No description
  • C 98.2%
  • Assembly 1%
  • Makefile 0.3%
  • Shell 0.2%
  • Python 0.1%
Find a file
Repository files (latest commit first)
Filename Latest commit message Latest commit date
Geert Uytterhoeven e062021441 i2c: riic: Always round-up when calculating bus period
commit de6b43798d9043a7c749a0428dbb02d5fff156e5 upstream.

Currently, the RIIC driver may run the I2C bus faster than requested,
which may cause subtle failures.  E.g. Biju reported a measured bus
speed of 450 kHz instead of the expected maximum of 400 kHz on RZ/G2L.

The initial calculation of the bus period uses DIV_ROUND_UP(), to make
sure the actual bus speed never becomes faster than the requested bus
speed.  However, the subsequent division-by-two steps do not use
round-up, which may lead to a too-small period, hence a too-fast and
possible out-of-spec bus speed.  E.g. on RZ/Five, requesting a bus speed
of 100 resp. 400 kHz will yield too-fast target bus speeds of 100806
resp. 403226 Hz instead of 97656 resp. 390625 Hz.

Fix this by using DIV_ROUND_UP() in the subsequent divisions, too.

Tested on RZ/A1H, RZ/A2M, and RZ/Five.

Fixes: d982d66514 ("i2c: riic: remove clock and frequency restrictions")
Reported-by: Biju Das <biju.das.jz@bp.renesas.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: <stable@vger.kernel.org> # v4.15+
Link: https://lore.kernel.org/r/c59aea77998dfea1b4456c4b33b55ab216fcbf5e.1732284746.git.geert+renesas@glider.be
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-01-09 13:23:28 +01:00
arch perf/x86/intel/pt: Fix buffer full but size is 0 case 2024-12-14 19:44:55 +01:00
block blk-iocost: Avoid using clamp() on inuse in __propagate_weights() 2024-12-19 18:05:04 +01:00
certs
crypto
Documentation PCI: Add 'reset_subordinate' to reset hierarchy below bridge 2024-12-14 19:44:54 +01:00
drivers i2c: riic: Always round-up when calculating bus period 2025-01-09 13:23:28 +01:00
fs erofs: fix incorrect symlink detection in fast symlink 2025-01-09 13:23:27 +01:00
include net: lapb: increase LAPB_HEADER_LEN 2024-12-19 18:05:03 +01:00
init
ipc
kernel tracing/kprobes: Skip symbol counting logic for module symbols in create_local_trace_kprobe() 2024-12-19 18:05:04 +01:00
lib lib: string_helpers: silence snprintf() output truncation warning 2024-12-14 19:44:39 +01:00
LICENSES
mm
net netfilter: ipset: Fix for recursive locking warning 2025-01-09 13:23:28 +01:00
samples samples/bpf: Fix a resource leak 2024-12-14 19:44:50 +01:00
scripts modpost: Add .irqentry.text to OTHER_SECTIONS 2024-12-14 19:44:56 +01:00
security apparmor: fix 'Do simple duplicate message elimination' 2024-12-14 19:44:34 +01:00
sound ALSA: usb: Fix UBSAN warning in parse_audio_unit() 2025-01-09 13:23:26 +01:00
tools
usr
virt KVM: arm64: Ignore PMCNTENSET_EL0 while checking for overflow status 2024-12-19 18:05:04 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.288 2024-12-19 18:05:05 +01:00
README

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.