Re: [PATCH] ASoC: dapm: Add support for multi register mux

[Lars-Peter Clausen]

On 04/04/2014 09:34 AM, Arun Shamanna Lakshmi wrote:
> > -----Original Message-----
> > From: Lars-Peter Clausen [mailto:lars@xxxxxxxxxx]
> > Sent: Friday, April 04, 2014 12:32 AM
> > To: Arun Shamanna Lakshmi
> > Cc: lgirdwood@xxxxxxxxx; broonie@xxxxxxxxxx;
> > swarren@xxxxxxxxxxxxx; perex@xxxxxxxx; tiwai@xxxxxxx; alsa-
> > devel@xxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; 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.

Yes, but you need to make sure to handle it also correctly in the put 
handler, since all of the registers need to be written to 0 in that case.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/