From: David Laight <David.Laight@ACULAB.COM>
To: 'Alexandre Belloni' <alexandre.belloni@bootlin.com>,
Linus Walleij <linus.walleij@linaro.org>
Cc: Ludovic Desroches <ludovic.desroches@microchip.com>,
Nicolas Ferre <nicolas.ferre@microchip.com>,
"Claudiu.Beznea@microchip.com" <Claudiu.Beznea@microchip.com>,
"linux-gpio@vger.kernel.org" <linux-gpio@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v2] pinctrl: at91-pio4: implement .get_multiple and .set_multiple
Date: Fri, 6 Sep 2019 09:05:36 +0000 [thread overview]
Message-ID: <2261eadf98584d13a490f2abd8777d4a@AcuMS.aculab.com> (raw)
In-Reply-To: <20190905144849.24882-1-alexandre.belloni@bootlin.com>
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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Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2019-09-06 9:05 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-05 14:48 [PATCH v2] pinctrl: at91-pio4: implement .get_multiple and .set_multiple Alexandre Belloni
2019-09-06 9:05 ` David Laight [this message]
2019-09-06 9:12 ` Alexandre Belloni
2019-09-06 9:46 ` David Laight
2019-09-06 10:42 ` Alexandre Belloni
2019-10-03 8:08 ` Linus Walleij
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