linux-kernel - Re: [PATCH v2] ASoC: tas5805m: fix pdn polarity

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Date:   Wed, 9 Mar 2022 15:56:12 +0000
From:   Mark Brown <broonie@...nel.org>
To:     John Keeping <john@...anate.com>
Cc:     alsa-devel@...a-project.org, Liam Girdwood <lgirdwood@...il.com>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>,
        Daniel Beer <daniel.beer@...rinstitute.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] ASoC: tas5805m: fix pdn polarity

On Wed, Mar 09, 2022 at 01:56:49PM +0000, John Keeping wrote:

> The binding defines the GPIO as "pdn-gpios" so when the GPIO is active
> the expectation is that the power down signal is asserted and this is
> how all other drivers using this GPIO name interpret the value.

> But the tas5805m driver inverts the sense from the normal expectation so
> when the powerdown GPIO is logically asserted the chip is running.

> This is a new driver that is not yet in a released kernel and has no
> in-tree users of the binding so fix the sense of the GPIO so that
> logically asserted means that the device is powered down.

> - Rewrite commit message to make it more obvious that this is a change
>   to the interpretation of the GPIO in the binding

I'm still not seeing the functional change here.  The actual state of
the GPIO is identical in both cases, all that's changing is the logical
view internally to the kernel.

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