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| author | Patrick Rudolph <patrick.rudolph@9elements.com> | 2023-08-17 11:25:26 +0200 |
|---|---|---|
| committer | Guenter Roeck <linux@roeck-us.net> | 2023-08-21 06:04:31 -0700 |
| commit | e7593bda6a2e2e46521567f0ddea940f4acda0db (patch) | |
| tree | 2ca4353050fd66d2c7792c83e60ddabc6fc452d4 /drivers/cpufreq/raspberrypi-cpufreq.c | |
| parent | 3fd2188e588ffd8d45df5ac92ab1089328211a86 (diff) | |
hwmon: pmbus: Fix -EIO seen on pli1209
After doing performance optimizations the pli1209 driver failed to
probe with a probabilty of 2%. It wasn't able to read the PMBUS_OPERATION
register due to an -EIO error.
An investigation showed that the PLI1209 takes 230 usec to execute the
CLEAR_FAULTS command. During that time it's busy and NACKs all requests
on the SMBUS interface. It also NACKs reads on PMBUS_STATUS_BYTE
making it impossible to poll the BUSY flag.
Add a custom write_data function to just wait for not BUSY unconditionally
after sending a CLEAR_FAULTS command.
TEST: Verified using an I2C bus analyser that no more NACKs are seen after
sending a CLEAR_FAULTS command.
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
Link: https://lore.kernel.org/r/20230817092527.808631-3-Naresh.Solanki@9elements.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'drivers/cpufreq/raspberrypi-cpufreq.c')
0 files changed, 0 insertions, 0 deletions