On Thursday, June 22, 2017 06:08:36 PM Florian Fainelli wrote: > Add an optional platform_suspend_ops callback: target_state, and a > helper function globally visible to get this called: > platform_suspend_target_state(). > > This is useful for platform specific drivers that may need to take a > slightly different suspend/resume path based on the system's > suspend/resume state being entered. > > Although this callback is optional and documented as such, it requires > a platform_suspend_ops::begin callback to be implemented in order to > provide an accurate suspend/resume state within the driver that > implements this platform_suspend_ops. > > Signed-off-by: Florian Fainelli <[email protected]> > --- > include/linux/suspend.h | 12 ++++++++++++ > kernel/power/suspend.c | 15 +++++++++++++++ > 2 files changed, 27 insertions(+) > > diff --git a/include/linux/suspend.h b/include/linux/suspend.h > index d9718378a8be..d998a04a90a2 100644 > --- a/include/linux/suspend.h > +++ b/include/linux/suspend.h > @@ -172,6 +172,15 @@ static inline void dpm_save_failed_step(enum > suspend_stat_step step) > * Called by the PM core if the suspending of devices fails. > * This callback is optional and should only be implemented by platforms > * which require special recovery actions in that situation. > + * > + * @target_state: Returns the suspend state the suspend_ops will be entering. > + * Called by device drivers that need to know the platform specific suspend > + * state the system is about to enter. > + * This callback is optional and should only be implemented by platforms > + * which require special handling of power management states within > + * drivers. It does require @begin to be implemented to provide the suspend > + * state. Return value is platform_suspend_ops specific, and may be a 1:1 > + * mapping to suspend_state_t when relevant. > */ > struct platform_suspend_ops { > int (*valid)(suspend_state_t state); > @@ -184,6 +193,7 @@ struct platform_suspend_ops { > bool (*suspend_again)(void); > void (*end)(void); > void (*recover)(void); > + int (*target_state)(void);
I would use unsigned int (the sign should not matter). > }; That's almost what I was thinking about except that the values returned by ->target_state should be unique, so it would be good to do something to ensure that. The concern is as follows. Say you have a driver develped for platform X where ->target_state returns A for "mem" and B for "standby". Then, the same IP is re-used on platform Y returning B for "mem" and C for "standby" and now the driver cannot distinguish between them. Moreover, even if they both returned A for "mem" there might be differences in how "mem" was defined by each of them and therefore in what the driver was expected to do to handle "mem" on X and Y. Thanks, Rafael
