[PATCH] clocksource/drivers/timer-mediatek: optimize systimer irq clear flow on Mediatek Socs

[Fengquan Chen]

1)ensure systimer is enabled before clear and disable interrupt, which only
for systimer in Mediatek Socs.

2)clear any pending timer-irq when shutdown to keep suspend flow clean,
when use systimer as tick-broadcast timer

Change-Id: Ia3eda83324af2fdaf5cbb3569a9bf020a11f8009
Signed-off-by: Fengquan Chen <fengquan.chen@xxxxxxxxxxxx>
---
 drivers/clocksource/timer-mediatek.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/clocksource/timer-mediatek.c b/drivers/clocksource/timer-mediatek.c
index 9318edc..9f1f095dc 100644
--- a/drivers/clocksource/timer-mediatek.c
+++ b/drivers/clocksource/timer-mediatek.c
@@ -75,6 +75,7 @@
 static void mtk_syst_ack_irq(struct timer_of *to)
 {
 	/* Clear and disable interrupt */
+	writel(SYST_CON_EN, SYST_CON_REG(to));
 	writel(SYST_CON_IRQ_CLR | SYST_CON_EN, SYST_CON_REG(to));
 }
 
@@ -111,6 +112,9 @@ static int mtk_syst_clkevt_next_event(unsigned long ticks,
 
 static int mtk_syst_clkevt_shutdown(struct clock_event_device *clkevt)
 {
+	/* Clear any irq */
+	mtk_syst_ack_irq(to_timer_of(clkevt));
+
 	/* Disable timer */
 	writel(0, SYST_CON_REG(to_timer_of(clkevt)));
 
-- 
1.8.1.1.dirty