// SPDX-License-Identifier: GPL-2.0 /* * 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. */ #include <linux/device/driver.h> #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 (!error && (dev = next_device(&i))) 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, const void *data, int (*match)(struct device *dev, const 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; if (!drv->bus->p) { pr_err("Driver '%s' was unable to register with bus_type '%s' because the bus was not initialized.\n", drv->name, drv->bus->name); return -EINVAL; } if ((drv->bus->probe && drv->probe) || (drv->bus->remove && drv->remove) || (drv->bus->shutdown && drv->shutdown)) pr_warn("Driver '%s' needs updating - please use " "bus_type methods\n", drv->name); other = driver_find(drv->name, drv->bus); if (other) { pr_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);