linux-kernel - Re: [PATCH] ASoC: codecs: wsa884x: allow sharing reset GPIO

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Message-ID: <84f9f1c4-0627-4986-8160-b4ab99469b81@linaro.org>
Date:   Wed, 18 Oct 2023 14:38:00 +0200
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To:     Mark Brown <broonie@...nel.org>
Cc:     Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
        Banajit Goswami <bgoswami@...cinc.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>, alsa-devel@...a-project.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ASoC: codecs: wsa884x: allow sharing reset GPIO

On 18/10/2023 14:35, Mark Brown wrote:
> On Wed, Oct 18, 2023 at 12:00:55PM +0200, Krzysztof Kozlowski wrote:
>> On some boards with multiple WSA8840/WSA8845 speakers, the reset
>> (shutdown) GPIO is shared between two speakers.  Request it as
>> GPIOD_FLAGS_BIT_NONEXCLUSIVE to allow such configurations.
> 
>>  	wsa884x->sd_n = devm_gpiod_get_optional(dev, "powerdown",
>> -						GPIOD_OUT_HIGH);
>> +						GPIOD_FLAGS_BIT_NONEXCLUSIVE | GPIOD_OUT_HIGH);
> 
> How do the speakers coordinate?

They don't and that's the generic problem of many Linux drivers. Not
only this one, but others as well.

Device unbind (remove()) or runtime suspend of one speaker will affect
other speaker. I don't think any other drivers solved this, because this
is rather core's GPIO issue, thus I am not solving it here either. :(

Best regards,
Krzysztof