Adds the basic API bits for Software Digital Radio (SDR) at the V4L2 API. A normal radio device is actually radio and hardware demod. As the demod is in hardware, several things that are required for the demodulate the signal (IF, bandwidth, sample rate, RF/IF filters, etc) are internal to the device and aren't part of the API. SDR radio, on the other hand, requires that every control needed by the tuner to be exposed on userspace, as userspace needs to adjust the software decoder to match it. As proposed at: http://comments.gmane.org/gmane.linux.drivers.video-input-infrastructure/63123 Add a new device node for SDR devices, and a VIDIOC_QUERYCAP capability (V4L2_CAP_SDR) to indicate that a devnode is SDR. The stream output format also needs to be different, as it should output sample data, instead of video streams. As we need to document SDR, add one initial format there that will be later be used. Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx> --- Documentation/DocBook/media/v4l/common.xml | 35 ++++++++++++++++++ Documentation/DocBook/media/v4l/pixfmt.xml | 41 ++++++++++++++++++++++ Documentation/DocBook/media/v4l/v4l2.xml | 1 + .../DocBook/media/v4l/vidioc-querycap.xml | 7 ++++ drivers/media/v4l2-core/v4l2-dev.c | 3 ++ include/media/v4l2-dev.h | 3 +- include/uapi/linux/videodev2.h | 11 ++++++ 7 files changed, 100 insertions(+), 1 deletion(-) diff --git a/Documentation/DocBook/media/v4l/common.xml b/Documentation/DocBook/media/v4l/common.xml index 1ddf354..f59c67d 100644 --- a/Documentation/DocBook/media/v4l/common.xml +++ b/Documentation/DocBook/media/v4l/common.xml @@ -513,6 +513,41 @@ the &v4l2-capability; returned by the &VIDIOC-QUERYCAP; ioctl when the device has one or more modulators.</para> </section> + <section id="sdr_tuner"> + <title>Software Digital Radio (SDR) Tuners and Modulators</title> + + <para>Those devices are special types of Radio devices that don't +have any analog demodulator. Instead, it samples the radio IF or baseband +and sends the samples for userspace to demodulate.</para> + <section> + <title>Tuners</title> + + <para>SDR receivers can have one or more tuners sampling RF signals. +Each tuner is associated with one or more inputs, depending on the number +of RF connectors on the tuner. The <structfield>type</structfield> field of +the respective &v4l2-input; returned by the &VIDIOC-ENUMINPUT; ioctl is set to +<constant>V4L2_INPUT_TYPE_TUNER</constant> and its +<structfield>tuner</structfield> field contains the index number of +the tuner input.</para> + +<para>To query and change tuner properties applications use the +&VIDIOC-G-TUNER; and &VIDIOC-S-TUNER; ioctl, respectively. The +&v4l2-tuner; returned by <constant>VIDIOC_G_TUNER</constant> also +contains signal status information applicable when the tuner of the +current SDR input is queried. In order to change the SDR input, +<constant>VIDIOC_S_TUNER</constant> with a new SDR index should be called. +Drivers must support both ioctls and set the +<constant>V4L2_CAP_SDR</constant> and <constant>V4L2_CAP_TUNER</constant> +flags in the &v4l2-capability; returned by the &VIDIOC-QUERYCAP; ioctl.</para> + </section> + + <section> + <title>Modulators</title> + <para>To be defined.</para> + </section> + </section> + + <section> <title>Radio Frequency</title> diff --git a/Documentation/DocBook/media/v4l/pixfmt.xml b/Documentation/DocBook/media/v4l/pixfmt.xml index 99b8d2a..e30075e 100644 --- a/Documentation/DocBook/media/v4l/pixfmt.xml +++ b/Documentation/DocBook/media/v4l/pixfmt.xml @@ -203,6 +203,47 @@ codes can be used.</entry> </table> </section> +<section> + <title>SDR format struture</title> + <table pgwide="1" frame="none" id="v4l2-sdr-format"> + <title>struct <structname>v4l2_sdr_format</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>sampleformat</structfield></entry> + <entry>The format of the samples used by the SDR device. + This is a little endian + <link linkend="v4l2-sdr-fourcc"> + four character code</link>.</entry> + </row> + </tbody> + </tgroup> + </table> + <table pgwide="1" frame="none" id="v4l2-sdr-fourcc"> + <title>SDR formats</title> + <tgroup cols="2"> + &cs-str; + <tbody valign="top"> + <row> + <entry><constant>V4L2_SDR_FMT_I8Q8</constant></entry> + <entry>Samples are given by a sequence of 8 bits in-phase(I) and + 8 bits quadrature (Q) samples taken from a + <emphasis>signal(t)</emphasis> represented by the following + expression: + <informalequation> + <alt>signal(t) = I cos(2π f t) - Q sin(2π f t)</alt> + <mathphrase><emphasis>signal(t) = I * cos(2π f<subscript>c</subscript> t) - Q * sin(2π f<subscript>c</subscript> t)</emphasis></mathphrase> + </informalequation> + </entry> + </row> + </tbody> + </tgroup> + </table> + +</section> + <section> <title>Standard Image Formats</title> diff --git a/Documentation/DocBook/media/v4l/v4l2.xml b/Documentation/DocBook/media/v4l/v4l2.xml index bfc93cd..b53a5cf 100644 --- a/Documentation/DocBook/media/v4l/v4l2.xml +++ b/Documentation/DocBook/media/v4l/v4l2.xml @@ -521,6 +521,7 @@ 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-querycap.xml b/Documentation/DocBook/media/v4l/vidioc-querycap.xml index d5a3c97..97bb25a 100644 --- a/Documentation/DocBook/media/v4l/vidioc-querycap.xml +++ b/Documentation/DocBook/media/v4l/vidioc-querycap.xml @@ -296,6 +296,13 @@ modulator programming see <xref linkend="tuner" />.</entry> </row> <row> + <entry><constant>V4L2_CAP_SDR</constant></entry> + <entry>0x00100000</entry> + <entry>The device is a Software Digital Radio. + For more information about SDR programming see +<xref linkend="sdr_tuner" />.</entry> + </row> + <row> <entry><constant>V4L2_CAP_READWRITE</constant></entry> <entry>0x01000000</entry> <entry>The device supports the <link diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c index 5923c5d..a48e070 100644 --- a/drivers/media/v4l2-core/v4l2-dev.c +++ b/drivers/media/v4l2-core/v4l2-dev.c @@ -796,6 +796,9 @@ int __video_register_device(struct video_device *vdev, int type, int nr, case VFL_TYPE_SUBDEV: name_base = "v4l-subdev"; break; + case VFL_TYPE_SDR: + name_base = "sdr"; + break; default: printk(KERN_ERR "%s called with unknown type: %d\n", __func__, type); diff --git a/include/media/v4l2-dev.h b/include/media/v4l2-dev.h index 95d1c91..95863bb 100644 --- a/include/media/v4l2-dev.h +++ b/include/media/v4l2-dev.h @@ -24,7 +24,8 @@ #define VFL_TYPE_VBI 1 #define VFL_TYPE_RADIO 2 #define VFL_TYPE_SUBDEV 3 -#define VFL_TYPE_MAX 4 +#define VFL_TYPE_SDR 4 +#define VFL_TYPE_MAX 5 /* Is this a receiver, transmitter or mem-to-mem? */ /* Ignored for VFL_TYPE_SUBDEV. */ diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h index 97fb392..4aa24c3 100644 --- a/include/uapi/linux/videodev2.h +++ b/include/uapi/linux/videodev2.h @@ -284,6 +284,7 @@ struct v4l2_capability { #define V4L2_CAP_AUDIO 0x00020000 /* has audio support */ #define V4L2_CAP_RADIO 0x00040000 /* is a radio device */ #define V4L2_CAP_MODULATOR 0x00080000 /* has a modulator */ +#define V4L2_CAP_SDR 0x00100000 /* is a SDR device */ #define V4L2_CAP_READWRITE 0x01000000 /* read/write systemcalls */ #define V4L2_CAP_ASYNCIO 0x02000000 /* async I/O */ @@ -1700,6 +1701,15 @@ struct v4l2_pix_format_mplane { __u8 reserved[11]; } __attribute__ ((packed)); + +struct v4l2_sdr_format { + __u32 sampleformat; +}; + +/* Sample format Description */ + +#define V4L2_SDR_FMT_I8Q8 v4l2_fourcc('I', '8', 'Q', '8') /* I 8bits, Q 8bits */ + /** * struct v4l2_format - stream data format * @type: enum v4l2_buf_type; type of the data stream @@ -1718,6 +1728,7 @@ struct v4l2_format { struct v4l2_window win; /* V4L2_BUF_TYPE_VIDEO_OVERLAY */ struct v4l2_vbi_format vbi; /* V4L2_BUF_TYPE_VBI_CAPTURE */ struct v4l2_sliced_vbi_format sliced; /* V4L2_BUF_TYPE_SLICED_VBI_CAPTURE */ + struct v4l2_sdr_format fmt; /* V4L2_BUF_TYPE_SDR_CAPTURE */ __u8 raw_data[200]; /* user-defined */ } fmt; }; -- 1.8.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
