On Fri, Feb 25, 2022 at 05:06:09PM +0100, Marcello Sylvester Bauer wrote:
> From: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>
>
> On PMBUS devices with multiple pages, the regulator ops need to be
> protected with the update mutex. This prevents accidentally changing
> the page in a separate thread while operating on the PMBUS_OPERATION
> register.
>
> Tested on Infineon xdpe11280 while a separate thread polls for sensor
> data.
>
> Signed-off-by: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>
> Signed-off-by: Marcello Sylvester Bauer <sylv@xxxxxxx>
Good catch. Applied.
Thanks,
Guenter
> ---
> drivers/hwmon/pmbus/pmbus_core.c | 16 +++++++++++++---
> 1 file changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
> index 776ee2237be2..f79930162256 100644
> --- a/drivers/hwmon/pmbus/pmbus_core.c
> +++ b/drivers/hwmon/pmbus/pmbus_core.c
> @@ -2386,10 +2386,14 @@ static int pmbus_regulator_is_enabled(struct regulator_dev *rdev)
> {
> struct device *dev = rdev_get_dev(rdev);
> struct i2c_client *client = to_i2c_client(dev->parent);
> + struct pmbus_data *data = i2c_get_clientdata(client);
> u8 page = rdev_get_id(rdev);
> int ret;
>
> + mutex_lock(&data->update_lock);
> ret = pmbus_read_byte_data(client, page, PMBUS_OPERATION);
> + mutex_unlock(&data->update_lock);
> +
> if (ret < 0)
> return ret;
>
> @@ -2400,11 +2404,17 @@ static int _pmbus_regulator_on_off(struct regulator_dev *rdev, bool enable)
> {
> struct device *dev = rdev_get_dev(rdev);
> struct i2c_client *client = to_i2c_client(dev->parent);
> + struct pmbus_data *data = i2c_get_clientdata(client);
> u8 page = rdev_get_id(rdev);
> + int ret;
>
> - return pmbus_update_byte_data(client, page, PMBUS_OPERATION,
> - PB_OPERATION_CONTROL_ON,
> - enable ? PB_OPERATION_CONTROL_ON : 0);
> + mutex_lock(&data->update_lock);
> + ret = pmbus_update_byte_data(client, page, PMBUS_OPERATION,
> + PB_OPERATION_CONTROL_ON,
> + enable ? PB_OPERATION_CONTROL_ON : 0);
> + mutex_unlock(&data->update_lock);
> +
> + return ret;
> }
>
> static int pmbus_regulator_enable(struct regulator_dev *rdev)
