[linux-dvb] Re: refactoring

[Holger Waechtler <holger@qanu.de>]

Andrew de Quincey wrote:

> [snip]
>
>  
> > the ioctl wrapper is only implemented
> > once for all drivers (the demod code could communicate with the frontend
> > infrastructure via a thin function-pointer-in-struct interface).
> >    
> Interesting idea this one - this is the sort of thing I'm trying to sort out 
> with the refactoring.
>
>
> I see it as:
>
> struct dvb_fe_functions {
>
> int (*set_symbol_rate)(....)
> ....
> };
>
> Then each frontend driver exposes its implementation of that function (if it 
> has one):
>
> extern int stv0299_set_symbol_rate(...);
>  
why not:

extern struct dvb_fe_functions stv0299_functions;

and in stv0299.c:

struct dvb_fe_functions stv0299_functions {
   int (*init)(....);
   int (*set_parameters)(....);
   int (*get_parameters)(....);
   int (*set_voltage)(....);
   int (*sleep)(....)
/* ... */
};

This way only a single pointer needs to get passed around.

> When attaching the frontend, the card driver just picks the functions it wants 
> from the demod implementation - it can supply its own implementation if it 
> needs to. Much neater than a clunky ioctl_override() function.
>  
yes...

Holger