1 // SPDX-License-Identifier: GPL-2.0 2 // RTC driver for ChromeOS Embedded Controller. 3 // 4 // Copyright (C) 2017 Google, Inc. 5 // Author: Stephen Barber <smbarber@chromium.org> 6 7 #include <linux/kernel.h> 8 #include <linux/module.h> 9 #include <linux/platform_data/cros_ec_commands.h> 10 #include <linux/platform_data/cros_ec_proto.h> 11 #include <linux/platform_device.h> 12 #include <linux/rtc.h> 13 #include <linux/slab.h> 14 15 #define DRV_NAME "cros-ec-rtc" 16 17 #define SECS_PER_DAY (24 * 60 * 60) 18 19 /** 20 * struct cros_ec_rtc - Driver data for EC RTC 21 * 22 * @cros_ec: Pointer to EC device 23 * @rtc: Pointer to RTC device 24 * @notifier: Notifier info for responding to EC events 25 * @saved_alarm: Alarm to restore when interrupts are reenabled 26 */ 27 struct cros_ec_rtc { 28 struct cros_ec_device *cros_ec; 29 struct rtc_device *rtc; 30 struct notifier_block notifier; 31 u32 saved_alarm; 32 }; 33 34 static int cros_ec_rtc_get(struct cros_ec_device *cros_ec, u32 command, 35 u32 *response) 36 { 37 int ret; 38 struct { 39 struct cros_ec_command msg; 40 struct ec_response_rtc data; 41 } __packed msg; 42 43 memset(&msg, 0, sizeof(msg)); 44 msg.msg.command = command; 45 msg.msg.insize = sizeof(msg.data); 46 47 ret = cros_ec_cmd_xfer_status(cros_ec, &msg.msg); 48 if (ret < 0) 49 return ret; 50 51 *response = msg.data.time; 52 53 return 0; 54 } 55 56 static int cros_ec_rtc_set(struct cros_ec_device *cros_ec, u32 command, 57 u32 param) 58 { 59 int ret; 60 struct { 61 struct cros_ec_command msg; 62 struct ec_response_rtc data; 63 } __packed msg; 64 65 memset(&msg, 0, sizeof(msg)); 66 msg.msg.command = command; 67 msg.msg.outsize = sizeof(msg.data); 68 msg.data.time = param; 69 70 ret = cros_ec_cmd_xfer_status(cros_ec, &msg.msg); 71 if (ret < 0) 72 return ret; 73 return 0; 74 } 75 76 /* Read the current time from the EC. */ 77 static int cros_ec_rtc_read_time(struct device *dev, struct rtc_time *tm) 78 { 79 struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev); 80 struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec; 81 int ret; 82 u32 time; 83 84 ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, &time); 85 if (ret) { 86 dev_err(dev, "error getting time: %d\n", ret); 87 return ret; 88 } 89 90 rtc_time64_to_tm(time, tm); 91 92 return 0; 93 } 94 95 /* Set the current EC time. */ 96 static int cros_ec_rtc_set_time(struct device *dev, struct rtc_time *tm) 97 { 98 struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev); 99 struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec; 100 int ret; 101 time64_t time = rtc_tm_to_time64(tm); 102 103 ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_VALUE, (u32)time); 104 if (ret < 0) { 105 dev_err(dev, "error setting time: %d\n", ret); 106 return ret; 107 } 108 109 return 0; 110 } 111 112 /* Read alarm time from RTC. */ 113 static int cros_ec_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 114 { 115 struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev); 116 struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec; 117 int ret; 118 u32 current_time, alarm_offset; 119 120 /* 121 * The EC host command for getting the alarm is relative (i.e. 5 122 * seconds from now) whereas rtc_wkalrm is absolute. Get the current 123 * RTC time first so we can calculate the relative time. 124 */ 125 ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, ¤t_time); 126 if (ret < 0) { 127 dev_err(dev, "error getting time: %d\n", ret); 128 return ret; 129 } 130 131 ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_ALARM, &alarm_offset); 132 if (ret < 0) { 133 dev_err(dev, "error getting alarm: %d\n", ret); 134 return ret; 135 } 136 137 rtc_time64_to_tm(current_time + alarm_offset, &alrm->time); 138 139 return 0; 140 } 141 142 /* Set the EC's RTC alarm. */ 143 static int cros_ec_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 144 { 145 struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev); 146 struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec; 147 int ret; 148 time64_t alarm_time; 149 u32 current_time, alarm_offset; 150 151 /* 152 * The EC host command for setting the alarm is relative 153 * (i.e. 5 seconds from now) whereas rtc_wkalrm is absolute. 154 * Get the current RTC time first so we can calculate the 155 * relative time. 156 */ 157 ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, ¤t_time); 158 if (ret < 0) { 159 dev_err(dev, "error getting time: %d\n", ret); 160 return ret; 161 } 162 163 alarm_time = rtc_tm_to_time64(&alrm->time); 164 165 if (alarm_time < 0 || alarm_time > U32_MAX) 166 return -EINVAL; 167 168 if (!alrm->enabled) { 169 /* 170 * If the alarm is being disabled, send an alarm 171 * clear command. 172 */ 173 alarm_offset = EC_RTC_ALARM_CLEAR; 174 cros_ec_rtc->saved_alarm = (u32)alarm_time; 175 } else { 176 /* Don't set an alarm in the past. */ 177 if ((u32)alarm_time <= current_time) 178 return -ETIME; 179 180 alarm_offset = (u32)alarm_time - current_time; 181 } 182 183 ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM, alarm_offset); 184 if (ret < 0) { 185 if (ret == -EINVAL && alarm_offset >= SECS_PER_DAY) { 186 /* 187 * RTC chips on some older Chromebooks can only handle 188 * alarms up to 24h in the future. Try to set an alarm 189 * below that limit to avoid suspend failures. 190 */ 191 ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM, 192 SECS_PER_DAY - 1); 193 } 194 195 if (ret < 0) { 196 dev_err(dev, "error setting alarm in %u seconds: %d\n", 197 alarm_offset, ret); 198 return ret; 199 } 200 } 201 202 return 0; 203 } 204 205 static int cros_ec_rtc_alarm_irq_enable(struct device *dev, 206 unsigned int enabled) 207 { 208 struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev); 209 struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec; 210 int ret; 211 u32 current_time, alarm_offset, alarm_value; 212 213 ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, ¤t_time); 214 if (ret < 0) { 215 dev_err(dev, "error getting time: %d\n", ret); 216 return ret; 217 } 218 219 if (enabled) { 220 /* Restore saved alarm if it's still in the future. */ 221 if (cros_ec_rtc->saved_alarm < current_time) 222 alarm_offset = EC_RTC_ALARM_CLEAR; 223 else 224 alarm_offset = cros_ec_rtc->saved_alarm - current_time; 225 226 ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM, 227 alarm_offset); 228 if (ret < 0) { 229 dev_err(dev, "error restoring alarm: %d\n", ret); 230 return ret; 231 } 232 } else { 233 /* Disable alarm, saving the old alarm value. */ 234 ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_ALARM, 235 &alarm_offset); 236 if (ret < 0) { 237 dev_err(dev, "error saving alarm: %d\n", ret); 238 return ret; 239 } 240 241 alarm_value = current_time + alarm_offset; 242 243 /* 244 * If the current EC alarm is already past, we don't want 245 * to set an alarm when we go through the alarm irq enable 246 * path. 247 */ 248 if (alarm_value < current_time) 249 cros_ec_rtc->saved_alarm = EC_RTC_ALARM_CLEAR; 250 else 251 cros_ec_rtc->saved_alarm = alarm_value; 252 253 alarm_offset = EC_RTC_ALARM_CLEAR; 254 ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM, 255 alarm_offset); 256 if (ret < 0) { 257 dev_err(dev, "error disabling alarm: %d\n", ret); 258 return ret; 259 } 260 } 261 262 return 0; 263 } 264 265 static int cros_ec_rtc_event(struct notifier_block *nb, 266 unsigned long queued_during_suspend, 267 void *_notify) 268 { 269 struct cros_ec_rtc *cros_ec_rtc; 270 struct rtc_device *rtc; 271 struct cros_ec_device *cros_ec; 272 u32 host_event; 273 274 cros_ec_rtc = container_of(nb, struct cros_ec_rtc, notifier); 275 rtc = cros_ec_rtc->rtc; 276 cros_ec = cros_ec_rtc->cros_ec; 277 278 host_event = cros_ec_get_host_event(cros_ec); 279 if (host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_RTC)) { 280 rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF); 281 return NOTIFY_OK; 282 } else { 283 return NOTIFY_DONE; 284 } 285 } 286 287 static const struct rtc_class_ops cros_ec_rtc_ops = { 288 .read_time = cros_ec_rtc_read_time, 289 .set_time = cros_ec_rtc_set_time, 290 .read_alarm = cros_ec_rtc_read_alarm, 291 .set_alarm = cros_ec_rtc_set_alarm, 292 .alarm_irq_enable = cros_ec_rtc_alarm_irq_enable, 293 }; 294 295 #ifdef CONFIG_PM_SLEEP 296 static int cros_ec_rtc_suspend(struct device *dev) 297 { 298 struct platform_device *pdev = to_platform_device(dev); 299 struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(&pdev->dev); 300 301 if (device_may_wakeup(dev)) 302 return enable_irq_wake(cros_ec_rtc->cros_ec->irq); 303 304 return 0; 305 } 306 307 static int cros_ec_rtc_resume(struct device *dev) 308 { 309 struct platform_device *pdev = to_platform_device(dev); 310 struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(&pdev->dev); 311 312 if (device_may_wakeup(dev)) 313 return disable_irq_wake(cros_ec_rtc->cros_ec->irq); 314 315 return 0; 316 } 317 #endif 318 319 static SIMPLE_DEV_PM_OPS(cros_ec_rtc_pm_ops, cros_ec_rtc_suspend, 320 cros_ec_rtc_resume); 321 322 static int cros_ec_rtc_probe(struct platform_device *pdev) 323 { 324 struct cros_ec_dev *ec_dev = dev_get_drvdata(pdev->dev.parent); 325 struct cros_ec_device *cros_ec = ec_dev->ec_dev; 326 struct cros_ec_rtc *cros_ec_rtc; 327 struct rtc_time tm; 328 int ret; 329 330 cros_ec_rtc = devm_kzalloc(&pdev->dev, sizeof(*cros_ec_rtc), 331 GFP_KERNEL); 332 if (!cros_ec_rtc) 333 return -ENOMEM; 334 335 platform_set_drvdata(pdev, cros_ec_rtc); 336 cros_ec_rtc->cros_ec = cros_ec; 337 338 /* Get initial time */ 339 ret = cros_ec_rtc_read_time(&pdev->dev, &tm); 340 if (ret) { 341 dev_err(&pdev->dev, "failed to read RTC time\n"); 342 return ret; 343 } 344 345 ret = device_init_wakeup(&pdev->dev, 1); 346 if (ret) { 347 dev_err(&pdev->dev, "failed to initialize wakeup\n"); 348 return ret; 349 } 350 351 cros_ec_rtc->rtc = devm_rtc_allocate_device(&pdev->dev); 352 if (IS_ERR(cros_ec_rtc->rtc)) 353 return PTR_ERR(cros_ec_rtc->rtc); 354 355 cros_ec_rtc->rtc->ops = &cros_ec_rtc_ops; 356 cros_ec_rtc->rtc->range_max = U32_MAX; 357 358 ret = devm_rtc_register_device(cros_ec_rtc->rtc); 359 if (ret) 360 return ret; 361 362 /* Get RTC events from the EC. */ 363 cros_ec_rtc->notifier.notifier_call = cros_ec_rtc_event; 364 ret = blocking_notifier_chain_register(&cros_ec->event_notifier, 365 &cros_ec_rtc->notifier); 366 if (ret) { 367 dev_err(&pdev->dev, "failed to register notifier\n"); 368 return ret; 369 } 370 371 return 0; 372 } 373 374 static void cros_ec_rtc_remove(struct platform_device *pdev) 375 { 376 struct cros_ec_rtc *cros_ec_rtc = platform_get_drvdata(pdev); 377 struct device *dev = &pdev->dev; 378 int ret; 379 380 ret = blocking_notifier_chain_unregister( 381 &cros_ec_rtc->cros_ec->event_notifier, 382 &cros_ec_rtc->notifier); 383 if (ret) 384 dev_err(dev, "failed to unregister notifier\n"); 385 } 386 387 static struct platform_driver cros_ec_rtc_driver = { 388 .probe = cros_ec_rtc_probe, 389 .remove_new = cros_ec_rtc_remove, 390 .driver = { 391 .name = DRV_NAME, 392 .pm = &cros_ec_rtc_pm_ops, 393 }, 394 }; 395 396 module_platform_driver(cros_ec_rtc_driver); 397 398 MODULE_DESCRIPTION("RTC driver for Chrome OS ECs"); 399 MODULE_AUTHOR("Stephen Barber <smbarber@chromium.org>"); 400 MODULE_LICENSE("GPL v2"); 401 MODULE_ALIAS("platform:" DRV_NAME); 402