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
__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.
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.
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.