linux-kernel - Re: [PATCH v5 02/11] mfd: Add max7360 support

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Message-Id: <D8PHKDVTYTQ5.1HT80KX538PRQ@bootlin.com>
Date: Tue, 25 Mar 2025 17:26:12 +0100
From: "Mathieu Dubois-Briand" <mathieu.dubois-briand@...tlin.com>
To: "Andy Shevchenko" <andriy.shevchenko@...el.com>
Cc: "Lee Jones" <lee@...nel.org>, "Rob Herring" <robh@...nel.org>,
 "Krzysztof Kozlowski" <krzk+dt@...nel.org>, "Conor Dooley"
 <conor+dt@...nel.org>, "Kamel Bouhara" <kamel.bouhara@...tlin.com>, "Linus
 Walleij" <linus.walleij@...aro.org>, "Bartosz Golaszewski" <brgl@...ev.pl>,
 "Dmitry Torokhov" <dmitry.torokhov@...il.com>,
 Uwe Kleine-König <ukleinek@...nel.org>, "Michael Walle"
 <mwalle@...nel.org>, "Mark Brown" <broonie@...nel.org>, "Greg
 Kroah-Hartman" <gregkh@...uxfoundation.org>, "Rafael J. Wysocki"
 <rafael@...nel.org>, "Danilo Krummrich" <dakr@...nel.org>,
 <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
 <linux-gpio@...r.kernel.org>, <linux-input@...r.kernel.org>,
 <linux-pwm@...r.kernel.org>, Grégory Clement
 <gregory.clement@...tlin.com>, "Thomas Petazzoni"
 <thomas.petazzoni@...tlin.com>
Subject: Re: [PATCH v5 02/11] mfd: Add max7360 support

On Wed Mar 19, 2025 at 12:10 PM CET, Andy Shevchenko wrote:
> On Tue, Mar 18, 2025 at 05:26:18PM +0100, mathieu.dubois-briand@...tlin.com wrote:
> > From: Kamel Bouhara <kamel.bouhara@...tlin.com>
> > +	ret = max7360_mask_irqs(regmap);
> > +	if (ret)
> > +		return dev_err_probe(dev, ret, "Could not mask interrupts\n");
>
> Hmm... As far as I can read this masks GPIO interrups. Does it do anything
> else? If it's covered by the GPIO/pin control drivers, one want probably to
> see that to be done there in the respective callback (init_hw_irq or alike,
> I don't remember the name by heart).
>

Hum, I'm not sure I can do that.

So the "inti" interrupt line is shared across the GPIO and the rotary
encoder functionalities.

On reset, GPIO interrupts are not masked. This means, if we do the
masking in the GPIO driver and the GPIO driver is not loaded but the
rotary encoder driver is, the rotary encoder driver might get a lot of
spurious interrupts.

So I believe it makes sense to mask the interrupts here, setting the
chip in a sane configuration, whatever child drivers are present.

Any thought about that?

-- 
Mathieu Dubois-Briand, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com