From: Benedikt Spranger <b.spranger@linutronix.de>
Date: Sat, 6 Mar 2010 17:47:10 +0100
Subject: ARM: AT91: PIT: Remove irq handler when clock event is unused

Setup and remove the interrupt handler in clock event mode selection.
This avoids calling the (shared) interrupt handler when the device is
not used.

Signed-off-by: Benedikt Spranger <b.spranger@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

---
 arch/arm/mach-at91/at91rm9200_time.c  |    1 +
 arch/arm/mach-at91/at91sam926x_time.c |    5 ++++-
 2 files changed, 5 insertions(+), 1 deletion(-)

--- a/arch/arm/mach-at91/at91rm9200_time.c
+++ b/arch/arm/mach-at91/at91rm9200_time.c
@@ -134,6 +134,7 @@ clkevt32k_mode(enum clock_event_mode mod
 		break;
 	case CLOCK_EVT_MODE_SHUTDOWN:
 	case CLOCK_EVT_MODE_UNUSED:
+		remove_irq(AT91_ID_SYS, &at91rm9200_timer_irq);
 	case CLOCK_EVT_MODE_RESUME:
 		irqmask = 0;
 		break;
--- a/arch/arm/mach-at91/at91sam926x_time.c
+++ b/arch/arm/mach-at91/at91sam926x_time.c
@@ -77,7 +77,7 @@ static struct clocksource pit_clk = {
 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
-
+static struct irqaction at91sam926x_pit_irq;
 /*
  * Clockevent device:  interrupts every 1/HZ (== pit_cycles * MCK/16)
  */
@@ -86,6 +86,8 @@ pit_clkevt_mode(enum clock_event_mode mo
 {
 	switch (mode) {
 	case CLOCK_EVT_MODE_PERIODIC:
+		/* Set up irq handler */
+		setup_irq(AT91_ID_SYS, &at91sam926x_pit_irq);
 		/* update clocksource counter */
 		pit_cnt += pit_cycle * PIT_PICNT(pit_read(AT91_PIT_PIVR));
 		pit_write(AT91_PIT_MR, (pit_cycle - 1) | AT91_PIT_PITEN
@@ -98,6 +100,7 @@ pit_clkevt_mode(enum clock_event_mode mo
 	case CLOCK_EVT_MODE_UNUSED:
 		/* disable irq, leaving the clocksource active */
 		pit_write(AT91_PIT_MR, (pit_cycle - 1) | AT91_PIT_PITEN);
+		remove_irq(AT91_ID_SYS, &at91sam926x_pit_irq);
 		break;
 	case CLOCK_EVT_MODE_RESUME:
 		break;