sh: TMU: Basic runtime PM support

Modify the SH TMU clock source/clock event device driver to support
runtime PM at a basic level (i.e. device clocks can be disabled and
enabled, but domain power must be on, because the devices have to
be marked as "irq safe").

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Magnus Damm <damm@opensource.se>

1 files changed, 65 insertions, 15 deletions

diff --git a/drivers/clocksource/sh_tmu.c b/drivers/clocksource/sh_tmu.c
index 81b0239718e..0cc4add8827 100644
--- a/drivers/clocksource/sh_tmu.c
+++ b/drivers/clocksource/sh_tmu.c
@@ -45,6 +45,7 @@ struct sh_tmu_priv {
         struct clock_event_device ced;
         struct clocksource cs;
         bool cs_enabled;
+        unsigned int enable_count;
 };
 
 static DEFINE_RAW_SPINLOCK(sh_tmu_lock);
@@ -109,7 +110,7 @@ static void sh_tmu_start_stop_ch(struct sh_tmu_priv *p, int start)
         raw_spin_unlock_irqrestore(&sh_tmu_lock, flags);
 }
 
-static int sh_tmu_enable(struct sh_tmu_priv *p)
+static int __sh_tmu_enable(struct sh_tmu_priv *p)
 {
         int ret;
 
@@ -137,7 +138,18 @@ static int sh_tmu_enable(struct sh_tmu_priv *p)
         return 0;
 }
 
-static void sh_tmu_disable(struct sh_tmu_priv *p)
+static int sh_tmu_enable(struct sh_tmu_priv *p)
+{
+        if (p->enable_count++ > 0)
+                return 0;
+
+        pm_runtime_get_sync(&p->pdev->dev);
+        dev_pm_syscore_device(&p->pdev->dev, true);
+
+        return __sh_tmu_enable(p);
+}
+
+static void __sh_tmu_disable(struct sh_tmu_priv *p)
 {
         /* disable channel */
         sh_tmu_start_stop_ch(p, 0);
@@ -149,6 +161,20 @@ static void sh_tmu_disable(struct sh_tmu_priv *p)
         clk_disable(p->clk);
 }
 
+static void sh_tmu_disable(struct sh_tmu_priv *p)
+{
+        if (WARN_ON(p->enable_count == 0))
+                return;
+
+        if (--p->enable_count > 0)
+                return;
+
+        __sh_tmu_disable(p);
+
+        dev_pm_syscore_device(&p->pdev->dev, false);
+        pm_runtime_put(&p->pdev->dev);
+}
+
 static void sh_tmu_set_next(struct sh_tmu_priv *p, unsigned long delta,
                             int periodic)
 {
@@ -205,11 +231,15 @@ static int sh_tmu_clocksource_enable(struct clocksource *cs)
         struct sh_tmu_priv *p = cs_to_sh_tmu(cs);
         int ret;
 
+        if (WARN_ON(p->cs_enabled))
+                return 0;
+
         ret = sh_tmu_enable(p);
         if (!ret) {
                 __clocksource_updatefreq_hz(cs, p->rate);
                 p->cs_enabled = true;
         }
+
         return ret;
 }
 
@@ -217,7 +247,8 @@ static void sh_tmu_clocksource_disable(struct clocksource *cs)
 {
         struct sh_tmu_priv *p = cs_to_sh_tmu(cs);
 
-        WARN_ON(!p->cs_enabled);
+        if (WARN_ON(!p->cs_enabled))
+                return;
 
         sh_tmu_disable(p);
         p->cs_enabled = false;
@@ -227,19 +258,26 @@ static void sh_tmu_clocksource_suspend(struct clocksource *cs)
 {
         struct sh_tmu_priv *p = cs_to_sh_tmu(cs);
 
-        if (p->cs_enabled)
-                sh_tmu_disable(p);
+        if (!p->cs_enabled)
+                return;
 
-        pm_genpd_syscore_poweroff(&p->pdev->dev);
+        if (--p->enable_count == 0) {
+                __sh_tmu_disable(p);
+                pm_genpd_syscore_poweroff(&p->pdev->dev);
+        }
 }
 
 static void sh_tmu_clocksource_resume(struct clocksource *cs)
 {
         struct sh_tmu_priv *p = cs_to_sh_tmu(cs);
 
-        pm_genpd_syscore_poweron(&p->pdev->dev);
-        if (p->cs_enabled)
-                sh_tmu_enable(p);
+        if (!p->cs_enabled)
+                return;
+
+        if (p->enable_count++ == 0) {
+                pm_genpd_syscore_poweron(&p->pdev->dev);
+                __sh_tmu_enable(p);
+        }
 }
 
 static int sh_tmu_register_clocksource(struct sh_tmu_priv *p,
@@ -434,6 +472,8 @@ static int sh_tmu_setup(struct sh_tmu_priv *p, struct platform_device *pdev)
                 ret = PTR_ERR(p->clk);
                 goto err1;
         }
+        p->cs_enabled = false;
+        p->enable_count = 0;
 
         return sh_tmu_register(p, (char *)dev_name(&p->pdev->dev),
                                cfg->clockevent_rating,
@@ -447,18 +487,17 @@ static int sh_tmu_setup(struct sh_tmu_priv *p, struct platform_device *pdev)
 static int __devinit sh_tmu_probe(struct platform_device *pdev)
 {
         struct sh_tmu_priv *p = platform_get_drvdata(pdev);
+        struct sh_timer_config *cfg = pdev->dev.platform_data;
         int ret;
 
         if (!is_early_platform_device(pdev)) {
-                struct sh_timer_config *cfg = pdev->dev.platform_data;
-
-                if (cfg->clocksource_rating || cfg->clockevent_rating)
-                        dev_pm_syscore_device(&pdev->dev, true);
+                pm_runtime_set_active(&pdev->dev);
+                pm_runtime_enable(&pdev->dev);
         }
 
         if (p) {
                 dev_info(&pdev->dev, "kept as earlytimer\n");
-                return 0;
+                goto out;
         }
 
         p = kmalloc(sizeof(*p), GFP_KERNEL);
@@ -471,8 +510,19 @@ static int __devinit sh_tmu_probe(struct platform_device *pdev)
         if (ret) {
                 kfree(p);
                 platform_set_drvdata(pdev, NULL);
+                pm_runtime_idle(&pdev->dev);
+                return ret;
         }
-        return ret;
+        if (is_early_platform_device(pdev))
+                return 0;
+
+ out:
+        if (cfg->clockevent_rating || cfg->clocksource_rating)
+                pm_runtime_irq_safe(&pdev->dev);
+        else
+                pm_runtime_idle(&pdev->dev);
+
+        return 0;
 }
 
 static int __devexit sh_tmu_remove(struct platform_device *pdev)