Re: [PATCH v1 03/10] thermal: core: Introduce thermal_cooling_device_create()

[Rafael J. Wysocki (Intel)]

On Fri, Sep 11, 2026 at 11:04 PM Armin Wolf <W_Armin@xxxxxx> wrote:
>
> Am 11.09.26 um 15:02 schrieb Rafael J. Wysocki:
>
> > From: "Rafael J. Wysocki" <rafael.j.wysocki@xxxxxxxxx>
> >
> > Currently, thermal cooling devices have no parents, but it would be
> > generally useful to be able to create them under specific parents in
> > the device hierarchy (for instance, it may help to identify the device
> > representing the actual cooling hardware).
> >
> > To make that possible, add thermal_cooling_device_create() that will
> > work like thermal_cooling_device_register() except that it will take
> > an additional parent argument (which may be NULL).
> >
> > Redefine thermal_cooling_device_register() as a static inline wrapper
> > around thermal_cooling_device_create().
>
> Hi,
>
> i like your idea with the new registration function, this gives us more time
> for migrating the other drivers. Should we mark the original function as
> deprecated?

Well, it's not a big deal if somebody uses it in new code IMV.

> For the patch itself:
>
> Reviewed-by: Armin Wolf <W_Armin@xxxxxx>

Thank you (and thanks for all the reviews)!

> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> > ---
> >   drivers/thermal/thermal_core.c | 28 ++++++++++++++++------------
> >   drivers/thermal/thermal_core.h |  3 ++-
> >   drivers/thermal/thermal_of.c   |  2 +-
> >   include/linux/thermal.h        | 19 ++++++++++++++-----
> >   4 files changed, 33 insertions(+), 19 deletions(-)
> >
> > diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> > index 82e2f0d8a26d..ac928c199829 100644
> > --- a/drivers/thermal/thermal_core.c
> > +++ b/drivers/thermal/thermal_core.c
> > @@ -1005,7 +1005,8 @@ thermal_cooling_device_alloc(const char *type, const struct thermal_cooling_devi
> >       return ERR_PTR(ret);
> >   }
> >
> > -int thermal_cooling_device_add(struct thermal_cooling_device *cdev, void *devdata)
> > +int thermal_cooling_device_add(struct thermal_cooling_device *cdev,
> > +                            struct device *parent, void *devdata)
> >   {
> >       unsigned long current_state;
> >       int ret;
> > @@ -1013,6 +1014,7 @@ int thermal_cooling_device_add(struct thermal_cooling_device *cdev, void *devdat
> >       mutex_init(&cdev->lock);
> >       INIT_LIST_HEAD(&cdev->thermal_instances);
> >       cdev->updated = false;
> > +     cdev->device.parent = parent;
> >       cdev->device.class = &thermal_class;
> >       cdev->device.release = thermal_cdev_release;
> >       device_initialize(&cdev->device);
> > @@ -1062,21 +1064,23 @@ int thermal_cooling_device_add(struct thermal_cooling_device *cdev, void *devdat
> >   }
> >
> >   /**
> > - * thermal_cooling_device_register() - register a new thermal cooling device
> > + * thermal_cooling_device_create() - register a new thermal cooling device
> > + * @parent:  parent device (optional).
> >    * @type:   the thermal cooling device type.
> >    * @devdata:        device private data.
> >    * @ops:    standard thermal cooling devices callbacks.
> >    *
> > - * This interface function adds a new thermal cooling device (fan/processor/...)
> > - * to /sys/class/thermal/ folder as cooling_device[0-*]. It tries to bind itself
> > - * to all the thermal zone devices registered at the same time.
> > + * Allocate and register a new thermal cooling device under the given parent (if
> > + * not NULL) and with the given type, device data, and operations.  During the
> > + * registration, it will be matched against all of the registered thermal zones
> > + * and it will be bound to the matching ones.
> >    *
> > - * Return: a pointer to the created struct thermal_cooling_device or an
> > - * ERR_PTR. Caller must check return value with IS_ERR*() helpers.
> > + * Return: A pointer to the created struct thermal_cooling_device or an ERR_PTR.
> > + * Callers must use IS_ERR*() helpers to check the return value.
> >    */
> > -struct thermal_cooling_device *
> > -thermal_cooling_device_register(const char *type, void *devdata,
> > -                             const struct thermal_cooling_device_ops *ops)
> > +struct thermal_cooling_device *thermal_cooling_device_create(
> > +                     struct device *parent, const char *type, void *devdata,
> > +                     const struct thermal_cooling_device_ops *ops)
> >   {
> >       struct thermal_cooling_device *cdev;
> >       int ret;
> > @@ -1085,13 +1089,13 @@ thermal_cooling_device_register(const char *type, void *devdata,
> >       if (IS_ERR(cdev))
> >               return cdev;
> >
> > -     ret = thermal_cooling_device_add(cdev, devdata);
> > +     ret = thermal_cooling_device_add(cdev, parent, devdata);
> >       if (ret)
> >               return ERR_PTR(ret);
> >
> >       return cdev;
> >   }
> > -EXPORT_SYMBOL_GPL(thermal_cooling_device_register);
> > +EXPORT_SYMBOL_GPL(thermal_cooling_device_create);
> >
> >   static void thermal_cooling_device_release(void *data)
> >   {
> > diff --git a/drivers/thermal/thermal_core.h b/drivers/thermal/thermal_core.h
> > index e98b0aa5aacc..7ef7c6cab437 100644
> > --- a/drivers/thermal/thermal_core.h
> > +++ b/drivers/thermal/thermal_core.h
> > @@ -270,7 +270,8 @@ void thermal_governor_update_tz(struct thermal_zone_device *tz,
> >   struct thermal_cooling_device *
> >   thermal_cooling_device_alloc(const char *type, const struct thermal_cooling_device_ops *ops);
> >
> > -int thermal_cooling_device_add(struct thermal_cooling_device *cdev, void *devdata);
> > +int thermal_cooling_device_add(struct thermal_cooling_device *cdev,
> > +                            struct device *parent, void *devdata);
> >
> >   /* Helpers */
> >   #define for_each_trip_desc(__tz, __td)      \
> > diff --git a/drivers/thermal/thermal_of.c b/drivers/thermal/thermal_of.c
> > index 0217a49b08ae..14dfac9359b8 100644
> > --- a/drivers/thermal/thermal_of.c
> > +++ b/drivers/thermal/thermal_of.c
> > @@ -561,7 +561,7 @@ thermal_of_cooling_device_register(struct device_node *np, u32 cdev_id,
> >       cdev->np = np;
> >       cdev->cdev_id = cdev_id;
> >
> > -     ret = thermal_cooling_device_add(cdev, devdata);
> > +     ret = thermal_cooling_device_add(cdev, NULL, devdata);
> >       if (ret)
> >               return ERR_PTR(ret);
> >
> > diff --git a/include/linux/thermal.h b/include/linux/thermal.h
> > index 083b4f533933..306ad17aed89 100644
> > --- a/include/linux/thermal.h
> > +++ b/include/linux/thermal.h
> > @@ -293,8 +293,9 @@ struct device *thermal_zone_device(struct thermal_zone_device *tzd);
> >   void thermal_zone_device_update(struct thermal_zone_device *,
> >                               enum thermal_notify_event);
> >
> > -struct thermal_cooling_device *thermal_cooling_device_register(const char *,
> > -             void *, const struct thermal_cooling_device_ops *);
> > +struct thermal_cooling_device *thermal_cooling_device_create(
> > +                     struct device *parent, const char *type, void *devdata,
> > +                     const struct thermal_cooling_device_ops *ops);
> >
> >   struct thermal_cooling_device *
> >   devm_thermal_cooling_device_register(struct device *dev, const char *type, void *devdata,
> > @@ -340,9 +341,9 @@ static inline void thermal_zone_device_update(struct thermal_zone_device *tz,
> >                                             enum thermal_notify_event event)
> >   { }
> >
> > -static inline struct thermal_cooling_device *
> > -thermal_cooling_device_register(const char *type, void *devdata,
> > -     const struct thermal_cooling_device_ops *ops)
> > +static inline struct thermal_cooling_device *thermal_cooling_device_create(
> > +                     struct device *parent, const char *type, void *devdata,
> > +                     const struct thermal_cooling_device_ops *ops)
> >   { return ERR_PTR(-ENODEV); }
> >
> >   static inline struct thermal_cooling_device *
> > @@ -391,4 +392,12 @@ static inline void thermal_pm_prepare(void) {}
> >   static inline void thermal_pm_complete(void) {}
> >   #endif /* CONFIG_THERMAL */
> >
> > +static inline struct thermal_cooling_device *thermal_cooling_device_register(
> > +                             const char *type, void *devdata,
> > +                             const struct thermal_cooling_device_ops *ops)
> > +{
> > +     return thermal_cooling_device_create(NULL, type, devdata, ops);
> > +}
> > +
> > +
> >   #endif /* __THERMAL_H__ */