patches/arm-at91-pit-remove-irq-handler-when-clock-is-unused.patch

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>
[bigeasy: redo the patch with NR_IRQS_LEGACY which is probably required since
commit 8fe82a55 ("ARM: at91: sparse irq support") which is included since v3.6.
Patch based on what Sami Pietikäinen <Sami.Pietikainen@wapice.com> suggested].
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 drivers/clocksource/timer-atmel-pit.c |    4 ++++
 drivers/clocksource/timer-atmel-st.c  |    1 +
 2 files changed, 5 insertions(+)

--- a/drivers/clocksource/timer-atmel-pit.c
+++ b/drivers/clocksource/timer-atmel-pit.c
@@ -90,6 +90,7 @@ static cycle_t read_pit_clk(struct clock
 	return elapsed;
 }
 
+static struct irqaction at91sam926x_pit_irq;
 /*
  * Clockevent device:  interrupts every 1/HZ (== pit_cycles * MCK/16)
  */
@@ -100,6 +101,8 @@ pit_clkevt_mode(enum clock_event_mode mo
 
 	switch (mode) {
 	case CLOCK_EVT_MODE_PERIODIC:
+		/* Set up irq handler */
+		setup_irq(at91sam926x_pit_irq.irq, &at91sam926x_pit_irq);
 		/* update clocksource counter */
 		data->cnt += data->cycle * PIT_PICNT(pit_read(data->base, AT91_PIT_PIVR));
 		pit_write(data->base, AT91_PIT_MR,
@@ -113,6 +116,7 @@ pit_clkevt_mode(enum clock_event_mode mo
 		/* disable irq, leaving the clocksource active */
 		pit_write(data->base, AT91_PIT_MR,
 			  (data->cycle - 1) | AT91_PIT_PITEN);
+		remove_irq(at91sam926x_pit_irq.irq, &at91sam926x_pit_irq);
 		break;
 	case CLOCK_EVT_MODE_RESUME:
 		break;
--- a/drivers/clocksource/timer-atmel-st.c
+++ b/drivers/clocksource/timer-atmel-st.c
@@ -131,6 +131,7 @@ clkevt32k_mode(enum clock_event_mode mod
 		break;
 	case CLOCK_EVT_MODE_SHUTDOWN:
 	case CLOCK_EVT_MODE_UNUSED:
+		remove_irq(NR_IRQS_LEGACY + AT91_ID_SYS, &at91rm9200_timer_irq);
 	case CLOCK_EVT_MODE_RESUME:
 		irqmask = 0;
 		break;