Watchdog: omap_wdt: add fine grain runtime-pm

The omap_wdt should only be in full active state when the
registers are being accessed. Otherwise the device can be
on lower power mode.

This patch is based on a patch created by Kalle Jokiniemi:
https://patchwork.kernel.org/patch/618231/
which is itself based on a patch created by Atal
Shargorodsky: http://lkml.org/lkml/2009/3/10/266.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Kalle Jokiniemi <kalle.jokiniemi@nokia.com>
Tested-by: Kalle Jokiniemi <kalle.jokiniemi@nokia.com>
Cc: Wim Van Sebroeck <wim@iguana.be>
Acked-by: Wim Van Sebroeck <wim@iguana.be>
Acked-by: Kevin Hilman <khilman@ti.com>

1 files changed, 23 insertions, 2 deletions

diff --git a/drivers/watchdog/omap_wdt.c b/drivers/watchdog/omap_wdt.c
index 3dd4971160ef..2b4acb86c191 100644
--- a/drivers/watchdog/omap_wdt.c
+++ b/drivers/watchdog/omap_wdt.c
@@ -124,6 +124,8 @@ static void omap_wdt_set_timeout(struct omap_wdt_dev *wdev)
         u32 pre_margin = GET_WLDR_VAL(timer_margin);
         void __iomem *base = wdev->base;
 
+        pm_runtime_get_sync(wdev->dev);
+
         /* just count up at 32 KHz */
         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x04)
                 cpu_relax();
@@ -131,6 +133,8 @@ static void omap_wdt_set_timeout(struct omap_wdt_dev *wdev)
         __raw_writel(pre_margin, base + OMAP_WATCHDOG_LDR);
         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x04)
                 cpu_relax();
+
+        pm_runtime_put_sync(wdev->dev);
 }
 
 /*
@@ -160,6 +164,8 @@ static int omap_wdt_open(struct inode *inode, struct file *file)
         omap_wdt_ping(wdev); /* trigger loading of new timeout value */
         omap_wdt_enable(wdev);
 
+        pm_runtime_put_sync(wdev->dev);
+
         return nonseekable_open(inode, file);
 }
 
@@ -171,6 +177,7 @@ static int omap_wdt_release(struct inode *inode, struct file *file)
          *      Shut off the timer unless NOWAYOUT is defined.
          */
 #ifndef CONFIG_WATCHDOG_NOWAYOUT
+        pm_runtime_get_sync(wdev->dev);
 
         omap_wdt_disable(wdev);
 
@@ -190,9 +197,11 @@ static ssize_t omap_wdt_write(struct file *file, const char __user *data,
 
         /* Refresh LOAD_TIME. */
         if (len) {
+                pm_runtime_get_sync(wdev->dev);
                 spin_lock(&wdt_lock);
                 omap_wdt_ping(wdev);
                 spin_unlock(&wdt_lock);
+                pm_runtime_put_sync(wdev->dev);
         }
         return len;
 }
@@ -224,15 +233,18 @@ static long omap_wdt_ioctl(struct file *file, unsigned int cmd,
                         return put_user(omap_prcm_get_reset_sources(),
                                         (int __user *)arg);
         case WDIOC_KEEPALIVE:
+                pm_runtime_get_sync(wdev->dev);
                 spin_lock(&wdt_lock);
                 omap_wdt_ping(wdev);
                 spin_unlock(&wdt_lock);
+                pm_runtime_put_sync(wdev->dev);
                 return 0;
         case WDIOC_SETTIMEOUT:
                 if (get_user(new_margin, (int __user *)arg))
                         return -EFAULT;
                 omap_wdt_adjust_timeout(new_margin);
 
+                pm_runtime_get_sync(wdev->dev);
                 spin_lock(&wdt_lock);
                 omap_wdt_disable(wdev);
                 omap_wdt_set_timeout(wdev);
@@ -240,6 +252,7 @@ static long omap_wdt_ioctl(struct file *file, unsigned int cmd,
 
                 omap_wdt_ping(wdev);
                 spin_unlock(&wdt_lock);
+                pm_runtime_put_sync(wdev->dev);
                 /* Fall */
         case WDIOC_GETTIMEOUT:
                 return put_user(timer_margin, (int __user *)arg);
@@ -345,8 +358,11 @@ static void omap_wdt_shutdown(struct platform_device *pdev)
 {
         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 
-        if (wdev->omap_wdt_users)
+        if (wdev->omap_wdt_users) {
+                pm_runtime_get_sync(wdev->dev);
                 omap_wdt_disable(wdev);
+                pm_runtime_put_sync(wdev->dev);
+        }
 }
 
 static int __devexit omap_wdt_remove(struct platform_device *pdev)
@@ -381,8 +397,11 @@ static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 {
         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 
-        if (wdev->omap_wdt_users)
+        if (wdev->omap_wdt_users) {
+                pm_runtime_get_sync(wdev->dev);
                 omap_wdt_disable(wdev);
+                pm_runtime_put_sync(wdev->dev);
+        }
 
         return 0;
 }
@@ -392,8 +411,10 @@ static int omap_wdt_resume(struct platform_device *pdev)
         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 
         if (wdev->omap_wdt_users) {
+                pm_runtime_get_sync(wdev->dev);
                 omap_wdt_enable(wdev);
                 omap_wdt_ping(wdev);
+                pm_runtime_put_sync(wdev->dev);
         }
 
         return 0;