[alsa-devel] [PATCH] ASoC: Add initial WM8995 driver

[Dimitris Papastamos]

On Wed, 2010-12-22 at 11:07 +0000, Mark Brown wrote:
> On Wed, Dec 22, 2010 at 10:54:39AM +0000, Liam Girdwood wrote:
> > On Wed, 2010-12-22 at 10:26 +0000, Dimitris Papastamos wrote:
> > > On Tue, 2010-12-21 at 20:38 +0000, Liam Girdwood wrote:
> > > > On Tue, 2010-12-21 at 17:16 +0000, Dimitris Papastamos wrote:
> 
> > > > > +static int wm8995_volatile(unsigned int reg)
> > > > > +{
> > > > > +	if (reg >= WM8995_MAX_REGISTER + 1)
> > > > > +		return 1;
> > > > > +
> 
> > > > return -EINVAL here.
> 
> > > The logic behind this is that out of bounds registers are considered
> > > volatile. 
> 
> > It does look a little odd since out of bounds generally means invalid. 
> 
> Most of the drivers that use this idiom use a constant like
> MAX_CACHED_REGISTER or similar which makes it clearer that there are
> more registers beyond the end of the register map.  The normal use is to
> allow access to partially documented diagnostic registers or to support
> register banks that are partially owned by something else (devices with
> an embedded DSP being the most obvious example).

Yes that makes sense.  I've changed the function to use
WM8995_MAX_CACHED_REGISTER instead.

Thanks,
Dimitris