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diff --git a/Documentation/media/uapi/v4l/dev-sdr.rst b/Documentation/media/uapi/v4l/dev-sdr.rst deleted file mode 100644 index 75595c58cb5b..000000000000 --- a/Documentation/media/uapi/v4l/dev-sdr.rst +++ /dev/null @@ -1,114 +0,0 @@ -.. 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/media/uapi/fdl-appendix.rst. -.. -.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections - -.. _sdr: - -************************************** -Software Defined Radio Interface (SDR) -************************************** - -SDR is an abbreviation of Software Defined Radio, the radio device which -uses application software for modulation or demodulation. This interface -is intended for controlling and data streaming of such devices. - -SDR devices are accessed through character device special files named -``/dev/swradio0`` to ``/dev/swradio255`` with major number 81 and -dynamically allocated minor numbers 0 to 255. - - -Querying Capabilities -===================== - -Devices supporting the SDR receiver interface set the -``V4L2_CAP_SDR_CAPTURE`` and ``V4L2_CAP_TUNER`` flag in the -``capabilities`` field of struct -:c:type:`v4l2_capability` returned by the -:ref:`VIDIOC_QUERYCAP` ioctl. That flag means the -device has an Analog to Digital Converter (ADC), which is a mandatory -element for the SDR receiver. - -Devices supporting the SDR transmitter interface set the -``V4L2_CAP_SDR_OUTPUT`` and ``V4L2_CAP_MODULATOR`` flag in the -``capabilities`` field of struct -:c:type:`v4l2_capability` returned by the -:ref:`VIDIOC_QUERYCAP` ioctl. That flag means the -device has an Digital to Analog Converter (DAC), which is a mandatory -element for the SDR transmitter. - -At least one of the read/write, streaming or asynchronous I/O methods -must be supported. - - -Supplemental Functions -====================== - -SDR devices can support :ref:`controls <control>`, and must support -the :ref:`tuner` ioctls. Tuner ioctls are used for setting the -ADC/DAC sampling rate (sampling frequency) and the possible radio -frequency (RF). - -The ``V4L2_TUNER_SDR`` tuner type is used for setting SDR device ADC/DAC -frequency, and the ``V4L2_TUNER_RF`` tuner type is used for setting -radio frequency. The tuner index of the RF tuner (if any) must always -follow the SDR tuner index. Normally the SDR tuner is #0 and the RF -tuner is #1. - -The :ref:`VIDIOC_S_HW_FREQ_SEEK` ioctl is -not supported. - - -Data Format Negotiation -======================= - -The SDR device uses the :ref:`format` ioctls to select the -capture and output format. Both the sampling resolution and the data -streaming format are bound to that selectable format. In addition to the -basic :ref:`format` ioctls, the -:ref:`VIDIOC_ENUM_FMT` ioctl must be supported as -well. - -To use the :ref:`format` ioctls applications set the ``type`` -field of a struct :c:type:`v4l2_format` to -``V4L2_BUF_TYPE_SDR_CAPTURE`` or ``V4L2_BUF_TYPE_SDR_OUTPUT`` and use -the struct :c:type:`v4l2_sdr_format` ``sdr`` member -of the ``fmt`` union as needed per the desired operation. Currently -there is two fields, ``pixelformat`` and ``buffersize``, of struct -struct :c:type:`v4l2_sdr_format` which are used. -Content of the ``pixelformat`` is V4L2 FourCC code of the data format. -The ``buffersize`` field is maximum buffer size in bytes required for -data transfer, set by the driver in order to inform application. - - -.. c:type:: v4l2_sdr_format - -.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| - -.. flat-table:: struct v4l2_sdr_format - :header-rows: 0 - :stub-columns: 0 - :widths: 1 1 2 - - * - __u32 - - ``pixelformat`` - - The data format or type of compression, set by the application. - This is a little endian - :ref:`four character code <v4l2-fourcc>`. V4L2 defines SDR - formats in :ref:`sdr-formats`. - * - __u32 - - ``buffersize`` - - Maximum size in bytes required for data. Value is set by the - driver. - * - __u8 - - ``reserved[24]`` - - This array is reserved for future extensions. Drivers and - applications must set it to zero. - - -An SDR device may support :ref:`read/write <rw>` and/or streaming -(:ref:`memory mapping <mmap>` or :ref:`user pointer <userp>`) I/O. |