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+.. Permission is granted to copy, distribute and/or modify this
+.. document under the terms of the GNU Free Documentation License,
+.. Version 1.1 or any later version published by the Free Software
+.. Foundation, with no Invariant Sections, no Front-Cover Texts
+.. and no Back-Cover Texts. A copy of the license is included at
+.. Documentation/userspace-api/media/fdl-appendix.rst.
+..
+.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
+
+.. _VIDIOC_S_HW_FREQ_SEEK:
+
+***************************
+ioctl VIDIOC_S_HW_FREQ_SEEK
+***************************
+
+Name
+====
+
+VIDIOC_S_HW_FREQ_SEEK - Perform a hardware frequency seek
+
+
+Synopsis
+========
+
+.. c:function:: int ioctl( int fd, VIDIOC_S_HW_FREQ_SEEK, struct v4l2_hw_freq_seek *argp )
+ :name: VIDIOC_S_HW_FREQ_SEEK
+
+
+Arguments
+=========
+
+``fd``
+ File descriptor returned by :ref:`open() <func-open>`.
+
+``argp``
+ Pointer to struct :c:type:`v4l2_hw_freq_seek`.
+
+
+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 struct
+:c:type:`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 struct
+:c:type:`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
+:ref:`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
+:ref:`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``
+error code is returned and no seek takes place.
+
+
+.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
+
+.. c:type:: v4l2_hw_freq_seek
+
+.. flat-table:: struct v4l2_hw_freq_seek
+ :header-rows: 0
+ :stub-columns: 0
+ :widths: 1 1 2
+
+ * - __u32
+ - ``tuner``
+ - The tuner index number. This is the same value as in the struct
+ :c:type:`v4l2_input` ``tuner`` field and the struct
+ :c:type:`v4l2_tuner` ``index`` field.
+ * - __u32
+ - ``type``
+ - The tuner type. This is the same value as in the struct
+ :c:type:`v4l2_tuner` ``type`` field. See
+ :c:type:`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 struct :c:type:`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 struct
+ :c:type:`v4l2_tuner` ``capability`` field has the
+ ``V4L2_TUNER_CAP_LOW`` flag set, in units of 62.5 Hz or if the
+ struct :c:type:`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 struct
+ :c:type:`v4l2_tuner` ``capability`` field has the
+ ``V4L2_TUNER_CAP_LOW`` flag set, in units of 62.5 Hz or if the
+ struct :c:type:`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
+============
+
+On success 0 is returned, on error -1 and the ``errno`` variable is set
+appropriately. The generic error codes are described at the
+:ref:`Generic Error Codes <gen-errors>` chapter.
+
+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.