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Message-ID: <2261eadf98584d13a490f2abd8777d4a@AcuMS.aculab.com>
Date: Fri, 6 Sep 2019 09:05:36 +0000
From: David Laight <David.Laight@...LAB.COM>
To: 'Alexandre Belloni' <alexandre.belloni@...tlin.com>,
Linus Walleij <linus.walleij@...aro.org>
CC: Ludovic Desroches <ludovic.desroches@...rochip.com>,
Nicolas Ferre <nicolas.ferre@...rochip.com>,
"Claudiu.Beznea@...rochip.com" <Claudiu.Beznea@...rochip.com>,
"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH v2] pinctrl: at91-pio4: implement .get_multiple and
.set_multiple
From: Alexandre Belloni
> Implement .get_multiple and .set_multiple to allow reading or setting
> multiple pins simultaneously. Pins in the same bank will all be switched at
> the same time, improving synchronization and performances.
Actually it won't 'improve synchronisation', instead it will lead to
random synchronisation errors and potential metastability if one
pin is used as a clock and another as data, or if the code is reading
a free-flowing counter.
It will improve performance though.
David
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