| 1 | /* |
| 2 | * RTC subsystem, base class |
| 3 | * |
| 4 | * Copyright (C) 2005 Tower Technologies |
| 5 | * Author: Alessandro Zummo <a.zummo@towertech.it> |
| 6 | * |
| 7 | * class skeleton from drivers/hwmon/hwmon.c |
| 8 | * |
| 9 | * This program is free software; you can redistribute it and/or modify |
| 10 | * it under the terms of the GNU General Public License version 2 as |
| 11 | * published by the Free Software Foundation. |
| 12 | */ |
| 13 | |
| 14 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 15 | |
| 16 | #include <linux/module.h> |
| 17 | #include <linux/of.h> |
| 18 | #include <linux/rtc.h> |
| 19 | #include <linux/kdev_t.h> |
| 20 | #include <linux/idr.h> |
| 21 | #include <linux/slab.h> |
| 22 | #include <linux/workqueue.h> |
| 23 | |
| 24 | #include "rtc-core.h" |
| 25 | |
| 26 | |
| 27 | static DEFINE_IDA(rtc_ida); |
| 28 | struct class *rtc_class; |
| 29 | |
| 30 | static void rtc_device_release(struct device *dev) |
| 31 | { |
| 32 | struct rtc_device *rtc = to_rtc_device(dev); |
| 33 | ida_simple_remove(&rtc_ida, rtc->id); |
| 34 | kfree(rtc); |
| 35 | } |
| 36 | |
| 37 | #ifdef CONFIG_RTC_HCTOSYS_DEVICE |
| 38 | /* Result of the last RTC to system clock attempt. */ |
| 39 | int rtc_hctosys_ret = -ENODEV; |
| 40 | #endif |
| 41 | |
| 42 | #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE) |
| 43 | /* |
| 44 | * On suspend(), measure the delta between one RTC and the |
| 45 | * system's wall clock; restore it on resume(). |
| 46 | */ |
| 47 | |
| 48 | static struct timespec64 old_rtc, old_system, old_delta; |
| 49 | |
| 50 | |
| 51 | static int rtc_suspend(struct device *dev) |
| 52 | { |
| 53 | struct rtc_device *rtc = to_rtc_device(dev); |
| 54 | struct rtc_time tm; |
| 55 | struct timespec64 delta, delta_delta; |
| 56 | int err; |
| 57 | |
| 58 | if (timekeeping_rtc_skipsuspend()) |
| 59 | return 0; |
| 60 | |
| 61 | if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0) |
| 62 | return 0; |
| 63 | |
| 64 | /* snapshot the current RTC and system time at suspend*/ |
| 65 | err = rtc_read_time(rtc, &tm); |
| 66 | if (err < 0) { |
| 67 | pr_debug("%s: fail to read rtc time\n", dev_name(&rtc->dev)); |
| 68 | return 0; |
| 69 | } |
| 70 | |
| 71 | getnstimeofday64(&old_system); |
| 72 | old_rtc.tv_sec = rtc_tm_to_time64(&tm); |
| 73 | |
| 74 | |
| 75 | /* |
| 76 | * To avoid drift caused by repeated suspend/resumes, |
| 77 | * which each can add ~1 second drift error, |
| 78 | * try to compensate so the difference in system time |
| 79 | * and rtc time stays close to constant. |
| 80 | */ |
| 81 | delta = timespec64_sub(old_system, old_rtc); |
| 82 | delta_delta = timespec64_sub(delta, old_delta); |
| 83 | if (delta_delta.tv_sec < -2 || delta_delta.tv_sec >= 2) { |
| 84 | /* |
| 85 | * if delta_delta is too large, assume time correction |
| 86 | * has occured and set old_delta to the current delta. |
| 87 | */ |
| 88 | old_delta = delta; |
| 89 | } else { |
| 90 | /* Otherwise try to adjust old_system to compensate */ |
| 91 | old_system = timespec64_sub(old_system, delta_delta); |
| 92 | } |
| 93 | |
| 94 | return 0; |
| 95 | } |
| 96 | |
| 97 | static int rtc_resume(struct device *dev) |
| 98 | { |
| 99 | struct rtc_device *rtc = to_rtc_device(dev); |
| 100 | struct rtc_time tm; |
| 101 | struct timespec64 new_system, new_rtc; |
| 102 | struct timespec64 sleep_time; |
| 103 | int err; |
| 104 | |
| 105 | if (timekeeping_rtc_skipresume()) |
| 106 | return 0; |
| 107 | |
| 108 | rtc_hctosys_ret = -ENODEV; |
| 109 | if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0) |
| 110 | return 0; |
| 111 | |
| 112 | /* snapshot the current rtc and system time at resume */ |
| 113 | getnstimeofday64(&new_system); |
| 114 | err = rtc_read_time(rtc, &tm); |
| 115 | if (err < 0) { |
| 116 | pr_debug("%s: fail to read rtc time\n", dev_name(&rtc->dev)); |
| 117 | return 0; |
| 118 | } |
| 119 | |
| 120 | new_rtc.tv_sec = rtc_tm_to_time64(&tm); |
| 121 | new_rtc.tv_nsec = 0; |
| 122 | |
| 123 | if (new_rtc.tv_sec < old_rtc.tv_sec) { |
| 124 | pr_debug("%s: time travel!\n", dev_name(&rtc->dev)); |
| 125 | return 0; |
| 126 | } |
| 127 | |
| 128 | /* calculate the RTC time delta (sleep time)*/ |
| 129 | sleep_time = timespec64_sub(new_rtc, old_rtc); |
| 130 | |
| 131 | /* |
| 132 | * Since these RTC suspend/resume handlers are not called |
| 133 | * at the very end of suspend or the start of resume, |
| 134 | * some run-time may pass on either sides of the sleep time |
| 135 | * so subtract kernel run-time between rtc_suspend to rtc_resume |
| 136 | * to keep things accurate. |
| 137 | */ |
| 138 | sleep_time = timespec64_sub(sleep_time, |
| 139 | timespec64_sub(new_system, old_system)); |
| 140 | |
| 141 | if (sleep_time.tv_sec >= 0) |
| 142 | timekeeping_inject_sleeptime64(&sleep_time); |
| 143 | rtc_hctosys_ret = 0; |
| 144 | return 0; |
| 145 | } |
| 146 | |
| 147 | static SIMPLE_DEV_PM_OPS(rtc_class_dev_pm_ops, rtc_suspend, rtc_resume); |
| 148 | #define RTC_CLASS_DEV_PM_OPS (&rtc_class_dev_pm_ops) |
| 149 | #else |
| 150 | #define RTC_CLASS_DEV_PM_OPS NULL |
| 151 | #endif |
| 152 | |
| 153 | |
| 154 | /** |
| 155 | * rtc_device_register - register w/ RTC class |
| 156 | * @dev: the device to register |
| 157 | * |
| 158 | * rtc_device_unregister() must be called when the class device is no |
| 159 | * longer needed. |
| 160 | * |
| 161 | * Returns the pointer to the new struct class device. |
| 162 | */ |
| 163 | struct rtc_device *rtc_device_register(const char *name, struct device *dev, |
| 164 | const struct rtc_class_ops *ops, |
| 165 | struct module *owner) |
| 166 | { |
| 167 | struct rtc_device *rtc; |
| 168 | struct rtc_wkalrm alrm; |
| 169 | int of_id = -1, id = -1, err; |
| 170 | |
| 171 | if (dev->of_node) |
| 172 | of_id = of_alias_get_id(dev->of_node, "rtc"); |
| 173 | else if (dev->parent && dev->parent->of_node) |
| 174 | of_id = of_alias_get_id(dev->parent->of_node, "rtc"); |
| 175 | |
| 176 | if (of_id >= 0) { |
| 177 | id = ida_simple_get(&rtc_ida, of_id, of_id + 1, |
| 178 | GFP_KERNEL); |
| 179 | if (id < 0) |
| 180 | dev_warn(dev, "/aliases ID %d not available\n", |
| 181 | of_id); |
| 182 | } |
| 183 | |
| 184 | if (id < 0) { |
| 185 | id = ida_simple_get(&rtc_ida, 0, 0, GFP_KERNEL); |
| 186 | if (id < 0) { |
| 187 | err = id; |
| 188 | goto exit; |
| 189 | } |
| 190 | } |
| 191 | |
| 192 | rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL); |
| 193 | if (rtc == NULL) { |
| 194 | err = -ENOMEM; |
| 195 | goto exit_ida; |
| 196 | } |
| 197 | |
| 198 | rtc->id = id; |
| 199 | rtc->ops = ops; |
| 200 | rtc->owner = owner; |
| 201 | rtc->irq_freq = 1; |
| 202 | rtc->max_user_freq = 64; |
| 203 | rtc->dev.parent = dev; |
| 204 | rtc->dev.class = rtc_class; |
| 205 | rtc->dev.groups = rtc_get_dev_attribute_groups(); |
| 206 | rtc->dev.release = rtc_device_release; |
| 207 | |
| 208 | mutex_init(&rtc->ops_lock); |
| 209 | spin_lock_init(&rtc->irq_lock); |
| 210 | spin_lock_init(&rtc->irq_task_lock); |
| 211 | init_waitqueue_head(&rtc->irq_queue); |
| 212 | |
| 213 | /* Init timerqueue */ |
| 214 | timerqueue_init_head(&rtc->timerqueue); |
| 215 | INIT_WORK(&rtc->irqwork, rtc_timer_do_work); |
| 216 | /* Init aie timer */ |
| 217 | rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, (void *)rtc); |
| 218 | /* Init uie timer */ |
| 219 | rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, (void *)rtc); |
| 220 | /* Init pie timer */ |
| 221 | hrtimer_init(&rtc->pie_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
| 222 | rtc->pie_timer.function = rtc_pie_update_irq; |
| 223 | rtc->pie_enabled = 0; |
| 224 | |
| 225 | strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE); |
| 226 | dev_set_name(&rtc->dev, "rtc%d", id); |
| 227 | |
| 228 | /* Check to see if there is an ALARM already set in hw */ |
| 229 | err = __rtc_read_alarm(rtc, &alrm); |
| 230 | |
| 231 | if (!err && !rtc_valid_tm(&alrm.time)) |
| 232 | rtc_initialize_alarm(rtc, &alrm); |
| 233 | |
| 234 | rtc_dev_prepare(rtc); |
| 235 | |
| 236 | err = device_register(&rtc->dev); |
| 237 | if (err) { |
| 238 | /* This will free both memory and the ID */ |
| 239 | put_device(&rtc->dev); |
| 240 | goto exit; |
| 241 | } |
| 242 | |
| 243 | rtc_dev_add_device(rtc); |
| 244 | rtc_proc_add_device(rtc); |
| 245 | |
| 246 | dev_info(dev, "rtc core: registered %s as %s\n", |
| 247 | rtc->name, dev_name(&rtc->dev)); |
| 248 | |
| 249 | return rtc; |
| 250 | |
| 251 | exit_ida: |
| 252 | ida_simple_remove(&rtc_ida, id); |
| 253 | |
| 254 | exit: |
| 255 | dev_err(dev, "rtc core: unable to register %s, err = %d\n", |
| 256 | name, err); |
| 257 | return ERR_PTR(err); |
| 258 | } |
| 259 | EXPORT_SYMBOL_GPL(rtc_device_register); |
| 260 | |
| 261 | |
| 262 | /** |
| 263 | * rtc_device_unregister - removes the previously registered RTC class device |
| 264 | * |
| 265 | * @rtc: the RTC class device to destroy |
| 266 | */ |
| 267 | void rtc_device_unregister(struct rtc_device *rtc) |
| 268 | { |
| 269 | mutex_lock(&rtc->ops_lock); |
| 270 | /* |
| 271 | * Remove innards of this RTC, then disable it, before |
| 272 | * letting any rtc_class_open() users access it again |
| 273 | */ |
| 274 | rtc_dev_del_device(rtc); |
| 275 | rtc_proc_del_device(rtc); |
| 276 | device_del(&rtc->dev); |
| 277 | rtc->ops = NULL; |
| 278 | mutex_unlock(&rtc->ops_lock); |
| 279 | put_device(&rtc->dev); |
| 280 | } |
| 281 | EXPORT_SYMBOL_GPL(rtc_device_unregister); |
| 282 | |
| 283 | static void devm_rtc_device_release(struct device *dev, void *res) |
| 284 | { |
| 285 | struct rtc_device *rtc = *(struct rtc_device **)res; |
| 286 | |
| 287 | rtc_device_unregister(rtc); |
| 288 | } |
| 289 | |
| 290 | static int devm_rtc_device_match(struct device *dev, void *res, void *data) |
| 291 | { |
| 292 | struct rtc **r = res; |
| 293 | |
| 294 | return *r == data; |
| 295 | } |
| 296 | |
| 297 | /** |
| 298 | * devm_rtc_device_register - resource managed rtc_device_register() |
| 299 | * @dev: the device to register |
| 300 | * @name: the name of the device |
| 301 | * @ops: the rtc operations structure |
| 302 | * @owner: the module owner |
| 303 | * |
| 304 | * @return a struct rtc on success, or an ERR_PTR on error |
| 305 | * |
| 306 | * Managed rtc_device_register(). The rtc_device returned from this function |
| 307 | * are automatically freed on driver detach. See rtc_device_register() |
| 308 | * for more information. |
| 309 | */ |
| 310 | |
| 311 | struct rtc_device *devm_rtc_device_register(struct device *dev, |
| 312 | const char *name, |
| 313 | const struct rtc_class_ops *ops, |
| 314 | struct module *owner) |
| 315 | { |
| 316 | struct rtc_device **ptr, *rtc; |
| 317 | |
| 318 | ptr = devres_alloc(devm_rtc_device_release, sizeof(*ptr), GFP_KERNEL); |
| 319 | if (!ptr) |
| 320 | return ERR_PTR(-ENOMEM); |
| 321 | |
| 322 | rtc = rtc_device_register(name, dev, ops, owner); |
| 323 | if (!IS_ERR(rtc)) { |
| 324 | *ptr = rtc; |
| 325 | devres_add(dev, ptr); |
| 326 | } else { |
| 327 | devres_free(ptr); |
| 328 | } |
| 329 | |
| 330 | return rtc; |
| 331 | } |
| 332 | EXPORT_SYMBOL_GPL(devm_rtc_device_register); |
| 333 | |
| 334 | /** |
| 335 | * devm_rtc_device_unregister - resource managed devm_rtc_device_unregister() |
| 336 | * @dev: the device to unregister |
| 337 | * @rtc: the RTC class device to unregister |
| 338 | * |
| 339 | * Deallocated a rtc allocated with devm_rtc_device_register(). Normally this |
| 340 | * function will not need to be called and the resource management code will |
| 341 | * ensure that the resource is freed. |
| 342 | */ |
| 343 | void devm_rtc_device_unregister(struct device *dev, struct rtc_device *rtc) |
| 344 | { |
| 345 | int rc; |
| 346 | |
| 347 | rc = devres_release(dev, devm_rtc_device_release, |
| 348 | devm_rtc_device_match, rtc); |
| 349 | WARN_ON(rc); |
| 350 | } |
| 351 | EXPORT_SYMBOL_GPL(devm_rtc_device_unregister); |
| 352 | |
| 353 | static int __init rtc_init(void) |
| 354 | { |
| 355 | rtc_class = class_create(THIS_MODULE, "rtc"); |
| 356 | if (IS_ERR(rtc_class)) { |
| 357 | pr_err("couldn't create class\n"); |
| 358 | return PTR_ERR(rtc_class); |
| 359 | } |
| 360 | rtc_class->pm = RTC_CLASS_DEV_PM_OPS; |
| 361 | rtc_dev_init(); |
| 362 | return 0; |
| 363 | } |
| 364 | subsys_initcall(rtc_init); |