c7650728a7
In the current code, if the user configures a bitrate, a default SJW value of 1 is used. If the user configures both a bitrate and a SJW value, can_calc_bittiming() silently limits the SJW value to SJW max and TSEG2. We came to the conclusion that if the user provided an invalid SJW value, it's best to bail out and inform the user [1]. [1] https://lore.kernel.org/all/CAMZ6RqKqhmTgUZiwe5uqUjBDnhhC2iOjZ791+Y845btJYwVDKg@mail.gmail.com Further the ISO 11898-1:2015 standard mandates that "SJW shall be less than or equal to the minimum of these two items: Phase_Seg1 and Phase_Seg2." [2] The current code is missing that check. [2] https://lore.kernel.org/all/BL3PR11MB64844E3FC13C55433CDD0B3DFB449@BL3PR11MB6484.namprd11.prod.outlook.com The previous patches introduced 1) can_sjw_set_default() - sets a default value for SJW if unset 2) can_sjw_check() - implements a SJW check against SJW max, Phase Seg1 and Phase Seg2. In the error case this function reports the error to user space via netlink. Replace both the open-coded SJW default setting and the open-coded and insufficient checks of SJW with the helper functions can_sjw_set_default() and can_sjw_check(). Link: https://lore.kernel.org/all/20230202110854.2318594-16-mkl@pengutronix.de Link: https://lore.kernel.org/all/CAMZ6RqKqhmTgUZiwe5uqUjBDnhhC2iOjZ791+Y845btJYwVDKg@mail.gmail.com Link: https://lore.kernel.org/all/BL3PR11MB64844E3FC13C55433CDD0B3DFB449@BL3PR11MB6484.namprd11.prod.outlook.com Suggested-by: Thomas Kopp <Thomas.Kopp@microchip.com> Suggested-by: Vincent Mailhol <vincent.mailhol@gmail.com> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
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.