ioctl VIDIOC_S_HW_FREQ_SEEK

&manvol;

VIDIOC_S_HW_FREQ_SEEK

Perform a hardware frequency seek

    	int ioctl
    	int fd
    	int request
    	struct v4l2_hw_freq_seek
    *argp

## Arguments

`fd`

- &fd;

`request`

- VIDIOC_S_HW_FREQ_SEEK

`argp`

## Description

Start a hardware frequency seek from the current frequency. To do this applications initialize the tuner, type, seek_upward, wrap_around, spacing, rangelow and rangehigh fields, and zero out the reserved array of a &v4l2-hw-freq-seek; and call the `VIDIOC_S_HW_FREQ_SEEK` ioctl with a pointer to this structure.

The rangelow and rangehigh fields can be set to a non-zero value to tell the driver to search a specific band. If the &v4l2-tuner; capability field has the `V4L2_TUNER_CAP_HWSEEK_PROG_LIM` flag set, these values must fall within one of the bands returned by &VIDIOC-ENUM-FREQ-BANDS;. If the `V4L2_TUNER_CAP_HWSEEK_PROG_LIM` flag is not set, then these values must exactly match those of one of the bands returned by &VIDIOC-ENUM-FREQ-BANDS;. If the current frequency of the tuner does not fall within the selected band it will be clamped to fit in the band before the seek is started.

If an error is returned, then the original frequency will be restored.

This ioctl is supported if the `V4L2_CAP_HW_FREQ_SEEK` capability is set.

If this ioctl is called from a non-blocking filehandle, then &EAGAIN; is returned and no seek takes place.

## struct v4l2_hw_freq_seek

&cs-str;
__u32 | tuner | The tuner index number. This is the same value as in the &v4l2-input; tuner field and the &v4l2-tuner; index field.
__u32 | type | The tuner type. This is the same value as in the &v4l2-tuner; type field. See v4l2-tuner-type
__u32 | seek_upward | If non-zero, seek upward from the current frequency, else seek downward.
__u32 | wrap_around | If non-zero, wrap around when at the end of the frequency range, else stop seeking. The &v4l2-tuner; capability field will tell you what the hardware supports.
__u32 | spacing | If non-zero, defines the hardware seek resolution in Hz. The driver selects the nearest value that is supported by the device. If spacing is zero a reasonable default value is used.
__u32 | rangelow | If non-zero, the lowest tunable frequency of the band to search in units of 62.5 kHz, or if the &v4l2-tuner; capability field has the `V4L2_TUNER_CAP_LOW` flag set, in units of 62.5 Hz or if the &v4l2-tuner; capability field has the `V4L2_TUNER_CAP_1HZ` flag set, in units of 1 Hz. If rangelow is zero a reasonable default value is used.
__u32 | rangehigh | If non-zero, the highest tunable frequency of the band to search in units of 62.5 kHz, or if the &v4l2-tuner; capability field has the `V4L2_TUNER_CAP_LOW` flag set, in units of 62.5 Hz or if the &v4l2-tuner; capability field has the `V4L2_TUNER_CAP_1HZ` flag set, in units of 1 Hz. If rangehigh is zero a reasonable default value is used.
__u32 | reserved[5] | Reserved for future extensions. Applications must set the array to zero.

&return-value;

EINVAL

- The tuner index is out of bounds, the wrap_around value is not supported or one of the values in the type, rangelow or rangehigh fields is wrong.

EAGAIN

- Attempted to call `VIDIOC_S_HW_FREQ_SEEK` with the filehandle in non-blocking mode.

ENODATA

- The hardware seek found no channels.

EBUSY

- Another hardware seek is already in progress.