Linux kernel source tree
Find a file
Maksim Kiselev f9f4fda15e pinctrl: mcp23s08: init reg_defaults from HW at probe and switch cache type
The probe function does not guarantee that chip registers are in their
default state. Thus using reg_defaults for regmap is incorrect.

For example, the chip may have already been configured by the bootloader
before the Linux driver loads, or the mcp might not have a reset at all
and not reset a state between reboots.

In such cases, using reg_defaults leads to the cache values diverging
from the actual registers values in the chip.

Previous attempts to fix consequences of this issue were made in
'commit 3ede3f8b4b ("pinctrl: mcp23s08: Reset all pins to input at
probe")', but this is insufficient. The OLAT register reset is also
required. And there's still potential for new issues arising due to cache
desynchronization of other registers.

Therefore, remove reg_defaults and provide num_reg_defaults_raw. In that
case the cache defaults being initialized from hardware.

Also switch cache type to REGCACHE_MAPLE, which is aware of (in)valid
cache entries.

And remove the force reset all pins to input at probe as it is no longer
required.

Link: https://lore.kernel.org/all/20251009132651.649099-2-bigunclemax@gmail.com/
Suggested-by: Mike Looijmans <mike.looijmans@topic.nl>
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Suggested-by: Sander Vanheule <sander@svanheule.net>
Signed-off-by: Maksim Kiselev <bigunclemax@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2025-10-29 23:19:08 +01:00
arch Kbuild fixes for 6.18 #1 2025-10-11 15:47:12 -07:00
block block-6.18-20251009 2025-10-10 10:37:13 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto This push contains the following changes: 2025-10-10 08:56:16 -07:00
Documentation dt-bindings: pinctrl: stm32: Support I/O synchronization parameters 2025-10-28 10:43:01 +01:00
drivers pinctrl: mcp23s08: init reg_defaults from HW at probe and switch cache type 2025-10-29 23:19:08 +01:00
fs - Avoid -Wflex-array-member-not-at-end warnings 2025-10-10 14:06:02 -07:00
include pinctrl: pinconf-generic: Add properties 'skew-delay-{in,out}put-ps' 2025-10-28 10:43:01 +01:00
init printk changes for 6.18 2025-10-04 11:13:11 -07:00
io_uring io_uring/zcrx: increment fallback loop src offset 2025-10-08 07:26:14 -06:00
ipc namespace-6.18-rc1 2025-09-29 11:20:29 -07:00
kernel tracing fixes for v6.18: 2025-10-11 16:06:04 -07:00
lib lib/test_kho: use kho_preserve_vmalloc instead of storing addresses in fdt 2025-10-07 13:48:56 -07:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
mm slab hotfix for 6.18-rc1 2025-10-11 10:40:24 -07:00
net bpf-fixes 2025-10-11 10:31:38 -07:00
rust 7 hotfixes. All 7 are cc:stable and all 7 are for MM. 2025-10-11 10:14:55 -07:00
samples Char/Misc/IIO/Binder changes for 6.18-rc1 2025-10-04 16:26:32 -07:00
scripts Kbuild fixes for 6.18 #1 2025-10-11 15:47:12 -07:00
security integrity-v6.18 2025-10-05 10:48:33 -07:00
sound sound fixes for 6.18-rc1 2025-10-10 09:55:19 -07:00
tools - Remove a bunch of asm implementing condition flags testing in KVM's 2025-10-11 11:19:16 -07:00
usr gen_init_cpio: Ignore fsync() returning EINVAL on pipes 2025-10-07 09:53:05 -07:00
virt hyperv-next for v6.18 2025-10-07 08:40:15 -07:00
.clang-format memblock: drop for_each_free_mem_pfn_range_in_zone_from() 2025-09-14 08:49:03 +03:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +02:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: remove Alyssa Rosenzweig 2025-09-18 21:17:31 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore .gitignore: ignore compile_commands.json globally 2025-08-12 15:53:55 -07:00
.mailmap MAINTAINERS, .mailmap: update Umang's email address 2025-10-07 13:48:55 -07:00
.pylintrc tools: docs: parse-headers.py: move it from sphinx dir 2025-08-29 15:54:42 -06:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS USB/Thunderbolt changes for 6.18-rc1 2025-10-04 16:07:08 -07:00
Kbuild sched: Make migrate_{en,dis}able() inline 2025-09-25 09:57:16 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS MAINTAINERS: add Microchip RISC-V pinctrl drivers/bindings to entry 2025-10-24 11:08:25 +02:00
Makefile Linux 6.18-rc1 2025-10-12 13:42:36 -07:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

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 reStructuredText 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.