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authorLinus Walleij <linus.walleij@linaro.org>2015-06-16 09:00:44 +0200
committerLinus Walleij <linus.walleij@linaro.org>2015-07-17 11:49:54 +0200
commit8ed3912e17973e48701f65efe4493811914fc5fe (patch)
treedb139165adc2dd3b1f529f6158b71be246da0d6e /arch/arm/mach-ep93xx
parentd5878e6e2289418ba870db4afa9e1805e78eb8ee (diff)
ARM: ep93xx: update comment on timer usage
When refactoring the EP93xx timer some of the documentation git out of date. Update it. Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'arch/arm/mach-ep93xx')
-rw-r--r--arch/arm/mach-ep93xx/timer-ep93xx.c13
1 files changed, 6 insertions, 7 deletions
diff --git a/arch/arm/mach-ep93xx/timer-ep93xx.c b/arch/arm/mach-ep93xx/timer-ep93xx.c
index 9edaa754b689..ac48ac1fd16d 100644
--- a/arch/arm/mach-ep93xx/timer-ep93xx.c
+++ b/arch/arm/mach-ep93xx/timer-ep93xx.c
@@ -18,15 +18,14 @@
* is free-running, and can't generate interrupts.
*
* The 508 kHz timers are ideal for use for the timer interrupt, as the
- * most common values of HZ divide 508 kHz nicely. We pick one of the 16
- * bit timers (timer 1) since we don't need more than 16 bits of reload
- * value as long as HZ >= 8.
+ * most common values of HZ divide 508 kHz nicely. We pick the 32 bit
+ * timer (timer 3) to get as long sleep intervals as possible when using
+ * CONFIG_NO_HZ.
*
* The higher clock rate of timer 4 makes it a better choice than the
- * other timers for use in gettimeoffset(), while the fact that it can't
- * generate interrupts means we don't have to worry about not being able
- * to use this timer for something else. We also use timer 4 for keeping
- * track of lost jiffies.
+ * other timers for use as clock source and for sched_clock(), providing
+ * a stable 40 bit time base.
+ *************************************************************************
*/
#define EP93XX_TIMER_REG(x) (EP93XX_TIMER_BASE + (x))
#define EP93XX_TIMER1_LOAD EP93XX_TIMER_REG(0x00)