[ARM] rtc-sa1100: don't assume CLOCK_TICK_RATE to be a constant

As Nicolas and Russell pointed out, CLOCK_TICK_RATE is no more
a constant on PXA when multiple processors and platforms are
selected, change TIMER_FREQ in rtc-sa1100.c into a variable.

Since the code to decide the clock tick rate is re-used from
timer.c, introduce a common get_clock_tick_rate() for this.

Signed-off-by: Eric Miao <eric.miao@marvell.com>
Acked-by: Nicolas Pitre <nico@marvell.com>

2 files changed, 10 insertions, 0 deletions

diff --git a/arch/arm/mach-pxa/include/mach/hardware.h b/arch/arm/mach-pxa/include/mach/hardware.h
index e2d6784aa7ef..c666796911cb 100644
--- a/arch/arm/mach-pxa/include/mach/hardware.h
+++ b/arch/arm/mach-pxa/include/mach/hardware.h
@@ -291,6 +291,8 @@
  */
 extern unsigned int get_memclk_frequency_10khz(void);
 
+/* return the clock tick rate of the OS timer */
+extern unsigned long get_clock_tick_rate(void);
 #endif
 
 #if defined(CONFIG_MACH_ARMCORE) && defined(CONFIG_PCI)
diff --git a/arch/arm/mach-pxa/include/mach/timex.h b/arch/arm/mach-pxa/include/mach/timex.h
index b05fc6683c47..af6760a50e1a 100644
--- a/arch/arm/mach-pxa/include/mach/timex.h
+++ b/arch/arm/mach-pxa/include/mach/timex.h
@@ -10,6 +10,14 @@
  * published by the Free Software Foundation.
  */
 
+/* Various drivers are still using the constant of CLOCK_TICK_RATE, for
+ * those drivers to at least work, the definition is provided here.
+ *
+ * NOTE: this is no longer accurate when multiple processors and boards
+ * are selected, newer drivers should not depend on this any more.  Use
+ * either the clocksource/clockevent or get this at run-time by calling
+ * get_clock_tick_rate() (as defined in generic.c).
+ */
 
 #if defined(CONFIG_PXA25x)
 /* PXA250/210 timer base */