netdev - Re: [PATCH] p54spi: convert to devicetree

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Message-ID: <19ca470e-8219-5ba9-3de6-f4560278f87b@linaro.org>
Date:   Wed, 15 Mar 2023 08:11:07 +0100
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To:     Arnd Bergmann <arnd@...db.de>, Arnd Bergmann <arnd@...nel.org>,
        Christian Lamparter <chunkeey@...glemail.com>,
        Kalle Valo <kvalo@...nel.org>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        Linux-OMAP <linux-omap@...r.kernel.org>,
        Tony Lindgren <tony@...mide.com>,
        Aaro Koskinen <aaro.koskinen@....fi>,
        Felipe Balbi <balbi@...nel.org>,
        "David S . Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Benoît Cousson <bcousson@...libre.com>,
        Russell King <linux@...linux.org.uk>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Johannes Berg <johannes@...solutions.net>,
        linux-wireless@...r.kernel.org, Netdev <netdev@...r.kernel.org>,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] p54spi: convert to devicetree

On 15/03/2023 07:50, Arnd Bergmann wrote:
> On Wed, Mar 15, 2023, at 07:32, Krzysztof Kozlowski wrote:
>> On 14/03/2023 22:40, Arnd Bergmann wrote:
>>
>>>>> +
>>>>> +  power-gpios:
>>>>
>>>> If this is GPIO driving some power pin, then it should be
>>>> "powerdown-gpios" (like in /bindings/gpio/gpio-consumer-common.yaml)
>>>
>>> As far as I can tell, it's the opposite: the gpio turns the power on
>>> in 'high' state. I could make it GPIO_ACTIVE_LOW and call it powerdown,
>>> if you think that's better, but I don't think that is how it was
>>> meant.
>>
>> Whether this is active low or high, I think does not matter. If this is
>> pin responsible to control the power, then we use the name
>> "powerdown-gpios". Effectively powerup GPIO is the same as powerdown,
>> just reversed.
> 
> Ok, so should I make this GPIO_ACTIVE_LOW and adapt the patch to
> call it powerdown in both the code and dt for consistency?

If you have schematics (or datasheet) then this should reflect truth. If
not, then judging by the old code it is something like powerdown, so yes
- ACTIVE_LOW and reverse values in the code.

Best regards,
Krzysztof