On 19/06/12 19:33, Hans de Goede wrote:
Hi,
On 06/19/2012 06:47 PM, Hans de Goede wrote:
Hi,
<snip long discussion about having a fixed set of bands versus
a way to enumerate bands, including their rangelow, rangehigh
and capabilities>
Ok, you've convinced me. I agree that having a way to actually
enumerate ranges, rather then having a fixed set of ranges, is
better.
Which brings us back many weeks to the proposal for making
it possible to enumerate bands on radio devices. Rather
then digging up the old mails lets start anew, I propose
the following API for this:
1. A radio device can have multiple tuners, but only 1 can
be active (streaming audio to the associated audio input)
at the same time.
2. Radio device tuners are enumerated by calling G_TUNER
with an increasing index until EINVAL gets returned
3. G_FREQUENCY will always return the frequency and index
of the currently active tuner
4. When calling S_TUNER on a radio device, the active
tuner will be set to the v4l2_tuner index field
5. When calling S_FREQUENCY on a radio device, the active
tuner will be set to the v4l2_frequency tuner field
6. On a G_TUNER call on a radio device the rxsubchans,
audmode, signal and afc v4l2_tuner fields are only
filled on for the active tuner (as returned by
G_FREQUENCY) for inactive tuners these fields are reported
as 0.
p.s.
I forgot:
7. When calling VIDIOC_S_HW_FREQ_SEEK on a radio device, the active
tuner will be set to the v4l2_hw_freq_seek tuner field
8. When changing the active tuner with S_TUNER or S_HW_FREQ_SEEK,
the current frequency may be changed to fit in the range of the
new active tuner
9. For backwards compatibility reasons tuner 0 should be the tuner
with the broadest possible FM range
I need to think about all these proposals. I know that when I worked with the
cadet driver I didn't like those multiple tuners at all.
But I need to read up on these new discussions and think about it. I doubt I'll
have time tomorrow, so it's probably going to be Thursday or Friday.
Regards,
Hans
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