[linux-dvb] I2C NAKs and fails to respond during init of TDA18211

Michael Krufky mkrufky at gmail.com
Thu Nov 8 16:42:44 CET 2007


On 11/8/07, MikeW <mw_phil at yahoo.co.uk> wrote:
> Michael Krufky <mkrufky <at> linuxtv.org> writes:
>
> > You might want to take a look at the tda18271 driver recently merged
> > into the master branch, located under dvb/frontends ...
> >
> > Perhaps this driver might be enough to bring up the tda18211-- I don't
> > have the spec for the 18211, so I cannot say that for sure, but I was
> > under the impression that the tda18211 is exactly a tda18271, but DVB
> > only.
> >
> > Let me know if there's anything that I can do to help you.
> >
> > Regards,
> >
> > Mike Krufky
> >
> Thanks.
>
> I also note in your repository code that there is no account taken
> of whether the chip is in Master or Slave mode - the 18211 needs
> different frequency setting depending on whether it is running the
> 16MHz crystal (Master), or whether it just has the 16MHz input (Slave).
>
> This is relevant if you have a dual-tuner configuration,
> increasingly common to allow PVR and viewing on different channels.
>
> In Master mode you set the required frequency on the Main PLL,
> in Slave mode you have to use the Cal PLL.
> Also set CALVCO_forLOn: EB1[2] and a few other bits !

I am aware of this, but currently do not have a dual tda18271 device
to play with, so I left this feature out of the code.

I'd recommend to pass such information (master / slave , etc) into the
driver via a tda18271_config struct, declared inside tda18271.h and
passed in by the host driver.

I expect that either I would end up with a new device eventually, or
somebody like yourself would have such a device and improve upon my
code.

This is open source -- please feel free to make changes as you see fit
and send them in -- I would be happy to integrate them into the
official source tree.

Additionally, your earlier email mentioned that you have broken up the
tune function into smaller functions.  This would be an improvement,
and I would also be happy to apply such a change to the current
driver.  So far, I have only tested it in analog mode.  I've also
heard that the driver works for ATSC and QAM (usa) , but it is still
not tested with DVB-T.   I suspect that it will be nicer to have that
large function broken down to smaller functions, but I haven't had the
need to do it yet myself, so I haven't spent the time.

Please feel free to send in patches -- This driver has the potential
to support every flavor of this chip, in all supported analog and
digital video standards.

If you prefer, I can arrange for a separate repository to be set up
for the purposes of the tda182x1 work.

Let me know what you think.

Cheers,

Mike Krufky



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