ARM: 6153/1: nomadik MTU to use dynamic shift and mult assignment

This removes the hard-coded shift values for the MTU timer, since
the different platforms using this has very different running
frequencies doing this dynamically is a better idea. Also take
this opportunity to make a more through shutdown of the MTU
clockevent when requested.

Acked-by: Alessandro Rubini <rubini@unipv.it>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/plat-nomadik/include/plat/mtu.h

@@ -1,6 +1,12 @@
 #ifndef __PLAT_MTU_H
 #define __PLAT_MTU_H
 
+/*
+ * Guaranteed runtime conversion range in seconds for
+ * the clocksource and clockevent.
+ */
+#define MTU_MIN_RANGE 4
+
 /* should be set by the platform code */
 extern void __iomem *mtu_base;
 

arch/arm/plat-nomadik/timer.c

@@ -42,7 +42,6 @@ static struct clocksource nmdk_clksrc = {
 	.rating		= 200,
 	.read		= nmdk_read_timer_dummy,
 	.mask		= CLOCKSOURCE_MASK(32),
-	.shift		= 20,
 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
@@ -82,6 +81,12 @@ static void nmdk_clkevt_mode(enum clock_event_mode mode,
 	case CLOCK_EVT_MODE_UNUSED:
 		/* disable irq */
 		writel(0, mtu_base + MTU_IMSC);
+		/* disable timer */
+		cr = readl(mtu_base + MTU_CR(1));
+		cr &= ~MTU_CRn_ENA;
+		writel(cr, mtu_base + MTU_CR(1));
+		/* load some high default value */
+		writel(0xffffffff, mtu_base + MTU_LR(1));
 		break;
 	case CLOCK_EVT_MODE_RESUME:
 		break;
@@ -98,7 +103,6 @@ static int nmdk_clkevt_next(unsigned long evt, struct clock_event_device *ev)
 static struct clock_event_device nmdk_clkevt = {
 	.name		= "mtu_1",
 	.features	= CLOCK_EVT_FEAT_ONESHOT,
-	.shift		= 32,
 	.rating		= 200,
 	.set_mode	= nmdk_clkevt_mode,
 	.set_next_event	= nmdk_clkevt_next,
@@ -151,6 +155,7 @@ void __init nmdk_timer_init(void)
 	} else {
 		cr |= MTU_CRn_PRESCALE_1;
 	}
+	clocksource_calc_mult_shift(&nmdk_clksrc, rate, MTU_MIN_RANGE);
 
 	/* Timer 0 is the free running clocksource */
 	writel(cr, mtu_base + MTU_CR(0));
@@ -158,7 +163,6 @@ void __init nmdk_timer_init(void)
 	writel(0, mtu_base + MTU_BGLR(0));
 	writel(cr | MTU_CRn_ENA, mtu_base + MTU_CR(0));
 
-	nmdk_clksrc.mult = clocksource_hz2mult(rate, nmdk_clksrc.shift);
 	/* Now the scheduling clock is ready */
 	nmdk_clksrc.read = nmdk_read_timer;
 
@@ -175,8 +179,10 @@ void __init nmdk_timer_init(void)
 	} else {
 		cr |= MTU_CRn_PRESCALE_1;
 	}
+	clockevents_calc_mult_shift(&nmdk_clkevt, rate, MTU_MIN_RANGE);
+
 	writel(cr | MTU_CRn_ONESHOT, mtu_base + MTU_CR(1)); /* off, currently */
-	nmdk_clkevt.mult = div_sc(rate, NSEC_PER_SEC, nmdk_clkevt.shift);
+
 	nmdk_clkevt.max_delta_ns =
 		clockevent_delta2ns(0xffffffff, &nmdk_clkevt);
 	nmdk_clkevt.min_delta_ns =