[linux-dvb] Re: Proposal for new frontend architecture

[Andrew de Quincey <adq_dvb@lidskialf.net>]

On Tuesday 14 Sep 2004 16:54, Gerd Knorr wrote:
> Michael Hunold <hunold-ml@web.de> writes:
> > - add a probe_this_i2c_id_on_this_i2c_bus() function to i2c-core
> >
> > To get the configuration out of the frontend driver:
> > - PLL functions are implemented by the driver, not the frontend and are
> > provided when FE_REGISTER is called.
> > - when PLL access is necessary, functions from the driver are called
> > - same goes for other stuff like voltage, symbolrate, inversion and
> > other settings
>
> Hmm, how about adding a ->command() style callback to i2c_adapter?
> With that we can:
>
>   * let the frontend pull config information from the driver, i.e.
>     instead of a i2c_driver->command(SET_FOO) we'll use
>     i2c_adapter->command(GET_FOO).  Main difference is that the pull
>     approach allows the frontend driver to fetch config info in the
>     i2c_driver->adapter_attach() callback, _before_ doing the actual
>     probing and device registering.
>
>   * allows the frontend ask the driver for certain stuff like setting
>     the PLL.

Interesting idea - so that would let us say things like "probe on this couple 
of addresses, but NOT this one".... as well as supplying extra configuration.

Hmmmm... could this be a way to restrict which devices are allowed on the bus 
as well? It could pass a structure describing the i2c device, and the adapter 
could tell it to continue probing or not, as well as returning configuration 
information.