sh: CMT: Basic runtime PM support

Modify the SH CMT 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, 36 insertions, 8 deletions

diff --git a/drivers/clocksource/sh_cmt.c b/drivers/clocksource/sh_cmt.c
index a515605bf8f5..a5f7829f2799 100644
--- a/drivers/clocksource/sh_cmt.c
+++ b/drivers/clocksource/sh_cmt.c
@@ -33,6 +33,7 @@
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/pm_domain.h>
+#include <linux/pm_runtime.h>
 
 struct sh_cmt_priv {
         void __iomem *mapbase;
@@ -52,6 +53,7 @@ struct sh_cmt_priv {
         struct clock_event_device ced;
         struct clocksource cs;
         unsigned long total_cycles;
+        bool cs_enabled;
 };
 
 static DEFINE_RAW_SPINLOCK(sh_cmt_lock);
@@ -155,6 +157,9 @@ static int sh_cmt_enable(struct sh_cmt_priv *p, unsigned long *rate)
 {
         int k, ret;
 
+        pm_runtime_get_sync(&p->pdev->dev);
+        dev_pm_syscore_device(&p->pdev->dev, true);
+
         /* enable clock */
         ret = clk_enable(p->clk);
         if (ret) {
@@ -221,6 +226,9 @@ static void sh_cmt_disable(struct sh_cmt_priv *p)
 
         /* stop clock */
         clk_disable(p->clk);
+
+        dev_pm_syscore_device(&p->pdev->dev, false);
+        pm_runtime_put(&p->pdev->dev);
 }
 
 /* private flags */
@@ -451,17 +459,26 @@ static int sh_cmt_clocksource_enable(struct clocksource *cs)
         int ret;
         struct sh_cmt_priv *p = cs_to_sh_cmt(cs);
 
+        WARN_ON(p->cs_enabled);
+
         p->total_cycles = 0;
 
         ret = sh_cmt_start(p, FLAG_CLOCKSOURCE);
-        if (!ret)
+        if (!ret) {
                 __clocksource_updatefreq_hz(cs, p->rate);
+                p->cs_enabled = true;
+        }
         return ret;
 }
 
 static void sh_cmt_clocksource_disable(struct clocksource *cs)
 {
-        sh_cmt_stop(cs_to_sh_cmt(cs), FLAG_CLOCKSOURCE);
+        struct sh_cmt_priv *p = cs_to_sh_cmt(cs);
+
+        WARN_ON(!p->cs_enabled);
+
+        sh_cmt_stop(p, FLAG_CLOCKSOURCE);
+        p->cs_enabled = false;
 }
 
 static void sh_cmt_clocksource_suspend(struct clocksource *cs)
@@ -693,6 +710,7 @@ static int sh_cmt_setup(struct sh_cmt_priv *p, struct platform_device *pdev)
                 dev_err(&p->pdev->dev, "registration failed\n");
                 goto err1;
         }
+        p->cs_enabled = false;
 
         ret = setup_irq(irq, &p->irqaction);
         if (ret) {
@@ -711,18 +729,17 @@ err0:
 static int __devinit sh_cmt_probe(struct platform_device *pdev)
 {
         struct sh_cmt_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);
@@ -735,8 +752,19 @@ static int __devinit sh_cmt_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_cmt_remove(struct platform_device *pdev)