[linux-dvb] HowTo for new tuner

Michael Krufky mkrufky at linuxtv.org
Thu Aug 2 17:06:29 CEST 2007

Markus Rechberger wrote:
> On 8/2/07, Michael Krufky <mkrufky at linuxtv.org> wrote:
>> MikeW wrote:
>>> Markus Rechberger <mrechberger <at> gmail.com> writes:
>>>> Hi Mike,
>>>> Can you shed some more light about the capabilities of the tuner you
>>>> intend to add support for?
>>>> regards,
>>>> Markus
>>> Example:
>>> http://www.nxp.com/acrobat_download/literature/9397/75015475.pdf
>>> Regards,
>>> MikeW
>> Mike,
>> I have already written a completely functional driver for the TDA18271 silicon.
>>  DVB-T has not yet been tested on it, but I doubt it will be any problem.  I
>> understand that you are working with the TDA18211 -- do you know how similar it
>> is to the 18271?  I haven't google'd the 18211 yet, but I'll take a look.
>> I am currently working to refactor the tuning api between the dvb and v4l
>> subsystems -- this is my reasoning for not having released my tda18271 code
>> publicly, as of yet.  It does work, however, and I have only tested it so far
>> using analog broadcasts.  The difference for tuning DVB-T is only some small
>> changes to certain registers.
>> Based on what I see in the pdf that you linked above, I wouldn't be surprised if
>> the tda18211 featureset is merely a small subset of the tda18271, meant
>> specifically for DVB-T.
>> How much progress have you already made with your driver?
>> I'd be happy to help you if you have any further questions... If the 18211 is
>> indeed program compatible with the 18271, except for the limited featureset,
>> then I'd hate to see somebody do double-work.
>> Regards,
>> Michael Krufky
> As already mentioned in the IRC channel, following userspace library
> adds support for multistandard/hybrid tuners which can do DVB and/or
> analogue TV
> (code sample for a userspace tuner library)
> http://mcentral.de/hg/~mrec/em28xx-userspace2/file/1ac5bacf3cfc/tuner/userspace/tuner-xc3028.c
> current features:
> * it's easy to reuse tuners within v4l and dvb
> * floating point calculations
> * abstraction of the v4l and dvb framework, which helps reusing that
> code for OSX lateron
> * bugs will moreover crash the userspace client and leave the kernel
> in a stable state
> of course there's still space for some additional features.
> this code is intended to be merged with linux 2.6.24.
> A small userspace daemon will take care that the requested tuner
> module gets loaded.
> The usuage of such userspace tuner is straightforward and similar like
> the other DVB tuners.
> config.tunerid = /* tunerid */
> config.vendorid = /* vendorid */;
> config.productid = /* productid */
> config.config = 0; /* configuration 1 in demod client, can match up
> with vendor & productid */
> dvb_attach(tuner_stub_attach, dvb_dev->frontend, &dev->i2c_adap, NULL,
> NULL, &config);
> A more accurate documentation about it will come ab later when I have
> more time for that.
> p.s.
> Mike I hope that's fine now :-)

LOL, cool, Markus.

For the record, to other readers, I emailed Markus privately asking him not to

I dont have much to say about Markus' new method -- I haven't had time to look
into it yet, but it sounds like a nice idea.  Meanwhile, i think that Mike,
working on the 18211, might be better off working with me, as I have high
suspicions that his silicon is a subset of the one I've already worked on.

We'll see what happens.


Michael Krufky

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