The i8253 clockevent & clocksource driver uses PIT_LATCH
except for two cases where it uses LATCH:

1)
	/* VIA686a test code... reset the latch if count > max + 1 */
	if (count > LATCH) {

LATCH is based on CLOCK_TICK_RATE which is defined as
PIT_TICK_RATE on x86 so this should just be the later.

2)
	...
	switch (mode) {
	case CLOCK_EVT_MODE_PERIODIC:
		/* binary, mode 2, LSB/MSB, ch 0 */
		outb_p(0x34, PIT_MODE);
		outb_p(LATCH & 0xff , PIT_CH0);	/* LSB */
		outb_p(LATCH >> 8 , PIT_CH0);		/* MSB */
	...

MIPS and ARM are the only other arches that use this driver. In
the MIPS case CLOCK_TICK_RATE is defined as the same value as
PIT_TICK_RATE. For ARM, the only machine that uses it is
Footbridge which has a totally bogus CLOCK_TICK_RATE according
to the comments. Furthermore, the clockevent_i8253_init()
initializes the clockevent with PIT_TIC_RATE, so there's
no reason to use the generic LATCH.

This is part of work to remove and depecrate the global
CLOCK_TICK_RATE symbol.

Signed-off-by: Deepak Saxena <dsaxena@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>

arm, mips and x86 implement i8253 based clockevents. All the same code
copied. Create a common implementation in drivers/clocksource/i8253.c.

About time to rename drivers/clocksource/ to something else.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20110609130621.921710458@linutronix.de

We don't want to add endless selects and module ifdefs.

Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Now that all extra ifdeffed implementations are gone, depend the lock
export on PCSPKR_PLATFORM

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Russell King <linux@arm.linux.org.uk>

Move them to drivers/clocksource/i8253.c and remove the
implementations in arch/

[ tglx: Avoid the extra file in lib - folded arch patches in. The
  export will become conditional in a later step ]

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Link: http://lkml.kernel.org/r/20110601180610.221426078@duck.linux-mips.net
Cc: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Link: http://lkml.kernel.org/r/20110601180610.054254048@duck.linux-mips.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

 arch/arm/mach-footbridge/isa-timer.c |    2 +-
 arch/mips/cobalt/time.c              |    2 +-
 arch/mips/jazz/irq.c                 |    2 +-
 arch/mips/kernel/i8253.c             |    2 +-
 arch/mips/mti-malta/malta-time.c     |    2 +-
 arch/mips/sgi-ip22/ip22-time.c       |    2 +-
 arch/mips/sni/time.c                 |    2 +-
 arch/x86/kernel/apic/apic.c          |    2 +-
 arch/x86/kernel/apm_32.c             |    2 +-
 arch/x86/kernel/hpet.c               |    2 +-
 arch/x86/kernel/i8253.c              |    2 +-
 arch/x86/kernel/time.c               |    2 +-
 drivers/block/hd.c                   |    2 +-
 drivers/clocksource/i8253.c          |    2 +-
 drivers/input/gameport/gameport.c    |    2 +-
 drivers/input/joystick/analog.c      |    2 +-
 drivers/input/misc/pcspkr.c          |    2 +-
 include/linux/i8253.h                |   11 +++++++++++
 sound/drivers/pcsp/pcsp.h            |    2 +-
 19 files changed, 29 insertions(+), 18 deletions(-)

This is based upon both arch/arm/mach-footbridge/isa-timer.c and
arch/x86/kernel/i8253.c.

Acked-by: John Stultz <john.stultz@linaro.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>