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1/*
2 * devfreq-event: a framework to provide raw data and events of devfreq devices
3 *
4 * Copyright (C) 2015 Samsung Electronics
5 * Author: Chanwoo Choi <cw00.choi@samsung.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * This driver is based on drivers/devfreq/devfreq.c.
12 */
13
14#include <linux/devfreq-event.h>
15#include <linux/kernel.h>
16#include <linux/err.h>
17#include <linux/init.h>
18#include <linux/export.h>
19#include <linux/slab.h>
20#include <linux/list.h>
21#include <linux/of.h>
22
23static struct class *devfreq_event_class;
24
25/* The list of all devfreq event list */
26static LIST_HEAD(devfreq_event_list);
27static DEFINE_MUTEX(devfreq_event_list_lock);
28
29#define to_devfreq_event(DEV) container_of(DEV, struct devfreq_event_dev, dev)
30
31/**
32 * devfreq_event_enable_edev() - Enable the devfreq-event dev and increase
33 * the enable_count of devfreq-event dev.
34 * @edev : the devfreq-event device
35 *
36 * Note that this function increase the enable_count and enable the
37 * devfreq-event device. The devfreq-event device should be enabled before
38 * using it by devfreq device.
39 */
40int devfreq_event_enable_edev(struct devfreq_event_dev *edev)
41{
42 int ret = 0;
43
44 if (!edev || !edev->desc)
45 return -EINVAL;
46
47 mutex_lock(&edev->lock);
48 if (edev->desc->ops && edev->desc->ops->enable
49 && edev->enable_count == 0) {
50 ret = edev->desc->ops->enable(edev);
51 if (ret < 0)
52 goto err;
53 }
54 edev->enable_count++;
55err:
56 mutex_unlock(&edev->lock);
57
58 return ret;
59}
60EXPORT_SYMBOL_GPL(devfreq_event_enable_edev);
61
62/**
63 * devfreq_event_disable_edev() - Disable the devfreq-event dev and decrease
64 * the enable_count of the devfreq-event dev.
65 * @edev : the devfreq-event device
66 *
67 * Note that this function decrease the enable_count and disable the
68 * devfreq-event device. After the devfreq-event device is disabled,
69 * devfreq device can't use the devfreq-event device for get/set/reset
70 * operations.
71 */
72int devfreq_event_disable_edev(struct devfreq_event_dev *edev)
73{
74 int ret = 0;
75
76 if (!edev || !edev->desc)
77 return -EINVAL;
78
79 mutex_lock(&edev->lock);
80 if (edev->enable_count <= 0) {
81 dev_warn(&edev->dev, "unbalanced enable_count\n");
82 ret = -EIO;
83 goto err;
84 }
85
86 if (edev->desc->ops && edev->desc->ops->disable
87 && edev->enable_count == 1) {
88 ret = edev->desc->ops->disable(edev);
89 if (ret < 0)
90 goto err;
91 }
92 edev->enable_count--;
93err:
94 mutex_unlock(&edev->lock);
95
96 return ret;
97}
98EXPORT_SYMBOL_GPL(devfreq_event_disable_edev);
99
100/**
101 * devfreq_event_is_enabled() - Check whether devfreq-event dev is enabled or
102 * not.
103 * @edev : the devfreq-event device
104 *
105 * Note that this function check whether devfreq-event dev is enabled or not.
106 * If return true, the devfreq-event dev is enabeld. If return false, the
107 * devfreq-event dev is disabled.
108 */
109bool devfreq_event_is_enabled(struct devfreq_event_dev *edev)
110{
111 bool enabled = false;
112
113 if (!edev || !edev->desc)
114 return enabled;
115
116 mutex_lock(&edev->lock);
117
118 if (edev->enable_count > 0)
119 enabled = true;
120
121 mutex_unlock(&edev->lock);
122
123 return enabled;
124}
125EXPORT_SYMBOL_GPL(devfreq_event_is_enabled);
126
127/**
128 * devfreq_event_set_event() - Set event to devfreq-event dev to start.
129 * @edev : the devfreq-event device
130 *
131 * Note that this function set the event to the devfreq-event device to start
132 * for getting the event data which could be various event type.
133 */
134int devfreq_event_set_event(struct devfreq_event_dev *edev)
135{
136 int ret;
137
138 if (!edev || !edev->desc)
139 return -EINVAL;
140
141 if (!edev->desc->ops || !edev->desc->ops->set_event)
142 return -EINVAL;
143
144 if (!devfreq_event_is_enabled(edev))
145 return -EPERM;
146
147 mutex_lock(&edev->lock);
148 ret = edev->desc->ops->set_event(edev);
149 mutex_unlock(&edev->lock);
150
151 return ret;
152}
153EXPORT_SYMBOL_GPL(devfreq_event_set_event);
154
155/**
156 * devfreq_event_get_event() - Get {load|total}_count from devfreq-event dev.
157 * @edev : the devfreq-event device
158 * @edata : the calculated data of devfreq-event device
159 *
160 * Note that this function get the calculated event data from devfreq-event dev
161 * after stoping the progress of whole sequence of devfreq-event dev.
162 */
163int devfreq_event_get_event(struct devfreq_event_dev *edev,
164 struct devfreq_event_data *edata)
165{
166 int ret;
167
168 if (!edev || !edev->desc)
169 return -EINVAL;
170
171 if (!edev->desc->ops || !edev->desc->ops->get_event)
172 return -EINVAL;
173
174 if (!devfreq_event_is_enabled(edev))
175 return -EINVAL;
176
177 edata->total_count = edata->load_count = 0;
178
179 mutex_lock(&edev->lock);
180 ret = edev->desc->ops->get_event(edev, edata);
181 if (ret < 0)
182 edata->total_count = edata->load_count = 0;
183 mutex_unlock(&edev->lock);
184
185 return ret;
186}
187EXPORT_SYMBOL_GPL(devfreq_event_get_event);
188
189/**
190 * devfreq_event_reset_event() - Reset all opeations of devfreq-event dev.
191 * @edev : the devfreq-event device
192 *
193 * Note that this function stop all operations of devfreq-event dev and reset
194 * the current event data to make the devfreq-event device into initial state.
195 */
196int devfreq_event_reset_event(struct devfreq_event_dev *edev)
197{
198 int ret = 0;
199
200 if (!edev || !edev->desc)
201 return -EINVAL;
202
203 if (!devfreq_event_is_enabled(edev))
204 return -EPERM;
205
206 mutex_lock(&edev->lock);
207 if (edev->desc->ops && edev->desc->ops->reset)
208 ret = edev->desc->ops->reset(edev);
209 mutex_unlock(&edev->lock);
210
211 return ret;
212}
213EXPORT_SYMBOL_GPL(devfreq_event_reset_event);
214
215/**
216 * devfreq_event_get_edev_by_phandle() - Get the devfreq-event dev from
217 * devicetree.
218 * @dev : the pointer to the given device
219 * @index : the index into list of devfreq-event device
220 *
221 * Note that this function return the pointer of devfreq-event device.
222 */
223struct devfreq_event_dev *devfreq_event_get_edev_by_phandle(struct device *dev,
224 int index)
225{
226 struct device_node *node;
227 struct devfreq_event_dev *edev;
228
229 if (!dev->of_node)
230 return ERR_PTR(-EINVAL);
231
232 node = of_parse_phandle(dev->of_node, "devfreq-events", index);
233 if (!node)
234 return ERR_PTR(-ENODEV);
235
236 mutex_lock(&devfreq_event_list_lock);
237 list_for_each_entry(edev, &devfreq_event_list, node) {
238 if (edev->dev.parent && edev->dev.parent->of_node == node)
239 goto out;
240 }
241
242 list_for_each_entry(edev, &devfreq_event_list, node) {
243 if (!strcmp(edev->desc->name, node->name))
244 goto out;
245 }
246 edev = NULL;
247out:
248 mutex_unlock(&devfreq_event_list_lock);
249
250 if (!edev) {
251 of_node_put(node);
252 return ERR_PTR(-ENODEV);
253 }
254
255 of_node_put(node);
256
257 return edev;
258}
259EXPORT_SYMBOL_GPL(devfreq_event_get_edev_by_phandle);
260
261/**
262 * devfreq_event_get_edev_count() - Get the count of devfreq-event dev
263 * @dev : the pointer to the given device
264 *
265 * Note that this function return the count of devfreq-event devices.
266 */
267int devfreq_event_get_edev_count(struct device *dev)
268{
269 int count;
270
271 if (!dev->of_node) {
272 dev_err(dev, "device does not have a device node entry\n");
273 return -EINVAL;
274 }
275
276 count = of_property_count_elems_of_size(dev->of_node, "devfreq-events",
277 sizeof(u32));
278 if (count < 0) {
279 dev_err(dev,
280 "failed to get the count of devfreq-event in %s node\n",
281 dev->of_node->full_name);
282 return count;
283 }
284
285 return count;
286}
287EXPORT_SYMBOL_GPL(devfreq_event_get_edev_count);
288
289static void devfreq_event_release_edev(struct device *dev)
290{
291 struct devfreq_event_dev *edev = to_devfreq_event(dev);
292
293 kfree(edev);
294}
295
296/**
297 * devfreq_event_add_edev() - Add new devfreq-event device.
298 * @dev : the device owning the devfreq-event device being created
299 * @desc : the devfreq-event device's decriptor which include essential
300 * data for devfreq-event device.
301 *
302 * Note that this function add new devfreq-event device to devfreq-event class
303 * list and register the device of the devfreq-event device.
304 */
305struct devfreq_event_dev *devfreq_event_add_edev(struct device *dev,
306 struct devfreq_event_desc *desc)
307{
308 struct devfreq_event_dev *edev;
309 static atomic_t event_no = ATOMIC_INIT(0);
310 int ret;
311
312 if (!dev || !desc)
313 return ERR_PTR(-EINVAL);
314
315 if (!desc->name || !desc->ops)
316 return ERR_PTR(-EINVAL);
317
318 if (!desc->ops->set_event || !desc->ops->get_event)
319 return ERR_PTR(-EINVAL);
320
321 edev = kzalloc(sizeof(struct devfreq_event_dev), GFP_KERNEL);
322 if (!edev)
323 return ERR_PTR(-ENOMEM);
324
325 mutex_init(&edev->lock);
326 edev->desc = desc;
327 edev->enable_count = 0;
328 edev->dev.parent = dev;
329 edev->dev.class = devfreq_event_class;
330 edev->dev.release = devfreq_event_release_edev;
331
332 dev_set_name(&edev->dev, "event.%d", atomic_inc_return(&event_no) - 1);
333 ret = device_register(&edev->dev);
334 if (ret < 0) {
335 put_device(&edev->dev);
336 return ERR_PTR(ret);
337 }
338 dev_set_drvdata(&edev->dev, edev);
339
340 INIT_LIST_HEAD(&edev->node);
341
342 mutex_lock(&devfreq_event_list_lock);
343 list_add(&edev->node, &devfreq_event_list);
344 mutex_unlock(&devfreq_event_list_lock);
345
346 return edev;
347}
348EXPORT_SYMBOL_GPL(devfreq_event_add_edev);
349
350/**
351 * devfreq_event_remove_edev() - Remove the devfreq-event device registered.
352 * @dev : the devfreq-event device
353 *
354 * Note that this function remove the registered devfreq-event device.
355 */
356int devfreq_event_remove_edev(struct devfreq_event_dev *edev)
357{
358 if (!edev)
359 return -EINVAL;
360
361 WARN_ON(edev->enable_count);
362
363 mutex_lock(&devfreq_event_list_lock);
364 list_del(&edev->node);
365 mutex_unlock(&devfreq_event_list_lock);
366
367 device_unregister(&edev->dev);
368
369 return 0;
370}
371EXPORT_SYMBOL_GPL(devfreq_event_remove_edev);
372
373static int devm_devfreq_event_match(struct device *dev, void *res, void *data)
374{
375 struct devfreq_event_dev **r = res;
376
377 if (WARN_ON(!r || !*r))
378 return 0;
379
380 return *r == data;
381}
382
383static void devm_devfreq_event_release(struct device *dev, void *res)
384{
385 devfreq_event_remove_edev(*(struct devfreq_event_dev **)res);
386}
387
388/**
389 * devm_devfreq_event_add_edev() - Resource-managed devfreq_event_add_edev()
390 * @dev : the device owning the devfreq-event device being created
391 * @desc : the devfreq-event device's decriptor which include essential
392 * data for devfreq-event device.
393 *
394 * Note that this function manages automatically the memory of devfreq-event
395 * device using device resource management and simplify the free operation
396 * for memory of devfreq-event device.
397 */
398struct devfreq_event_dev *devm_devfreq_event_add_edev(struct device *dev,
399 struct devfreq_event_desc *desc)
400{
401 struct devfreq_event_dev **ptr, *edev;
402
403 ptr = devres_alloc(devm_devfreq_event_release, sizeof(*ptr),
404 GFP_KERNEL);
405 if (!ptr)
406 return ERR_PTR(-ENOMEM);
407
408 edev = devfreq_event_add_edev(dev, desc);
409 if (IS_ERR(edev)) {
410 devres_free(ptr);
411 return ERR_PTR(-ENOMEM);
412 }
413
414 *ptr = edev;
415 devres_add(dev, ptr);
416
417 return edev;
418}
419EXPORT_SYMBOL_GPL(devm_devfreq_event_add_edev);
420
421/**
422 * devm_devfreq_event_remove_edev()- Resource-managed devfreq_event_remove_edev()
423 * @dev : the device owning the devfreq-event device being created
424 * @edev : the devfreq-event device
425 *
426 * Note that this function manages automatically the memory of devfreq-event
427 * device using device resource management.
428 */
429void devm_devfreq_event_remove_edev(struct device *dev,
430 struct devfreq_event_dev *edev)
431{
432 WARN_ON(devres_release(dev, devm_devfreq_event_release,
433 devm_devfreq_event_match, edev));
434}
435EXPORT_SYMBOL_GPL(devm_devfreq_event_remove_edev);
436
437/*
438 * Device attributes for devfreq-event class.
439 */
440static ssize_t name_show(struct device *dev, struct device_attribute *attr,
441 char *buf)
442{
443 struct devfreq_event_dev *edev = to_devfreq_event(dev);
444
445 if (!edev || !edev->desc)
446 return -EINVAL;
447
448 return sprintf(buf, "%s\n", edev->desc->name);
449}
450static DEVICE_ATTR_RO(name);
451
452static ssize_t enable_count_show(struct device *dev,
453 struct device_attribute *attr, char *buf)
454{
455 struct devfreq_event_dev *edev = to_devfreq_event(dev);
456
457 if (!edev || !edev->desc)
458 return -EINVAL;
459
460 return sprintf(buf, "%d\n", edev->enable_count);
461}
462static DEVICE_ATTR_RO(enable_count);
463
464static struct attribute *devfreq_event_attrs[] = {
465 &dev_attr_name.attr,
466 &dev_attr_enable_count.attr,
467 NULL,
468};
469ATTRIBUTE_GROUPS(devfreq_event);
470
471static int __init devfreq_event_init(void)
472{
473 devfreq_event_class = class_create(THIS_MODULE, "devfreq-event");
474 if (IS_ERR(devfreq_event_class)) {
475 pr_err("%s: couldn't create class\n", __FILE__);
476 return PTR_ERR(devfreq_event_class);
477 }
478
479 devfreq_event_class->dev_groups = devfreq_event_groups;
480
481 return 0;
482}
483subsys_initcall(devfreq_event_init);