On Sun April 21 2013 21:00:29 Mauro Carvalho Chehab wrote:
This is a version 3 of the V4L2 API bits to support Software Digital
Radio (SDR).
Changes from version 2:
- Patches got better described and named;
- Merged all SDR analog TV into just one field;
- Documented what parts of the [RFC v2013-04-11] SDR API
REQUIREMENT SPECIFICATION are being addressed on the
patches that touch on the V4L2 external API.
With regards to the [RFC v2013-04-11] SDR requirements spec[1], v3
implements:
- operation mode inquire (Rx/Tx)
- implemented via VIDIOC_QUERYCAP;
- get/set doesn't make sense, as different devnodes
are used for RX and TX;
- sampling resolution
- implemented via VIDIOC_ENUM_FMT/VIDIOC_G_FMT/VIDIOC_S_FMT.
- sampling rate
- get/set - implemented via VIDIOC_G_TUNER/VIDIOC_S_TUNER.
- inquire HW - TODO (planning is to also use the same
ioctl's for it);
- It may make sense to move it out of TUNER ioctl, as
this is actually ADC/DAC settings. For the initial
tests, I'll likely use as is, but IMO, the beter is to
split it out of VIDIOC_G_TUNER/VIDIOC_S_TUNER.
- inversion
- TODO. If needed, probably will use VIDIOC_G_TUNER.
- RF frequency
- implemented using VIDIOC_S_FREQUENCY/VIDIOC_G_FREQUENCY
- scale: 62.5 Hz.
- TODO: add a lower scale, for very low freqs.
- IF frequency
- implemented via VIDIOC_G_TUNER/VIDIOC_S_TUNER.
- tuner lock (frequency synthesizer / PLL)
- TODO. May eventually use tuner-strength
- tuner gains
- TODO (V4L2 controls).
- enable/disable auto gain
- TODO (V4L2 controls).
- tuner filters
- TODO (V4L2 controls).
- pass RF standard to tuner?
- Partially implemented. It doesn't pass V4L2 analog TV
types yet.
- TODO: add VIDIOC_S_STD support for SDR radio
- antenna switch
- implemented via VIDIOC_G_TUNER/VIDIOC_S_TUNER.
- external LNA
- TODO (maybe there's already a V4L2 control for it)
- device locking between multiple APIs
- TODO (well, there are resource locking already between
DVB and V4L at driver level)
I have some patches here:
http://git.linuxtv.org/hverkuil/media_tree.git/shortlog/refs/heads/tuner
adding support for tuner ownership (as discussed in the past) to V4L2.
It's untested, and it needs to be integrated in DVB as well. The actual
struct dealing with the tuner ownership is not tied to V4L2 so I am hoping
it can be integrated in DVB without too much effort.
As I understand it a pure DVB driver does not have to deal with tuner
ownership, so this is a problem only if V4L2 is involved as well. I think
that adding a struct tuner_owners pointer to some DVB internal struct would
be sufficient, and the DVB core can check if it is non-NULL and attempt to
take tuner ownership using it.
With yet another tuner mode we need something like this. I don't have time
to work further on this for the next few weeks, so I am hoping you might
find it useful.
I reviewed part of your patch series, but I did not go in-depth with the
tuner-core patches.
[1]
http://permalink.gmane.org/gmane.linux.drivers.video-input-infrastructure/63323
TODO:
- check if VB2 require changes (might require trivial ones, due
to the new buffer type);
- add a SDR driver testing the new features - likely a cx88 driver,
but as cx88 doesn't use VB2,
Of course, you can also convert cx88 to vb2 :-)
I might use some other driver. The advantage
of using cx88 is that it has 2 ADC, one baseband and another IF that can
be used at the same time, 8-bits or 10-bits and up to ~35 MHz of
sampling rate.
Nice work!
Regards,
Hans
Mauro Carvalho Chehab (10):
[media] Add initial SDR support at V4L2 API
[media] videodev2.h: Remove the unused old V4L1 buffer types
[media] V4L2 api: Add a buffer capture type for SDR
[media] V4L2 sdr API: Add fields for VIDIOC_[G|S]_TUNER
[media] v4l2-ioctl: Add tuner ioctl support for SDR radio type
[media] tuner-core: consider SDR as radio
[media] tuner-core: add SDR support for g_tuner
[media] tuner-core: store tuner ranges at tuner struct
[media] tuner-core: add support to get the tuner frequency range
[media] tuner-core: add support for SDR set_tuner
Documentation/DocBook/media/v4l/common.xml | 35 +++
Documentation/DocBook/media/v4l/dev-capture.xml| 26 +-
Documentation/DocBook/media/v4l/io.xml | 6 +
Documentation/DocBook/media/v4l/pixfmt.xml | 41 +++
Documentation/DocBook/media/v4l/v4l2.xml | 1 +
