video overlay
vidioc_s_fmt_vid_out: pointer to the function that implements VIDIOC_S_FMT ioctl logic for video out in single plane mode
vidioc_s_fmt_vid_out_overlay: pointer to the function that implements VIDIOC_S_FMT ioctl logic for video overlay output
vidioc_s_fmt_vbi_cap: pointer to the function that implements VIDIOC_S_FMT ioctl logic for raw VBI capture
vidioc_s_fmt_vbi_out: pointer to the function that implements VIDIOC_S_FMT ioctl logic for raw VBI output
vidioc_s_fmt_sliced_vbi_cap: pointer to the function that implements VIDIOC_S_FMT ioctl logic for sliced VBI capture
vidioc_s_fmt_sliced_vbi_out: pointer to the function that implements VIDIOC_S_FMT ioctl logic for sliced VBI output
vidioc_s_fmt_vid_cap_mplane: pointer to the function that implements VIDIOC_S_FMT ioctl logic for video capture in multiple plane mode
vidioc_s_fmt_vid_out_mplane: pointer to the function that implements VIDIOC_S_FMT ioctl logic for video out in multiplane plane mode
vidioc_s_fmt_sdr_cap: pointer to the function that implements VIDIOC_S_FMT ioctl logic for Software Defined Radio capture
vidioc_s_fmt_sdr_out: pointer to the function that implements VIDIOC_S_FMT ioctl logic for Software Defined Radio output
vidioc_s_fmt_meta_cap: pointer to the function that implements VIDIOC_S_FMT ioctl logic for metadata capture
vidioc_s_fmt_meta_out: pointer to the function that implements VIDIOC_S_FMT ioctl logic for metadata output
vidioc_try_fmt_vid_cap: pointer to the function that implements VIDIOC_TRY_FMT ioctl logic for video capture in single plane mode
vidioc_try_fmt_vid_overlay: pointer to the function that implements VIDIOC_TRY_FMT ioctl logic for video overlay
vidioc_try_fmt_vid_out: pointer to the function that implements VIDIOC_TRY_FMT ioctl logic for video out in single plane mode
vidioc_try_fmt_vid_out_overlay: pointer to the function that implements VIDIOC_TRY_FMT ioctl logic for video overlay output
vidioc_try_fmt_vbi_cap: pointer to the function that implements VIDIOC_TRY_FMT ioctl logic for raw VBI capture
vidioc_try_fmt_vbi_out: pointer to the function that implements VIDIOC_TRY_FMT ioctl logic for raw VBI output
vidioc_try_fmt_sliced_vbi_cap: pointer to the function that implements VIDIOC_TRY_FMT ioctl logic for sliced VBI capture
vidioc_try_fmt_sliced_vbi_out: pointer to the function that implements VIDIOC_TRY_FMT ioctl logic for sliced VBI output
vidioc_try_fmt_vid_cap_mplane: pointer to the function that implements VIDIOC_TRY_FMT ioctl logic for video capture in multiple plane mode
vidioc_try_fmt_vid_out_mplane: pointer to the function that implements VIDIOC_TRY_FMT ioctl logic for video out in multiplane plane mode
vidioc_try_fmt_sdr_cap: pointer to the function that implements VIDIOC_TRY_FMT ioctl logic for Software Defined Radio capture
vidioc_try_fmt_sdr_out: pointer to the function that implements VIDIOC_TRY_FMT ioctl logic for Software Defined Radio output
vidioc_try_fmt_meta_cap: pointer to the function that implements VIDIOC_TRY_FMT ioctl logic for metadata capture
vidioc_try_fmt_meta_out: pointer to the function that implements VIDIOC_TRY_FMT ioctl logic for metadata output
vidioc_reqbufs: pointer to the function that implements VIDIOC_REQBUFS ioctl
vidioc_querybuf: pointer to the function that implements VIDIOC_QUERYBUF ioctl
vidioc_qbuf: pointer to the function that implements VIDIOC_QBUF ioctl
vidioc_expbuf: pointer to the function that implements VIDIOC_EXPBUF ioctl
vidioc_dqbuf: pointer to the function that implements VIDIOC_DQBUF ioctl
vidioc_create_bufs: pointer to the function that implements VIDIOC_CREATE_BUFS ioctl
vidioc_prepare_buf: pointer to the function that implements VIDIOC_PREPARE_BUF ioctl
vidioc_remove_bufs: pointer to the function that implements VIDIOC_REMOVE_BUFS ioctl
vidioc_overlay: pointer to the function that implements VIDIOC_OVERLAY ioctl
vidioc_g_fbuf: pointer to the function that implements VIDIOC_G_FBUF ioctl
vidioc_s_fbuf: pointer to the function that implements VIDIOC_S_FBUF ioctl
vidioc_streamon: pointer to the function that implements VIDIOC_STREAMON ioctl
vidioc_streamoff: pointer to the function that implements VIDIOC_STREAMOFF ioctl
vidioc_g_std: pointer to the function that implements VIDIOC_G_STD ioctl
vidioc_s_std: pointer to the function that implements VIDIOC_S_STD ioctl
vidioc_querystd: pointer to the function that implements VIDIOC_QUERYSTD ioctl
vidioc_enum_input: pointer to the function that implements VIDIOC_ENUM_INPUT ioctl
vidioc_g_input: pointer to the function that implements VIDIOC_G_INPUT ioctl
vidioc_s_input: pointer to the function that implements VIDIOC_S_INPUT ioctl
vidioc_enum_output: pointer to the function that implements VIDIOC_ENUM_OUTPUT ioctl
vidioc_g_output: pointer to the function that implements VIDIOC_G_OUTPUT ioctl
vidioc_s_output: pointer to the function that implements VIDIOC_S_OUTPUT ioctl
vidioc_queryctrl: pointer to the function that implements VIDIOC_QUERYCTRL ioctl
vidioc_query_ext_ctrl: pointer to the function that implements VIDIOC_QUERY_EXT_CTRL ioctl
vidioc_g_ctrl: pointer to the function that implements VIDIOC_G_CTRL ioctl
vidioc_s_ctrl: pointer to the function that implements VIDIOC_S_CTRL ioctl
vidioc_g_ext_ctrls: pointer to the function that implements VIDIOC_G_EXT_CTRLS ioctl
vidioc_s_ext_ctrls: pointer to the function that implements VIDIOC_S_EXT_CTRLS ioctl
vidioc_try_ext_ctrls: pointer to the function that implements VIDIOC_TRY_EXT_CTRLS ioctl
vidioc_querymenu: pointer to the function that implements VIDIOC_QUERYMENU ioctl
vidioc_enumaudio: pointer to the function that implements VIDIOC_ENUMAUDIO ioctl
vidioc_g_audio: pointer to the function that implements VIDIOC_G_AUDIO ioctl
vidioc_s_audio: pointer to the function that implements VIDIOC_S_AUDIO ioctl
vidioc_enumaudout: pointer to the function that implements VIDIOC_ENUMAUDOUT ioctl
vidioc_g_audout: pointer to the function that implements VIDIOC_G_AUDOUT ioctl
vidioc_s_audout: pointer to the function that implements VIDIOC_S_AUDOUT ioctl
vidioc_g_modulator: pointer to the function that implements VIDIOC_G_MODULATOR ioctl
vidioc_s_modulator: pointer to the function that implements VIDIOC_S_MODULATOR ioctl
vidioc_g_pixelaspect: pointer to the function that implements the pixelaspect part of the VIDIOC_CROPCAP ioctl
vidioc_g_selection: pointer to the function that implements VIDIOC_G_SELECTION ioctl
vidioc_s_selection: pointer to the function that implements VIDIOC_S_SELECTION ioctl
vidioc_g_jpegcomp: pointer to the function that implements VIDIOC_G_JPEGCOMP ioctl
vidioc_s_jpegcomp: pointer to the function that implements VIDIOC_S_JPEGCOMP ioctl
vidioc_g_enc_index: pointer to the function that implements VIDIOC_G_ENC_INDEX ioctl
vidioc_encoder_cmd: pointer to the function that implements VIDIOC_ENCODER_CMD ioctl
vidioc_try_encoder_cmd: pointer to the function that implements VIDIOC_TRY_ENCODER_CMD ioctl
vidioc_decoder_cmd: pointer to the function that implements VIDIOC_DECODER_CMD ioctl
vidioc_try_decoder_cmd: pointer to the function that implements VIDIOC_TRY_DECODER_CMD ioctl
vidioc_g_parm: pointer to the function that implements VIDIOC_G_PARM ioctl
vidioc_s_parm: pointer to the function that implements VIDIOC_S_PARM ioctl
vidioc_g_tuner: pointer to the function that implements VIDIOC_G_TUNER ioctl
vidioc_s_tuner: pointer to the function that implements VIDIOC_S_TUNER ioctl
vidioc_g_frequency: pointer to the function that implements VIDIOC_G_FREQUENCY ioctl
vidioc_s_frequency: pointer to the function that implements VIDIOC_S_FREQUENCY ioctl
vidioc_enum_freq_bands: pointer to the function that implements VIDIOC_ENUM_FREQ_BANDS ioctl
vidioc_g_sliced_vbi_cap: pointer to the function that implements VIDIOC_G_SLICED_VBI_CAP ioctl
vidioc_log_status: pointer to the function that implements VIDIOC_LOG_STATUS ioctl
vidioc_s_hw_freq_seek: pointer to the function that implements VIDIOC_S_HW_FREQ_SEEK ioctl
vidioc_g_register: pointer to the function that implements VIDIOC_DBG_G_REGISTER ioctl
vidioc_s_register: pointer to the function that implements VIDIOC_DBG_S_REGISTER ioctl
vidioc_g_chip_info: pointer to the function that implements VIDIOC_DBG_G_CHIP_INFO ioctl
vidioc_enum_framesizes: pointer to the function that implements VIDIOC_ENUM_FRAMESIZES ioctl
vidioc_enum_frameintervals: pointer to the function that implements VIDIOC_ENUM_FRAMEINTERVALS ioctl
vidioc_s_dv_timings: pointer to the function that implements VIDIOC_S_DV_TIMINGS ioctl
vidioc_g_dv_timings: pointer to the function that implements VIDIOC_G_DV_TIMINGS ioctl
vidioc_query_dv_timings: pointer to the function that implements VIDIOC_QUERY_DV_TIMINGS ioctl
vidioc_enum_dv_timings: pointer to the function that implements VIDIOC_ENUM_DV_TIMINGS ioctl
vidioc_dv_timings_cap: pointer to the function that implements VIDIOC_DV_TIMINGS_CAP ioctl
vidioc_g_edid: pointer to the function that implements VIDIOC_G_EDID ioctl
vidioc_s_edid: pointer to the function that implements VIDIOC_S_EDID ioctl
vidioc_subscribe_event: pointer to the function that implements VIDIOC_SUBSCRIBE_EVENT ioctl
vidioc_unsubscribe_event: pointer to the function that implements VIDIOC_UNSUBSCRIBE_EVENT ioctl
vidioc_default: pointed used to allow other ioctls

const char *v4l2_norm_to_name(v4l2_std_id id)¶: Ancillary routine to analog TV standard name from its ID.

Parameters

v4l2_std_id id: analog TV standard ID.

Return

returns a string with the name of the analog TV standard. If the standard is not found or if id points to multiple standard, it returns “Unknown”.

void v4l2_video_std_frame_period(int id, struct v4l2_fract *frameperiod)¶: Ancillary routine that fills a struct v4l2_fract pointer with the default framerate fraction.

Parameters

int id: analog TV standard ID.
struct v4l2_fract *frameperiod: struct v4l2_fract pointer to be filled

int v4l2_video_std_construct(struct v4l2_standard *vs, int id, const char *name)¶: Ancillary routine that fills in the fields of a v4l2_standard structure according to the id parameter.

Parameters

struct v4l2_standard *vs: struct v4l2_standard pointer to be filled
int id: analog TV standard ID.
const char *name: name of the standard to be used

Description

Note

This ancillary routine is obsolete. Shouldn’t be used on newer drivers.

int v4l_video_std_enumstd(struct v4l2_standard *vs, v4l2_std_id id)¶: Ancillary routine that fills in the fields of a v4l2_standard structure according to the id and vs->index parameters.

Parameters

struct v4l2_standard *vs: struct v4l2_standard pointer to be filled.
v4l2_std_id id: analog TV standard ID.

void v4l_printk_ioctl(const char *prefix, unsigned int cmd)¶: Ancillary routine that prints the ioctl in a human-readable format.

Parameters

const char *prefix: prefix to be added at the ioctl prints.
unsigned int cmd: ioctl name

Description

Note

If prefix != NULL, then it will issue a printk(KERN_DEBUG "``s: “, prefix)`` first.

long int v4l2_compat_ioctl32(struct file *file, unsigned int cmd, unsigned long arg)¶: 32 Bits compatibility layer for 64 bits processors

Parameters

struct file *file: Pointer to struct file.
unsigned int cmd: Ioctl name.
unsigned long arg: Ioctl argument.

v4l2_kioctl¶: Typedef: Typedef used to pass an ioctl handler.

Syntax

long v4l2_kioctl (struct file *file, unsigned int cmd, void *arg)

Parameters

struct file *file: Pointer to struct file.
unsigned int cmd: Ioctl name.
void *arg: Ioctl argument.

long int video_usercopy(struct file *file, unsigned int cmd, unsigned long int arg, v4l2_kioctl func)¶: copies data from/to userspace memory when an ioctl is issued.

Parameters

struct file *file: Pointer to struct file.
unsigned int cmd: Ioctl name.
unsigned long int arg: Ioctl argument.
v4l2_kioctl func: function that will handle the ioctl

Description

Note

This routine should be used only inside the V4L2 core.

long int video_ioctl2(struct file *file, unsigned int cmd, unsigned long int arg)¶: Handles a V4L2 ioctl.

Parameters

struct file *file: Pointer to struct file.
unsigned int cmd: Ioctl name.
unsigned long int arg: Ioctl argument.

Description

Method used to hancle an ioctl. Should be used to fill the v4l2_ioctl_ops.unlocked_ioctl on all V4L2 drivers.

The Linux Kernel

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2.27. V4L2 common functions and data structures¶