From: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
Date: Wed, 19 May 2010 14:16:07 +0000 (-0400)
Subject: Allocate device number dynamically.
X-Git-Url: http://git.cascardo.eti.br/?p=cascardo%2Fkernel%2Fsamples%2Fchar2%2F.git;a=commitdiff_plain;h=2808766508d8ef444e7cc4636b37534a910e5600

Allocate device number dynamically.
---

diff --git a/hellochar.c b/hellochar.c
index 576968b..e50ac2a 100644
--- a/hellochar.c
+++ b/hellochar.c
@@ -20,21 +20,21 @@
 #include <linux/fs.h>
 
 MODULE_LICENSE("GPL");
-static int major = 10;
-module_param_named(major, major, int, S_IRUGO | S_IWUSR);
+static dev_t devnum;
 
 static int __init ch_init(void)
 {
 	int r;
-	r = register_chrdev_region(MKDEV(major, 0), 256, "hello");
+	r = alloc_chrdev_region(&devnum, 0, 256, "hello");
 	if (r)
 		return r;
+	printk(KERN_DEBUG "Allocate major %d\n", MAJOR(devnum));
 	return 0;
 }
 
 static void __exit ch_exit(void)
 {
-	unregister_chrdev_region(MKDEV(major, 0), 256);
+	unregister_chrdev_region(devnum, 256);
 }
 
 module_init(ch_init);