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authorSantosh Shilimkar <santosh.shilimkar@ti.com>2013-01-31 21:02:00 +0530
committerTony Lindgren <tony@atomide.com>2013-02-01 14:51:22 -0800
commit8f0de0d62f29e47f5142737dad7561f108f69e92 (patch)
tree69a7627eab131309d5e4654fd1bbbce330f15f43 /arch/arm/plat-omap
parent14e067c1a5280fe6fe5d3348a0bae87bc4da16db (diff)
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ARM: OMAP2+: Get rid of custom OMAP_32K_TIMER_HZ
The timekeeping doesn't depend on HZ value in presence of fine grained clocksource and hence there should not be any time drift because of HZ value which was chosen to be divisor of 32768. OMAP has been using HZ = 128 value to avoid any time drift issues because of 32768 HZ clock. But with various measurements performed with HZ = 100, no time drift is observed and it also proves the point about HZ not having impact on time keeping on OMAP. Very informative thread on this topic is here: https://lkml.org/lkml/2013/1/29/435 Special thanks to John Stulz, Arnd Bergmann and Russell King for their valuable suggestions. Cc: Arnd Bergmann <arnd@arndb.de> Cc: Russell King <linux@arm.linux.org.uk> Cc: John Stultz <john.stultz@linaro.org> Cc: Tony Lindgren <tony@atomide.com> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Tested-by: Lokesh Vutla <lokeshvutla@ti.com> Signed-off-by: Tony Lindgren <tony@atomide.com>
Diffstat (limited to 'arch/arm/plat-omap')
-rw-r--r--arch/arm/plat-omap/Kconfig9
-rw-r--r--arch/arm/plat-omap/include/plat/timex.h8
2 files changed, 0 insertions, 17 deletions
diff --git a/arch/arm/plat-omap/Kconfig b/arch/arm/plat-omap/Kconfig
index 665870d..1fbac36 100644
--- a/arch/arm/plat-omap/Kconfig
+++ b/arch/arm/plat-omap/Kconfig
@@ -177,15 +177,6 @@ config OMAP3_L2_AUX_SECURE_SERVICE_SET_ID
help
PPA routine service ID for setting L2 auxiliary control register.
-config OMAP_32K_TIMER_HZ
- int "Kernel internal timer frequency for 32KHz timer"
- range 32 1024
- depends on OMAP_32K_TIMER
- default "128"
- help
- Kernel internal timer frequency should be a divisor of 32768,
- such as 64 or 128.
-
config OMAP_DM_TIMER
bool "Use dual-mode timer"
depends on ARCH_OMAP16XX || ARCH_OMAP2PLUS
diff --git a/arch/arm/plat-omap/include/plat/timex.h b/arch/arm/plat-omap/include/plat/timex.h
index 6d35767..e27d2da 100644
--- a/arch/arm/plat-omap/include/plat/timex.h
+++ b/arch/arm/plat-omap/include/plat/timex.h
@@ -28,14 +28,6 @@
#if !defined(__ASM_ARCH_OMAP_TIMEX_H)
#define __ASM_ARCH_OMAP_TIMEX_H
-/*
- * OMAP 32KHz timer updates time one jiffie at a time from a secondary timer,
- * and that's why the CLOCK_TICK_RATE is not 32768.
- */
-#ifdef CONFIG_OMAP_32K_TIMER
-#define CLOCK_TICK_RATE (CONFIG_OMAP_32K_TIMER_HZ)
-#else
#define CLOCK_TICK_RATE (HZ * 100000UL)
-#endif
#endif /* __ASM_ARCH_OMAP_TIMEX_H */