diff options
| author | Adam Wujek <dev_public@wujek.eu> | 2022-04-20 14:51:25 +0000 |
|---|---|---|
| committer | Guenter Roeck <linux@roeck-us.net> | 2022-04-25 09:15:20 -0700 |
| commit | 75d2b2b06bd8407d03a3f126bc8b95eb356906c7 (patch) | |
| tree | 445fbf5e68b97a77275990fafa6213c3fcc88116 /drivers/hwmon | |
| parent | 4aaaaf0f279836f06d3b9d0ffeec7a1e1a04ceef (diff) | |
hwmon: (pmbus) disable PEC if not enabled
Explicitly disable PEC when the client does not support it.
The problematic scenario is the following. A device with enabled PEC
support is up and running and a kernel driver is loaded.
Then the driver is unloaded (or device unbound), the HW device
is reconfigured externally (e.g. by i2cset) to advertise itself as not
supporting PEC. Without a new code, at the second load of the driver
(or bind) the "flags" variable is not updated to avoid PEC usage. As a
consequence the further communication with the device is done with
the PEC enabled, which is wrong and may fail.
The implementation first disable the I2C_CLIENT_PEC flag, then the old
code enable it if needed.
Fixes: 4e5418f787ec ("hwmon: (pmbus_core) Check adapter PEC support")
Signed-off-by: Adam Wujek <dev_public@wujek.eu>
Link: https://lore.kernel.org/r/20220420145059.431061-1-dev_public@wujek.eu
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'drivers/hwmon')
| -rw-r--r-- | drivers/hwmon/pmbus/pmbus_core.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c index b2618b1d529e..d93574d6a1fb 100644 --- a/drivers/hwmon/pmbus/pmbus_core.c +++ b/drivers/hwmon/pmbus/pmbus_core.c @@ -2326,6 +2326,9 @@ static int pmbus_init_common(struct i2c_client *client, struct pmbus_data *data, data->has_status_word = true; } + /* Make sure PEC is disabled, will be enabled later if needed */ + client->flags &= ~I2C_CLIENT_PEC; + /* Enable PEC if the controller and bus supports it */ if (!(data->flags & PMBUS_NO_CAPABILITY)) { ret = i2c_smbus_read_byte_data(client, PMBUS_CAPABILITY); |