clocksource: samsung_pwm_timer: Handle suspend/resume correctly

Current suspend/resume handling of the driver was broken, because:
 - periodic timer was being enabled in CLOCK_EVT_MODE_RESUME mode, which
   does not seem to be correct behavior looking at other platforms,
 - PWM divisors need to be restored, but they were not,
 - clockevent interrupt mask needs to be restored, but it was not,
 - clocksource was being restored in clockevent resume callback.

This patch fixes issues mentioned above, making suspend/resume handling
in the driver correct.

Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com>
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>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>

1 files changed, 28 insertions, 14 deletions

diff --git a/drivers/clocksource/samsung_pwm_timer.c b/drivers/clocksource/samsung_pwm_timer.c
index b3112dc293ba..ac60f8b8a5f7 100644
--- a/drivers/clocksource/samsung_pwm_timer.c
+++ b/drivers/clocksource/samsung_pwm_timer.c
@@ -207,17 +207,6 @@ static int samsung_set_next_event(unsigned long cycles,
         return 0;
 }
 
-static void samsung_timer_resume(void)
-{
-        /* event timer restart */
-        samsung_time_setup(pwm.event_id, pwm.clock_count_per_tick - 1);
-        samsung_time_start(pwm.event_id, true);
-
-        /* source timer restart */
-        samsung_time_setup(pwm.source_id, pwm.tcnt_max);
-        samsung_time_start(pwm.source_id, true);
-}
-
 static void samsung_set_mode(enum clock_event_mode mode,
                                 struct clock_event_device *evt)
 {
@@ -234,20 +223,29 @@ static void samsung_set_mode(enum clock_event_mode mode,
 
         case CLOCK_EVT_MODE_UNUSED:
         case CLOCK_EVT_MODE_SHUTDOWN:
-                break;
-
         case CLOCK_EVT_MODE_RESUME:
-                samsung_timer_resume();
                 break;
         }
 }
 
+static void samsung_clockevent_resume(struct clock_event_device *cev)
+{
+        samsung_timer_set_prescale(pwm.event_id, pwm.tscaler_div);
+        samsung_timer_set_divisor(pwm.event_id, pwm.tdiv);
+
+        if (pwm.variant.has_tint_cstat) {
+                u32 mask = (1 << pwm.event_id);
+                writel(mask | (mask << 5), pwm.base + REG_TINT_CSTAT);
+        }
+}
+
 static struct clock_event_device time_event_device = {
         .name           = "samsung_event_timer",
         .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
         .rating         = 200,
         .set_next_event = samsung_set_next_event,
         .set_mode       = samsung_set_mode,
+        .resume         = samsung_clockevent_resume,
 };
 
 static irqreturn_t samsung_clock_event_isr(int irq, void *dev_id)
@@ -298,6 +296,20 @@ static void __init samsung_clockevent_init(void)
         }
 }
 
+static void samsung_clocksource_suspend(struct clocksource *cs)
+{
+        samsung_time_stop(pwm.source_id);
+}
+
+static void samsung_clocksource_resume(struct clocksource *cs)
+{
+        samsung_timer_set_prescale(pwm.source_id, pwm.tscaler_div);
+        samsung_timer_set_divisor(pwm.source_id, pwm.tdiv);
+
+        samsung_time_setup(pwm.source_id, pwm.tcnt_max);
+        samsung_time_start(pwm.source_id, true);
+}
+
 static cycle_t samsung_clocksource_read(struct clocksource *c)
 {
         return ~readl_relaxed(pwm.source_reg);
@@ -307,6 +319,8 @@ static struct clocksource samsung_clocksource = {
         .name           = "samsung_clocksource_timer",
         .rating         = 250,
         .read           = samsung_clocksource_read,
+        .suspend        = samsung_clocksource_suspend,
+        .resume         = samsung_clocksource_resume,
         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 };