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

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Message-ID: <CAMRc=MeJh2H0zYg5mfkuZreNoRAOWar9oR68+xrAar+-W2gJqg@mail.gmail.com>
Date: Fri, 11 Jul 2025 12:22:40 +0200
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Hugo Villeneuve <hugo@...ovil.com>
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 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.

Thanks!
Bart