time: move PIT_TICK_RATE to linux/timex.h

PIT_TICK_RATE is currently defined in four architectures, but in three
different places.  While linux/timex.h is not the perfect place for it, it
is still a reasonable replacement for those drivers that traditionally use
asm/timex.h to get CLOCK_TICK_RATE and expect it to be the PIT frequency.

Note that for Alpha, the actual value changed from 1193182UL to 1193180UL.
 This is unlikely to make a difference, and probably can only improve
accuracy.  There was a discussion on the correct value of CLOCK_TICK_RATE
a few years ago, after which every existing instance was getting changed
to 1193182.  According to the specification, it should be
1193181.818181...

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Len Brown <lenb@kernel.org>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Dmitry Torokhov <dtor@mail.ru>
Cc: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/alpha/include/asm/8253pit.h

@@ -1,10 +1,3 @@
 /*
  * 8253/8254 Programmable Interval Timer
  */
-
-#ifndef _8253PIT_H
-#define _8253PIT_H
-
-#define PIT_TICK_RATE 	1193180UL
-
-#endif

arch/alpha/kernel/sys_ruffian.c

@@ -14,6 +14,7 @@
 #include <linux/sched.h>
 #include <linux/pci.h>
 #include <linux/ioport.h>
+#include <linux/timex.h>
 #include <linux/init.h>
 
 #include <asm/ptrace.h>

arch/mips/include/asm/i8253.h

@@ -12,8 +12,6 @@
 #define PIT_CH0			0x40
 #define PIT_CH2			0x42
 
-#define PIT_TICK_RATE		1193182UL
-
 extern spinlock_t i8253_lock;
 
 extern void setup_pit_timer(void);

arch/powerpc/include/asm/8253pit.h

@@ -1,10 +1,3 @@
-#ifndef _ASM_POWERPC_8253PIT_H
-#define _ASM_POWERPC_8253PIT_H
-
 /*
  * 8253/8254 Programmable Interval Timer
  */
-
-#define PIT_TICK_RATE	1193182UL
-
-#endif	/* _ASM_POWERPC_8253PIT_H */

arch/x86/include/asm/timex.h

@@ -4,9 +4,7 @@
 #include <asm/processor.h>
 #include <asm/tsc.h>
 
-/* The PIT ticks at this frequency (in HZ): */
-#define PIT_TICK_RATE		1193182
-
+/* Assume we use the PIT time source for the clock tick */
 #define CLOCK_TICK_RATE		PIT_TICK_RATE
 
 #define ARCH_HAS_READ_CURRENT_TIMER

arch/x86/kernel/i8253.c

@@ -7,6 +7,7 @@
 #include <linux/spinlock.h>
 #include <linux/jiffies.h>
 #include <linux/module.h>
+#include <linux/timex.h>
 #include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/io.h>

arch/x86/kernel/tsc.c

@@ -9,6 +9,7 @@
 #include <linux/delay.h>
 #include <linux/clocksource.h>
 #include <linux/percpu.h>
+#include <linux/timex.h>
 
 #include <asm/hpet.h>
 #include <asm/timer.h>