driver.h

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * The driver-specific portions of the driver model
  4 *
  5 * Copyright (c) 2001-2003 Patrick Mochel <mochel@osdl.org>
  6 * Copyright (c) 2004-2009 Greg Kroah-Hartman <gregkh@suse.de>
  7 * Copyright (c) 2008-2009 Novell Inc.
  8 * Copyright (c) 2012-2019 Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  9 * Copyright (c) 2012-2019 Linux Foundation
 10 *
 11 * See Documentation/driver-api/driver-model/ for more information.
 12 */
 13
 14#ifndef _DEVICE_DRIVER_H_
 15#define _DEVICE_DRIVER_H_
 16
 17#include <linux/kobject.h>
 18#include <linux/klist.h>
 19#include <linux/pm.h>
 20#include <linux/device/bus.h>
 21#include <linux/module.h>
 22
 23/**
 24 * enum probe_type - device driver probe type to try
 25 *	Device drivers may opt in for special handling of their
 26 *	respective probe routines. This tells the core what to
 27 *	expect and prefer.
 28 *
 29 * @PROBE_DEFAULT_STRATEGY: Used by drivers that work equally well
 30 *	whether probed synchronously or asynchronously.
 31 * @PROBE_PREFER_ASYNCHRONOUS: Drivers for "slow" devices which
 32 *	probing order is not essential for booting the system may
 33 *	opt into executing their probes asynchronously.
 34 * @PROBE_FORCE_SYNCHRONOUS: Use this to annotate drivers that need
 35 *	their probe routines to run synchronously with driver and
 36 *	device registration (with the exception of -EPROBE_DEFER
 37 *	handling - re-probing always ends up being done asynchronously).
 38 *
 39 * Note that the end goal is to switch the kernel to use asynchronous
 40 * probing by default, so annotating drivers with
 41 * %PROBE_PREFER_ASYNCHRONOUS is a temporary measure that allows us
 42 * to speed up boot process while we are validating the rest of the
 43 * drivers.
 44 */
 45enum probe_type {
 46	PROBE_DEFAULT_STRATEGY,
 47	PROBE_PREFER_ASYNCHRONOUS,
 48	PROBE_FORCE_SYNCHRONOUS,
 49};
 50
 51/**
 52 * struct device_driver - The basic device driver structure
 53 * @name:	Name of the device driver.
 54 * @bus:	The bus which the device of this driver belongs to.
 55 * @owner:	The module owner.
 56 * @mod_name:	Used for built-in modules.
 57 * @suppress_bind_attrs: Disables bind/unbind via sysfs.
 58 * @probe_type:	Type of the probe (synchronous or asynchronous) to use.
 59 * @of_match_table: The open firmware table.
 60 * @acpi_match_table: The ACPI match table.
 61 * @probe:	Called to query the existence of a specific device,
 62 *		whether this driver can work with it, and bind the driver
 63 *		to a specific device.
 64 * @sync_state:	Called to sync device state to software state after all the
 65 *		state tracking consumers linked to this device (present at
 66 *		the time of late_initcall) have successfully bound to a
 67 *		driver. If the device has no consumers, this function will
 68 *		be called at late_initcall_sync level. If the device has
 69 *		consumers that are never bound to a driver, this function
 70 *		will never get called until they do.
 71 * @remove:	Called when the device is removed from the system to
 72 *		unbind a device from this driver.
 73 * @shutdown:	Called at shut-down time to quiesce the device.
 74 * @suspend:	Called to put the device to sleep mode. Usually to a
 75 *		low power state.
 76 * @resume:	Called to bring a device from sleep mode.
 77 * @groups:	Default attributes that get created by the driver core
 78 *		automatically.
 79 * @dev_groups:	Additional attributes attached to device instance once
 80 *		it is bound to the driver.
 81 * @pm:		Power management operations of the device which matched
 82 *		this driver.
 83 * @coredump:	Called when sysfs entry is written to. The device driver
 84 *		is expected to call the dev_coredump API resulting in a
 85 *		uevent.
 86 * @p:		Driver core's private data, no one other than the driver
 87 *		core can touch this.
 88 * @p_cb:	Callbacks private to the driver core; no one other than the
 89 *		driver core is allowed to touch this.
 90 *
 91 * The device driver-model tracks all of the drivers known to the system.
 92 * The main reason for this tracking is to enable the driver core to match
 93 * up drivers with new devices. Once drivers are known objects within the
 94 * system, however, a number of other things become possible. Device drivers
 95 * can export information and configuration variables that are independent
 96 * of any specific device.
 97 */
 98struct device_driver {
 99	const char		*name;
100	const struct bus_type	*bus;
101
102	struct module		*owner;
103	const char		*mod_name;	/* used for built-in modules */
104
105	bool suppress_bind_attrs;	/* disables bind/unbind via sysfs */
106	enum probe_type probe_type;
107
108	const struct of_device_id	*of_match_table;
109	const struct acpi_device_id	*acpi_match_table;
110
111	int (*probe) (struct device *dev);
112	void (*sync_state)(struct device *dev);
113	int (*remove) (struct device *dev);
114	void (*shutdown) (struct device *dev);
115	int (*suspend) (struct device *dev, pm_message_t state);
116	int (*resume) (struct device *dev);
117	const struct attribute_group **groups;
118	const struct attribute_group **dev_groups;
119
120	const struct dev_pm_ops *pm;
121	void (*coredump) (struct device *dev);
122
123	struct driver_private *p;
124	struct {
125		/*
126		 * Called after remove() and after all devres entries have been
127		 * processed. This is a Rust only callback.
128		 */
129		void (*post_unbind_rust)(struct device *dev);
130	} p_cb;
131};
132
133
134int __must_check driver_register(struct device_driver *drv);
135void driver_unregister(struct device_driver *drv);
136
137struct device_driver *driver_find(const char *name, const struct bus_type *bus);
138bool __init driver_probe_done(void);
139void wait_for_device_probe(void);
140void __init wait_for_init_devices_probe(void);
141
142/* sysfs interface for exporting driver attributes */
143
144struct driver_attribute {
145	struct attribute attr;
146	ssize_t (*show)(struct device_driver *driver, char *buf);
147	ssize_t (*store)(struct device_driver *driver, const char *buf,
148			 size_t count);
149};
150
151#define DRIVER_ATTR_RW(_name) \
152	struct driver_attribute driver_attr_##_name = __ATTR_RW(_name)
153#define DRIVER_ATTR_RO(_name) \
154	struct driver_attribute driver_attr_##_name = __ATTR_RO(_name)
155#define DRIVER_ATTR_WO(_name) \
156	struct driver_attribute driver_attr_##_name = __ATTR_WO(_name)
157
158int __must_check driver_create_file(const struct device_driver *driver,
159				    const struct driver_attribute *attr);
160void driver_remove_file(const struct device_driver *driver,
161			const struct driver_attribute *attr);
162
163int driver_set_override(struct device *dev, const char **override,
164			const char *s, size_t len);
165int __must_check driver_for_each_device(struct device_driver *drv, struct device *start,
166					void *data, device_iter_t fn);
167struct device *driver_find_device(const struct device_driver *drv,
168				  struct device *start, const void *data,
169				  device_match_t match);
170
171/**
172 * driver_find_device_by_name - device iterator for locating a particular device
173 * of a specific name.
174 * @drv: the driver we're iterating
175 * @name: name of the device to match
176 */
177static inline struct device *driver_find_device_by_name(const struct device_driver *drv,
178							const char *name)
179{
180	return driver_find_device(drv, NULL, name, device_match_name);
181}
182
183/**
184 * driver_find_device_by_of_node- device iterator for locating a particular device
185 * by of_node pointer.
186 * @drv: the driver we're iterating
187 * @np: of_node pointer to match.
188 */
189static inline struct device *
190driver_find_device_by_of_node(const struct device_driver *drv,
191			      const struct device_node *np)
192{
193	return driver_find_device(drv, NULL, np, device_match_of_node);
194}
195
196/**
197 * driver_find_device_by_fwnode- device iterator for locating a particular device
198 * by fwnode pointer.
199 * @drv: the driver we're iterating
200 * @fwnode: fwnode pointer to match.
201 */
202static inline struct device *
203driver_find_device_by_fwnode(struct device_driver *drv,
204			     const struct fwnode_handle *fwnode)
205{
206	return driver_find_device(drv, NULL, fwnode, device_match_fwnode);
207}
208
209/**
210 * driver_find_device_by_devt- device iterator for locating a particular device
211 * by devt.
212 * @drv: the driver we're iterating
213 * @devt: devt pointer to match.
214 */
215static inline struct device *driver_find_device_by_devt(const struct device_driver *drv,
216							dev_t devt)
217{
218	return driver_find_device(drv, NULL, &devt, device_match_devt);
219}
220
221static inline struct device *driver_find_next_device(const struct device_driver *drv,
222						     struct device *start)
223{
224	return driver_find_device(drv, start, NULL, device_match_any);
225}
226
227#ifdef CONFIG_ACPI
228/**
229 * driver_find_device_by_acpi_dev : device iterator for locating a particular
230 * device matching the ACPI_COMPANION device.
231 * @drv: the driver we're iterating
232 * @adev: ACPI_COMPANION device to match.
233 */
234static inline struct device *
235driver_find_device_by_acpi_dev(const struct device_driver *drv,
236			       const struct acpi_device *adev)
237{
238	return driver_find_device(drv, NULL, adev, device_match_acpi_dev);
239}
240#else
241static inline struct device *
242driver_find_device_by_acpi_dev(const struct device_driver *drv, const void *adev)
243{
244	return NULL;
245}
246#endif
247
248void driver_deferred_probe_add(struct device *dev);
249int driver_deferred_probe_check_state(struct device *dev);
250void driver_init(void);
251
252/**
253 * module_driver() - Helper macro for drivers that don't do anything
254 * special in module init/exit. This eliminates a lot of boilerplate.
255 * Each module may only use this macro once, and calling it replaces
256 * module_init() and module_exit().
257 *
258 * @__driver: driver name
259 * @__register: register function for this driver type
260 * @__unregister: unregister function for this driver type
261 * @...: Additional arguments to be passed to __register and __unregister.
262 *
263 * Use this macro to construct bus specific macros for registering
264 * drivers, and do not use it on its own.
265 */
266#define module_driver(__driver, __register, __unregister, ...) \
267static int __init __driver##_init(void) \
268{ \
269	return __register(&(__driver) , ##__VA_ARGS__); \
270} \
271module_init(__driver##_init); \
272static void __exit __driver##_exit(void) \
273{ \
274	__unregister(&(__driver) , ##__VA_ARGS__); \
275} \
276module_exit(__driver##_exit);
277
278/**
279 * builtin_driver() - Helper macro for drivers that don't do anything
280 * special in init and have no exit. This eliminates some boilerplate.
281 * Each driver may only use this macro once, and calling it replaces
282 * device_initcall (or in some cases, the legacy __initcall).  This is
283 * meant to be a direct parallel of module_driver() above but without
284 * the __exit stuff that is not used for builtin cases.
285 *
286 * @__driver: driver name
287 * @__register: register function for this driver type
288 * @...: Additional arguments to be passed to __register
289 *
290 * Use this macro to construct bus specific macros for registering
291 * drivers, and do not use it on its own.
292 */
293#define builtin_driver(__driver, __register, ...) \
294static int __init __driver##_init(void) \
295{ \
296	return __register(&(__driver) , ##__VA_ARGS__); \
297} \
298device_initcall(__driver##_init);
299
300#endif	/* _DEVICE_DRIVER_H_ */