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clockevents: Allow set-state callbacks to be optional 

Its mandatory for the drivers to provide set_state_{oneshot|periodic}()
(only if related modes are supported) and set_state_shutdown() callbacks
today, if they are implementing the new set-state interface.

But this leads to unnecessary noop callbacks for drivers which don't
want to implement them. Over that, it will lead to a full function call
for nothing really useful.

Lets make all set-state callbacks optional.

Suggested-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: http://lkml.kernel.org/r/1436256875-15562-1-git-send-email-daniel.lezcano@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Viresh Kumar 2015-07-07 10:14:35 +02:00 committed by Thomas Gleixner
parent 747d34e731
commit 7c4a976cd5
1 changed files with 9 additions and 15 deletions
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24
kernel/time/clockevents.c
View File

@ -120,19 +120,25 @@ static int __clockevents_switch_state(struct clock_event_device *dev,
/* The clockevent device is getting replaced. Shut it down. */
case CLOCK_EVT_STATE_SHUTDOWN:
return dev->set_state_shutdown(dev);
if (dev->set_state_shutdown)
return dev->set_state_shutdown(dev);
return 0;
case CLOCK_EVT_STATE_PERIODIC:
/* Core internal bug */
if (!(dev->features & CLOCK_EVT_FEAT_PERIODIC))
return -ENOSYS;
return dev->set_state_periodic(dev);
if (dev->set_state_periodic)
return dev->set_state_periodic(dev);
return 0;
case CLOCK_EVT_STATE_ONESHOT:
/* Core internal bug */
if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT))
return -ENOSYS;
return dev->set_state_oneshot(dev);
if (dev->set_state_oneshot)
return dev->set_state_oneshot(dev);
return 0;
case CLOCK_EVT_STATE_ONESHOT_STOPPED:
/* Core internal bug */
@ -471,18 +477,6 @@ static int clockevents_sanity_check(struct clock_event_device *dev)
if (dev->features & CLOCK_EVT_FEAT_DUMMY)
return 0;
/* New state-specific callbacks */
if (!dev->set_state_shutdown)
return -EINVAL;
if ((dev->features & CLOCK_EVT_FEAT_PERIODIC) &&
!dev->set_state_periodic)
return -EINVAL;
if ((dev->features & CLOCK_EVT_FEAT_ONESHOT) &&
!dev->set_state_oneshot)
return -EINVAL;
return 0;
}