CAN in Automation (CiA) 301 v4.2.0 recommends a sample point location of
87.5% percent for all bitrates. However, some CAN controllers have
difficulties meeting this for higher bitrates.
Change can_set_bitrate() to use a sample point of 75.0% for bitrates
over 800 kbit/s, 80.0% for bitrates over 500 kbit/s, and 87.5% for all
other bitrates. This is in line with the sample point locations used by
the Linux kernel.
Regard a sample point error of more than +/- 5.0% as an error in setting
the bitrate. Previously, any sample rate error was accepted without
providing any feedback to the caller. This is in line with the CAN
sample point calculation criteria used by the Linux kernel.
Signed-off-by: Henrik Brix Andersen <hebad@vestas.com>
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