[PATCH 08/10] PM / Domains: Add support for removing PM domains

[Jon Hunter]

On 12/09/16 08:21, Ulf Hansson wrote:
> On 9 September 2016 at 17:17, Jon Hunter <jonathanh at nvidia.com> wrote:
>>
>> On 09/09/16 14:54, Jon Hunter wrote:
>>> On 08/09/16 12:49, Ulf Hansson wrote:
>>>> On 16 August 2016 at 11:49, Jon Hunter <jonathanh at nvidia.com> wrote:
>>>>> The genpd framework allows users to add PM domains via the pm_genpd_init()
>>>>> function, however, there is no corresponding function to remove a PM
>>>>> domain. For most devices this may be fine as the PM domains are never
>>>>> removed, however, for devices that wish to populate the PM domains from
>>>>> within a driver, having the ability to remove a PM domain if the probing
>>>>> of the device fails or the driver is unloaded is necessary.
>>>>>
>>>>> Add the function pm_genpd_remove() to remove a PM domain by referencing
>>>>> it's generic_pm_domain structure.
>>>>>
>>>>> PM domains can only be removed if they are not a parent domain to
>>>>> another PM domain and have no devices associated with them.
>>>>
>>>> I think we should also check if the there's is a provider registered
>>>> for the genpd, as it should also prevent the genpd from being removed.
>>>> Right?
>>>
>>> Yes I would agree. I had thought that after patch #4 of this series that
>>> only the provider itself would be able to call this. However, we should
>>> probably still verify that the provider has correctly remove itself.
>>
>> So now I have the following. I am still not 100% happy. I cannot clear
>> the ->provider when calling of_genpd_del_provider() and so I cannot use
>> this to verify if the provider is present and so I need to check the
>> list of providers and it gets a bit messy. I have been wracking my
>> brains to find a better alternative (including a single function to
>> remove the provider and domains at once but there are issues with that
>> as well).
> 
> Instead of using the ->provider pointer to know whether the genpd has
> a valid provider, why not just add an additional ->has_provider bool
> flag in the genpd struct?
> 
> Simply set the flag when adding the provider and reset it when
> removing it. Wouldn't that work?

Yes. I was trying not to add to much clutter to the struct. However, may
be this is the best option.

Cheers
Jon

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