Re: [PATCH v2 1/2] PM: domains: add device managed version of dev_pm_domain_attach|detach_list()

[Dikshita Agarwal <quic_dikshita@quicinc.com>]

On 8/8/2024 4:11 PM, Dhruva Gole wrote:
> On Aug 07, 2024 at 12:45:46 +0530, Dikshita Agarwal wrote:
>> Add the devres-enabled version of dev_pm_domain_attach|detach_list.
>> If client drivers use devm_pm_domain_attach_list() to attach the
>> PM domains, devm_pm_domain_detach_list() will be invoked implicitly
>> during remove phase.
>>
>> Signed-off-by: Dikshita Agarwal <quic_dikshita@quicinc.com>
>> ---
>>  drivers/base/power/common.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
>>  include/linux/pm_domain.h   | 13 +++++++++++++
>>  2 files changed, 57 insertions(+)
>>
>> diff --git a/drivers/base/power/common.c b/drivers/base/power/common.c
>> index 327d168..729d6c2 100644
>> --- a/drivers/base/power/common.c
>> +++ b/drivers/base/power/common.c
>> @@ -277,6 +277,50 @@ int dev_pm_domain_attach_list(struct device *dev,
>>  EXPORT_SYMBOL_GPL(dev_pm_domain_attach_list);
>>  
>>  /**
>> + * devm_pm_domain_detach_list - devres-enabled version of dev_pm_domain_detach_list.
>> + * @_list: The list of PM domains to detach.
>> + *
>> + * This function reverse the actions from devm_pm_domain_attach_list().
>> + * it will be invoked during the remove phase from drivers implicitly if driver
>> + * uses devm_pm_domain_attach_list() to attach the PM domains.
>> + */
>> +void devm_pm_domain_detach_list(void *_list)
>> +{
>> +	struct dev_pm_domain_list *list = _list;
>> +
>> +	dev_pm_domain_detach_list(list);
>> +}
>> +EXPORT_SYMBOL_GPL(devm_pm_domain_detach_list);
>> +
>> +/**
>> + * devm_pm_domain_attach_list - devres-enabled version of dev_pm_domain_attach_list
>> + * @dev: The device used to lookup the PM domains for.
>> + * @data: The data used for attaching to the PM domains.
>> + * @list: An out-parameter with an allocated list of attached PM domains.
>> + *
>> + * NOTE: this will also handle calling devm_pm_domain_detach_list() for
>> + * you during remove phase.
>> + *
>> + * Returns the number of attached PM domains or a negative error code in case of
>> + * a failure.
>> + */
>> +int devm_pm_domain_attach_list(struct device *dev,
>> +			       const struct dev_pm_domain_attach_data *data,
>> +			       struct dev_pm_domain_list **list)
>> +{
>> +	int ret, num_pds = 0;
> 
> Do we require this =0? In the very next line you're initing this anyway.
> 
That's correct, will fix this. Thanks.
>> +
>> +	num_pds = dev_pm_domain_attach_list(dev, data, list);
>> +
>> +	ret = devm_add_action_or_reset(dev, devm_pm_domain_detach_list, *list);
>> +	if (ret)
>> +		return ret;
>> +
>> +	return num_pds;
>> +}
>> +EXPORT_SYMBOL_GPL(devm_pm_domain_attach_list);
>> +
>> +/**
>>   * dev_pm_domain_detach - Detach a device from its PM domain.
>>   * @dev: Device to detach.
>>   * @power_off: Used to indicate whether we should power off the device.
>> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
>> index 772d328..efd517017 100644
>> --- a/include/linux/pm_domain.h
>> +++ b/include/linux/pm_domain.h
>> @@ -450,8 +450,12 @@ struct device *dev_pm_domain_attach_by_name(struct device *dev,
>>  int dev_pm_domain_attach_list(struct device *dev,
>>  			      const struct dev_pm_domain_attach_data *data,
>>  			      struct dev_pm_domain_list **list);
>> +int devm_pm_domain_attach_list(struct device *dev,
>> +			       const struct dev_pm_domain_attach_data *data,
>> +			       struct dev_pm_domain_list **list);
>>  void dev_pm_domain_detach(struct device *dev, bool power_off);
>>  void dev_pm_domain_detach_list(struct dev_pm_domain_list *list);
>> +void devm_pm_domain_detach_list(void *list);
> 
> Why not just call it dev_pm_domain_list *list? Why make it void? I am a
> bit confused.
> 
This comment is not clear to me, could you pls elaborate?
This is just a stub API like others in this file for !CONFIG_PM case.

Thanks,
Dikshita
>