diff options
Diffstat (limited to 'kernel/drivers/base/driver.c')
| -rw-r--r-- | kernel/drivers/base/driver.c | 224 |
1 files changed, 224 insertions, 0 deletions
diff --git a/kernel/drivers/base/driver.c b/kernel/drivers/base/driver.c new file mode 100644 index 000000000..4eabfe28d --- /dev/null +++ b/kernel/drivers/base/driver.c @@ -0,0 +1,224 @@ +/* + * driver.c - centralized device driver management + * + * Copyright (c) 2002-3 Patrick Mochel + * Copyright (c) 2002-3 Open Source Development Labs + * Copyright (c) 2007 Greg Kroah-Hartman <gregkh@suse.de> + * Copyright (c) 2007 Novell Inc. + * + * This file is released under the GPLv2 + * + */ + +#include <linux/device.h> +#include <linux/module.h> +#include <linux/errno.h> +#include <linux/slab.h> +#include <linux/string.h> +#include <linux/sysfs.h> +#include "base.h" + +static struct device *next_device(struct klist_iter *i) +{ + struct klist_node *n = klist_next(i); + struct device *dev = NULL; + struct device_private *dev_prv; + + if (n) { + dev_prv = to_device_private_driver(n); + dev = dev_prv->device; + } + return dev; +} + +/** + * driver_for_each_device - Iterator for devices bound to a driver. + * @drv: Driver we're iterating. + * @start: Device to begin with + * @data: Data to pass to the callback. + * @fn: Function to call for each device. + * + * Iterate over the @drv's list of devices calling @fn for each one. + */ +int driver_for_each_device(struct device_driver *drv, struct device *start, + void *data, int (*fn)(struct device *, void *)) +{ + struct klist_iter i; + struct device *dev; + int error = 0; + + if (!drv) + return -EINVAL; + + klist_iter_init_node(&drv->p->klist_devices, &i, + start ? &start->p->knode_driver : NULL); + while ((dev = next_device(&i)) && !error) + error = fn(dev, data); + klist_iter_exit(&i); + return error; +} +EXPORT_SYMBOL_GPL(driver_for_each_device); + +/** + * driver_find_device - device iterator for locating a particular device. + * @drv: The device's driver + * @start: Device to begin with + * @data: Data to pass to match function + * @match: Callback function to check device + * + * This is similar to the driver_for_each_device() function above, but + * it returns a reference to a device that is 'found' for later use, as + * determined by the @match callback. + * + * The callback should return 0 if the device doesn't match and non-zero + * if it does. If the callback returns non-zero, this function will + * return to the caller and not iterate over any more devices. + */ +struct device *driver_find_device(struct device_driver *drv, + struct device *start, void *data, + int (*match)(struct device *dev, void *data)) +{ + struct klist_iter i; + struct device *dev; + + if (!drv || !drv->p) + return NULL; + + klist_iter_init_node(&drv->p->klist_devices, &i, + (start ? &start->p->knode_driver : NULL)); + while ((dev = next_device(&i))) + if (match(dev, data) && get_device(dev)) + break; + klist_iter_exit(&i); + return dev; +} +EXPORT_SYMBOL_GPL(driver_find_device); + +/** + * driver_create_file - create sysfs file for driver. + * @drv: driver. + * @attr: driver attribute descriptor. + */ +int driver_create_file(struct device_driver *drv, + const struct driver_attribute *attr) +{ + int error; + + if (drv) + error = sysfs_create_file(&drv->p->kobj, &attr->attr); + else + error = -EINVAL; + return error; +} +EXPORT_SYMBOL_GPL(driver_create_file); + +/** + * driver_remove_file - remove sysfs file for driver. + * @drv: driver. + * @attr: driver attribute descriptor. + */ +void driver_remove_file(struct device_driver *drv, + const struct driver_attribute *attr) +{ + if (drv) + sysfs_remove_file(&drv->p->kobj, &attr->attr); +} +EXPORT_SYMBOL_GPL(driver_remove_file); + +int driver_add_groups(struct device_driver *drv, + const struct attribute_group **groups) +{ + return sysfs_create_groups(&drv->p->kobj, groups); +} + +void driver_remove_groups(struct device_driver *drv, + const struct attribute_group **groups) +{ + sysfs_remove_groups(&drv->p->kobj, groups); +} + +/** + * driver_register - register driver with bus + * @drv: driver to register + * + * We pass off most of the work to the bus_add_driver() call, + * since most of the things we have to do deal with the bus + * structures. + */ +int driver_register(struct device_driver *drv) +{ + int ret; + struct device_driver *other; + + BUG_ON(!drv->bus->p); + + if ((drv->bus->probe && drv->probe) || + (drv->bus->remove && drv->remove) || + (drv->bus->shutdown && drv->shutdown)) + printk(KERN_WARNING "Driver '%s' needs updating - please use " + "bus_type methods\n", drv->name); + + other = driver_find(drv->name, drv->bus); + if (other) { + printk(KERN_ERR "Error: Driver '%s' is already registered, " + "aborting...\n", drv->name); + return -EBUSY; + } + + ret = bus_add_driver(drv); + if (ret) + return ret; + ret = driver_add_groups(drv, drv->groups); + if (ret) { + bus_remove_driver(drv); + return ret; + } + kobject_uevent(&drv->p->kobj, KOBJ_ADD); + + return ret; +} +EXPORT_SYMBOL_GPL(driver_register); + +/** + * driver_unregister - remove driver from system. + * @drv: driver. + * + * Again, we pass off most of the work to the bus-level call. + */ +void driver_unregister(struct device_driver *drv) +{ + if (!drv || !drv->p) { + WARN(1, "Unexpected driver unregister!\n"); + return; + } + driver_remove_groups(drv, drv->groups); + bus_remove_driver(drv); +} +EXPORT_SYMBOL_GPL(driver_unregister); + +/** + * driver_find - locate driver on a bus by its name. + * @name: name of the driver. + * @bus: bus to scan for the driver. + * + * Call kset_find_obj() to iterate over list of drivers on + * a bus to find driver by name. Return driver if found. + * + * This routine provides no locking to prevent the driver it returns + * from being unregistered or unloaded while the caller is using it. + * The caller is responsible for preventing this. + */ +struct device_driver *driver_find(const char *name, struct bus_type *bus) +{ + struct kobject *k = kset_find_obj(bus->p->drivers_kset, name); + struct driver_private *priv; + + if (k) { + /* Drop reference added by kset_find_obj() */ + kobject_put(k); + priv = to_driver(k); + return priv->driver; + } + return NULL; +} +EXPORT_SYMBOL_GPL(driver_find); |