linux-kernel - [PATCH 1/2] ARM: AT91: PIT: Remove irq handler when clock event is unused

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Date:	Fri, 20 Dec 2013 11:45:40 +0100
From:	Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To:	linux-arm-kernel@...ts.infradead.org
Cc:	linux-kernel@...r.kernel.org, Andrew Victor <linux@...im.org.za>,
	Nicolas Ferre <nicolas.ferre@...el.com>,
	Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>,
	Daniel Lezcano <daniel.lezcano@...aro.org>,
	Sami Pietikäinen <Sami.Pietikainen@...ice.com>,
	tglx@...utronix.de, Benedikt Spranger <b.spranger@...utronix.de>,
	Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Subject: [PATCH 1/2] ARM: AT91: PIT: Remove irq handler when clock event is unused

From: Benedikt Spranger <b.spranger@...utronix.de>

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@...utronix.de>
Signed-off-by: Thomas Gleixner <tglx@...utronix.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@...ice.com> suggested].
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
---
 arch/arm/mach-at91/at91rm9200_time.c  | 1 +
 arch/arm/mach-at91/at91sam926x_time.c | 5 ++++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-at91/at91rm9200_time.c b/arch/arm/mach-at91/at91rm9200_time.c
index bc7b363..fd34d55 100644
--- 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 mode, struct clock_event_device *dev)
 		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;
diff --git a/arch/arm/mach-at91/at91sam926x_time.c b/arch/arm/mach-at91/at91sam926x_time.c
index bb39232..1c4c487 100644
--- 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 mode, struct clock_event_device *dev)
 {
 	switch (mode) {
 	case CLOCK_EVT_MODE_PERIODIC:
+		/* Set up irq handler */
+		setup_irq(at91sam926x_pit_irq.irq, &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 mode, struct clock_event_device *dev)
 	case CLOCK_EVT_MODE_UNUSED:
 		/* disable irq, leaving the clocksource active */
 		pit_write(AT91_PIT_MR, (pit_cycle - 1) | AT91_PIT_PITEN);
+		remove_irq(at91sam926x_pit_irq.irq, &at91sam926x_pit_irq);
 		break;
 	case CLOCK_EVT_MODE_RESUME:
 		break;
-- 
1.8.5.1

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