[ARM] Fix sparse warnings in ds1620.c

drivers/char/ds1620.c:230:19: warning: incorrect type in argument 1 (different address spaces)
drivers/char/ds1620.c:230:19:    expected void [noderef] *to<asn:1>
drivers/char/ds1620.c:230:19:    got char *buf
drivers/char/ds1620.c:230:19: warning: incorrect type in initializer (different address spaces)
drivers/char/ds1620.c:230:19:    expected void [noderef] *to<asn:1>
drivers/char/ds1620.c:230:19:    got char *buf
...
drivers/char/ds1620.c:383:52: warning: Using plain integer as NULL pointer

drivers/char/ds1620.c

@@ -213,7 +213,7 @@ static void ds1620_read_state(struct therm *therm)
 }
 
 static ssize_t
-ds1620_read(struct file *file, char *buf, size_t count, loff_t *ptr)
+ds1620_read(struct file *file, char __user *buf, size_t count, loff_t *ptr)
 {
 	signed int cur_temp;
 	signed char cur_temp_degF;
@@ -233,8 +233,14 @@ static int
 ds1620_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
 {
 	struct therm therm;
+	union {
+		struct therm __user *therm;
+		int __user *i;
+	} uarg;
 	int i;
 
+	uarg.i = (int __user *)arg;
+
 	switch(cmd) {
 	case CMD_SET_THERMOSTATE:
 	case CMD_SET_THERMOSTATE2:
@@ -242,11 +248,11 @@ ds1620_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned
 			return -EPERM;
 
 		if (cmd == CMD_SET_THERMOSTATE) {
-			if (get_user(therm.hi, (int *)arg))
+			if (get_user(therm.hi, uarg.i))
 				return -EFAULT;
 			therm.lo = therm.hi - 3;
 		} else {
-			if (copy_from_user(&therm, (void *)arg, sizeof(therm)))
+			if (copy_from_user(&therm, uarg.therm, sizeof(therm)))
 				return -EFAULT;
 		}
 
@@ -264,10 +270,10 @@ ds1620_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned
 		therm.hi >>= 1;
 
 		if (cmd == CMD_GET_THERMOSTATE) {
-			if (put_user(therm.hi, (int *)arg))
+			if (put_user(therm.hi, uarg.i))
 				return -EFAULT;
 		} else {
-			if (copy_to_user((void *)arg, &therm, sizeof(therm)))
+			if (copy_to_user(uarg.therm, &therm, sizeof(therm)))
 				return -EFAULT;
 		}
 		break;
@@ -279,23 +285,23 @@ ds1620_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned
 		if (cmd == CMD_GET_TEMPERATURE)
 			i >>= 1;
 
-		return put_user(i, (int *)arg) ? -EFAULT : 0;
+		return put_user(i, uarg.i) ? -EFAULT : 0;
 
 	case CMD_GET_STATUS:
 		i = ds1620_in(THERM_READ_CONFIG, 8) & 0xe3;
 
-		return put_user(i, (int *)arg) ? -EFAULT : 0;
+		return put_user(i, uarg.i) ? -EFAULT : 0;
 
 	case CMD_GET_FAN:
 		i = netwinder_get_fan();
 
-		return put_user(i, (int *)arg) ? -EFAULT : 0;
+		return put_user(i, uarg.i) ? -EFAULT : 0;
 
 	case CMD_SET_FAN:
 		if (!capable(CAP_SYS_ADMIN))
 			return -EPERM;
 
-		if (get_user(i, (int *)arg))
+		if (get_user(i, uarg.i))
 			return -EFAULT;
 
 		netwinder_set_fan(i);
@@ -377,7 +383,7 @@ static int __init ds1620_init(void)
 		return ret;
 
 #ifdef THERM_USE_PROC
-	proc_therm_ds1620 = create_proc_entry("therm", 0, 0);
+	proc_therm_ds1620 = create_proc_entry("therm", 0, NULL);
 	if (proc_therm_ds1620)
 		proc_therm_ds1620->read_proc = proc_therm_ds1620_read;
 	else