[PATCH 3/3] ARM: move U300 timer to dynamic clock lookup

[Linus Walleij]

This moves the U300 timer code to look up its clock rate from the
clock framework as is apropriate and also switches it over to use
the generic code for *calc_mult_shift() on clock source and clock
event.

Signed-off-by: Linus Walleij <linus.walleij at stericsson.com>
---
 arch/arm/mach-u300/clock.c |    6 +++++-
 arch/arm/mach-u300/timer.c |   17 ++++++++---------
 2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/arch/arm/mach-u300/clock.c b/arch/arm/mach-u300/clock.c
index 7a94729..60acf9e 100644
--- a/arch/arm/mach-u300/clock.c
+++ b/arch/arm/mach-u300/clock.c
@@ -1204,10 +1204,14 @@ static struct clk timer_clk = {
 	.lock       = __SPIN_LOCK_UNLOCKED(timer_clk.lock),
 };
 
+/*
+ * There is a binary divider in the hardware that divides
+ * the 13MHz PLL by 13 down to 1 MHz.
+ */
 static struct clk app_timer_clk = {
 	.name       = "TIMER_APP",
 	.parent	    = &slow_clk,
-	.rate       = 13000000,
+	.rate       = 1000000,
 	.hw_ctrld   = true,
 	.reset	    = true,
 	.res_reg    = U300_SYSCON_VBASE + U300_SYSCON_RSR,
diff --git a/arch/arm/mach-u300/timer.c b/arch/arm/mach-u300/timer.c
index 16465e3..9a7cfbf 100644
--- a/arch/arm/mach-u300/timer.c
+++ b/arch/arm/mach-u300/timer.c
@@ -25,6 +25,8 @@
 #include <asm/mach/time.h>
 #include <asm/mach/irq.h>
 
+/* Be able to sleep for atleast 4 seconds (usually more) */
+#define APPTIMER_MIN_RANGE 4
 
 /*
  * APP side special timer registers
@@ -308,8 +310,6 @@ static struct clock_event_device clockevent_u300_1mhz = {
 	.name           = "GPT1",
 	.rating         = 300, /* Reasonably fast and accurate clock event */
 	.features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
-	/* 22 calculated using the algorithm in arch/mips/kernel/time.c */
-	.shift          = 22,
 	.set_next_event = u300_set_next_event,
 	.set_mode       = u300_set_mode,
 };
@@ -342,8 +342,6 @@ static struct clocksource clocksource_u300_1mhz = {
 	.rating         = 300, /* Reasonably fast and accurate clock source */
 	.read           = u300_get_cycles,
 	.mask           = CLOCKSOURCE_MASK(32), /* 32 bits */
-	/* 22 calculated using the algorithm in arch/mips/kernel/time.c */
-	.shift          = 22,
 	.flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
@@ -369,11 +367,13 @@ unsigned long long notrace sched_clock(void)
 static void __init u300_timer_init(void)
 {
 	struct clk *clk;
+	unsigned long rate;
 
 	/* Clock the interrupt controller */
 	clk = clk_get_sys("apptimer", NULL);
 	BUG_ON(IS_ERR(clk));
 	clk_enable(clk);
+	rate = clk_get_rate(clk);
 
 	/*
 	 * Disable the "OS" and "DD" timers - these are designed for Symbian!
@@ -412,15 +412,14 @@ static void __init u300_timer_init(void)
 	writel(U300_TIMER_APP_EGPT2_TIMER_ENABLE,
 		U300_TIMER_APP_VBASE + U300_TIMER_APP_EGPT2);
 
-	/* This is a pure microsecond clock source */
-	clocksource_u300_1mhz.mult =
-		clocksource_khz2mult(1000, clocksource_u300_1mhz.shift);
+	clocksource_calc_mult_shift(&clocksource_u300_1mhz,
+				    rate, APPTIMER_MIN_RANGE);
 	if (clocksource_register(&clocksource_u300_1mhz))
 		printk(KERN_ERR "timer: failed to initialize clock "
 		       "source %s\n", clocksource_u300_1mhz.name);
 
-	clockevent_u300_1mhz.mult =
-		div_sc(1000000, NSEC_PER_SEC, clockevent_u300_1mhz.shift);
+	clockevents_calc_mult_shift(&clockevent_u300_1mhz,
+				    rate, APPTIMER_MIN_RANGE);
 	/* 32bit counter, so 32bits delta is max */
 	clockevent_u300_1mhz.max_delta_ns =
 		clockevent_delta2ns(0xffffffff, &clockevent_u300_1mhz);
-- 
1.6.3.3