1 // SPDX-License-Identifier: GPL-2.0
3  * Generic Counter interface
7 #include <linux/counter.h>
22 #include "counter-chrdev.h"
23 #include "counter-sysfs.h"
25 #define COUNTER_NAME	"counter"
27 /* Provides a unique ID for each counter device */
31 	struct counter_device counter;  member
42 	struct counter_device *const counter =  in counter_device_release()  local
45 	counter_chrdev_remove(counter);  in counter_device_release()
46 	ida_free(&counter_ida, dev->id);  in counter_device_release()
48 	kfree(container_of(counter, struct counter_device_allochelper, counter));  in counter_device_release()
57 	.name = "counter",
58 	.dev_name = "counter",
64  * counter_priv - access counter device private data
65  * @counter: counter device
67  * Get the counter device private data
69 void *counter_priv(const struct counter_device *const counter)  in counter_priv()  argument
72 		container_of(counter, struct counter_device_allochelper, counter);  in counter_priv()
74 	return &ch->privdata;  in counter_priv()
76 EXPORT_SYMBOL_NS_GPL(counter_priv, COUNTER);
79  * counter_alloc - allocate a counter_device
82  * This is part one of counter registration. The structure is allocated
90 	struct counter_device *counter;  in counter_alloc()  local
98 	counter = &ch->counter;  in counter_alloc()
99 	dev = &counter->dev;  in counter_alloc()
103 	if (err < 0)  in counter_alloc()
105 	dev->id = err;  in counter_alloc()
107 	mutex_init(&counter->ops_exist_lock);  in counter_alloc()
108 	dev->type = &counter_device_type;  in counter_alloc()
109 	dev->bus = &counter_bus_type;  in counter_alloc()
110 	dev->devt = MKDEV(MAJOR(counter_devt), dev->id);  in counter_alloc()
112 	err = counter_chrdev_add(counter);  in counter_alloc()
113 	if (err < 0)  in counter_alloc()
118 	err = dev_set_name(dev, COUNTER_NAME "%d", dev->id);  in counter_alloc()
122 	return counter;  in counter_alloc()
126 	counter_chrdev_remove(counter);  in counter_alloc()
129 	ida_free(&counter_ida, dev->id);  in counter_alloc()
136 EXPORT_SYMBOL_NS_GPL(counter_alloc, COUNTER);
138 void counter_put(struct counter_device *counter)  in counter_put()  argument
140 	put_device(&counter->dev);  in counter_put()
142 EXPORT_SYMBOL_NS_GPL(counter_put, COUNTER);
145  * counter_add - complete registration of a counter
146  * @counter: the counter to add
148  * This is part two of counter registration.
152 int counter_add(struct counter_device *counter)  in counter_add()  argument
155 	struct device *dev = &counter->dev;  in counter_add()
157 	if (counter->parent) {  in counter_add()
158 		dev->parent = counter->parent;  in counter_add()
159 		dev->of_node = counter->parent->of_node;  in counter_add()
162 	err = counter_sysfs_add(counter);  in counter_add()
163 	if (err < 0)  in counter_add()
167 	return cdev_device_add(&counter->chrdev, dev);  in counter_add()
169 EXPORT_SYMBOL_NS_GPL(counter_add, COUNTER);
172  * counter_unregister - unregister Counter from the system
173  * @counter:	pointer to Counter to unregister
175  * The Counter is unregistered from the system.
177 void counter_unregister(struct counter_device *const counter)  in counter_unregister()  argument
179 	if (!counter)  in counter_unregister()
182 	cdev_device_del(&counter->chrdev, &counter->dev);  in counter_unregister()
184 	mutex_lock(&counter->ops_exist_lock);  in counter_unregister()
186 	counter->ops = NULL;  in counter_unregister()
187 	wake_up(&counter->events_wait);  in counter_unregister()
189 	mutex_unlock(&counter->ops_exist_lock);  in counter_unregister()
191 EXPORT_SYMBOL_NS_GPL(counter_unregister, COUNTER);
193 static void devm_counter_release(void *counter)  in devm_counter_release()  argument
195 	counter_unregister(counter);  in devm_counter_release()
198 static void devm_counter_put(void *counter)  in devm_counter_put()  argument
200 	counter_put(counter);  in devm_counter_put()
204  * devm_counter_alloc - allocate a counter_device
213 	struct counter_device *counter;  in devm_counter_alloc()  local
216 	counter = counter_alloc(sizeof_priv);  in devm_counter_alloc()
217 	if (!counter)  in devm_counter_alloc()
220 	err = devm_add_action_or_reset(dev, devm_counter_put, counter);  in devm_counter_alloc()
221 	if (err < 0)  in devm_counter_alloc()
224 	return counter;  in devm_counter_alloc()
226 EXPORT_SYMBOL_NS_GPL(devm_counter_alloc, COUNTER);
229  * devm_counter_add - complete registration of a counter
231  * @counter: the counter to add
237 		     struct counter_device *const counter)  in devm_counter_add()  argument
241 	err = counter_add(counter);  in devm_counter_add()
242 	if (err < 0)  in devm_counter_add()
245 	return devm_add_action_or_reset(dev, devm_counter_release, counter);  in devm_counter_add()
247 EXPORT_SYMBOL_NS_GPL(devm_counter_add, COUNTER);
256 	if (err < 0)  in counter_init()
259 	err = alloc_chrdev_region(&counter_devt, 0, COUNTER_DEV_MAX,  in counter_init()
261 	if (err < 0)  in counter_init()
264 	return 0;  in counter_init()
281 MODULE_DESCRIPTION("Generic Counter interface");