Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: platform/i2c busses: pm runtime and system sleep | Date | Sat, 18 Dec 2010 00:01:25 +0100 |
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On Friday, December 17, 2010, Mark Brown wrote: > On Fri, Dec 17, 2010 at 02:49:25PM +0100, Rafael J. Wysocki wrote: > > On Friday, December 17, 2010, Mark Brown wrote: > > > > By, for example, providing default implementations which the buses can > > > use if they choose to. > > > OK, so we have generic_subsys_pm_ops. Do we need anything beyond that? > > Hrm. Possibly just some fiddling with those or alternative versions. > For example, looking at the I2C bus suspend it's this: > > static int i2c_device_pm_suspend(struct device *dev) > { > const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; > > if (pm) { > if (pm_runtime_suspended(dev)) > return 0; > else > return pm->suspend ? pm->suspend(dev) : 0; > } > > return i2c_legacy_suspend(dev, PMSG_SUSPEND); > } > > Ideally the if (pm) block could just be factored out into the pm core as > there's nothing I2C-specific about that at all. Possibly even the whole > logic surrounding fall back to legacy, though that smells a bit.
No, the legacy is i2c-specific.
> The generic suspend operation doesn't fit here: > > int pm_generic_suspend(struct device *dev) > { > return __pm_generic_call(dev, PM_EVENT_SUSPEND); > } > EXPORT_SYMBOL_GPL(pm_generic_suspend);
Well, looking at __pm_generic_call(), I think it does.
It appears to do exactly what the pm block above does, so it should be possible to have something like this:
static int i2c_device_pm_suspend(struct device *dev) { const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; return pm ? pm_generic_suspend(dev) : i2c_legacy_suspend(dev, PMSG_SUSPEND); }
if I'm not missing anything.
Thanks, Rafael
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