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Marek Vasut 39c025721d i2c: imx: Implement errata ERR007805 or e7805 bus frequency limit
The i.MX8MP Mask Set Errata for Mask 1P33A, Rev. 2.0 has description of
errata ERR007805 as below. This errata is found on all MX8M{M,N,P,Q},
MX7{S,D}, MX6{UL{,L,Z},S{,LL,X},S,D,DL,Q,DP,QP} . MX7ULP, MX8Q, MX8X
are not affected. MX53 and older status is unknown, as the errata
first appears in MX6 errata sheets from 2016 and the latest errata
sheet for MX53 is from 2015. Older SoC errata sheets predate the
MX53 errata sheet. MX8ULP and MX9 status is unknown as the errata
sheet is not available yet.

"
ERR007805 I2C: When the I2C clock speed is configured for 400 kHz,
the SCL low period violates the I2C spec of 1.3 uS min

Description: When the I2C module is programmed to operate at the
maximum clock speed of 400 kHz (as defined by the I2C spec), the SCL
clock low period violates the I2C spec of 1.3 uS min. The user must
reduce the clock speed to obtain the SCL low time to meet the 1.3us
I2C minimum required. This behavior means the SoC is not compliant
to the I2C spec at 400kHz.

Workaround: To meet the clock low period requirement in fast speed
mode, SCL must be configured to 384KHz or less.
"

Implement the workaround by matching on the affected SoC specific
compatible strings and by limiting the maximum bus frequency in case
the SoC is affected.

Signed-off-by: Marek Vasut <marex@denx.de>
To: linux-i2c@vger.kernel.org
Acked-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
2022-04-15 23:13:52 +02:00
Documentation linux-kselftest-kunit-fixes-5.18-rc2 2022-04-08 15:06:11 -10:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
arch Driver core changes for 5.18-rc2 2022-04-10 09:55:09 -10:00
block for-5.18/block-2022-04-01 2022-04-01 16:20:00 -07:00
certs Kbuild updates for v5.18 2022-03-31 11:59:03 -07:00
crypto for-5.18/64bit-pi-2022-03-25 2022-03-26 12:01:35 -07:00
drivers i2c: imx: Implement errata ERR007805 or e7805 bus frequency limit 2022-04-15 23:13:52 +02:00
fs Driver core changes for 5.18-rc2 2022-04-10 09:55:09 -10:00
include Driver core changes for 5.18-rc2 2022-04-10 09:55:09 -10:00
init Kbuild updates for v5.18 2022-03-31 11:59:03 -07:00
ipc fs: allocate inode by using alloc_inode_sb() 2022-03-22 15:57:03 -07:00
kernel - A couple of fixes to cgroup-related handling of perf events 2022-04-10 07:08:22 -10:00
lib Driver core changes for 5.18-rc2 2022-04-10 09:55:09 -10:00
mm - Allow the compiler to optimize away unused percpu accesses and change 2022-04-10 06:56:46 -10:00
net NFS client bugfixes for Linux 5.18 2022-04-08 07:39:17 -10:00
samples dma-mapping updates for Linux 5.18 2022-03-29 08:50:14 -07:00
scripts modpost: restore the warning message for missing symbol versions 2022-04-03 03:11:51 +09:00
security hardening updates for v5.18-rc1-fix1 2022-03-31 11:43:01 -07:00
sound sound fixes for 5.18-rc1 2022-04-01 10:32:46 -07:00
tools - Fix the MSI message data struct definition 2022-04-10 07:12:27 -10:00
usr Kbuild updates for v5.18 2022-03-31 11:59:03 -07:00
virt KVM: Remove dirty handling from gfn_to_pfn_cache completely 2022-04-02 05:34:41 -04:00
.clang-format genirq/msi: Make interrupt allocation less convoluted 2021-12-16 22:22:20 +01:00
.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 .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: update Vasily Averin's email address 2022-04-08 14:20:36 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: replace a Microchip AT91 maintainer 2022-02-09 11:30:01 +01:00
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 v5.18 first rc pull request 2022-04-08 18:29:02 -10:00
Makefile Linux 5.18-rc2 2022-04-10 14:21:36 -10:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.