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 <damm@opensource.se>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mach-shmobile/Kconfig b/arch/arm/mach-shmobile/Kconfig
index f2b88c5..4c704b4 100644
--- a/arch/arm/mach-shmobile/Kconfig
+++ b/arch/arm/mach-shmobile/Kconfig
@@ -70,6 +70,18 @@
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