linux-kernel - Re: [PATCH v2 1/2] PM: domains: add device managed version of dev_pm_domain_attach|detach

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Message-ID: <9b852bed-0daf-634c-13c9-00c6b8dd327a@quicinc.com>
Date: Thu, 8 Aug 2024 16:29:12 +0530
From: Dikshita Agarwal <quic_dikshita@...cinc.com>
To: Dhruva Gole <d-gole@...com>
CC: "Rafael J. Wysocki" <rafael@...nel.org>, Pavel Machek <pavel@....cz>,
        "Len
 Brown" <len.brown@...el.com>,
        Greg Kroah-Hartman
	<gregkh@...uxfoundation.org>,
        Stanimir Varbanov
	<stanimir.k.varbanov@...il.com>,
        Vikash Garodia <quic_vgarodia@...cinc.com>,
        Bjorn Andersson <andersson@...nel.org>,
        "Konrad Dybcio"
	<konrad.dybcio@...aro.org>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Ulf
 Hansson <ulf.hansson@...aro.org>,
        Bryan O'Donoghue
	<bryan.odonoghue@...aro.org>,
        <linux-pm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-media@...r.kernel.org>, <linux-arm-msm@...r.kernel.org>
Subject: Re: [PATCH v2 1/2] PM: domains: add device managed version of
 dev_pm_domain_attach|detach_list()



On 8/8/2024 4:25 PM, Dikshita Agarwal wrote:
> 
> 
> 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@...cinc.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?
Ah! Sorry, pls ignore my below comment. But can you still explain the
concern here?

> This is just a stub API like others in this file for !CONFIG_PM case.

> 
> Thanks,
> Dikshita
>>
>