2 files changed, 17 insertions, 0 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index a04f507e7f2c..93e40b65fd0b 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -657,6 +657,7 @@ config HZ
         default 128 if ARCH_L7200
         default 200 if ARCH_EBSA110 || ARCH_S3C2410
         default OMAP_32K_TIMER_HZ if ARCH_OMAP && OMAP_32K_TIMER
+        default AT91_TIMER_HZ if ARCH_AT91
         default 100
 
 config AEABI
diff --git a/arch/arm/mach-at91/Kconfig b/arch/arm/mach-at91/Kconfig
index 05a9f8a1b45e..214733e897e5 100644
--- a/arch/arm/mach-at91/Kconfig
+++ b/arch/arm/mach-at91/Kconfig
@@ -219,6 +219,22 @@ config AT91_PROGRAMMABLE_CLOCKS
           Select this if you need to program one or more of the PCK0..PCK3
           programmable clock outputs.
 
+config AT91_TIMER_HZ
+       int "Kernel HZ (jiffies per second)"
+       range 32 1024
+       depends on ARCH_AT91
+       default "128" if ARCH_AT91RM9200
+       default "100"
+       help
+          On AT91rm9200 chips where you're using a system clock derived
+          from the 32768 Hz hardware clock, this tick rate should divide
+          it exactly: use a power-of-two value, such as 128 or 256, to
+          reduce timing errors caused by rounding.
+
+          On AT91sam926x chips, or otherwise when using a higher precision
+          system clock (of at least several MHz), rounding is less of a
+          problem so it can be safer to use a decimal values like 100.
+
 endmenu
 
 endif