clocksource: armada-370-xp: Enable timer divider only when needed

The current code sets the timer divider bits always. However, when
the 25 MHz timer is enabled, this is not needed and has no effect.
As this causes some confusion, rework the code so the divider is
set only when needed, i.e. when the 25 MHz timer is not in use.

Acked-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

drivers/clocksource/time-armada-370-xp.c

@@ -76,6 +76,7 @@
 static void __iomem *timer_base, *local_base;
 static unsigned int timer_clk;
 static bool timer25Mhz = true;
+static u32 enable_mask;
 
 /*
  * Number of timer ticks per jiffy.
@@ -121,8 +122,7 @@ armada_370_xp_clkevt_next_event(unsigned long delta,
 	/*
 	 * Enable the timer.
 	 */
-	local_timer_ctrl_clrset(TIMER0_RELOAD_EN,
-				TIMER0_EN | TIMER0_DIV(TIMER_DIVIDER_SHIFT));
+	local_timer_ctrl_clrset(TIMER0_RELOAD_EN, enable_mask);
 	return 0;
 }
 
@@ -141,9 +141,7 @@ armada_370_xp_clkevt_mode(enum clock_event_mode mode,
 		/*
 		 * Enable timer.
 		 */
-		local_timer_ctrl_clrset(0, TIMER0_RELOAD_EN |
-					   TIMER0_EN |
-					   TIMER0_DIV(TIMER_DIVIDER_SHIFT));
+		local_timer_ctrl_clrset(0, TIMER0_RELOAD_EN | enable_mask);
 	} else {
 		/*
 		 * Disable timer.
@@ -240,10 +238,13 @@ static void __init armada_370_xp_timer_common_init(struct device_node *np)
 	WARN_ON(!timer_base);
 	local_base = of_iomap(np, 1);
 
-	if (timer25Mhz)
+	if (timer25Mhz) {
 		set = TIMER0_25MHZ;		
-	else
+		enable_mask = TIMER0_EN;
+	} else {
 		clr = TIMER0_25MHZ;
+		enable_mask = TIMER0_EN | TIMER0_DIV(TIMER_DIVIDER_SHIFT);
+	}
 	timer_ctrl_clrset(clr, set);
 	local_timer_ctrl_clrset(clr, set);
 
@@ -267,8 +268,7 @@ static void __init armada_370_xp_timer_common_init(struct device_node *np)
 	writel(0xffffffff, timer_base + TIMER0_VAL_OFF);
 	writel(0xffffffff, timer_base + TIMER0_RELOAD_OFF);
 
-	timer_ctrl_clrset(0, TIMER0_EN | TIMER0_RELOAD_EN |
-			     TIMER0_DIV(TIMER_DIVIDER_SHIFT));
+	timer_ctrl_clrset(0, TIMER0_RELOAD_EN | enable_mask);
 
 	clocksource_mmio_init(timer_base + TIMER0_VAL_OFF,
 			      "armada_370_xp_clocksource",