RE: [PATCH] power_supply: Register battery as a thermal zone

From: Tc, Jenny
Date: Wed May 09 2012 - 05:34:01 EST


>
> > Battery and charger contribute to Thermals in most of the embedded
> > devices. So, it makes sense to identify them as Thermal zones in a
> > particular platform.
> >
> > This patch registers a thermal zone if the power supply is reporting a
> > temperature property. The thermal zone will be used by platform's
> > thermal management solution.
> >
> > Signed-off-by: Jenny TC <jenny.tc@xxxxxxxxx>
> > ---
>
> > +#ifdef CONFIG_THERMAL
> > +static int power_supply_read_temp(struct thermal_zone_device *tzd,
> > + unsigned long *temp)
> > +{
> > + struct power_supply *psy;
> > + union power_supply_propval val;
> > + int ret;
> > +
> > + WARN_ON(tzd == NULL);
> > + psy = tzd->devdata;
> > + WARN_ON(psy == NULL);
>
>
> These WARN_ONs seem unnecessary since you will oops if either of them
> are NULL anyway.
>

Agreed.

> > + ret = psy->get_property(psy,
> > + POWER_SUPPLY_PROP_TEMP, &val);
> > + if (!ret)
> > + *temp = val.intval * 100;
> > + return ret;
> > +}
>
>
> <snip>
>
> > int power_supply_register(struct device *parent, struct power_supply
> > *psy) {
> > struct device *dev;
> > int rc;
> > +#ifdef CONFIG_THERMAL
> > + int i;
> > +#endif
> >
> > dev = kzalloc(sizeof(*dev), GFP_KERNEL);
> > if (!dev)
> > @@ -196,7 +223,21 @@ int power_supply_register(struct device *parent,
> struct power_supply *psy)
> > rc = device_add(dev);
> > if (rc)
> > goto device_add_failed;
> > -
> > +#ifdef CONFIG_THERMAL
> > + /* Register battery zone device psy reports temperature */
> > + for (i = 0; i < psy->num_properties; i++) {
> > + if (psy->properties[i] == POWER_SUPPLY_PROP_TEMP) {
> > + psy->tzd = thermal_zone_device_register(
> > + (char *)psy->name, 0, psy,
> > + &psy_tzd_ops, 0, 0, 0, 0);
> > + if (IS_ERR(psy->tzd)) {
> > + rc = PTR_ERR(psy->tzd);
> > + goto therm_zone_reg_failed;
> > + }
> > + break;
> > + }
> > + }
> > +#endif
>
>
> This would be better moved into its own function, so you can minimise the
> amount of ifdefs needed. Having extra ifdefs for variable declarations and
> exit paths is especially ugly :-/. Ideally you can have a single #ifdef
> CONFIG_THERMAL block, and define empty functions for the
> !CONFIG_THERMAL case.
>

Agreed. I will submit another patch in a few minutes.

> ~Ryan
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