From: Greg KH <greg@kroah.com>
This adds /sys/class/mem which enables all misc char devices to show up
properly in udev.
Note, the misc_init() call has been moved to a subsys_initcall as it
seems there are a lot of platform specific misc devices that are calling
misc_register before misc_init() is called.
Has been posted to lkml a few times in the past and tested by a wide
range of people.
drivers/char/misc.c | 92 ++++++++++++++++++++++++++++++++++++++++++++-
include/linux/miscdevice.h | 3 +
2 files changed, 93 insertions(+), 2 deletions(-)
diff -puN drivers/char/misc.c~sysfs-misc-device-support drivers/char/misc.c
--- 25/drivers/char/misc.c~sysfs-misc-device-support 2003-12-22 20:19:17.000000000 -0800
+++ 25-akpm/drivers/char/misc.c 2003-12-22 20:19:17.000000000 -0800
@@ -47,7 +47,7 @@
#include <linux/devfs_fs_kernel.h>
#include <linux/stat.h>
#include <linux/init.h>
-
+#include <linux/device.h>
#include <linux/tty.h>
#include <linux/kmod.h>
@@ -180,6 +180,91 @@ fail:
return err;
}
+/* Misc class implementation */
+
+/*
+ * TODO for 2.7:
+ * - add a struct class_device to struct miscdevice and make all usages of
+ * them dynamic. This will let us get rid of struct misc_dev below.
+ */
+struct misc_dev {
+ struct list_head node;
+ dev_t dev;
+ struct class_device class_dev;
+};
+#define to_misc_dev(d) container_of(d, struct misc_dev, class_dev)
+
+static LIST_HEAD(misc_dev_list);
+static spinlock_t misc_dev_list_lock = SPIN_LOCK_UNLOCKED;
+
+static void release_misc_dev(struct class_device *class_dev)
+{
+ struct misc_dev *misc_dev = to_misc_dev(class_dev);
+ kfree(misc_dev);
+}
+
+static struct class misc_class = {
+ .name = "misc",
+ .release = &release_misc_dev,
+};
+
+static ssize_t show_dev(struct class_device *class_dev, char *buf)
+{
+ struct misc_dev *misc_dev = to_misc_dev(class_dev);
+ return print_dev_t(buf, misc_dev->dev);
+}
+static CLASS_DEVICE_ATTR(dev, S_IRUGO, show_dev, NULL);
+
+static void misc_add_class_device(struct miscdevice *misc)
+{
+ struct misc_dev *misc_dev = NULL;
+ int retval;
+
+ misc_dev = kmalloc(sizeof(*misc_dev), GFP_KERNEL);
+ if (!misc_dev)
+ return;
+ memset(misc_dev, 0x00, sizeof(*misc_dev));
+
+ misc_dev->dev = MKDEV(MISC_MAJOR, misc->minor);
+ misc_dev->class_dev.dev = misc->dev;
+ misc_dev->class_dev.class = &misc_class;
+ snprintf(misc_dev->class_dev.class_id, BUS_ID_SIZE, "%s", misc->name);
+ retval = class_device_register(&misc_dev->class_dev);
+ if (retval)
+ goto error;
+ class_device_create_file(&misc_dev->class_dev, &class_device_attr_dev);
+ spin_lock(&misc_dev_list_lock);
+ list_add(&misc_dev->node, &misc_dev_list);
+ spin_unlock(&misc_dev_list_lock);
+ return;
+error:
+ kfree(misc_dev);
+}
+
+static void misc_remove_class_device(struct miscdevice *misc)
+{
+ struct misc_dev *misc_dev = NULL;
+ struct list_head *tmp;
+ int found = 0;
+
+ spin_lock(&misc_dev_list_lock);
+ list_for_each(tmp, &misc_dev_list) {
+ misc_dev = list_entry(tmp, struct misc_dev, node);
+ if ((MINOR(misc_dev->dev) == misc->minor)) {
+ found = 1;
+ break;
+ }
+ }
+ if (found) {
+ list_del(&misc_dev->node);
+ spin_unlock(&misc_dev_list_lock);
+ class_device_unregister(&misc_dev->class_dev);
+ } else {
+ spin_unlock(&misc_dev_list_lock);
+ }
+}
+
+
static struct file_operations misc_fops = {
.owner = THIS_MODULE,
.open = misc_open,
@@ -236,6 +321,7 @@ int misc_register(struct miscdevice * mi
devfs_mk_cdev(MKDEV(MISC_MAJOR, misc->minor),
S_IFCHR|S_IRUSR|S_IWUSR|S_IRGRP, misc->devfs_name);
+ misc_add_class_device(misc);
/*
* Add it to the front, so that later devices can "override"
@@ -265,6 +351,7 @@ int misc_deregister(struct miscdevice *
down(&misc_sem);
list_del(&misc->list);
+ misc_remove_class_device(misc);
devfs_remove(misc->devfs_name);
if (i < DYNAMIC_MINORS && i>0) {
misc_minors[i>>3] &= ~(1 << (misc->minor & 7));
@@ -285,6 +372,7 @@ static int __init misc_init(void)
if (ent)
ent->proc_fops = &misc_proc_fops;
#endif
+ class_register(&misc_class);
#ifdef CONFIG_MVME16x
rtc_MK48T08_init();
#endif
@@ -319,4 +407,4 @@ static int __init misc_init(void)
}
return 0;
}
-module_init(misc_init);
+subsys_initcall(misc_init);
diff -puN include/linux/miscdevice.h~sysfs-misc-device-support include/linux/miscdevice.h
--- 25/include/linux/miscdevice.h~sysfs-misc-device-support 2003-12-22 20:19:17.000000000 -0800
+++ 25-akpm/include/linux/miscdevice.h 2003-12-22 20:19:17.000000000 -0800
@@ -36,12 +36,15 @@
#define TUN_MINOR 200
+struct device;
+
struct miscdevice
{
int minor;
const char *name;
struct file_operations *fops;
struct list_head list;
+ struct device *dev;
char devfs_name[64];
};
_