[pvrusb2] FM tuner support...?

[Mike Isely]

On Sun, 12 Nov 2006, Felix Lighter wrote:

> A yelled hello to Mike Isley,
> 
> Thanks for your work on the hauppauge driver, and your great web pages
> on the topic.
> You mention that FM tuner support shouldn't be hard to implement. Do
> you have any pointers on how to go about beginning this effort? I ran
> usbsnoop while I started up the win2k FM radio program, and now have a
> nice 10M log file. Where do I go from here?

Unfortunately I don't have any specific pointers.  But I'd probably start with 
a reading of the V4L2 API specification.  Next I'd probably go look at a V4L 
driver which includes radio support.

My gut feeling is that the V4L side of this implementation should be pretty 
straight-forward.  The hardware side also should not be too bad either; it 
should be just a matter of reprogramming the cx23416 to spit out straight MP3 
audio and adjust the pathway in front of it to decode FM radio.  What makes 
that relatively easy is that the USB snoop log you've got contains the magic 
sequence you need to do that.

If you haven't already done so, use decode_log (a utility included with the 
standalone driver) to further dissect that log output.  With decode_log you'll 
be able to translate the sequence of USB transactions in the log into the 
actual chip register read / writes and the cx23416 commands that are being 
issued to the part.  The pvrusb2 web documentation has information on how to 
do this (though now that I think of it, this might be slightly though not 
fatally out of date).

If you figure out what's needed specifically to enable the radio, I'd be 
willing to work with you to update the driver appropriately.

> 
> Thanks in advance. I'm off to read the list archives.

Have fun!

  -Mike


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