[alsa-devel] [PATCH RFT] ASoC: ak4642: Fix up max_register setting

[Mark Brown]

On Tue, Jun 30, 2015 at 07:25:57PM +0800, Axel Lin wrote:
> 2015-06-30 18:46 GMT+08:00 Mark Brown <broonie at kernel.org>:

> >>  static const struct regmap_config ak4642_regmap = {
> >>       .reg_bits               = 8,
> >>       .val_bits               = 8,
> >> -     .max_register           = ARRAY_SIZE(ak4642_reg) + 1,
> >> +     .max_register           = FIL1_3,
> >>       .reg_defaults           = ak4642_reg,
> >> -     .num_reg_defaults       = ARRAY_SIZE(ak4642_reg),
> >> +     .num_reg_defaults       = FIL1_3 + 1,

> > This change is incorrect, the number of register defaults must match the
> > size of the array of register defaults being passed in.  Why are you
> > changing this?

> Because I reuse the same reg_default for ak4642 and ak4643.
> According to the datasheet:
> For ak4642, the valid registers are 0x0 ~ 0x1f (FIL1_3)
> For ak4643, the valid registers are 0x0 ~ 0x24 (SPK_MS)
> The default registers for 0x0 ~ 0x1f are the same for ak4642 and ak4643.

Ah, I see.  That definitely deserves a comment since it's very unusual -
possibly also with a BUILD_BUG_ON() for the define being less than
ARRAY_SIZE().

> Or do you prefer having separate reg_default for ak4642 and ak4643?
> (Then it can use ARRAY_SIZE() here.)

No, what you're doing is OK but really ought to have comments so it's
clearer.
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