Re: [PATCH v11 19/27] iommu/exynos: add support for power management subsystems.

[Tomasz Figa <t.figa-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>]

On 18.03.2014 12:23, Cho KyongHo wrote:
> On Fri, 14 Mar 2014 17:07:53 +0100, Tomasz Figa wrote:
>> Hi KyongHo,
>>
>> On 14.03.2014 06:10, Cho KyongHo wrote:

[snip]

>>> @@ -677,11 +679,40 @@ static int __init exynos_sysmmu_probe(struct platform_device *pdev)
>>>    	platform_set_drvdata(pdev, data);
>>>
>>>    	pm_runtime_enable(dev);
>>> +	data->runtime_active = !pm_runtime_enabled(dev);
>>
>> Hmm, this seems to be a bit misleading. The field is named
>> runtime_active, but the assignment makes it true if PM runtime is _not_
>> enabled (i.e. inactive). Is this correct?
>>
>
> I agree that it may lead misunderstood.
> data->runtime_active actually indicates if electric power is asserted
> to the System MMU. pm_runtime_enable() call must enable runtime pm
> for the given device. If runtime pm is not enabled although pm_runtime_enable()
> is called, CONFIG_PM_RUNTIME is not configured.
>
> Actually, it is replacible with
> if (IS_ENABLED(CONFIG_PM_RUNTIME))
>      data->runtime_active = true;

I would keep it as !pm_runtime_enabled(dev), but rename the field to 
something more meaningful, like data->is_powered_on.

Best regards,
Tomasz