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 * @edev : the devfreq-event device 350 * 351 * Note that this function removes 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