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

[Armin Wolf <W_Armin@gmx.de>]

Am 14.09.26 um 12:18 schrieb Rafael J. Wysocki (Intel):

> On Fri, Sep 11, 2026 at 11:04 PM Armin Wolf <W_Armin@gmx.de> wrote:
>> Am 11.09.26 um 15:02 schrieb Rafael J. Wysocki:
>>
>>> From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
>>>
>>> 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.

Ok.

>> For the patch itself:
>>
>> Reviewed-by: Armin Wolf <W_Armin@gmx.de>
> Thank you (and thanks for all the reviews)!
>
>>> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>>> ---
>>>    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__ */