Re: [PATCH v2 4/4] hwmon: (pmbus/core): Notify hwmon events

[Guenter Roeck <linux@xxxxxxxxxxxx>]

On 2/14/23 06:11, Naresh Solanki wrote:
> Hi,
>
> On 11-02-2023 09:16 pm, Guenter Roeck wrote:
> > On Tue, Feb 07, 2023 at 01:02:41PM +0100, Naresh Solanki wrote:
> > > From: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>
> > >
> > > Notify hwmon events using the pmbus irq handler.
> > >
> > > Signed-off-by: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>
> > > Signed-off-by: Naresh Solanki <Naresh.Solanki@xxxxxxxxxxxxx>
> > > ...
> > > Changes in V2
> > > - Remove __maybe_unsed attribute as its not needed.
> > > ---
> > >   drivers/hwmon/pmbus/pmbus_core.c | 48 ++++++++++++++++++++++++++++----
> > >   1 file changed, 43 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
> > > index d5403baad60a..f6778a9c7126 100644
> > > --- a/drivers/hwmon/pmbus/pmbus_core.c
> > > +++ b/drivers/hwmon/pmbus/pmbus_core.c
> > > @@ -2735,8 +2735,36 @@ static const struct pmbus_status_category __maybe_unused pmbus_status_flag_map[]
> > >       },
> > >   };
> > > +#define to_dev_attr(_dev_attr) \
> > > +    container_of(_dev_attr, struct device_attribute, attr)
> > > +
> > > +static void pmbus_notify(struct pmbus_data *data, int page, int reg, int flags)
> > > +{
> > > +    int i;
> > > +
> > > +    for (i = 0; i < data->num_attributes; i++) {
> > > +        struct device_attribute *da = to_dev_attr(data->group.attrs[i]);
> > > +        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
> > > +        int index = attr->index;
> > > +        u16 smask = pb_index_to_mask(index);
> > > +        u8 spage = pb_index_to_page(index);
> > > +        u16 sreg = pb_index_to_reg(index);
> > > +
> > > +        if (reg == sreg && page == spage && (smask & flags)) {
> > > +            dev_dbg(data->dev, "sysfs notify: %s", da->attr.name);
> > > +            sysfs_notify(&data->dev->kobj, NULL, da->attr.name);
> > > +            kobject_uevent(&data->dev->kobj, KOBJ_CHANGE);
> > > +            flags &= ~smask;
> > > +        }
> > > +
> > > +        if (!flags)
> > > +            break;
> > > +    }
> > > +}
> > > +
> > > +static int pmbus_get_flags(struct pmbus_data *data, u8 page, unsigned int *flags,
> > > +               bool notify)
> > > -static int __maybe_unused pmbus_get_flags(struct pmbus_data *data, u8 page, unsigned int *flags)
> > >   {
> > >       int i, status, ret;
> > >       const struct pmbus_status_category *cat;
> > > @@ -2764,6 +2792,10 @@ static int __maybe_unused pmbus_get_flags(struct pmbus_data *data, u8 page, unsi
> > >               if (status & bit->pflag)
> > >                   *flags |= bit->rflag;
> > >           }
> > > +
> > > +        if (notify && status)
> > > +            pmbus_notify(data, page, cat->reg, status);
> > > +
> > >       }
> > >       /*
> > > @@ -2866,7 +2898,7 @@ static int pmbus_regulator_get_error_flags(struct regulator_dev *rdev, unsigned
> > >       struct i2c_client *client = to_i2c_client(dev->parent);
> > >       struct pmbus_data *data = i2c_get_clientdata(client);
> > > -    return pmbus_get_flags(data, rdev_get_id(rdev), flags);
> > > +    return pmbus_get_flags(data, rdev_get_id(rdev), flags, false);
> > >   }
> > >   static int pmbus_regulator_get_status(struct regulator_dev *rdev)
> > > @@ -3108,10 +3140,14 @@ static irqreturn_t pmbus_fault_handler(int irq, void *pdata)
> > >   {
> > >       struct pmbus_data *data = pdata;
> > >       struct i2c_client *client = to_i2c_client(data->dev);
> > > -    int i, status;
> > > +    int i, status, ret;
> > > -    mutex_lock(&data->update_lock);
> > >       for (i = 0; i < data->info->pages; i++) {
> > > +        ret = pmbus_get_flags(data, i, &status, true);
> > > +        if (ret)
> > > +            return ret;
> > > +
> > > +        mutex_lock(&data->update_lock);
> >
> > You should introduce a locked version of pmbus_get_flags() and call
> > that function, and keep the existing locking in place.
> I'm not sure if you meant to have pmbus_get_flags that wont use lock?


__pmbus_get_flags(...)
{
	/* no lock acquired here */
}

pmbus_get_flags(...)
{
	int ret;

	mutex_lock(&data->update_lock);
	ret = __pmbus_get_flags(...);
	mutex_unlock(&data->update_lock);
	return ret;
}

Then call __pmbus_get_flags() from above code.

Guenter

> > >           status = pmbus_read_status_word(client, i);
> > >           if (status < 0) {
> > >               mutex_unlock(&data->update_lock);
> > > @@ -3120,8 +3156,10 @@ static irqreturn_t pmbus_fault_handler(int irq, void *pdata)
> > >           if (status & ~(PB_STATUS_OFF | PB_STATUS_BUSY | PB_STATUS_POWER_GOOD_N))
> > >               pmbus_clear_fault_page(client, i);
> > > +
> > > +        mutex_unlock(&data->update_lock);
> > >       }
> > > -    mutex_unlock(&data->update_lock);
> > > +
> >
> > This would add a second empty line (not that it matters because the code
> > should not change the locking in the first place).
> Will remove the new line
> > >       return IRQ_HANDLED;
> > >   }