linux-kernel - Re: [PATCH] gpio: pca953x: use regmap_update

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Message-Id: <20250714093328.4aad6ae61a6eda364b7b7738@hugovil.com>
Date: Mon, 14 Jul 2025 09:33:28 -0400
From: Hugo Villeneuve <hugo@...ovil.com>
To: Bartosz Golaszewski <brgl@...ev.pl>
Cc: Linus Walleij <linus.walleij@...aro.org>, Hugo Villeneuve
 <hvilleneuve@...onoff.com>, linux-gpio@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH] gpio: pca953x: use regmap_update_bits() to improve
 efficiency

On Fri, 11 Jul 2025 12:22:40 +0200
Bartosz Golaszewski <brgl@...ev.pl> wrote:

Hi Bart,


> On Wed, Jul 9, 2025 at 10:10 PM Hugo Villeneuve <hugo@...ovil.com> wrote:
> >
> > From: Hugo Villeneuve <hvilleneuve@...onoff.com>
> >
> > Using regmap_update_bits() allows to reduce the number of I2C transfers
> > when updating bits that haven't changed on non-volatile registers.
> >
> > For example on a PCAL6416, when changing a GPIO direction from input to
> > output, the number of I2C transfers can be reduced from 4 to just 1 if
> > the pull resistors configuration hasn't changed and the output value
> > is the same as before.
> >
> > Signed-off-by: Hugo Villeneuve <hvilleneuve@...onoff.com>
> > ---
> 
> Nice! Can you rebase it on top of gpio/for-next, it doesn't apply
> after recent changes to the driver.

Sure, I will send a V2 shortly.

Hugo.