From: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
Date: Tue, 8 Dec 2009 11:27:04 +0000 (-0200)
Subject: Use misc device.
X-Git-Url: http://git.cascardo.info/?p=cascardo%2Fkernel%2Fsamples%2F02.char%2F.git;a=commitdiff_plain;h=25d2ba26a1d460609aeb150a8c56c446791486f6

Use misc device.
---

diff --git a/helloc.c b/helloc.c
index 0db07e3..8103f60 100644
--- a/helloc.c
+++ b/helloc.c
@@ -5,6 +5,8 @@
 #include <linux/cdev.h>
 /* Needed for copying to/from user space */
 #include <asm/uaccess.h>
+/* Needed for using misc device stuff */
+#include <linux/miscdevice.h>
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>");
@@ -41,48 +43,22 @@ static struct file_operations helloc_fops = {
 	.read = helloc_read,
 };
 
-/* the device number and the char device struct */
-static dev_t dev;
-static struct cdev *cdev;
+static struct miscdevice hello_misc = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = "helloc",
+	.fops = &helloc_fops,
+};
 
 static int __init helloc_init(void)
 {
 	int r;
-	/* allocate any major number with only one minor */
-	r = alloc_chrdev_region(&dev, 0, 1, "helloc");
-	if (r)
-		goto out_region;
-	r = -ENOMEM;
-	/* print the major number allocated so we can create our device node */
-	printk(KERN_INFO "Allocated major number %d\n", MAJOR(dev));
-	/* allocate the character device struct */
-	cdev = cdev_alloc();
-	if (!cdev)
-		goto out_alloc;
-	/* set the module owner and the file operations of our chardev */
-	cdev->owner = THIS_MODULE;
-	cdev->ops = &helloc_fops;
-	/* register the chardev to the system */
-	r = cdev_add(cdev, dev, 1);
-	if (r)
-		goto out_add;
-	return 0;
-out_add:
-	/* release memory allocated to the cdev device */
-	kfree(cdev);
-out_alloc:
-	/* release the device number allocated */
-	unregister_chrdev_region(dev, 1);
-out_region:
+	r = misc_register(&hello_misc);
 	return r;
 }
 
 static void __exit helloc_exit(void)
 {
-	/* remove the chardev from the system */
-	cdev_del(cdev);
-	/* release the device number allocated */
-	unregister_chrdev_region(dev, 1);
+	misc_deregister(&hello_misc);
 }
 
 module_init(helloc_init);