EXPORT_SYMBOL(sony_pic_camera_command);
 
 /* gprs/edge modem (SZ460N and SZ210P), thanks to Joshua Wise */
-static void sony_pic_set_wwanpower(u8 state)
+static void __sony_pic_set_wwanpower(u8 state)
 {
        state = !!state;
-       mutex_lock(&spic_dev.lock);
-       if (spic_dev.wwan_power == state) {
-               mutex_unlock(&spic_dev.lock);
+       if (spic_dev.wwan_power == state)
                return;
-       }
        sony_pic_call2(0xB0, state);
        sony_pic_call1(0x82);
        spic_dev.wwan_power = state;
-       mutex_unlock(&spic_dev.lock);
 }
 
 static ssize_t sony_pic_wwanpower_store(struct device *dev,
                return -EINVAL;
 
        value = simple_strtoul(buffer, NULL, 10);
-       sony_pic_set_wwanpower(value);
+       mutex_lock(&spic_dev.lock);
+       __sony_pic_set_wwanpower(value);
+       mutex_unlock(&spic_dev.lock);
 
        return count;
 }