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SubjectRe: [PATCH 05/17] mmc: mmci: Put the device into low power state at system suspend
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Ulf Hansson <ulf.hansson@linaro.org> writes:

> On 4 February 2014 20:22, Kevin Hilman <khilman@linaro.org> wrote:
>> Ulf Hansson <ulf.hansson@linaro.org> writes:
>>
>>> Due to the available runtime PM callbacks, we are now able to put our
>>> device into low power state at system suspend.
>>>
>>> Earlier we could not accomplish this without trusting a power domain
>>> for the device to take care of it. Now we are able to cope with
>>> scenarios both with and without a power domain.
>>>
>>> Cc: Russell King <linux@arm.linux.org.uk>
>>> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
>>> ---
>>> drivers/mmc/host/mmci.c | 45 +++++++++++++++++++++++++--------------------
>>> 1 file changed, 25 insertions(+), 20 deletions(-)
>>>
>>> diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
>>> index c88da1c..074e0cb 100644
>>> --- a/drivers/mmc/host/mmci.c
>>> +++ b/drivers/mmc/host/mmci.c
>>> @@ -1723,33 +1723,38 @@ static int mmci_remove(struct amba_device *dev)
>>> return 0;
>>> }
>>>
>>> -#ifdef CONFIG_SUSPEND
>>> -static int mmci_suspend(struct device *dev)
>>> +#ifdef CONFIG_PM_SLEEP
>>> +static int mmci_suspend_late(struct device *dev)
>>> {
>>> - struct amba_device *adev = to_amba_device(dev);
>>> - struct mmc_host *mmc = amba_get_drvdata(adev);
>>> + int ret = 0;
>>>
>>> - if (mmc) {
>>> - struct mmci_host *host = mmc_priv(mmc);
>>> - pm_runtime_get_sync(dev);
>>> - writel(0, host->base + MMCIMASK0);
>>> - }
>>> + if (pm_runtime_status_suspended(dev))
>>> + return 0;
>>>
>>> - return 0;
>>> + if (dev->pm_domain && dev->pm_domain->ops.runtime_suspend)
>>> + ret = dev->pm_domain->ops.runtime_suspend(dev);
>>> + else
>>> + ret = dev->bus->pm->runtime_suspend(dev);
>>> +
>>> + if (!ret)
>>> + pm_runtime_set_suspended(dev);
>>
>> Isn't this basically open-coding pm_runtime_suspend()...
>
> It is similar, but with once big difference.
>
> Since the PM core prevents pm_runtime_suspend() from invoking our
> ->runtime_suspend callback during system suspend (it does so by
> invoking pm_runtime_get_sync() before starting the suspend sequence),
> we then need to make the driver handle that by itself.

Yeah, I still think we need to allow a bus/pm_domain to override that
behavior.


Kevin


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