From: Hans Verkuil <hverkuil@xs4all.nl>
To: Antti Palosaari <crope@iki.fi>
Cc: linux-media@vger.kernel.org
Subject: Re: [REVIEW PATCH 10/13] DocBook: Software Defined Radio Interface
Date: Sat, 25 Jan 2014 09:26:27 +0100 [thread overview]
Message-ID: <52E37533.6010607@xs4all.nl> (raw)
In-Reply-To: <1390511333-25837-11-git-send-email-crope@iki.fi>
A few comments below...
On 01/23/2014 10:08 PM, Antti Palosaari wrote:
> Document V4L2 SDR interface.
>
> Cc: Hans Verkuil <hverkuil@xs4all.nl>
> Signed-off-by: Antti Palosaari <crope@iki.fi>
> ---
> Documentation/DocBook/media/v4l/compat.xml | 10 ++
> Documentation/DocBook/media/v4l/dev-sdr.xml | 104 +++++++++++++++++++++
> Documentation/DocBook/media/v4l/io.xml | 6 ++
> Documentation/DocBook/media/v4l/pixfmt.xml | 8 ++
> Documentation/DocBook/media/v4l/v4l2.xml | 1 +
> Documentation/DocBook/media/v4l/vidioc-g-fmt.xml | 7 ++
> .../DocBook/media/v4l/vidioc-querycap.xml | 6 ++
> 7 files changed, 142 insertions(+)
> create mode 100644 Documentation/DocBook/media/v4l/dev-sdr.xml
>
> diff --git a/Documentation/DocBook/media/v4l/compat.xml b/Documentation/DocBook/media/v4l/compat.xml
> index c4cac6d..83f64ce 100644
> --- a/Documentation/DocBook/media/v4l/compat.xml
> +++ b/Documentation/DocBook/media/v4l/compat.xml
> @@ -2535,6 +2535,16 @@ fields changed from _s32 to _u32.
> </orderedlist>
> </section>
>
> + <section>
> + <title>V4L2 in Linux 3.14</title>
This should be 3.15.
> + <orderedlist>
> + <listitem>
> + <para>Added Software Defined Radio (SDR) Interface.
> + </para>
> + </listitem>
> + </orderedlist>
> + </section>
> +
> <section id="other">
> <title>Relation of V4L2 to other Linux multimedia APIs</title>
>
> diff --git a/Documentation/DocBook/media/v4l/dev-sdr.xml b/Documentation/DocBook/media/v4l/dev-sdr.xml
> new file mode 100644
> index 0000000..332b87f
> --- /dev/null
> +++ b/Documentation/DocBook/media/v4l/dev-sdr.xml
> @@ -0,0 +1,104 @@
> + <title>Software Defined Radio Interface (SDR)</title>
> +
> + <para>
> +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.
> + </para>
> +
> + <para>
> +SDR devices are accessed through character device special files named
> +<filename>/dev/swradio0</filename> to <filename>/dev/swradio255</filename>
> +with major number 81 and dynamically allocated minor numbers 0 to 255.
> + </para>
> +
> + <section>
> + <title>Querying Capabilities</title>
> +
> + <para>
> +Devices supporting the SDR receiver interface set the
> +<constant>V4L2_CAP_SDR_CAPTURE</constant> and
> +<constant>V4L2_CAP_TUNER</constant> flag in the
> +<structfield>capabilities</structfield> field of &v4l2-capability;
> +returned by the &VIDIOC-QUERYCAP; ioctl. That flag means the device has an
> +Analog to Digital Converter (ADC), which is a mandatory element for the SDR receiver.
> +At least one of the read/write, streaming or asynchronous I/O methods must
> +be supported.
> + </para>
> + </section>
> +
> + <section>
> + <title>Supplemental Functions</title>
> +
> + <para>
> +SDR devices can support <link linkend="control">controls</link>, and must
> +support the <link linkend="tuner">tuner</link> ioctls. Tuner ioctls are used
> +for setting the ADC sampling rate (sampling frequency) and the possible RF tuner
> +frequency.
> + </para>
> +
> + <para>
> +The <constant>V4L2_TUNER_ADC</constant> tuner type is used for ADC tuners, and
> +the <constant>V4L2_TUNER_RF</constant> tuner type is used for RF tuners. The
> +tuner index of the RF tuner (if any) must always follow the ADC tuner index.
> +Normally the ADC tuner is #0 and the RF tuner is #1.
> + </para>
> +
> + <para>
> +The &VIDIOC-S-HW-FREQ-SEEK; ioctl is not supported.
> + </para>
> + </section>
> +
> + <section>
> + <title>Data Format Negotiation</title>
> +
> + <para>
> +The SDR capture device uses the <link linkend="format">format</link> ioctls to
> +select the capture format. Both the sampling resolution and the data streaming
I understand why the data streaming format is bound to the format, but why is
the sampling resolution bound by it as well?
> +format are bound to that selectable format. In addition to the basic
> +<link linkend="format">format</link> ioctls, the &VIDIOC-ENUM-FMT; ioctl
> +must be supported as well.
> + </para>
> +
> + <para>
> +To use the <link linkend="format">format</link> ioctls applications set the
> +<structfield>type</structfield> field of a &v4l2-format; to
> +<constant>V4L2_BUF_TYPE_SDR_CAPTURE</constant> and use the &v4l2-format-sdr;
> +<structfield>sdr</structfield> member of the <structfield>fmt</structfield>
> +union as needed per the desired operation.
> +Currently only the <structfield>pixelformat</structfield> field of
> +&v4l2-format-sdr; is used. The content of that field is the V4L2 fourcc code
> +of the data format.
> + </para>
> +
> + <table pgwide="1" frame="none" id="v4l2-format-sdr">
> + <title>struct <structname>v4l2_format_sdr</structname></title>
> + <tgroup cols="3">
> + &cs-str;
> + <tbody valign="top">
> + <row>
> + <entry>__u32</entry>
> + <entry><structfield>pixelformat</structfield></entry>
> + <entry>
> +The data format or type of compression, set by the application. This is a
> +little endian <link linkend="v4l2-fourcc">four character code</link>.
> +V4L2 defines SDR formats in <xref linkend="sdr-formats" />.
> + </entry>
> + </row>
> + <row>
> + <entry>__u8</entry>
> + <entry><structfield>reserved[28]</structfield></entry>
> + <entry>This array is reserved for future extensions.
> +Drivers and applications must set it to zero.</entry>
> + </row>
> + </tbody>
> + </tgroup>
> + </table>
> +
> + <para>
> +An SDR device may support <link linkend="rw">read/write</link>
> +and/or streaming (<link linkend="mmap">memory mapping</link>
> +or <link linkend="userp">user pointer</link>) I/O.
> + </para>
> +
> + </section>
> diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml
> index 2c4c068..1fb11e8 100644
> --- a/Documentation/DocBook/media/v4l/io.xml
> +++ b/Documentation/DocBook/media/v4l/io.xml
> @@ -1005,6 +1005,12 @@ should set this to 0.</entry>
> <entry>Buffer for video output overlay (OSD), see <xref
> linkend="osd" />.</entry>
> </row>
> + <row>
> + <entry><constant>V4L2_BUF_TYPE_SDR_CAPTURE</constant></entry>
> + <entry>11</entry>
> + <entry>Buffer for Software Defined Radio (SDR), see <xref
> + linkend="sdr" />.</entry>
> + </row>
> </tbody>
> </tgroup>
> </table>
> diff --git a/Documentation/DocBook/media/v4l/pixfmt.xml b/Documentation/DocBook/media/v4l/pixfmt.xml
> index 72d72bd..f586d34 100644
> --- a/Documentation/DocBook/media/v4l/pixfmt.xml
> +++ b/Documentation/DocBook/media/v4l/pixfmt.xml
> @@ -811,6 +811,14 @@ extended control <constant>V4L2_CID_MPEG_STREAM_TYPE</constant>, see
> </table>
> </section>
>
> + <section id="sdr-formats">
> + <title>SDR Formats</title>
> +
> + <para>These formats are used for <link linkend="sdr">SDR Capture</link>
> +interface only.</para>
> +
> + </section>
> +
> <section id="pixfmt-reserved">
> <title>Reserved Format Identifiers</title>
>
> diff --git a/Documentation/DocBook/media/v4l/v4l2.xml b/Documentation/DocBook/media/v4l/v4l2.xml
> index 74b7f27..6dd899c 100644
> --- a/Documentation/DocBook/media/v4l/v4l2.xml
> +++ b/Documentation/DocBook/media/v4l/v4l2.xml
> @@ -537,6 +537,7 @@ and discussions on the V4L mailing list.</revremark>
> <section id="ttx"> &sub-dev-teletext; </section>
> <section id="radio"> &sub-dev-radio; </section>
> <section id="rds"> &sub-dev-rds; </section>
> + <section id="sdr"> &sub-dev-sdr; </section>
> <section id="event"> &sub-dev-event; </section>
> <section id="subdev"> &sub-dev-subdev; </section>
> </chapter>
> diff --git a/Documentation/DocBook/media/v4l/vidioc-g-fmt.xml b/Documentation/DocBook/media/v4l/vidioc-g-fmt.xml
> index ee8f56e..ffed137 100644
> --- a/Documentation/DocBook/media/v4l/vidioc-g-fmt.xml
> +++ b/Documentation/DocBook/media/v4l/vidioc-g-fmt.xml
> @@ -172,6 +172,13 @@ capture and output devices.</entry>
> </row>
> <row>
> <entry></entry>
> + <entry>&v4l2-format-sdr;</entry>
> + <entry><structfield>sdr</structfield></entry>
> + <entry>Definition of an data format, see
s/an data/a data/
> +<xref linkend="pixfmt" />, used by SDR capture devices.</entry>
> + </row>
> + <row>
> + <entry></entry>
> <entry>__u8</entry>
> <entry><structfield>raw_data</structfield>[200]</entry>
> <entry>Place holder for future extensions.</entry>
> diff --git a/Documentation/DocBook/media/v4l/vidioc-querycap.xml b/Documentation/DocBook/media/v4l/vidioc-querycap.xml
> index d5a3c97..370d49d 100644
> --- a/Documentation/DocBook/media/v4l/vidioc-querycap.xml
> +++ b/Documentation/DocBook/media/v4l/vidioc-querycap.xml
> @@ -296,6 +296,12 @@ modulator programming see
> <xref linkend="tuner" />.</entry>
> </row>
> <row>
> + <entry><constant>V4L2_CAP_SDR_CAPTURE</constant></entry>
> + <entry>0x00100000</entry>
> + <entry>The device supports the
> +<link linkend="sdr">SDR Capture</link> interface.</entry>
> + </row>
> + <row>
> <entry><constant>V4L2_CAP_READWRITE</constant></entry>
> <entry>0x01000000</entry>
> <entry>The device supports the <link
>
Regards,
Hans
next prev parent reply other threads:[~2014-01-25 8:26 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-23 21:08 [REVIEW PATCH 00/13] SDR API Antti Palosaari
2014-01-23 21:08 ` [REVIEW PATCH 01/13] v4l: add device type for Software Defined Radio Antti Palosaari
2014-01-23 21:08 ` [REVIEW PATCH 02/13] v4l: add new tuner types for SDR Antti Palosaari
2014-01-23 21:08 ` [REVIEW PATCH 03/13] v4l: 1 Hz resolution flag for tuners Antti Palosaari
2014-01-23 21:08 ` [REVIEW PATCH 04/13] v4l: add stream format for SDR receiver Antti Palosaari
2014-01-23 21:08 ` [REVIEW PATCH 05/13] v4l: define own IOCTL ops for SDR FMT Antti Palosaari
2014-01-23 21:08 ` [REVIEW PATCH 06/13] v4l: enable some IOCTLs for SDR receiver Antti Palosaari
2014-01-23 21:08 ` [REVIEW PATCH 07/13] v4l: add device capability flag " Antti Palosaari
2014-01-23 21:08 ` [REVIEW PATCH 08/13] v4l: do not allow modulator ioctls for non-radio devices Antti Palosaari
2014-01-23 21:08 ` [REVIEW PATCH 09/13] DocBook: document 1 Hz flag Antti Palosaari
2014-01-23 21:08 ` [REVIEW PATCH 10/13] DocBook: Software Defined Radio Interface Antti Palosaari
2014-01-25 8:26 ` Hans Verkuil [this message]
2014-01-25 13:01 ` Antti Palosaari
2014-01-25 13:44 ` Hans Verkuil
2014-01-23 21:08 ` [REVIEW PATCH 11/13] DocBook: mark SDR API as Experimental Antti Palosaari
2014-01-25 8:27 ` Hans Verkuil
2014-01-23 21:08 ` [REVIEW PATCH 12/13] v4l2-framework.txt: add SDR device type Antti Palosaari
2014-01-23 21:08 ` [REVIEW PATCH 13/13] devices.txt: add video4linux device for Software Defined Radio Antti Palosaari
2014-01-25 8:27 ` Hans Verkuil
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