On Thu, Jan 27, 2011 at 04:18:41PM -0800, Kevin Hilman wrote:
> When runtime PM is enabled, each OMAP i2c device is suspended after
> each i2c xfer. However, there are two cases when the static suspend
> methods must be used to ensure the devices are suspended:
>
> 1) runtime PM is disabled, either at compile time or dynamically
> via /sys/devices/.../power/control.
> 2) an i2c client driver uses i2c during it's suspend callback, thus
> leaving the i2c driver active (NOTE: runtime suspend transitions are
> disabled during system suspend, so i2c activity during system
> suspend will runtime resume the device, but not runtime (re)suspend it.)
>
> Since the actual work to suspend the device is handled by the
> subsytem, call the bus methods to take care of it.
>
> NOTE: This takes care of a known suspend problem on OMAP3 where the
> TWL RTC driver does i2c xfers during its suspend path leaving the i2c
> driver in an active state (since runtime suspend transistions are
> disabled.)
>
> Signed-off-by: Kevin Hilman <khilman@xxxxxx>
> ---
> Ben, this is a regression in 2.6.38 so hopefully this can be queued
> in the 2.6.38-rc cycle. Thanks.
Ok, after all the discussions should I keep it in my -rc queue?
> drivers/i2c/busses/i2c-omap.c | 28 ++++++++++++++++++++++++++++
> 1 files changed, 28 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
> index b605ff3..0541df9 100644
> --- a/drivers/i2c/busses/i2c-omap.c
> +++ b/drivers/i2c/busses/i2c-omap.c
> @@ -1137,12 +1137,40 @@ omap_i2c_remove(struct platform_device *pdev)
> return 0;
> }
>
> +#ifdef CONFIG_SUSPEND
> +static int omap_i2c_suspend(struct device *dev)
> +{
> + if (!pm_runtime_suspended(dev))
> + if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_suspend)
> + dev->bus->pm->runtime_suspend(dev);
> +
> + return 0;
> +}
> +
> +static int omap_i2c_resume(struct device *dev)
> +{
> + if (!pm_runtime_suspended(dev))
> + if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_resume)
> + dev->bus->pm->runtime_resume(dev);
> +
> + return 0;
> +}
> +
> +static struct dev_pm_ops omap_i2c_pm_ops = {
> + .suspend = omap_i2c_suspend,
> + .resume = omap_i2c_resume,
> +};
> +#else
> +#define omap_i2c_pm_ops NULL
> +#endif
> +
> static struct platform_driver omap_i2c_driver = {
> .probe = omap_i2c_probe,
> .remove = omap_i2c_remove,
> .driver = {
> .name = "omap_i2c",
> .owner = THIS_MODULE,
> + .pm = &omap_i2c_pm_ops,
> },
> };
>
> --
> 1.7.3.5
>
> --
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--
Ben Dooks, ben@xxxxxxxxx, http://www.fluff.org/ben/
Large Hadron Colada: A large Pina Colada that makes the universe disappear.
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