Em Ter, 2005-11-29 ?s 09:47 -0500, Steve Toth escreveu:
> Johannes Stezenbach wrote:
> > On Mon, Nov 28, 2005, Steve Toth wrote:
> 3) A totally different, longer term approach. (My actual preference).
> Have a single tuner.ko module which deals with ALL plls and tuning
> requirements (analog/digital). Have demods (and/or cx88) call a
> registratation mechansim "tuner_register_pll" with a number of callbacks
> and capabilities. This would require a lot of rework on all of the
> demods but nicely bring tuning back into a single place. tuner.ko would
> then be a dependency on dvb_core (?) and cx88xx (or possibly even a
> newer v4l_core / v4l2_compat?).
IMHO, this is a good approach, and not so difficult to handle. In fact,
from V4L side, we have two tuner handlers (both currently merged at
tuner.ko):
tuner-core.c - generic functions, capable of handling any kind of
tuners. It handles V4L ioctls and passes, via callback, to specific
tuners;
tuner-simple.c - for "simple tuners" that have:
- cut-off freqs/switch control byte
- a generic way to configure the device:
div= freq + Video IF + offset
(freq is, in fact, freq / 62500; Video IF maybe also Radio IF, for
radio mode)
4 values to be passed to tuner (div MSB, div LSB, config switch,
generic control byte)
Specific tests for a few tuners.
This about the same as dvb-pll.c does:
div = (freq + desc->entries[i].offset) /
desc->entries[i].stepsize;
buf[0] = div >> 8;
buf[1] = div & 0xff;
buf[2] = desc->entries[i].cb1;
buf[3] = desc->entries[i].cb2;
Also:
1) most (all?) dvb plls are also at V4L;
2) tuner struct at V4L2 API have a reserved value that means it is
Digital TV. There are also some control functions to enable/disable
tuner mode (from radio <--> TV) that can be extended to include also
Digital TV. This way, tuner can do proper enabling/disabling
analog/digital modes on hybrid cards.
So, for me, it seems that would be easy to integrate both codes into
one.
> Steve
>
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Cheers,
Mauro.
