On Tue, Dec 20, 2011 at 10:26 AM, Mauro Carvalho Chehab
<mchehab@xxxxxxxxxx> wrote:
> On 20-12-2011 12:52, Antti Palosaari wrote:
>>>> + /* reset demod */
>>>> + /* it is recommended to HW reset chip using RST_N pin */
>>>> + if (fe->callback) {
>>>> + ret = fe->callback(fe, 0, 0, 0);
>>>
>>> This looks weird on my eyes. The fe->callback is tuner-dependent.
>>> So, the command you should use there requires a test for the tuner
>>> type.
>>>
>>> In other words, if you're needing to use it, the code should be doing
>>> something similar to:
>>>
>>> if (fe->callback&& priv->tuner_type == TUNER_XC2028)
>>> ret = fe->callback(fe, 0, XC2028_TUNER_RESET, 0);
>>>
>>> (the actual coding will depend on how do you store the tuner type, and
>>> what are the commands for the tuner you're using)
>>>
>>> That's said, it probably makes sense to deprecate fe->callback in favor
>>> or a more generic set of callbacks, like fe->tuner_reset().
>>
>> Yes it is wrong because there was no DEMOD defined. But, the callback
>> itself is correctly. IIRC there was only TUNER defined and no DEMOD.
>> Look callback definition from the API. It is very simply to fix. But at
>> the time left it like that, because I wanted to avoid touching one file
>> more. I will fix it properly later (2 line change).
>>
>> And it was not a bug, it was just my known decision. I just forget to comment it as FIXME or TODO.
>
> Feel free to touch on other files, provided that you fix that. There's
> no default behavior for fe->callback, as it were written in order to
> provide ways for the tuner to call the bridge driver for some device-specific
> reasons. So, the commands are defined with macros, and the callback code
> should be device-specific.
This generic callback was written for the BRIDGE driver to be called
by any frontend COMPONENT, not specifically the tuner, perhaps a demod
or LNB, but at the time of writing, we only needed it from the tuner
so the DVB_FRONTEND_COMPONENT_TUNER(0) was the only #define created at
the time. This was written with forward-compatibility in mind, so
lets please not deprecate it unless we actually have to -- I see
additional uses for this coming in the future.
In order to use fe callback properly, please add "#define
DVB_FRONTEND_COMPONENT_DEMOD 1" to dvb-core/dvb_frontend.h , and
simply call your callback as fe->callback(adap_state,
DVB_FRONTEND_COMPONENT_DEMOD, CMD, ARG) ... This way, the callback
knows that it is being called by the demod and not the tuner, it is
receiving command CMD with argument ARG.
I can imagine a need one day to perhaps convert the "int arg" into a
"void* arg", but such a need doesn't exist today. I don't think it
gets any more generic than this.
int (*callback)(void *adapter_priv, int component, int cmd, int arg);
Cheers,
Mike
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