Re: [RFC PATCH 4/4] sdio: pm: set device's power state after driver runtime suspended it

Rafael J. Wysocki
2012-10-18T23:39:25Z

On Friday 12 of October 2012 11:12:41 Aaron Lu wrote:
> In sdio bus level runtime callback function, after call the driver's
> runtime suspend callback, we will check if the device supports a
> platform level power management, and if so, a proper power state is
> chosen by the corresponding platform callback and then set.
>
> Platform level runtime wakeup is also set, if device is enabled for
> runtime wakeup by its driver, it will be armed the ability to generate
> a wakeup event by the platform.
>
> Signed-off-by: Aaron Lu <aaron.lu@intel.com>
> ---
> drivers/mmc/core/sdio_bus.c | 49 +++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 47 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/core/sdio_bus.c b/drivers/mmc/core/sdio_bus.c
> index aaec9e2..d83dea8 100644
> --- a/drivers/mmc/core/sdio_bus.c
> +++ b/drivers/mmc/core/sdio_bus.c
> @@ -23,6 +23,7 @@
>
> #include "sdio_cis.h"
> #include "sdio_bus.h"
> +#include "sdio.h"
> #include "sdio_acpi.h"
>
> /* show configuration fields */
> @@ -194,10 +195,54 @@ static int sdio_bus_remove(struct device *dev)
> }
>
> #ifdef CONFIG_PM
> +
> +static int sdio_bus_runtime_suspend(struct device *dev)
> +{
> + int ret;
> + sdio_power_t state;
> +
> + ret = pm_generic_runtime_suspend(dev);
> + if (ret)
> + goto out;
> +
> + if (!platform_sdio_power_manageable(dev))
> + goto out;
> +
> + platform_sdio_run_wake(dev, true);
> +
> + state = platform_sdio_choose_power_state(dev);
> + if (state == SDIO_POWER_ERROR) {
> + ret = -EIO;
> + goto out;
> + }
> +
> + ret = platform_sdio_set_power_state(dev, state);
> +
> +out:
> + return ret;
> +}
> +
> +static int sdio_bus_runtime_resume(struct device *dev)
> +{
> + int ret;
> +
> + if (platform_sdio_power_manageable(dev)) {
> + platform_sdio_run_wake(dev, false);
> + ret = platform_sdio_set_power_state(dev, SDIO_D0);
> + if (ret)
> + goto out;
> + }
> +
> + ret = pm_generic_runtime_resume(dev);
> +
> +out:
> + return ret;
> +}
> +

Most likely we will need to make analogous changes for other bus types that
don't support power management natively, like platform, SPI, I2C etc. In all
of them the _runtime_suspend() and _runtime_resume() routine will look
almost exactly the same except for the platform_sdio_ prefix.

For this reason, I think it would be better to simply define two functions
acpi_pm_runtime_suspend() and acpi_pm_runtime_resume() that will do all of
the ACPI-specific operations related to runtime suspend/resume. Then, we
will be able to use these functions for all of the bus types in question
in the same way (we may also need to add analogous functions for system
suspend/resume handling).

If we do that, then the sdio_platform_pm_ops structure from the previous
patch won't be necessary any more.

Thanks,
Rafael

--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.