[alsa-devel] [PATCH] ASoC: dapm: Add support for multi register mux

[Arun Shamanna Lakshmi]

> -----Original Message-----
> From: Lars-Peter Clausen [mailto:lars at metafoo.de]
> Sent: Friday, April 04, 2014 12:32 AM
> To: Arun Shamanna Lakshmi
> Cc: lgirdwood at gmail.com; broonie at kernel.org;
> swarren at wwwdotorg.org; perex at perex.cz; tiwai at suse.de; alsa-
> devel at alsa-project.org; linux-kernel at vger.kernel.org; Songhee Baek
> Subject: Re: [PATCH] ASoC: dapm: Add support for multi register mux
> 
> On 04/03/2014 10:11 PM, Arun Shamanna Lakshmi wrote:
> [...]
> >> Here as well, default for bit_pos should be 0.
> >
> > This means when 'None' of the options are selected, by default, it
> > enumerates to 0. Since we are using __ffs, BIT(0) of Register-0 also
> > enumerates to 0. That's the reason why I used just ffs in the first place.
> > Let me know your opinion. My value table looks like below.
> >
> > #define MUX_VALUE(npart, nbit)	(nbit + 32 * npart)
> > static const int mux_values[] = {
> > 	0,
> > 	MUX_VALUE(0, 0),
> > 	.
> > 	.
> > 	.
> > 	MUX_VALUE(0, 31),
> > 	/* above inputs are for part0 mux */
> > 	MUX_VALUE(1, 0),
> > 	.
> > 	.
> > 	.
> > 	MUX_VALUE(1, 31),
> > 	/* above inputs are for part1 mux */
> > 	MUX_VALUE(2, 0),
> > 	.
> > 	.
> > 	.
> > 	MUX_VALUE(2, 31),
> > 	/* above inputs are for part2 mux */
> > };
> 
> Ok, so having none of the input selected should be a valid user selectable
> option?

Yes. If 'None' is selected, it goes and clears the register. So, can we have ffs( )
instead of __ffs( ) ? It would fix this case.

- Arun