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| author | Patrick Rudolph <patrick.rudolph@9elements.com> | 2023-08-17 12:25:26 +0300 |
|---|---|---|
| committer | Guenter Roeck <linux@roeck-us.net> | 2023-08-21 16:04:31 +0300 |
| commit | e7593bda6a2e2e46521567f0ddea940f4acda0db (patch) | |
| tree | 2ca4353050fd66d2c7792c83e60ddabc6fc452d4 /drivers | |
| parent | 3fd2188e588ffd8d45df5ac92ab1089328211a86 (diff) | |
| download | linux-e7593bda6a2e2e46521567f0ddea940f4acda0db.tar.xz | |
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')
| -rw-r--r-- | drivers/hwmon/pmbus/pli1209bc.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/drivers/hwmon/pmbus/pli1209bc.c b/drivers/hwmon/pmbus/pli1209bc.c index 7d8bd3167b21..c95433790b11 100644 --- a/drivers/hwmon/pmbus/pli1209bc.c +++ b/drivers/hwmon/pmbus/pli1209bc.c @@ -5,6 +5,7 @@ * Copyright (c) 2022 9elements GmbH */ +#include <linux/delay.h> #include <linux/i2c.h> #include <linux/module.h> #include <linux/pmbus.h> @@ -53,6 +54,30 @@ static int pli1209bc_read_word_data(struct i2c_client *client, int page, } } +static int pli1209bc_write_byte(struct i2c_client *client, int page, u8 reg) +{ + int ret; + + switch (reg) { + case PMBUS_CLEAR_FAULTS: + ret = pmbus_write_byte(client, page, reg); + /* + * 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. + * + * Just wait for not BUSY unconditionally. + */ + usleep_range(250, 300); + break; + default: + ret = -ENODATA; + break; + } + return ret; +} + #if IS_ENABLED(CONFIG_SENSORS_PLI1209BC_REGULATOR) static const struct regulator_desc pli1209bc_reg_desc = { .name = "vout2", @@ -102,6 +127,7 @@ static struct pmbus_driver_info pli1209bc_info = { | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP | PMBUS_HAVE_STATUS_IOUT | PMBUS_HAVE_STATUS_INPUT, .read_word_data = pli1209bc_read_word_data, + .write_byte = pli1209bc_write_byte, #if IS_ENABLED(CONFIG_SENSORS_PLI1209BC_REGULATOR) .num_regulators = 1, .reg_desc = &pli1209bc_reg_desc, |