Re: [PATCH 2/4] ASoC: dt-bindings: Add support for the GPIOs driven amplifier

[Mark Brown]

On Thu, Apr 09, 2026 at 10:00:55AM -0500, Rob Herring wrote:
> On Wed, Apr 8, 2026 at 12:09 PM Herve Codina <herve.codina@xxxxxxxxxxx> wrote:

> > Mark suggested to merge this gpio-audio-amp with simple-amplifier.

> Merging driver and merging binding are separate questions.

Yes, my comments were purely about the driver.

> > I didn't want to set a particular limit related to the number of GPIOs
> > used for thje gain value. Of course 2^32 is obviously a lot.

> > What do you think about 16 for maxItems?

> What is the most you are aware of? Take that and double it.

> Seems to me 256 levels would be way more than a human ear could distinguish.

There's plenty of gain controls with way more than 256 bits of
resolution, though I'm not aware of any that are configured via GPIO.
The step size and absolute values you want can vary dramatically
depending on application, possibly in the same system (eg, a DAC that
can be connected to both headphones or speakers) so you often end up
making practical adjustments in a small subset of the available range
but that subset can vary a lot for the same part.

> I guess my point was that really we could deprecate simple-amplifier
> binding because this one can handle it and more. But I'm not
> suggesting we do that yet.

That's my thinking.

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