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Vincent Mailhol 39f66c9e22 can: bittiming: change unit of TDC parameters to clock periods
In the current implementation, all Transmission Delay Compensation
(TDC) parameters are expressed in time quantum. However, ISO 11898-1
actually specifies that these should be expressed in *minimum* time
quantum.

Furthermore, the minimum time quantum is specified to be "one node
clock period long" (c.f. paragraph 11.3.1.1 "Bit time"). For sake of
simplicity, we prefer to use the "clock period" term instead of
"minimum time quantum" because we believe that it is more broadly
understood.

This patch fixes that discrepancy by updating the documentation and
the formula for TDCO calculation.

N.B. In can_calc_tdco(), the sample point (in time quantum) was
calculated using a division, thus introducing a risk of rounding and
truncation errors. On top of changing the unit to clock period, we
also modified the formula to use only additions.

Link: https://lore.kernel.org/all/20210918095637.20108-3-mailhol.vincent@wanadoo.fr
Suggested-by: Stefan Mätje <Stefan.Maetje@esd.eu>
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2021-10-24 16:24:28 +02:00
arch Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-10-22 11:41:16 +01:00
block block-5.15-2021-10-17 2021-10-17 19:25:20 -10:00
certs certs: Add support for using elliptic curve keys for signing modules 2021-08-23 19:55:42 +03:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2021-08-30 12:57:10 -07:00
Documentation dt-bindings: net: macb: Add mdio bus child node 2021-10-24 13:44:39 +01:00
drivers can: bittiming: change unit of TDC parameters to clock periods 2021-10-24 16:24:28 +02:00
fs Two important filesystem fixes, marked for stable. The blocklisted 2021-10-20 10:23:05 -10:00
include can: bittiming: change unit of TDC parameters to clock periods 2021-10-24 16:24:28 +02:00
init bootconfig: init: Fix memblock leak in xbc_make_cmdline() 2021-10-10 22:27:40 -04:00
ipc ipc: remove memcg accounting for sops objects in do_semtimedop() 2021-09-14 10:22:11 -07:00
kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-10-22 11:41:16 +01:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-10-14 16:50:14 -07:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm memblock: exclude MEMBLOCK_NOMAP regions from kmemleak 2021-10-21 18:30:49 -10:00
net can: bcm: Use hrtimer_forward_now() 2021-10-24 16:24:28 +02:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-10-07 15:24:06 -07:00
scripts Tracing fixes for 5.15: 2021-10-16 10:51:41 -07:00
security Merge branch 'ucount-fixes-for-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2021-10-21 17:27:17 -10:00
sound ALSA: usb-audio: Fix microphone sound on Jieli webcam. 2021-10-19 08:07:01 +02:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-10-22 11:41:16 +01:00
usr .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
virt KVM: Remove tlbs_dirty 2021-09-23 11:01:12 -04:00
.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 .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.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 wireless-drivers-next patches for v5.16 2021-10-22 10:22:07 -07:00
Makefile Linux 5.15-rc6 2021-10-17 20:00:13 -10:00
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.