Re: [PATCH v1 1/1] drivers/hwmon/pmbus: Add mutex to regulator ops

[Guenter Roeck <linux@xxxxxxxxxxxx>]

On 2/26/22 15:42, Zev Weiss wrote:
> On Fri, Feb 25, 2022 at 08:06:09AM PST, 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>
> > ---
> > 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)
> > --
> > 2.35.1
>
> Looks like this doesn't cover pmbus_regulator_get_error_flags(), which
> was added recently -- perhaps rebase onto hwmon-next?

I applied the patch and made the necessary changes in
pmbus_regulator_get_error_flags(), so no need to send a patch for it.

Guenter