提交 23681e47 编写于 作者: G Greg Kroah-Hartman

[PATCH] Driver core: allow struct device to have a dev_t

This is the first step in moving class_device to being replaced by
struct device.  It allows struct device to export a dev_t and makes it
easy to dynamically create and destroy struct device as long as they are
associated with a specific class.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
上级 aa49b913
......@@ -142,6 +142,7 @@ int class_register(struct class * cls)
pr_debug("device class '%s': registering\n", cls->name);
INIT_LIST_HEAD(&cls->children);
INIT_LIST_HEAD(&cls->devices);
INIT_LIST_HEAD(&cls->interfaces);
init_MUTEX(&cls->sem);
error = kobject_set_name(&cls->subsys.kset.kobj, "%s", cls->name);
......
......@@ -15,6 +15,7 @@
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/kdev_t.h>
#include <asm/semaphore.h>
......@@ -98,6 +99,8 @@ static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
struct device *dev = to_dev(kobj);
if (dev->bus)
return 1;
if (dev->class)
return 1;
}
return 0;
}
......@@ -106,7 +109,11 @@ static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
{
struct device *dev = to_dev(kobj);
return dev->bus->name;
if (dev->bus)
return dev->bus->name;
if (dev->class)
return dev->class->name;
return NULL;
}
static int dev_uevent(struct kset *kset, struct kobject *kobj, char **envp,
......@@ -117,6 +124,16 @@ static int dev_uevent(struct kset *kset, struct kobject *kobj, char **envp,
int length = 0;
int retval = 0;
/* add the major/minor if present */
if (MAJOR(dev->devt)) {
add_uevent_var(envp, num_envp, &i,
buffer, buffer_size, &length,
"MAJOR=%u", MAJOR(dev->devt));
add_uevent_var(envp, num_envp, &i,
buffer, buffer_size, &length,
"MINOR=%u", MINOR(dev->devt));
}
/* add bus name of physical device */
if (dev->bus)
add_uevent_var(envp, num_envp, &i,
......@@ -161,6 +178,12 @@ static ssize_t store_uevent(struct device *dev, struct device_attribute *attr,
return count;
}
static ssize_t show_dev(struct device *dev, struct device_attribute *attr,
char *buf)
{
return print_dev_t(buf, dev->devt);
}
/*
* devices_subsys - structure to be registered with kobject core.
*/
......@@ -231,6 +254,7 @@ void device_initialize(struct device *dev)
klist_init(&dev->klist_children, klist_children_get,
klist_children_put);
INIT_LIST_HEAD(&dev->dma_pools);
INIT_LIST_HEAD(&dev->node);
init_MUTEX(&dev->sem);
device_init_wakeup(dev, 0);
}
......@@ -274,6 +298,31 @@ int device_add(struct device *dev)
dev->uevent_attr.store = store_uevent;
device_create_file(dev, &dev->uevent_attr);
if (MAJOR(dev->devt)) {
struct device_attribute *attr;
attr = kzalloc(sizeof(*attr), GFP_KERNEL);
if (!attr) {
error = -ENOMEM;
goto PMError;
}
attr->attr.name = "dev";
attr->attr.mode = S_IRUGO;
if (dev->driver)
attr->attr.owner = dev->driver->owner;
attr->show = show_dev;
error = device_create_file(dev, attr);
if (error) {
kfree(attr);
goto attrError;
}
dev->devt_attr = attr;
}
if (dev->class)
sysfs_create_link(&dev->class->subsys.kset.kobj, &dev->kobj,
dev->bus_id);
if ((error = device_pm_add(dev)))
goto PMError;
if ((error = bus_add_device(dev)))
......@@ -292,6 +341,11 @@ int device_add(struct device *dev)
BusError:
device_pm_remove(dev);
PMError:
if (dev->devt_attr) {
device_remove_file(dev, dev->devt_attr);
kfree(dev->devt_attr);
}
attrError:
kobject_uevent(&dev->kobj, KOBJ_REMOVE);
kobject_del(&dev->kobj);
Error:
......@@ -366,6 +420,10 @@ void device_del(struct device * dev)
if (parent)
klist_del(&dev->knode_parent);
if (dev->devt_attr)
device_remove_file(dev, dev->devt_attr);
if (dev->class)
sysfs_remove_link(&dev->class->subsys.kset.kobj, dev->bus_id);
device_remove_file(dev, &dev->uevent_attr);
/* Notify the platform of the removal, in case they
......@@ -450,3 +508,105 @@ EXPORT_SYMBOL_GPL(put_device);
EXPORT_SYMBOL_GPL(device_create_file);
EXPORT_SYMBOL_GPL(device_remove_file);
static void device_create_release(struct device *dev)
{
pr_debug("%s called for %s\n", __FUNCTION__, dev->bus_id);
kfree(dev);
}
/**
* device_create - creates a device and registers it with sysfs
* @cs: pointer to the struct class that this device should be registered to.
* @parent: pointer to the parent struct device of this new device, if any.
* @dev: the dev_t for the char device to be added.
* @fmt: string for the class device's name
*
* This function can be used by char device classes. A struct
* device will be created in sysfs, registered to the specified
* class.
* A "dev" file will be created, showing the dev_t for the device, if
* the dev_t is not 0,0.
* If a pointer to a parent struct device is passed in, the newly
* created struct device will be a child of that device in sysfs. The
* pointer to the struct 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 passed to this function must have previously
* been created with a call to class_create().
*/
struct device *device_create(struct class *class, struct device *parent,
dev_t devt, char *fmt, ...)
{
va_list args;
struct device *dev = NULL;
int retval = -ENODEV;
if (class == NULL || IS_ERR(class))
goto error;
if (parent == NULL) {
printk(KERN_WARNING "%s does not work yet for NULL parents\n", __FUNCTION__);
goto error;
}
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
if (!dev) {
retval = -ENOMEM;
goto error;
}
dev->devt = devt;
dev->class = class;
dev->parent = parent;
dev->release = device_create_release;
va_start(args, fmt);
vsnprintf(dev->bus_id, BUS_ID_SIZE, fmt, args);
va_end(args);
retval = device_register(dev);
if (retval)
goto error;
/* tie the class to the device */
down(&class->sem);
list_add_tail(&dev->node, &class->devices);
up(&class->sem);
return dev;
error:
kfree(dev);
return ERR_PTR(retval);
}
EXPORT_SYMBOL_GPL(device_create);
/**
* device_destroy - removes a device that was created with device_create()
* @class: the pointer to the struct class that this device was registered * with.
* @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_create()
*/
void device_destroy(struct class *class, dev_t devt)
{
struct device *dev = NULL;
struct device *dev_tmp;
down(&class->sem);
list_for_each_entry(dev_tmp, &class->devices, node) {
if (dev_tmp->devt == devt) {
dev = dev_tmp;
break;
}
}
up(&class->sem);
if (dev) {
list_del_init(&dev->node);
device_unregister(dev);
}
}
EXPORT_SYMBOL_GPL(device_destroy);
......@@ -142,6 +142,7 @@ struct class {
struct subsystem subsys;
struct list_head children;
struct list_head devices;
struct list_head interfaces;
struct semaphore sem; /* locks both the children and interfaces lists */
......@@ -305,6 +306,7 @@ struct device {
struct kobject kobj;
char bus_id[BUS_ID_SIZE]; /* position on parent bus */
struct device_attribute uevent_attr;
struct device_attribute *devt_attr;
struct semaphore sem; /* semaphore to synchronize calls to
* its driver.
......@@ -332,6 +334,11 @@ struct device {
struct dma_coherent_mem *dma_mem; /* internal for coherent mem
override */
/* class_device migration path */
struct list_head node;
struct class *class; /* optional*/
dev_t devt; /* dev_t, creates the sysfs "dev" */
void (*release)(struct device * dev);
};
......@@ -373,6 +380,13 @@ extern int device_attach(struct device * dev);
extern void driver_attach(struct device_driver * drv);
extern void device_reprobe(struct device *dev);
/*
* Easy functions for dynamically creating devices on the fly
*/
extern struct device *device_create(struct class *cls, struct device *parent,
dev_t devt, char *fmt, ...)
__attribute__((format(printf,4,5)));
extern void device_destroy(struct class *cls, dev_t devt);
/*
* Platform "fixup" functions - allow the platform to have their say
......
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