Mike Looijmans 5cf32cef3a pinctrl: mcp23s08: Reset all pins to input at probe
[ Upstream commit 3ede3f8b4b4b399b0ca41e44959f80d5cf84fc98 ]

At startup, the driver just assumes that all registers have their
default values. But after a soft reset, the chip will just be in the
state it was, and some pins may have been configured as outputs. Any
modification of the output register will cause these pins to be driven
low, which leads to unexpected/unwanted effects. To prevent this from
happening, set the chip's IO configuration register to a known safe
mode (all inputs) before toggling any other bits.

Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
Link: https://lore.kernel.org/20250314151803.28903-1-mike.looijmans@topic.nl
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-27 11:08:56 +01:00
2022-09-28 09:02:20 +02:00
2025-06-19 15:28:47 +02:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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