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Lars-Peter Clausen e2c9b875ba i2c: cadence: Support PEC for SMBus block read
[ Upstream commit 9fdf6d97f0 ]

SMBus packet error checking (PEC) is implemented by appending one
additional byte of checksum data at the end of the message. This provides
additional protection and allows to detect data corruption on the I2C bus.

SMBus block reads support variable length reads. The first byte in the read
message is the number of available data bytes.

The combination of PEC and block read is currently not supported by the
Cadence I2C driver.
 * When PEC is enabled the maximum transfer length for block reads
   increases from 33 to 34 bytes.
 * The I2C core smbus emulation layer relies on the driver updating the
   `i2c_msg` `len` field with the number of received bytes. The updated
   length is used when checking the PEC.

Add support to the Cadence I2C driver for handling SMBus block reads with
PEC. To determine the maximum transfer length uses the initial `len` value
of the `i2c_msg`. When PEC is enabled this will be 2, when it is disabled
it will be 1.

Once a read transfer is done also increment the `len` field by the amount
of received data bytes.

This change has been tested with a UCM90320 PMBus power monitor, which
requires block reads to access certain data fields, but also has PEC
enabled by default.

Fixes: df8eb5691c ("i2c: Add driver for Cadence I2C controller")
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Tested-by: Shubhrajyoti Datta <Shubhrajyoti.datta@amd.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2022-08-17 15:14:54 +02:00
arch bpf, x86: fix freeing of not-finalized bpf_prog_pack 2022-08-17 15:14:48 +02:00
block blk-mq: don't create hctx debugfs dir until q->debugfs_dir is created 2022-08-17 15:14:16 +02:00
certs certs: make system keyring depend on x509 parser 2022-07-24 12:53:55 -07:00
crypto crypto: s390 - do not depend on CRYPTO_HW for SIMD implementations 2022-07-06 20:04:06 -07:00
Documentation media: uapi: HEVC: Change pic_order_cnt definition in v4l2_hevc_dpb_entry 2022-08-17 15:14:50 +02:00
drivers i2c: cadence: Support PEC for SMBus block read 2022-08-17 15:14:54 +02:00
fs fs: check FMODE_LSEEK to control internal pipe splicing 2022-08-17 15:14:49 +02:00
include Bluetooth: When HCI work queue is drained, only queue chained work 2022-08-17 15:14:53 +02:00
init stack: Declare {randomize_,}kstack_offset to fix Sparse warnings 2022-08-17 15:14:14 +02:00
io_uring io_uring: Don't require reinitable percpu_ref 2022-08-17 15:14:20 +02:00
ipc ipc: Free mq_sysctls if ipc namespace creation failed 2022-06-22 17:47:41 -05:00
kernel bpf: fix potential 32-bit overflow when accessing ARRAY map element 2022-08-17 15:14:51 +02:00
lib kunit: executor: Fix a memory leak on failure in kunit_filter_tests 2022-08-17 15:14:48 +02:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm mm: Account dirty folios properly during splits 2022-08-17 15:14:38 +02:00
net Bluetooth: hci_sync: Fix not updating privacy_mode 2022-08-17 15:14:54 +02:00
samples sample: bpf: xdp_router_ipv4: Allow the kernel to send arp requests 2022-08-17 15:14:25 +02:00
scripts scripts/gdb: Fix gdb 'lx-symbols' command 2022-07-21 10:40:55 -07:00
security selinux: Add boundary check in put_entry() 2022-08-17 15:14:06 +02:00
sound ALSA: hda/realtek: Add a quirk for HP OMEN 15 (8786) mute LED 2022-08-17 15:13:46 +02:00
tools libbpf: Fix str_has_sfx()'s return value 2022-08-17 15:14:53 +02:00
usr Not a lot of material this cycle. Many singleton patches against various 2022-05-27 11:22:03 -07:00
virt KVM: Do not incorporate page offset into gfn=>pfn cache user address 2022-08-17 15:13:43 +02:00
.clang-format clang-format: Fix space after for_each macros 2022-05-20 19:27:16 +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 kbuild: split the second line of *.mod into *.usyms 2022-05-08 03:16:59 +09:00
.mailmap ARM: SoC fixes for 5.19, part 4 2022-07-27 09:43:07 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: mark ARM/PALM TREO SUPPORT orphan 2022-07-07 15:17:00 +02:00
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 io_uring: move to separate directory 2022-08-17 15:14:20 +02:00
Makefile io_uring: move to separate directory 2022-08-17 15:14:20 +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.