diff --git a/drivers/telephony/phonedev.c b/drivers/telephony/phonedev.c
index 3c987f4..7a6db1c 100644
--- a/drivers/telephony/phonedev.c
+++ b/drivers/telephony/phonedev.c
@@ -29,6 +29,7 @@
 #include <linux/kmod.h>
 #include <linux/sem.h>
 #include <linux/devfs_fs_kernel.h>
+#include <linux/mutex.h>
 
 #define PHONE_NUM_DEVICES	256
 
@@ -37,7 +38,7 @@
  */
 
 static struct phone_device *phone_device[PHONE_NUM_DEVICES];
-static DECLARE_MUTEX(phone_lock);
+static DEFINE_MUTEX(phone_lock);
 
 /*
  *    Open a phone device.
@@ -53,14 +54,14 @@
 	if (minor >= PHONE_NUM_DEVICES)
 		return -ENODEV;
 
-	down(&phone_lock);
+	mutex_lock(&phone_lock);
 	p = phone_device[minor];
 	if (p)
 		new_fops = fops_get(p->f_op);
 	if (!new_fops) {
-		up(&phone_lock);
+		mutex_unlock(&phone_lock);
 		request_module("char-major-%d-%d", PHONE_MAJOR, minor);
-		down(&phone_lock);
+		mutex_lock(&phone_lock);
 		p = phone_device[minor];
 		if (p == NULL || (new_fops = fops_get(p->f_op)) == NULL)
 		{
@@ -78,7 +79,7 @@
 	}
 	fops_put(old_fops);
 end:
-	up(&phone_lock);
+	mutex_unlock(&phone_lock);
 	return err;
 }
 
@@ -100,18 +101,18 @@
 		end = unit + 1;  /* enter the loop at least one time */
 	}
 	
-	down(&phone_lock);
+	mutex_lock(&phone_lock);
 	for (i = base; i < end; i++) {
 		if (phone_device[i] == NULL) {
 			phone_device[i] = p;
 			p->minor = i;
 			devfs_mk_cdev(MKDEV(PHONE_MAJOR,i),
 				S_IFCHR|S_IRUSR|S_IWUSR, "phone/%d", i);
-			up(&phone_lock);
+			mutex_unlock(&phone_lock);
 			return 0;
 		}
 	}
-	up(&phone_lock);
+	mutex_unlock(&phone_lock);
 	return -ENFILE;
 }
 
@@ -121,12 +122,12 @@
 
 void phone_unregister_device(struct phone_device *pfd)
 {
-	down(&phone_lock);
+	mutex_lock(&phone_lock);
 	if (phone_device[pfd->minor] != pfd)
 		panic("phone: bad unregister");
 	devfs_remove("phone/%d", pfd->minor);
 	phone_device[pfd->minor] = NULL;
-	up(&phone_lock);
+	mutex_unlock(&phone_lock);
 }