Subject: [PATCH] add class_simple support [01/10]
This patch adds a struct class_simple which can be used to create
"simple" class support for subsystems.
It also adds a class_release() callback for struct class, as it is
needed to properly handle the reference counting logic.
The following sysfs class patches all require this patch.
diff -Nru a/drivers/base/Makefile b/drivers/base/Makefile
--- a/drivers/base/Makefile Thu Jan 15 11:05:59 2004
+++ b/drivers/base/Makefile Thu Jan 15 11:05:59 2004
@@ -1,7 +1,7 @@
# Makefile for the Linux device tree
obj-y := core.o sys.o interface.o bus.o \
- driver.o class.o platform.o \
+ driver.o class.o class_simple.o platform.o \
cpu.o firmware.o init.o map.o
obj-y += power/
obj-$(CONFIG_FW_LOADER) += firmware_class.o
diff -Nru a/drivers/base/class.c b/drivers/base/class.c
--- a/drivers/base/class.c Thu Jan 15 11:06:02 2004
+++ b/drivers/base/class.c Thu Jan 15 11:06:02 2004
@@ -46,6 +46,19 @@
return ret;
}
+static void class_release(struct kobject * kobj)
+{
+ struct class *class = to_class(kobj);
+
+ pr_debug("class '%s': release.\n", class->name);
+
+ if (class->class_release)
+ class->class_release(class);
+ else
+ pr_debug("class '%s' does not have a release() function, "
+ "be careful\n", class->name);
+}
+
static struct sysfs_ops class_sysfs_ops = {
.show = class_attr_show,
.store = class_attr_store,
@@ -53,6 +66,7 @@
static struct kobj_type ktype_class = {
.sysfs_ops = &class_sysfs_ops,
+ .release = class_release,
};
/* Hotplug events for classes go to the class_obj subsys */
diff -Nru a/drivers/base/class_simple.c b/drivers/base/class_simple.c
--- /dev/null Wed Dec 31 16:00:00 1969
+++ b/drivers/base/class_simple.c Thu Jan 15 11:06:03 2004
@@ -0,0 +1,201 @@
+/*
+ * class_simple.c - a "simple" interface for classes for simple char devices.
+ *
+ * Copyright (c) 2003-2004 Greg Kroah-Hartman <greg@kroah.com>
+ * Copyright (c) 2003-2004 IBM Corp.
+ *
+ * This file is released under the GPLv2
+ *
+ */
+
+#define DEBUG 1
+
+#include <linux/device.h>
+#include <linux/kdev_t.h>
+#include <linux/err.h>
+
+struct class_simple {
+ struct class_device_attribute attr;
+ struct class class;
+};
+#define to_class_simple(d) container_of(d, struct class_simple, class)
+
+struct simple_dev {
+ struct list_head node;
+ dev_t dev;
+ struct class_device class_dev;
+};
+#define to_simple_dev(d) container_of(d, struct simple_dev, class_dev)
+
+static LIST_HEAD(simple_dev_list);
+static spinlock_t simple_dev_list_lock = SPIN_LOCK_UNLOCKED;
+
+static void release_simple_dev(struct class_device *class_dev)
+{
+ struct simple_dev *s_dev = to_simple_dev(class_dev);
+ kfree(s_dev);
+}
+
+static ssize_t show_dev(struct class_device *class_dev, char *buf)
+{
+ struct simple_dev *s_dev = to_simple_dev(class_dev);
+ return print_dev_t(buf, s_dev->dev);
+}
+
+static void class_simple_release(struct class *class)
+{
+ struct class_simple *cs = to_class_simple(class);
+ kfree(cs);
+}
+
+/**
+ * class_simple_create - create a struct class_simple structure
+ * @owner: pointer to the module that is to "own" this struct class_simple
+ * @name: pointer to a string for the name of this class.
+ *
+ * This is used to create a struct class_simple pointer that can then be used
+ * in calls to class_simple_device_add(). This is used when you do not wish to
+ * create a full blown class support for a type of char devices.
+ *
+ * Note, the pointer created here is to be destroyed when finished by making a
+ * call to class_simple_destroy().
+ */
+struct class_simple *class_simple_create(struct module *owner, char *name)
+{
+ struct class_simple *cs;
+ int retval;
+
+ cs = kmalloc(sizeof(*cs), GFP_KERNEL);
+ if (!cs) {
+ retval = -ENOMEM;
+ goto error;
+ }
+ memset(cs, 0x00, sizeof(*cs));
+
+ cs->class.name = name;
+ cs->class.class_release = class_simple_release;
+ cs->class.release = release_simple_dev;
+
+ cs->attr.attr.name = "dev";
+ cs->attr.attr.mode = S_IRUGO;
+ cs->attr.attr.owner = owner;
+ cs->attr.show = show_dev;
+ cs->attr.store = NULL;
+
+ retval = class_register(&cs->class);
+ if (retval)
+ goto error;
+
+ return cs;
+
+error:
+ kfree(cs);
+ return ERR_PTR(retval);
+}
+EXPORT_SYMBOL(class_simple_create);
+
+/**
+ * class_simple_destroy - destroys a struct class_simple structure
+ * @cs: pointer to the struct class_simple that is to be destroyed
+ *
+ * Note, the pointer to be destroyed must have been created with a call to
+ * class_simple_create().
+ */
+void class_simple_destroy(struct class_simple *cs)
+{
+ if ((cs == NULL) || (IS_ERR(cs)))
+ return;
+
+ class_unregister(&cs->class);
+}
+EXPORT_SYMBOL(class_simple_destroy);
+
+/**
+ * class_simple_device_add - adds a class device to sysfs for a character driver
+ * @cs: pointer to the struct class_simple that this device should be registered to.
+ * @dev: the dev_t for the device to be added.
+ * @device: a pointer to a struct device that is assiociated with this class device.
+ * @fmt: string for the class device's name
+ *
+ * This function can be used by simple char device classes that do not
+ * implement their own class device registration. A struct class_device will
+ * be created in sysfs, registered to the specified class. A "dev" file will
+ * be created, showing the dev_t for the device. The pointer to the struct
+ * class_device will be returned from the call. Any further sysfs files that
+ * might be required can be created using this pointer.
+ * Note: the struct class_device passed to this function must have previously been
+ * created with a call to class_simple_create().
+ */
+struct class_device *class_simple_device_add(struct class_simple *cs, dev_t dev, struct device *device, const char *fmt, ...)
+{
+ va_list args;
+ struct simple_dev *s_dev = NULL;
+ int retval;
+
+ if ((cs == NULL) || (IS_ERR(cs))) {
+ retval = -ENODEV;
+ goto error;
+ }
+
+ s_dev = kmalloc(sizeof(*s_dev), GFP_KERNEL);
+ if (!s_dev) {
+ retval = -ENOMEM;
+ goto error;
+ }
+ memset(s_dev, 0x00, sizeof(*s_dev));
+
+ s_dev->dev = dev;
+ s_dev->class_dev.dev = device;
+ s_dev->class_dev.class = &cs->class;
+
+ va_start(args,fmt);
+ vsnprintf(s_dev->class_dev.class_id, BUS_ID_SIZE, fmt, args);
+ va_end(args);
+ retval = class_device_register(&s_dev->class_dev);
+ if (retval)
+ goto error;
+
+ class_device_create_file(&s_dev->class_dev, &cs->attr);
+
+ spin_lock(&simple_dev_list_lock);
+ list_add(&s_dev->node, &simple_dev_list);
+ spin_unlock(&simple_dev_list_lock);
+
+ return &s_dev->class_dev;
+
+error:
+ kfree(s_dev);
+ return ERR_PTR(retval);
+}
+EXPORT_SYMBOL(class_simple_device_add);
+
+/**
+ * class_simple_device_remove - removes a class device that was created with class_simple_device_add()
+ * @dev: the dev_t of the device that was previously registered.
+ *
+ * This call unregisters and cleans up a class device that was created with a
+ * call to class_device_simple_add()
+ */
+void class_simple_device_remove(dev_t dev)
+{
+ struct simple_dev *s_dev = NULL;
+ struct list_head *tmp;
+ int found = 0;
+
+ spin_lock(&simple_dev_list_lock);
+ list_for_each(tmp, &simple_dev_list) {
+ s_dev = list_entry(tmp, struct simple_dev, node);
+ if (s_dev->dev == dev) {
+ found = 1;
+ break;
+ }
+ }
+ if (found) {
+ list_del(&s_dev->node);
+ spin_unlock(&simple_dev_list_lock);
+ class_device_unregister(&s_dev->class_dev);
+ } else {
+ spin_unlock(&simple_dev_list_lock);
+ }
+}
+EXPORT_SYMBOL(class_simple_device_remove);
diff -Nru a/include/linux/device.h b/include/linux/device.h
--- a/include/linux/device.h Thu Jan 15 11:05:58 2004
+++ b/include/linux/device.h Thu Jan 15 11:05:58 2004
@@ -46,6 +46,7 @@
struct device_driver;
struct class;
struct class_device;
+struct class_simple;
struct bus_type {
char * name;
@@ -155,6 +156,7 @@
int num_envp, char *buffer, int buffer_size);
void (*release)(struct class_device *dev);
+ void (*class_release)(struct class *class);
};
extern int class_register(struct class *);
@@ -246,6 +248,13 @@
extern int class_interface_register(struct class_interface *);
extern void class_interface_unregister(struct class_interface *);
+/* interface for class simple stuff */
+extern struct class_simple *class_simple_create(struct module *owner, char *name);
+extern void class_simple_destroy(struct class_simple *cs);
+extern struct class_device *class_simple_device_add(struct class_simple *cs, dev_t dev, struct device *device, const char *fmt, ...)
+ __attribute__((format(printf,4,5)));
+extern void class_simple_device_remove(dev_t dev);
+
struct device {
struct list_head node; /* node in sibling list */