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Jonas Gorski 1f619f8d54 i2c: iproc: reset bus after timeout if START_BUSY is stuck
[ Upstream commit 98f2e9e6d6 ]

If a transaction times out, the START_BUSY signal can stay up, and
subsequent transactaction attempts will fail as the bus is still
considered busy.

I can easily trigger this by attempting to read from an address with no
device, e.g. when running i2cdetect. After the first read times out, all
subsequent read attempts return busy.

To get to a working state again, the controller needs to be reset to
clear the START_BUSY signal. So check for START_BUSY still asserted on a
timeout, and do reset in case it is,

This is also done by the original non-upstream iproc-smbus driver
implementation [1].

Works around situations like:

    bcm-iproc-2c 1803b000.i2c: transaction timed out
    bcm-iproc-2c 1803b000.i2c: bus is busy
    bcm-iproc-2c 1803b000.i2c: bus is busy
    bcm-iproc-2c 1803b000.i2c: bus is busy
    bcm-iproc-2c 1803b000.i2c: bus is busy
    bcm-iproc-2c 1803b000.i2c: bus is busy
    ...

where the bus never recovers after a timeout.

[1] https://github.com/opencomputeproject/onie/blob/master/patches/kernel/3.2.69/driver-iproc-smbus.patch

Fixes: e6e5dd3566 ("i2c: iproc: Add Broadcom iProc I2C Driver")
Signed-off-by: Jonas Gorski <jonas.gorski@bisdn.de>
Cc: <stable@vger.kernel.org> # v4.0+
Acked-by: Ray Jui <ray.jui@broadcom.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20260717085507.34209-1-jonas.gorski@bisdn.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2026-08-23 14:17:30 +02:00
arch fs/resctrl: Fix double-add of pseudo-locked region's RMID to free list 2026-08-23 14:17:24 +02:00
block partitions: aix: bound the pp_count scan to the ppe array 2026-07-24 15:51:24 +02:00
certs X.509: Fix validation of ASN.1 certificate header 2026-07-24 15:51:59 +02:00
crypto crypto: rsa-pkcs1pad: Don't WARN on an empty digest 2026-08-19 17:13:55 +02:00
Documentation PCI: Move Resizable BAR code to rebar.c 2026-07-24 15:51:58 +02:00
drivers i2c: iproc: reset bus after timeout if START_BUSY is stuck 2026-08-23 14:17:30 +02:00
fs binfmt_misc: restore write access when removing an entry 2026-08-23 14:17:29 +02:00
include fs: don't block write during exec on pre-content watched files 2026-08-23 14:17:29 +02:00
init bootconfig: move xbc_snprint_cmdline() to lib/bootconfig.c 2026-08-23 14:17:24 +02:00
io_uring io_uring/io-wq: re-check IO_WQ_BIT_EXIT for each linked work item 2026-07-24 15:51:21 +02:00
ipc ipc/shm: serialize orphan cleanup with shm_nattch updates 2026-06-19 13:33:38 +02:00
kernel fs: don't block write during exec on pre-content watched files 2026-08-23 14:17:29 +02:00
lib bootconfig: fix NULL-pointer arithmetic in xbc_snprint_cmdline() 2026-08-23 14:17:24 +02:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm mm/vmstat: fold stranded per-cpu node stats when a node comes online 2026-08-23 14:17:28 +02:00
net net: pktgen: fix proc entry use-after-free 2026-08-23 14:17:29 +02:00
samples tracing/events: Fix to check the simple_tsk_fn creation 2026-07-24 15:51:42 +02:00
scripts kconfig: fix potential NULL pointer dereference in conf_askvalue 2026-07-24 15:51:28 +02:00
security selinux: avoid sk_socket dereference in selinux_sctp_bind_connect() 2026-08-23 14:17:21 +02:00
sound ALSA: seq: close a re-opened queue timer in the destructor 2026-08-23 14:17:26 +02:00
tools selftests/ftrace: refactor eprobes test to fix argument checks 2026-08-19 17:14:13 +02:00
usr kbuild: hdrcheck: fix cross build with clang 2025-06-27 11:05:22 +01:00
virt KVM: Move kvm_io_bus_get_dev() locking responsibilities to callers 2026-07-24 15:52:02 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore Remove *.orig pattern from .gitignore 2024-10-17 15:11:10 +02:00
.mailmap mailmap: add Andrej Shadura 2021-10-18 20:22:03 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS staging: rtl8712: Remove driver using deprecated API wext 2025-12-07 06:09:36 +09:00
Makefile Linux 5.15.216 2026-08-19 17:14:18 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -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 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.