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: <efb17431-82a6-bcc9-cade-896d0dca958e@quicinc.com>
Date: Tue, 13 Aug 2024 17:53:50 +0530
From: Dikshita Agarwal <quic_dikshita@...cinc.com>
To: Ulf Hansson <ulf.hansson@...aro.org>
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>,
        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 8/13/2024 4:22 PM, Ulf Hansson wrote:
> On Wed, 7 Aug 2024 at 09:16, Dikshita Agarwal <quic_dikshita@...cinc.com> 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);
> 
> I think this function should be internal and hence made static -
> unless there is a good reason to export it?
Yeah, it should be static and no need of exporting it.
Will make the changes.
> 
>> +
>> +/**
>> + * 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;
> 
> There is no need to initialize num_pds to 0 here, as the below calls
> take care of it.
> 
Right, will be fixed in next revision.
>> +
>> +       num_pds = dev_pm_domain_attach_list(dev, data, list);
>> +
> 
> We should add a check if num_pds is zero here, as in that case there
> is no reason to add a devres callback for it.
> 
Sure, will add the below check.
if (!num_pds)
    return 0;

Thanks,
Dikshita
>> +       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);
> 
> [...]
> 
> Kind regards
> Uffe