Re: [PATCH 05/17] mmc: mmci: Put the device into low power state at system suspend

From: Kevin Hilman
Date: Tue Feb 04 2014 - 14:22:54 EST


Ulf Hansson <ulf.hansson@xxxxxxxxxx> 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@xxxxxxxxxxxxxxxx>
> Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> ---
> 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()...

> + return ret;
> }
>
> -static int mmci_resume(struct device *dev)
> +static int mmci_resume_early(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);
> - writel(MCI_IRQENABLE, host->base + MMCIMASK0);
> - pm_runtime_put(dev);
> - }
> + if (pm_runtime_status_suspended(dev))
> + return 0;
>
> - return 0;
> + if (dev->pm_domain && dev->pm_domain->ops.runtime_resume)
> + ret = dev->pm_domain->ops.runtime_resume(dev);
> + else
> + ret = dev->bus->pm->runtime_resume(dev);
> +
> + return ret;

...and this is pm_runtime_resume()? (though both terribly simplified.)

This is starting to show that building with PM_SLEEP but not PM_RUNTIME
is going to force open-coding a lot of stuff that the runtime PM
framework already provides. So either we need some helper functions so
we're not sprinkling manual calls to bus/pm_domain callbacks all over
the place, or maybe where we need to go is have a way for platforms that
really are "runtime PM centric" to declare that even PM_SLEEP depends on
PM_RUNTIME.

I'm trying to thing of a good reason to not make PM_SLEEP depend on
PM_RUNTIME for platforms like this.

Kevin

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/