Driver core: udev triggered device-<>driver binding
We get two per-bus sysfs files:
ls-l /sys/subsystem/usb
drwxr-xr-x 2 root root 0 2007-02-16 16:42 devices
drwxr-xr-x 7 root root 0 2007-02-16 14:55 drivers
-rw-r--r-- 1 root root 4096 2007-02-16 16:42 drivers_autoprobe
--w------- 1 root root 4096 2007-02-16 16:42 drivers_probe
The flag "drivers_autoprobe" controls the behavior of the bus to bind
devices by default, or just initialize the device and leave it alone.
The command "drivers_probe" accepts a bus_id and the bus tries to bind a
driver to this device.
Systems who want to control the driver binding with udev, switch off the
bus initiated probing:
echo 0 > /sys/subsystem/usb/drivers_autoprobe
echo 0 > /sys/subsystem/pcmcia/drivers_autoprobe
...
and initiate the probing with udev rules like:
ACTION=="add", SUBSYSTEM=="usb", ATTR{subsystem/drivers_probe}="$kernel"
ACTION=="add", SUBSYSTEM=="pcmcia", ATTR{subsystem/drivers_probe}="$kernel"
...
Custom driver binding can happen in earlier rules by something like:
ACTION=="add", SUBSYSTEM=="usb", \
ATTRS{idVendor}=="1234", ATTRS{idProduct}=="5678" \
ATTR{subsystem/drivers/<custom-driver>/bind}="$kernel"
This is intended to solve the modprobe.conf mess with "install-rules", custom
bind/unbind-scripts and all the weird things people invented over the years.
It should also provide the functionality "libusual" was supposed to do.
With udev, one can just write a udev rule to drive all USB-disks at the
third port of USB-hub by the "ub" driver, and everything else by
usb-storage. One can also instruct udev to bind different wireless
drivers to identical cards - just selected by the pcmcia slot-number, and
whatever ...
To use the mentioned rules, it needs udev version 106, to be able to
write ATTR{}="$kernel" to sysfs files.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Kay Sievers
Greg Kroah-Hartman
Родитель
a456b7023e
Коммит
b8c5cec23d
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@ -27,6 +27,9 @@
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#define to_driver(obj) container_of(obj, struct device_driver, kobj)
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static int __must_check bus_rescan_devices_helper(struct device *dev,
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void *data);
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static ssize_t
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drv_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
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{
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@ -133,7 +136,6 @@ static decl_subsys(bus, &ktype_bus, NULL);
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#ifdef CONFIG_HOTPLUG
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/* Manually detach a device from its associated driver. */
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static int driver_helper(struct device *dev, void *data)
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{
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@ -199,6 +201,33 @@ static ssize_t driver_bind(struct device_driver *drv,
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}
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static DRIVER_ATTR(bind, S_IWUSR, NULL, driver_bind);
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static ssize_t show_drivers_autoprobe(struct bus_type *bus, char *buf)
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{
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return sprintf(buf, "%d\n", bus->drivers_autoprobe);
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}
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static ssize_t store_drivers_autoprobe(struct bus_type *bus,
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const char *buf, size_t count)
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{
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if (buf[0] == '0')
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bus->drivers_autoprobe = 0;
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else
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bus->drivers_autoprobe = 1;
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return count;
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}
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static ssize_t store_drivers_probe(struct bus_type *bus,
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const char *buf, size_t count)
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{
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struct device *dev;
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dev = bus_find_device(bus, NULL, (void *)buf, driver_helper);
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if (!dev)
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return -ENODEV;
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if (bus_rescan_devices_helper(dev, NULL) != 0)
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return -EINVAL;
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return count;
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}
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#endif
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static struct device * next_device(struct klist_iter * i)
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@ -425,7 +454,8 @@ int bus_attach_device(struct device * dev)
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if (bus) {
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dev->is_registered = 1;
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ret = device_attach(dev);
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if (bus->drivers_autoprobe)
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ret = device_attach(dev);
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if (ret >= 0) {
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klist_add_tail(&dev->knode_bus, &bus->klist_devices);
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ret = 0;
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@ -515,9 +545,41 @@ static void remove_bind_files(struct device_driver *drv)
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driver_remove_file(drv, &driver_attr_bind);
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driver_remove_file(drv, &driver_attr_unbind);
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}
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static int add_probe_files(struct bus_type *bus)
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{
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int retval;
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bus->drivers_probe_attr.attr.name = "drivers_probe";
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bus->drivers_probe_attr.attr.mode = S_IWUSR;
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bus->drivers_probe_attr.attr.owner = bus->owner;
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bus->drivers_probe_attr.store = store_drivers_probe;
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retval = bus_create_file(bus, &bus->drivers_probe_attr);
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if (retval)
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goto out;
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bus->drivers_autoprobe_attr.attr.name = "drivers_autoprobe";
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bus->drivers_autoprobe_attr.attr.mode = S_IWUSR | S_IRUGO;
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bus->drivers_autoprobe_attr.attr.owner = bus->owner;
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bus->drivers_autoprobe_attr.show = show_drivers_autoprobe;
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bus->drivers_autoprobe_attr.store = store_drivers_autoprobe;
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retval = bus_create_file(bus, &bus->drivers_autoprobe_attr);
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if (retval)
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bus_remove_file(bus, &bus->drivers_probe_attr);
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out:
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return retval;
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}
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static void remove_probe_files(struct bus_type *bus)
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{
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bus_remove_file(bus, &bus->drivers_autoprobe_attr);
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bus_remove_file(bus, &bus->drivers_probe_attr);
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}
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#else
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static inline int add_bind_files(struct device_driver *drv) { return 0; }
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static inline void remove_bind_files(struct device_driver *drv) {}
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static inline int add_probe_files(struct bus_type *bus) { return 0; }
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static inline void remove_probe_files(struct bus_type *bus) {}
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#endif
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/**
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@ -541,9 +603,11 @@ int bus_add_driver(struct device_driver *drv)
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if ((error = kobject_register(&drv->kobj)))
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goto out_put_bus;
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error = driver_attach(drv);
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if (error)
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goto out_unregister;
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if (drv->bus->drivers_autoprobe) {
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error = driver_attach(drv);
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if (error)
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goto out_unregister;
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}
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klist_add_tail(&drv->knode_bus, &bus->klist_drivers);
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module_add_driver(drv->owner, drv);
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@ -762,6 +826,12 @@ int bus_register(struct bus_type * bus)
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klist_init(&bus->klist_devices, klist_devices_get, klist_devices_put);
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klist_init(&bus->klist_drivers, NULL, NULL);
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bus->drivers_autoprobe = 1;
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retval = add_probe_files(bus);
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if (retval)
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goto bus_probe_files_fail;
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retval = bus_add_attrs(bus);
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if (retval)
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goto bus_attrs_fail;
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@ -770,6 +840,8 @@ int bus_register(struct bus_type * bus)
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return 0;
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bus_attrs_fail:
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remove_probe_files(bus);
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bus_probe_files_fail:
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kset_unregister(&bus->drivers);
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bus_drivers_fail:
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kset_unregister(&bus->devices);
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@ -779,7 +851,6 @@ out:
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return retval;
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}
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/**
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* bus_unregister - remove a bus from the system
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* @bus: bus.
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@ -791,6 +862,7 @@ void bus_unregister(struct bus_type * bus)
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{
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pr_debug("bus %s: unregistering\n", bus->name);
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bus_remove_attrs(bus);
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remove_probe_files(bus);
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kset_unregister(&bus->drivers);
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kset_unregister(&bus->devices);
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subsystem_unregister(&bus->subsys);
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@ -34,9 +34,24 @@ struct device;
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struct device_driver;
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struct class;
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struct class_device;
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struct bus_type;
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struct bus_attribute {
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struct attribute attr;
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ssize_t (*show)(struct bus_type *, char * buf);
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ssize_t (*store)(struct bus_type *, const char * buf, size_t count);
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};
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#define BUS_ATTR(_name,_mode,_show,_store) \
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struct bus_attribute bus_attr_##_name = __ATTR(_name,_mode,_show,_store)
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extern int __must_check bus_create_file(struct bus_type *,
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struct bus_attribute *);
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extern void bus_remove_file(struct bus_type *, struct bus_attribute *);
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struct bus_type {
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const char * name;
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struct module * owner;
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struct subsystem subsys;
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struct kset drivers;
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@ -49,6 +64,8 @@ struct bus_type {
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struct bus_attribute * bus_attrs;
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struct device_attribute * dev_attrs;
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struct driver_attribute * drv_attrs;
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struct bus_attribute drivers_autoprobe_attr;
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struct bus_attribute drivers_probe_attr;
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int (*match)(struct device * dev, struct device_driver * drv);
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int (*uevent)(struct device *dev, char **envp,
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@ -61,6 +78,8 @@ struct bus_type {
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int (*suspend_late)(struct device * dev, pm_message_t state);
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int (*resume_early)(struct device * dev);
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int (*resume)(struct device * dev);
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unsigned int drivers_autoprobe:1;
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};
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extern int __must_check bus_register(struct bus_type * bus);
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@ -102,21 +121,6 @@ extern int bus_unregister_notifier(struct bus_type *bus,
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#define BUS_NOTIFY_UNBIND_DRIVER 0x00000004 /* driver about to be
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unbound */
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/* sysfs interface for exporting bus attributes */
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struct bus_attribute {
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struct attribute attr;
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ssize_t (*show)(struct bus_type *, char * buf);
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ssize_t (*store)(struct bus_type *, const char * buf, size_t count);
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};
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#define BUS_ATTR(_name,_mode,_show,_store) \
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struct bus_attribute bus_attr_##_name = __ATTR(_name,_mode,_show,_store)
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extern int __must_check bus_create_file(struct bus_type *,
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struct bus_attribute *);
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extern void bus_remove_file(struct bus_type *, struct bus_attribute *);
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struct device_driver {
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const char * name;
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struct bus_type * bus;
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