From 5da3e714e30d40145f4dd37d79de6bbbcb9e6137 Mon Sep 17 00:00:00 2001 From: Magnus Damm Date: Thu, 29 Jul 2010 14:03:04 +0100 Subject: ARM: 6277/1: mach-shmobile: Allow users to select HZ, default to 128 Introduce SHMOBILE_TIMER_HZ for SH-Mobile. Allow users to select HZ on their system to minimize potential timer drift. Use 128 Hz as default to work well with the 32768 Hz RCLK. Signed-off-by: Magnus Damm Signed-off-by: Russell King --- arch/arm/Kconfig | 1 + arch/arm/mach-shmobile/Kconfig | 12 ++++++++++++ 2 files changed, 13 insertions(+) (limited to 'arch') diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 98922f7d2d12..db4f2ee3a750 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1189,6 +1189,7 @@ config HZ default 200 if ARCH_EBSA110 || ARCH_S3C2410 || ARCH_S5P6440 || ARCH_S5P6442 || ARCH_S5PV210 default OMAP_32K_TIMER_HZ if ARCH_OMAP && OMAP_32K_TIMER default AT91_TIMER_HZ if ARCH_AT91 + default SHMOBILE_TIMER_HZ if ARCH_SHMOBILE default 100 config THUMB2_KERNEL diff --git a/arch/arm/mach-shmobile/Kconfig b/arch/arm/mach-shmobile/Kconfig index f2b88c5fe142..4c704b4e8b34 100644 --- a/arch/arm/mach-shmobile/Kconfig +++ b/arch/arm/mach-shmobile/Kconfig @@ -70,6 +70,18 @@ endmenu menu "Timer and clock configuration" +config SHMOBILE_TIMER_HZ + int "Kernel HZ (jiffies per second)" + range 32 1024 + default "128" + help + Allows the configuration of the timer frequency. It is customary + to have the timer interrupt run at 1000 Hz or 100 Hz, but in the + case of low timer frequencies other values may be more suitable. + SH-Mobile systems using a 32768 Hz RCLK for clock events may want + to select a HZ value such as 128 that can evenly divide RCLK. + A HZ value that does not divide evenly may cause timer drift. + config SH_TIMER_CMT bool "CMT timer driver" default y -- cgit v1.2.1