Re: [PATCH 2.6] Class support for ppdev.c

[sebek64@post.cz (Marcel Sebek)]

On Sat, Apr 10, 2004 at 08:06:36PM +0200, Marcel Sebek wrote:
> On Sat, Apr 10, 2004 at 10:01:48AM -0700, Greg KH wrote:
> > On Sat, Apr 10, 2004 at 03:51:15PM +0200, Marcel Sebek wrote:
> > > This patch adds class support to ppdev.c.
> > > 
> > > The module compiles and loads ok.
> > 
> > Looks good, but we really shoulnd't be duplicating the devfs
> > functionality here.  We should only show the devices that the system
> > really has present, instead of always showing all of the devices.  Care
> > to fix your patch up to implement this instead?
> > 
> 
> Ok. Here is an updated patch.

And new updated patch. partport_find_number() needs to decrement refcount
by parport_put_port().


diff -urN linux-2.6/drivers/char/ppdev.c linux-2.6-new/drivers/char/ppdev.c
--- linux-2.6/drivers/char/ppdev.c	2004-04-10 21:38:17.000000000 +0200
+++ linux-2.6-new/drivers/char/ppdev.c	2004-04-10 21:40:31.000000000 +0200
@@ -59,6 +59,7 @@
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/sched.h>
+#include <linux/device.h>
 #include <linux/devfs_fs_kernel.h>
 #include <linux/ioctl.h>
 #include <linux/parport.h>
@@ -750,31 +751,58 @@
 	.release	= pp_release,
 };
 
+static struct class_simple *ppdev_class;
+
 static int __init ppdev_init (void)
 {
-	int i;
+	int i, err = 0;
+	struct parport *port;
 
 	if (register_chrdev (PP_MAJOR, CHRDEV, &pp_fops)) {
 		printk (KERN_WARNING CHRDEV ": unable to get major %d\n",
 			PP_MAJOR);
 		return -EIO;
 	}
+	ppdev_class = class_simple_create(THIS_MODULE, CHRDEV);
+	if (IS_ERR(ppdev_class)) {
+		err = PTR_ERR(ppdev_class);
+		goto out_chrdev;
+	}
 	devfs_mk_dir("parports");
 	for (i = 0; i < PARPORT_MAX; i++) {
-		devfs_mk_cdev(MKDEV(PP_MAJOR, i),
+		if ((port = parport_find_number(i))) {
+			class_simple_device_add(ppdev_class, MKDEV(PP_MAJOR, i),
+				NULL, "parport%d", i);
+			parport_put_port(port);
+		}
+		err = devfs_mk_cdev(MKDEV(PP_MAJOR, i),
 				S_IFCHR | S_IRUGO | S_IWUGO, "parports/%d", i);
+		if (err)
+			goto out_class;
 	}
 
 	printk (KERN_INFO PP_VERSION "\n");
-	return 0;
+	goto out;
+
+out_class:
+	for (i = 0; i < PARPORT_MAX; i++)
+		class_simple_device_remove(MKDEV(PP_MAJOR, i));
+	class_simple_destroy(ppdev_class);
+out_chrdev:
+	unregister_chrdev(PP_MAJOR, CHRDEV);
+out:
+	return err;
 }
 
 static void __exit ppdev_cleanup (void)
 {
 	int i;
 	/* Clean up all parport stuff */
-	for (i = 0; i < PARPORT_MAX; i++)
+	for (i = 0; i < PARPORT_MAX; i++) {
+		class_simple_device_remove(MKDEV(PP_MAJOR, i));
 		devfs_remove("parports/%d", i);
+	}
+	class_simple_destroy(ppdev_class);
 	devfs_remove("parports");
 	unregister_chrdev (PP_MAJOR, CHRDEV);
 }

-- 
Marcel Sebek
jabber: sebek@jabber.cz                     ICQ: 279852819
linux user number: 307850                 GPG ID: 5F88735E
GPG FP: 0F01 BAB8 3148 94DB B95D  1FCA 8B63 CA06 5F88 735E