[PATCH v3 1/2] ASoC: codecs: add support for ES8326

[Zhu Ning]

>Nothing ever restores the constraints if a clock is specified again, and
>in general it's odd that the enable/disable don't match up - if we're
>setting variable constraints I'd expect that in the freq == 0 case we
>should be setting ->sysclk_constraints to NULL rather than the contents.
>Indeed, we'll segfault here if the frequency is set to 0 without having
>first been set to some actual value.  It's also bad to modify static
>data potentially shared between multiple instances of the device in a
>system.
>
>Having said all that though I'm not clear why we're doing this
>constraint stuff at all, we never reference sysclk_constraints during
>startup and teardown and you'd usually do this because you want to set
>constraints that depend on the sysclk but this is just a constant set of
>constraints that should be set in the DAI desription.

Comes from 8316.c. Will remove the constraints. Will submit a patch later
to remove the constraints in es8316.c. We can assume that the producer(master)
provides correct mclk(sysclk) rate.

>>> One question on the interrupt handling: should there be an interrupt
>>> disable on suspend and conversely an interrupt enable on resume?
>>
>> That shouldn't be needed (in general the interrupt enable/disable stuff
>> shouldn't be needed at all).
>
>isn't there a risk of an interrupt being triggered after all the jack
>detection resources are disabled?

The jack detection resources are only disabled after codec power down?