linux-kernel - Re: [PATCH] pinctrl: sunxi: Use minimal debouncing period as default

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Message-ID: <Z30WTaDHQOotVnpl@collins>
Date: Tue, 7 Jan 2025 12:55:57 +0100
From: Paul Kocialkowski <paulk@...-base.io>
To: Maxime Ripard <mripard@...nel.org>
Cc: Linus Walleij <linus.walleij@...aro.org>,
	linux-arm-kernel@...ts.infradead.org, linux-sunxi@...ts.linux.dev,
	linux-kernel@...r.kernel.org,
	Uwe Kleine-König <ukleinek@...nel.org>,
	Chen-Yu Tsai <wens@...e.org>,
	Jernej Skrabec <jernej.skrabec@...il.com>,
	Samuel Holland <samuel@...lland.org>,
	Paul Kocialkowski <contact@...lk.fr>
Subject: Re: [PATCH] pinctrl: sunxi: Use minimal debouncing period as default

Hi,

Le Tue 17 Dec 24, 14:58, Maxime Ripard a écrit :
> On Tue, Dec 17, 2024 at 02:41:36PM +0100, Linus Walleij wrote:
> > On Tue, Nov 19, 2024 at 3:43 PM Maxime Ripard <mripard@...nel.org> wrote:
> > 
> > > [Paul]
> > > > The pinctrl code supports an input-debounce device-tree property to set
> > > > a specific debouncing period and choose which clock source is most
> > > > relevant. However the property is specified in microseconds, which is
> > > > longer than the minimal period achievable from the high-frequency
> > > > oscillator without a pre-scaler.
> > >
> > > That can be fixed by introducing a new property with a ns resolution.
> > 
> > Perhaps, but I think a setting of 0 should just yield the minimum
> > resolution in this case, as apparently the debounce cannot be
> > turned off? This would also make sense to expose for
> > gpiod_set_debounce() as explained in my other mail.
> 
> Yeah, if we want to have 0 == lowest resolution, I'm all for it.

I agree that it would be easier and less confusing than introducing a new
property just to have a finer resolution.

I could craft a patch in that direction then, with a mention about it in the
bindings.

Cheers,

Paul

-- 
Paul Kocialkowski,

Independent contractor - sys-base - https://www.sys-base.io/
Free software developer - https://www.paulk.fr/

Expert in multimedia, graphics and embedded hardware support with Linux.

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