Re: [PATCH RFCv1] v4l2: add support for SDR transmitter

[Antti Palosaari <crope@iki.fi>]

Moikka!

On 05/15/2015 12:25 PM, Hans Verkuil wrote:
> Hi Antti,
>
> Looks good, but the DocBook updates are missing. You probably planned to do that in
> RFCv2 or similar.

Yep, first code then doc.

> Which device will have sdr_out? What's the cheapest device and where can I buy it? I'd
> like to be able to test it (and add qv4l2 support),

I used HackRF One, it is likely 150-250e used one.

Currently I have implemented almost all radio features it has, only 
option to enable antenna power supply is missing (and firmware upgrade, 
but it is not radio feature).

Device is half-duplex - only RX or TX could be used at the time. Driver 
creates two device nodes, one for receiver and another for transmitter.

There is:
2 x struct video_device
2 x struct v4l2_device
2 x struct vb2_queue
2 x struct v4l2_ctrl_handler

Locking is still missing. I am not sure how it should be done, but 
likely I try add lock to start/stop streaming. When start streaming is 
called it sets some flag/lock and if another device node tries start 
streaming at same time error is returned.

Device uses Complex S8 format for both receiver and transmitter. I will 
add that format to vivid and then it should be possible generate beep 
using vivid and transmit it using HackRF (cat /dev/swradio0 > 
/dev/swradio1), where swradio0 is vivid and swradio1 is HackRF.

regards
Antti

-- 
http://palosaari.fi/