[linux-dvb] dvb-pll vs hardcoded tuner programming [WAS: Add support for the Avermedia 777 DVB-T card]

Michael Krufky mkrufky at linuxtv.org
Tue Jan 31 00:09:59 CET 2006

Hartmut Hackmann wrote:

>> Fair enough...  Although I am curious..... Exactly what do you plan 
>> to expand on in dvb-pll?  What fields do you need to add?
> I would like to add 2 functions:
> dvb_pll_init()
> This should wake up the tuner and initialize it to DVB mode. And
> dvb_pll_sleep()
> which puts the tuner to sleep mode resp. puts it back to analog mode.
> As far as i currently know, both could provide byte lists as the 
> configure
> function currently does.
> You might not be aware of this: Some PLL chips have a 5th "hidden" 
> programming
> byte that is accessibe by writing a special value into byte 2. This is
> what i wish / need to modify.

dvb_pll_init() and dvb_pll_sleep() , I agree would be great additions to 
the dvb_pll_desc.  I can already think of some areas in the card 
programming where such functions could be moved...

About that 5th byte, yes, I am aware of it... Mac Michaels had mentioned 
the need for this when dealing with TUA6034... I will have to go back 
and take a look at how he handled that... but yes, I am happy to hear 
that you want to deal with that issue.

>> I have been working on the tuner-simple structs and dvb-pll structs, 
>> in an effort to make them similar to each other, such that eventually 
>> the dvb-pll tuners can be stored in tuner.ko 's multi-standard tuner 
>> array.  Of course, I will not do this right away... There is a lot of 
>> preparation that needs to be done on the analog side first, and I 
>> will go through the RFC process as well before dvb-pll becomes 
>> involved...
>> However, I *do* request that any tuner code that isnt using dvb-pll 
>> should be converted such that it will in the future.  I understand 
>> the situation that you are describing, and I see why this must wait 
>> in the case of saa7134-dvb, but we should try in cases where 
>> possible.  I'd like to see some type of conformity here.
> Ok. But there still is the question "what do we do with the silicon
> tuners". I currently see no way to handle these with a generic approach
> like the ones in dvb-pll and tuner-simple. This holds for both, the
> Philips as well as the Microtune chips.

I am only talking about the "simple tuners" -- not the silicon ones.  
Obviously, we need separate drivers for the silicon tuners, and they 
will remain untouched by the changes to the simple tuner code.

>> Please look at the recent changes to the tuner-* stuff, for an idea 
>> about what I'm talking about.  There are comments at the top of 
>> tuner-types.c that describe the general idea of the changes that I am 
>> working on.  Please let me know if you have any comments.
> Ok, i will do so. 

Based on what you're telling me...... I will put off all thoughts of 
consolidating dvb-pll stuff into the tuners struct... I was going to 
open up RFC discussion about it on the lists within the week, but it 
just doesnt pay right now.  Hopefully we can have your proposed changes 
make it in there first, as those will help to make the dvb tuner stuff 
more uniform across the board.

Best Regards,

Michael Krufky

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