1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * devfreq-event: a framework to provide raw data and events of devfreq devices
4  *
5  * Copyright (C) 2015 Samsung Electronics
6  * Author: Chanwoo Choi <cw00.choi@samsung.com>
7  *
8  * This driver is based on drivers/devfreq/devfreq.c.
9  */
10 
11 #include <linux/devfreq-event.h>
12 #include <linux/kernel.h>
13 #include <linux/err.h>
14 #include <linux/init.h>
15 #include <linux/export.h>
16 #include <linux/slab.h>
17 #include <linux/list.h>
18 #include <linux/of.h>
19 
20 static struct class *devfreq_event_class;
21 
22 /* The list of all devfreq event list */
23 static LIST_HEAD(devfreq_event_list);
24 static DEFINE_MUTEX(devfreq_event_list_lock);
25 
26 #define to_devfreq_event(DEV) container_of(DEV, struct devfreq_event_dev, dev)
27 
28 /**
29  * devfreq_event_enable_edev() - Enable the devfreq-event dev and increase
30  *				 the enable_count of devfreq-event dev.
31  * @edev	: the devfreq-event device
32  *
33  * Note that this function increase the enable_count and enable the
34  * devfreq-event device. The devfreq-event device should be enabled before
35  * using it by devfreq device.
36  */
37 int devfreq_event_enable_edev(struct devfreq_event_dev *edev)
38 {
39 	int ret = 0;
40 
41 	if (!edev || !edev->desc)
42 		return -EINVAL;
43 
44 	mutex_lock(&edev->lock);
45 	if (edev->desc->ops && edev->desc->ops->enable
46 			&& edev->enable_count == 0) {
47 		ret = edev->desc->ops->enable(edev);
48 		if (ret < 0)
49 			goto err;
50 	}
51 	edev->enable_count++;
52 err:
53 	mutex_unlock(&edev->lock);
54 
55 	return ret;
56 }
57 EXPORT_SYMBOL_GPL(devfreq_event_enable_edev);
58 
59 /**
60  * devfreq_event_disable_edev() - Disable the devfreq-event dev and decrease
61  *				  the enable_count of the devfreq-event dev.
62  * @edev	: the devfreq-event device
63  *
64  * Note that this function decrease the enable_count and disable the
65  * devfreq-event device. After the devfreq-event device is disabled,
66  * devfreq device can't use the devfreq-event device for get/set/reset
67  * operations.
68  */
69 int devfreq_event_disable_edev(struct devfreq_event_dev *edev)
70 {
71 	int ret = 0;
72 
73 	if (!edev || !edev->desc)
74 		return -EINVAL;
75 
76 	mutex_lock(&edev->lock);
77 	if (edev->enable_count <= 0) {
78 		dev_warn(&edev->dev, "unbalanced enable_count\n");
79 		ret = -EIO;
80 		goto err;
81 	}
82 
83 	if (edev->desc->ops && edev->desc->ops->disable
84 			&& edev->enable_count == 1) {
85 		ret = edev->desc->ops->disable(edev);
86 		if (ret < 0)
87 			goto err;
88 	}
89 	edev->enable_count--;
90 err:
91 	mutex_unlock(&edev->lock);
92 
93 	return ret;
94 }
95 EXPORT_SYMBOL_GPL(devfreq_event_disable_edev);
96 
97 /**
98  * devfreq_event_is_enabled() - Check whether devfreq-event dev is enabled or
99  *				not.
100  * @edev	: the devfreq-event device
101  *
102  * Note that this function check whether devfreq-event dev is enabled or not.
103  * If return true, the devfreq-event dev is enabeld. If return false, the
104  * devfreq-event dev is disabled.
105  */
106 bool devfreq_event_is_enabled(struct devfreq_event_dev *edev)
107 {
108 	bool enabled = false;
109 
110 	if (!edev || !edev->desc)
111 		return enabled;
112 
113 	mutex_lock(&edev->lock);
114 
115 	if (edev->enable_count > 0)
116 		enabled = true;
117 
118 	mutex_unlock(&edev->lock);
119 
120 	return enabled;
121 }
122 EXPORT_SYMBOL_GPL(devfreq_event_is_enabled);
123 
124 /**
125  * devfreq_event_set_event() - Set event to devfreq-event dev to start.
126  * @edev	: the devfreq-event device
127  *
128  * Note that this function set the event to the devfreq-event device to start
129  * for getting the event data which could be various event type.
130  */
131 int devfreq_event_set_event(struct devfreq_event_dev *edev)
132 {
133 	int ret;
134 
135 	if (!edev || !edev->desc)
136 		return -EINVAL;
137 
138 	if (!edev->desc->ops || !edev->desc->ops->set_event)
139 		return -EINVAL;
140 
141 	if (!devfreq_event_is_enabled(edev))
142 		return -EPERM;
143 
144 	mutex_lock(&edev->lock);
145 	ret = edev->desc->ops->set_event(edev);
146 	mutex_unlock(&edev->lock);
147 
148 	return ret;
149 }
150 EXPORT_SYMBOL_GPL(devfreq_event_set_event);
151 
152 /**
153  * devfreq_event_get_event() - Get {load|total}_count from devfreq-event dev.
154  * @edev	: the devfreq-event device
155  * @edata	: the calculated data of devfreq-event device
156  *
157  * Note that this function get the calculated event data from devfreq-event dev
158  * after stoping the progress of whole sequence of devfreq-event dev.
159  */
160 int devfreq_event_get_event(struct devfreq_event_dev *edev,
161 			    struct devfreq_event_data *edata)
162 {
163 	int ret;
164 
165 	if (!edev || !edev->desc)
166 		return -EINVAL;
167 
168 	if (!edev->desc->ops || !edev->desc->ops->get_event)
169 		return -EINVAL;
170 
171 	if (!devfreq_event_is_enabled(edev))
172 		return -EINVAL;
173 
174 	edata->total_count = edata->load_count = 0;
175 
176 	mutex_lock(&edev->lock);
177 	ret = edev->desc->ops->get_event(edev, edata);
178 	if (ret < 0)
179 		edata->total_count = edata->load_count = 0;
180 	mutex_unlock(&edev->lock);
181 
182 	return ret;
183 }
184 EXPORT_SYMBOL_GPL(devfreq_event_get_event);
185 
186 /**
187  * devfreq_event_reset_event() - Reset all opeations of devfreq-event dev.
188  * @edev	: the devfreq-event device
189  *
190  * Note that this function stop all operations of devfreq-event dev and reset
191  * the current event data to make the devfreq-event device into initial state.
192  */
193 int devfreq_event_reset_event(struct devfreq_event_dev *edev)
194 {
195 	int ret = 0;
196 
197 	if (!edev || !edev->desc)
198 		return -EINVAL;
199 
200 	if (!devfreq_event_is_enabled(edev))
201 		return -EPERM;
202 
203 	mutex_lock(&edev->lock);
204 	if (edev->desc->ops && edev->desc->ops->reset)
205 		ret = edev->desc->ops->reset(edev);
206 	mutex_unlock(&edev->lock);
207 
208 	return ret;
209 }
210 EXPORT_SYMBOL_GPL(devfreq_event_reset_event);
211 
212 /**
213  * devfreq_event_get_edev_by_phandle() - Get the devfreq-event dev from
214  *					 devicetree.
215  * @dev		: the pointer to the given device
216  * @index	: the index into list of devfreq-event device
217  *
218  * Note that this function return the pointer of devfreq-event device.
219  */
220 struct devfreq_event_dev *devfreq_event_get_edev_by_phandle(struct device *dev,
221 						      int index)
222 {
223 	struct device_node *node;
224 	struct devfreq_event_dev *edev;
225 
226 	if (!dev->of_node)
227 		return ERR_PTR(-EINVAL);
228 
229 	node = of_parse_phandle(dev->of_node, "devfreq-events", index);
230 	if (!node)
231 		return ERR_PTR(-ENODEV);
232 
233 	mutex_lock(&devfreq_event_list_lock);
234 	list_for_each_entry(edev, &devfreq_event_list, node) {
235 		if (edev->dev.parent && edev->dev.parent->of_node == node)
236 			goto out;
237 	}
238 
239 	list_for_each_entry(edev, &devfreq_event_list, node) {
240 		if (of_node_name_eq(node, edev->desc->name))
241 			goto out;
242 	}
243 	edev = NULL;
244 out:
245 	mutex_unlock(&devfreq_event_list_lock);
246 
247 	if (!edev) {
248 		of_node_put(node);
249 		return ERR_PTR(-ENODEV);
250 	}
251 
252 	of_node_put(node);
253 
254 	return edev;
255 }
256 EXPORT_SYMBOL_GPL(devfreq_event_get_edev_by_phandle);
257 
258 /**
259  * devfreq_event_get_edev_count() - Get the count of devfreq-event dev
260  * @dev		: the pointer to the given device
261  *
262  * Note that this function return the count of devfreq-event devices.
263  */
264 int devfreq_event_get_edev_count(struct device *dev)
265 {
266 	int count;
267 
268 	if (!dev->of_node) {
269 		dev_err(dev, "device does not have a device node entry\n");
270 		return -EINVAL;
271 	}
272 
273 	count = of_property_count_elems_of_size(dev->of_node, "devfreq-events",
274 						sizeof(u32));
275 	if (count < 0) {
276 		dev_err(dev,
277 			"failed to get the count of devfreq-event in %pOF node\n",
278 			dev->of_node);
279 		return count;
280 	}
281 
282 	return count;
283 }
284 EXPORT_SYMBOL_GPL(devfreq_event_get_edev_count);
285 
286 static void devfreq_event_release_edev(struct device *dev)
287 {
288 	struct devfreq_event_dev *edev = to_devfreq_event(dev);
289 
290 	kfree(edev);
291 }
292 
293 /**
294  * devfreq_event_add_edev() - Add new devfreq-event device.
295  * @dev		: the device owning the devfreq-event device being created
296  * @desc	: the devfreq-event device's decriptor which include essential
297  *		  data for devfreq-event device.
298  *
299  * Note that this function add new devfreq-event device to devfreq-event class
300  * list and register the device of the devfreq-event device.
301  */
302 struct devfreq_event_dev *devfreq_event_add_edev(struct device *dev,
303 						struct devfreq_event_desc *desc)
304 {
305 	struct devfreq_event_dev *edev;
306 	static atomic_t event_no = ATOMIC_INIT(-1);
307 	int ret;
308 
309 	if (!dev || !desc)
310 		return ERR_PTR(-EINVAL);
311 
312 	if (!desc->name || !desc->ops)
313 		return ERR_PTR(-EINVAL);
314 
315 	if (!desc->ops->set_event || !desc->ops->get_event)
316 		return ERR_PTR(-EINVAL);
317 
318 	edev = kzalloc(sizeof(struct devfreq_event_dev), GFP_KERNEL);
319 	if (!edev)
320 		return ERR_PTR(-ENOMEM);
321 
322 	mutex_init(&edev->lock);
323 	edev->desc = desc;
324 	edev->enable_count = 0;
325 	edev->dev.parent = dev;
326 	edev->dev.class = devfreq_event_class;
327 	edev->dev.release = devfreq_event_release_edev;
328 
329 	dev_set_name(&edev->dev, "event%d", atomic_inc_return(&event_no));
330 	ret = device_register(&edev->dev);
331 	if (ret < 0) {
332 		put_device(&edev->dev);
333 		return ERR_PTR(ret);
334 	}
335 	dev_set_drvdata(&edev->dev, edev);
336 
337 	INIT_LIST_HEAD(&edev->node);
338 
339 	mutex_lock(&devfreq_event_list_lock);
340 	list_add(&edev->node, &devfreq_event_list);
341 	mutex_unlock(&devfreq_event_list_lock);
342 
343 	return edev;
344 }
345 EXPORT_SYMBOL_GPL(devfreq_event_add_edev);
346 
347 /**
348  * devfreq_event_remove_edev() - Remove the devfreq-event device registered.
349  * @dev		: the devfreq-event device
350  *
351  * Note that this function remove the registered devfreq-event device.
352  */
353 int devfreq_event_remove_edev(struct devfreq_event_dev *edev)
354 {
355 	if (!edev)
356 		return -EINVAL;
357 
358 	WARN_ON(edev->enable_count);
359 
360 	mutex_lock(&devfreq_event_list_lock);
361 	list_del(&edev->node);
362 	mutex_unlock(&devfreq_event_list_lock);
363 
364 	device_unregister(&edev->dev);
365 
366 	return 0;
367 }
368 EXPORT_SYMBOL_GPL(devfreq_event_remove_edev);
369 
370 static int devm_devfreq_event_match(struct device *dev, void *res, void *data)
371 {
372 	struct devfreq_event_dev **r = res;
373 
374 	if (WARN_ON(!r || !*r))
375 		return 0;
376 
377 	return *r == data;
378 }
379 
380 static void devm_devfreq_event_release(struct device *dev, void *res)
381 {
382 	devfreq_event_remove_edev(*(struct devfreq_event_dev **)res);
383 }
384 
385 /**
386  * devm_devfreq_event_add_edev() - Resource-managed devfreq_event_add_edev()
387  * @dev		: the device owning the devfreq-event device being created
388  * @desc	: the devfreq-event device's decriptor which include essential
389  *		  data for devfreq-event device.
390  *
391  * Note that this function manages automatically the memory of devfreq-event
392  * device using device resource management and simplify the free operation
393  * for memory of devfreq-event device.
394  */
395 struct devfreq_event_dev *devm_devfreq_event_add_edev(struct device *dev,
396 						struct devfreq_event_desc *desc)
397 {
398 	struct devfreq_event_dev **ptr, *edev;
399 
400 	ptr = devres_alloc(devm_devfreq_event_release, sizeof(*ptr),
401 				GFP_KERNEL);
402 	if (!ptr)
403 		return ERR_PTR(-ENOMEM);
404 
405 	edev = devfreq_event_add_edev(dev, desc);
406 	if (IS_ERR(edev)) {
407 		devres_free(ptr);
408 		return ERR_PTR(-ENOMEM);
409 	}
410 
411 	*ptr = edev;
412 	devres_add(dev, ptr);
413 
414 	return edev;
415 }
416 EXPORT_SYMBOL_GPL(devm_devfreq_event_add_edev);
417 
418 /**
419  * devm_devfreq_event_remove_edev()- Resource-managed devfreq_event_remove_edev()
420  * @dev		: the device owning the devfreq-event device being created
421  * @edev	: the devfreq-event device
422  *
423  * Note that this function manages automatically the memory of devfreq-event
424  * device using device resource management.
425  */
426 void devm_devfreq_event_remove_edev(struct device *dev,
427 				struct devfreq_event_dev *edev)
428 {
429 	WARN_ON(devres_release(dev, devm_devfreq_event_release,
430 			       devm_devfreq_event_match, edev));
431 }
432 EXPORT_SYMBOL_GPL(devm_devfreq_event_remove_edev);
433 
434 /*
435  * Device attributes for devfreq-event class.
436  */
437 static ssize_t name_show(struct device *dev, struct device_attribute *attr,
438 			 char *buf)
439 {
440 	struct devfreq_event_dev *edev = to_devfreq_event(dev);
441 
442 	if (!edev || !edev->desc)
443 		return -EINVAL;
444 
445 	return sprintf(buf, "%s\n", edev->desc->name);
446 }
447 static DEVICE_ATTR_RO(name);
448 
449 static ssize_t enable_count_show(struct device *dev,
450 				  struct device_attribute *attr, char *buf)
451 {
452 	struct devfreq_event_dev *edev = to_devfreq_event(dev);
453 
454 	if (!edev || !edev->desc)
455 		return -EINVAL;
456 
457 	return sprintf(buf, "%d\n", edev->enable_count);
458 }
459 static DEVICE_ATTR_RO(enable_count);
460 
461 static struct attribute *devfreq_event_attrs[] = {
462 	&dev_attr_name.attr,
463 	&dev_attr_enable_count.attr,
464 	NULL,
465 };
466 ATTRIBUTE_GROUPS(devfreq_event);
467 
468 static int __init devfreq_event_init(void)
469 {
470 	devfreq_event_class = class_create(THIS_MODULE, "devfreq-event");
471 	if (IS_ERR(devfreq_event_class)) {
472 		pr_err("%s: couldn't create class\n", __FILE__);
473 		return PTR_ERR(devfreq_event_class);
474 	}
475 
476 	devfreq_event_class->dev_groups = devfreq_event_groups;
477 
478 	return 0;
479 }
480 subsys_initcall(devfreq_event_init);
481