linux-kernel - Re: [PATCH 09/21] input: gpio-keys: make legacy gpiolib optional

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Message-ID: <aJpOEq_5jqGTUr4x@smile.fi.intel.com>
Date: Mon, 11 Aug 2025 23:09:54 +0300
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc: Matti Vaittinen <mazziesaccount@...il.com>,
	Arnd Bergmann <arnd@...nel.org>,
	Bartosz Golaszewski <brgl@...ev.pl>,
	Linus Walleij <linus.walleij@...aro.org>,
	linux-gpio@...r.kernel.org, Lee Jones <lee@...nel.org>,
	Arnd Bergmann <arnd@...db.de>,
	Gatien Chevallier <gatien.chevallier@...s.st.com>,
	Fabrice Gasnier <fabrice.gasnier@...s.st.com>,
	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Charles Keepax <ckeepax@...nsource.cirrus.com>,
	Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
	Christophe JAILLET <christophe.jaillet@...adoo.fr>,
	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 09/21] input: gpio-keys: make legacy gpiolib optional

On Mon, Aug 11, 2025 at 12:21:51PM -0700, Dmitry Torokhov wrote:
> On Mon, Aug 11, 2025 at 03:52:19PM +0300, Andy Shevchenko wrote:
> > On Mon, Aug 11, 2025 at 01:34:43PM +0300, Matti Vaittinen wrote:
> > > On 08/08/2025 18:17, Arnd Bergmann wrote:

...

> > > As such, this patch seems Ok to me, you can treat this as an ack :) This,
> > > however made me ponder following - is this the tight way to handle the
> > > power-button IRQ? I don't see any other MFD devices doing this in same way,
> > > although I am pretty sure there are other PMICs with similar power-button
> > > IRQ...
> > > 
> > > I see for example the "drivers/mfd/rt5120.c" to invoke
> > > "drivers/input/misc/rt5120-pwrkey.c" instead of using the gpio-keys. This,
> > > however, feels like code duplication to me. I'd rather kept using the
> > > gpio-keys, but seeing:
> > > 
> > > git grep KEY_POWER drivers/mfd/
> > > drivers/mfd/rohm-bd71828.c:     .code = KEY_POWER,
> > > drivers/mfd/rohm-bd718x7.c:     .code = KEY_POWER,
> > > 
> > > makes me wonder if there is more widely used (better) way?
> > 
> > FWIW, on Intel platforms that use power button by PMIC we add a special driver
> > for each of such cases.
> 
> If we can make gpio-keys work for various power buttons that would be
> great IMO. The MFD drivers in question already are using device tree,
> but they do not define/expect nodes for the power buttons. If the nodes
> were there then I think gpio-keys would work out of the box?

Looking at the, e.g., https://elixir.bootlin.com/linux/v6.16/source/drivers/platform/x86/intel/mrfld_pwrbtn.c,
I am not sure it's as simply as it sounds. Basically it's an IRQ, which
requires IRQ handling and proper acking/masking/etc.

-- 
With Best Regards,
Andy Shevchenko