[alsa-devel] SOC_VALUE_ENUM usages in cs42l52 & cs42l73 drivers

[Brian Austin]

On Tue, 18 Feb 2014, Takashi Iwai wrote:

> Hi,
>
> as I audited through ASoC codec drivers recently, I noticed that
> cs42l52 and cs42l73 drivers have some strange SOC_VALUE_ENUM usages.
>
> For example, cs42l52.c has the following code snippet:
>
> static const char * const left_swap_text[] = {
> 	"Left", "LR 2", "Right"};
> ....
> static const unsigned int swap_values[] = { 0, 1, 3 };
>
> static const struct soc_enum adca_swap_enum =
> 	SOC_VALUE_ENUM_SINGLE(CS42L52_ADC_PCM_MIXER, 2, 1,
> 			      ARRAY_SIZE(left_swap_text),
> 			      left_swap_text,
> 			      swap_values);
>
> Note that the third argument of SOC_VALUE_ENUM_SINGLE() is the mask
> bits.  Passing 1 means only the least bit is evaluated no matter what
> value is assigned while swap_values can be 0, 1 or 3.
> I suppose here meant 3, but would like to know how the code is
> supposed to work.  There are three value-enum definitions in
> cs42l52.c, and all pass 1 there.
>
> Similarly, cs42l73.c has four definitions, but with different masks:
>
> 	SOC_VALUE_ENUM_SINGLE(CS42L73_MMIXCTL, 6, 1, ...
> 	SOC_VALUE_ENUM_SINGLE(CS42L73_MMIXCTL, 4, 3, ...
> 	SOC_VALUE_ENUM_SINGLE(CS42L73_MMIXCTL, 2, 5, ...
> 	SOC_VALUE_ENUM_SINGLE(CS42L73_MMIXCTL, 0, 7, ...
>
> while values can be either 0, 1 or 2.  Something really fishy here.
>
>
> thanks,
>
> Takashi
Let me bring up a board and see how the registers get set. To be honest, I 
don't know why the 3 value is the way it is...

-Brian