clocksource: samsung_pwm_timer: Do not use clocksource_mmio

In case of Samsung PWM timer, clocksource MMIO can not be used, because
custom suspend/resume callbacks are required.
Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Mark Brown <broonie@linaro.org>
Tested-by: Sylwester Nawrocki <sylvester.nawrocki@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>

drivers/clocksource/Kconfig

@@ -99,7 +99,6 @@ config CLKSRC_EXYNOS_MCT
 
 config CLKSRC_SAMSUNG_PWM
 	bool
-	select CLKSRC_MMIO
 	help
 	  This is a new clocksource driver for the PWM timer found in
 	  Samsung S3C, S5P and Exynos SoCs, replacing an earlier driver

drivers/clocksource/samsung_pwm_timer.c

@@ -298,6 +298,18 @@ static void __init samsung_clockevent_init(void)
 	}
 }
 
+static cycle_t samsung_clocksource_read(struct clocksource *c)
+{
+	return ~readl_relaxed(pwm.source_reg);
+}
+
+static struct clocksource samsung_clocksource = {
+	.name		= "samsung_clocksource_timer",
+	.rating		= 250,
+	.read		= samsung_clocksource_read,
+	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
 /*
  * Override the global weak sched_clock symbol with this
  * local implementation which uses the clocksource to get some
@@ -307,7 +319,7 @@ static void __init samsung_clockevent_init(void)
  */
 static u32 notrace samsung_read_sched_clock(void)
 {
-	return ~__raw_readl(pwm.source_reg);
+	return samsung_clocksource_read(NULL);
 }
 
 static void __init samsung_clocksource_init(void)
@@ -334,9 +346,8 @@ static void __init samsung_clocksource_init(void)
 	setup_sched_clock(samsung_read_sched_clock,
 						pwm.variant.bits, clock_rate);
 
-	ret = clocksource_mmio_init(pwm.source_reg, "samsung_clocksource_timer",
-					clock_rate, 250, pwm.variant.bits,
-					clocksource_mmio_readl_down);
+	samsung_clocksource.mask = CLOCKSOURCE_MASK(pwm.variant.bits);
+	ret = clocksource_register_hz(&samsung_clocksource, clock_rate);
 	if (ret)
 		panic("samsung_clocksource_timer: can't register clocksource\n");
 }