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authorViresh Kumar <viresh.kumar@linaro.org>2015-07-07 10:14:35 +0200
committerThomas Gleixner <tglx@linutronix.de>2015-07-07 10:44:45 +0200
commit7c4a976cd55972b68c75a978f171b6db5df4ce66 (patch)
tree269c05a4c91fefe5f1e5d10fd21940169c41f9de /kernel
parentclocksource/imx: Define clocksource for mx27 (diff)
downloadlinux-7c4a976cd55972b68c75a978f171b6db5df4ce66.tar.xz
linux-7c4a976cd55972b68c75a978f171b6db5df4ce66.zip
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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/time/clockevents.c24
1 files changed, 9 insertions, 15 deletions
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 08ccc3da3ca0..50eb107f1198 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -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;
}