[alsa-devel] [PATCH] ASoC: wm8903: add regulator handling

[Stephen Warren]

On 03/20/2017 03:13 AM, Linus Walleij wrote:
> The WM8903 has four different voltage inputs: AVDD, CPVDD, DBVDD
> and DCVDD. On the Qualcomm APQ8060 Dragonboard these are all
> supplied from proper regulators and thus need activating and
> binding.
>
> This is a quick-and-dirty solution just grabbing and enabling the
> regulator supplies on probe() and disabling them on remove() and
> the errorpath. More elaborate power management is likely possible.
>
> I assume the nVidia designs using this codec have some hard-wired
> always-on power and will be happy with using the dummy regulators
> for this. But someone from the nVidia camp should probably check
> whether they can bind these to proper regulators instead.
>
> We also amend the DT binding document. A small change like this
> does not warrant a separate patch for augmenting these.

Tested-by: Stephen Warren <swarren at nvidia.com>

Sorry for the slow response.

Tested using NVIDIA springbank/seaboard board. Just in case anyone reads 
this later and wonders how: I will point out that in the baseline 
v4.11-rc4, the LCD (or perhaps just its backlight) doesn't work on this 
HW any more, but since the GUI login prompt plays a sound, I was still 
able to validate the WM8903 change.