1 files changed, 13 insertions, 0 deletions

diff --git a/drivers/power/jz4740-battery.c b/drivers/power/jz4740-battery.c
index a8108a73593e..02414db6a94c 100644
--- a/drivers/power/jz4740-battery.c
+++ b/drivers/power/jz4740-battery.c
@@ -19,6 +19,7 @@
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
+#include <linux/io.h>
 
 #include <linux/delay.h>
 #include <linux/gpio.h>
@@ -47,6 +48,8 @@ struct jz_battery {
 
         struct power_supply battery;
         struct delayed_work work;
+
+        struct mutex lock;
 };
 
 static inline struct jz_battery *psy_to_jz_battery(struct power_supply *psy)
@@ -68,6 +71,8 @@ static long jz_battery_read_voltage(struct jz_battery *battery)
         unsigned long val;
         long voltage;
 
+        mutex_lock(&battery->lock);
+
         INIT_COMPLETION(battery->read_completion);
 
         enable_irq(battery->irq);
@@ -91,6 +96,8 @@ static long jz_battery_read_voltage(struct jz_battery *battery)
         battery->cell->disable(battery->pdev);
         disable_irq(battery->irq);
 
+        mutex_unlock(&battery->lock);
+
         return voltage;
 }
 
@@ -240,6 +247,11 @@ static int __devinit jz_battery_probe(struct platform_device *pdev)
         struct jz_battery *jz_battery;
         struct power_supply *battery;
 
+        if (!pdata) {
+                dev_err(&pdev->dev, "No platform_data supplied\n");
+                return -ENXIO;
+        }
+
         jz_battery = kzalloc(sizeof(*jz_battery), GFP_KERNEL);
         if (!jz_battery) {
                 dev_err(&pdev->dev, "Failed to allocate driver structure\n");
@@ -291,6 +303,7 @@ static int __devinit jz_battery_probe(struct platform_device *pdev)
         jz_battery->pdev = pdev;
 
         init_completion(&jz_battery->read_completion);
+        mutex_init(&jz_battery->lock);
 
         INIT_DELAYED_WORK(&jz_battery->work, jz_battery_work);