1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (c) 2019-2020 Intel Corporation
5 * Please see Documentation/driver-api/auxiliary_bus.rst for more information.
8 #define pr_fmt(fmt) "%s:%s: " fmt, KBUILD_MODNAME, __func__
10 #include <linux/device.h>
11 #include <linux/init.h>
12 #include <linux/slab.h>
13 #include <linux/module.h>
14 #include <linux/pm_domain.h>
15 #include <linux/pm_runtime.h>
16 #include <linux/string.h>
17 #include <linux/auxiliary_bus.h>
20 static const struct auxiliary_device_id *auxiliary_match_id(const struct auxiliary_device_id *id,
21 const struct auxiliary_device *auxdev)
23 for (; id->name[0]; id++) {
24 const char *p = strrchr(dev_name(&auxdev->dev), '.');
29 match_size = p - dev_name(&auxdev->dev);
31 /* use dev_name(&auxdev->dev) prefix before last '.' char to match to */
32 if (strlen(id->name) == match_size &&
33 !strncmp(dev_name(&auxdev->dev), id->name, match_size))
39 static int auxiliary_match(struct device *dev, struct device_driver *drv)
41 struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
42 struct auxiliary_driver *auxdrv = to_auxiliary_drv(drv);
44 return !!auxiliary_match_id(auxdrv->id_table, auxdev);
47 static int auxiliary_uevent(struct device *dev, struct kobj_uevent_env *env)
52 p = strrchr(name, '.');
54 return add_uevent_var(env, "MODALIAS=%s%.*s", AUXILIARY_MODULE_PREFIX,
55 (int)(p - name), name);
58 static const struct dev_pm_ops auxiliary_dev_pm_ops = {
59 SET_RUNTIME_PM_OPS(pm_generic_runtime_suspend, pm_generic_runtime_resume, NULL)
60 SET_SYSTEM_SLEEP_PM_OPS(pm_generic_suspend, pm_generic_resume)
63 static int auxiliary_bus_probe(struct device *dev)
65 struct auxiliary_driver *auxdrv = to_auxiliary_drv(dev->driver);
66 struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
69 ret = dev_pm_domain_attach(dev, true);
71 dev_warn(dev, "Failed to attach to PM Domain : %d\n", ret);
75 ret = auxdrv->probe(auxdev, auxiliary_match_id(auxdrv->id_table, auxdev));
77 dev_pm_domain_detach(dev, true);
82 static void auxiliary_bus_remove(struct device *dev)
84 struct auxiliary_driver *auxdrv = to_auxiliary_drv(dev->driver);
85 struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
88 auxdrv->remove(auxdev);
89 dev_pm_domain_detach(dev, true);
92 static void auxiliary_bus_shutdown(struct device *dev)
94 struct auxiliary_driver *auxdrv = NULL;
95 struct auxiliary_device *auxdev;
98 auxdrv = to_auxiliary_drv(dev->driver);
99 auxdev = to_auxiliary_dev(dev);
102 if (auxdrv && auxdrv->shutdown)
103 auxdrv->shutdown(auxdev);
106 static struct bus_type auxiliary_bus_type = {
108 .probe = auxiliary_bus_probe,
109 .remove = auxiliary_bus_remove,
110 .shutdown = auxiliary_bus_shutdown,
111 .match = auxiliary_match,
112 .uevent = auxiliary_uevent,
113 .pm = &auxiliary_dev_pm_ops,
117 * auxiliary_device_init - check auxiliary_device and initialize
118 * @auxdev: auxiliary device struct
120 * This is the first step in the two-step process to register an
123 * When this function returns an error code, then the device_initialize will
124 * *not* have been performed, and the caller will be responsible to free any
125 * memory allocated for the auxiliary_device in the error path directly.
127 * It returns 0 on success. On success, the device_initialize has been
128 * performed. After this point any error unwinding will need to include a call
129 * to auxiliary_device_uninit(). In this post-initialize error scenario, a call
130 * to the device's .release callback will be triggered, and all memory clean-up
131 * is expected to be handled there.
133 int auxiliary_device_init(struct auxiliary_device *auxdev)
135 struct device *dev = &auxdev->dev;
138 pr_err("auxiliary_device has a NULL dev->parent\n");
143 pr_err("auxiliary_device has a NULL name\n");
147 dev->bus = &auxiliary_bus_type;
148 device_initialize(&auxdev->dev);
151 EXPORT_SYMBOL_GPL(auxiliary_device_init);
154 * __auxiliary_device_add - add an auxiliary bus device
155 * @auxdev: auxiliary bus device to add to the bus
156 * @modname: name of the parent device's driver module
158 * This is the second step in the two-step process to register an
161 * This function must be called after a successful call to
162 * auxiliary_device_init(), which will perform the device_initialize. This
163 * means that if this returns an error code, then a call to
164 * auxiliary_device_uninit() must be performed so that the .release callback
165 * will be triggered to free the memory associated with the auxiliary_device.
167 * The expectation is that users will call the "auxiliary_device_add" macro so
168 * that the caller's KBUILD_MODNAME is automatically inserted for the modname
169 * parameter. Only if a user requires a custom name would this version be
172 int __auxiliary_device_add(struct auxiliary_device *auxdev, const char *modname)
174 struct device *dev = &auxdev->dev;
178 dev_err(dev, "auxiliary device modname is NULL\n");
182 ret = dev_set_name(dev, "%s.%s.%d", modname, auxdev->name, auxdev->id);
184 dev_err(dev, "auxiliary device dev_set_name failed: %d\n", ret);
188 ret = device_add(dev);
190 dev_err(dev, "adding auxiliary device failed!: %d\n", ret);
194 EXPORT_SYMBOL_GPL(__auxiliary_device_add);
197 * auxiliary_find_device - auxiliary device iterator for locating a particular device.
198 * @start: Device to begin with
199 * @data: Data to pass to match function
200 * @match: Callback function to check device
202 * This function returns a reference to a device that is 'found'
203 * for later use, as determined by the @match callback.
205 * The callback should return 0 if the device doesn't match and non-zero
206 * if it does. If the callback returns non-zero, this function will
207 * return to the caller and not iterate over any more devices.
209 struct auxiliary_device *auxiliary_find_device(struct device *start,
211 int (*match)(struct device *dev, const void *data))
215 dev = bus_find_device(&auxiliary_bus_type, start, data, match);
219 return to_auxiliary_dev(dev);
221 EXPORT_SYMBOL_GPL(auxiliary_find_device);
224 * __auxiliary_driver_register - register a driver for auxiliary bus devices
225 * @auxdrv: auxiliary_driver structure
226 * @owner: owning module/driver
227 * @modname: KBUILD_MODNAME for parent driver
229 int __auxiliary_driver_register(struct auxiliary_driver *auxdrv,
230 struct module *owner, const char *modname)
234 if (WARN_ON(!auxdrv->probe) || WARN_ON(!auxdrv->id_table))
238 auxdrv->driver.name = kasprintf(GFP_KERNEL, "%s.%s", modname,
241 auxdrv->driver.name = kasprintf(GFP_KERNEL, "%s", modname);
242 if (!auxdrv->driver.name)
245 auxdrv->driver.owner = owner;
246 auxdrv->driver.bus = &auxiliary_bus_type;
247 auxdrv->driver.mod_name = modname;
249 ret = driver_register(&auxdrv->driver);
251 kfree(auxdrv->driver.name);
255 EXPORT_SYMBOL_GPL(__auxiliary_driver_register);
258 * auxiliary_driver_unregister - unregister a driver
259 * @auxdrv: auxiliary_driver structure
261 void auxiliary_driver_unregister(struct auxiliary_driver *auxdrv)
263 driver_unregister(&auxdrv->driver);
264 kfree(auxdrv->driver.name);
266 EXPORT_SYMBOL_GPL(auxiliary_driver_unregister);
268 void __init auxiliary_bus_init(void)
270 WARN_ON(bus_register(&auxiliary_bus_type));