[alsa-devel] [PATCH v2 2/7] MFD: twl6040: Convert to i2c driver, and separate it from twl core

[Peter Ujfalusi]

On 02/07/2012 03:29 PM, Mark Brown wrote:
> and it looks like you'll save a bunch more code if you're able to
> convert over to using a regmap cache.  Note that as a first pass you
> just need to define which registers are volatile and enable a cache type
> - if defaults are omitted then the values will be read back from the
> device to start off with.

There's one thing which I need to sort out before I enable the regmap
cache for the twl6040 MFD (and remove all other caching of vibra
controls in the MFD, and from the ASoC codec driver):
In the codec driver I have one 'shadow' register which does not exist on
the HW. I'm going to need to have access to that shadow register's bits
in the future transparently.
I was wondering if we could add support to regmap for such SW only
registers. This would only make sens if the cache is enabled. We could
have a callback let's say shadow_reg() in remap_config struct. If it is
a shadow reg we never reach out for the HW and operate only on the cache.
Is this something we can add to regmap?

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