1 /* 2 * Real Time Clock interface for Linux on Atmel AT91RM9200 3 * 4 * Copyright (C) 2002 Rick Bronson 5 * 6 * Converted to RTC class model by Andrew Victor 7 * 8 * Ported to Linux 2.6 by Steven Scholz 9 * Based on s3c2410-rtc.c Simtec Electronics 10 * 11 * Based on sa1100-rtc.c by Nils Faerber 12 * Based on rtc.c by Paul Gortmaker 13 * 14 * This program is free software; you can redistribute it and/or 15 * modify it under the terms of the GNU General Public License 16 * as published by the Free Software Foundation; either version 17 * 2 of the License, or (at your option) any later version. 18 * 19 */ 20 21 #include <linux/module.h> 22 #include <linux/kernel.h> 23 #include <linux/platform_device.h> 24 #include <linux/time.h> 25 #include <linux/rtc.h> 26 #include <linux/bcd.h> 27 #include <linux/interrupt.h> 28 #include <linux/spinlock.h> 29 #include <linux/ioctl.h> 30 #include <linux/completion.h> 31 #include <linux/io.h> 32 #include <linux/of.h> 33 #include <linux/of_device.h> 34 #include <linux/suspend.h> 35 #include <linux/uaccess.h> 36 37 #include "rtc-at91rm9200.h" 38 39 #define at91_rtc_read(field) \ 40 __raw_readl(at91_rtc_regs + field) 41 #define at91_rtc_write(field, val) \ 42 __raw_writel((val), at91_rtc_regs + field) 43 44 #define AT91_RTC_EPOCH 1900UL /* just like arch/arm/common/rtctime.c */ 45 46 struct at91_rtc_config { 47 bool use_shadow_imr; 48 }; 49 50 static const struct at91_rtc_config *at91_rtc_config; 51 static DECLARE_COMPLETION(at91_rtc_updated); 52 static DECLARE_COMPLETION(at91_rtc_upd_rdy); 53 static unsigned int at91_alarm_year = AT91_RTC_EPOCH; 54 static void __iomem *at91_rtc_regs; 55 static int irq; 56 static DEFINE_SPINLOCK(at91_rtc_lock); 57 static u32 at91_rtc_shadow_imr; 58 static bool suspended; 59 static DEFINE_SPINLOCK(suspended_lock); 60 static unsigned long cached_events; 61 static u32 at91_rtc_imr; 62 63 static void at91_rtc_write_ier(u32 mask) 64 { 65 unsigned long flags; 66 67 spin_lock_irqsave(&at91_rtc_lock, flags); 68 at91_rtc_shadow_imr |= mask; 69 at91_rtc_write(AT91_RTC_IER, mask); 70 spin_unlock_irqrestore(&at91_rtc_lock, flags); 71 } 72 73 static void at91_rtc_write_idr(u32 mask) 74 { 75 unsigned long flags; 76 77 spin_lock_irqsave(&at91_rtc_lock, flags); 78 at91_rtc_write(AT91_RTC_IDR, mask); 79 /* 80 * Register read back (of any RTC-register) needed to make sure 81 * IDR-register write has reached the peripheral before updating 82 * shadow mask. 83 * 84 * Note that there is still a possibility that the mask is updated 85 * before interrupts have actually been disabled in hardware. The only 86 * way to be certain would be to poll the IMR-register, which is is 87 * the very register we are trying to emulate. The register read back 88 * is a reasonable heuristic. 89 */ 90 at91_rtc_read(AT91_RTC_SR); 91 at91_rtc_shadow_imr &= ~mask; 92 spin_unlock_irqrestore(&at91_rtc_lock, flags); 93 } 94 95 static u32 at91_rtc_read_imr(void) 96 { 97 unsigned long flags; 98 u32 mask; 99 100 if (at91_rtc_config->use_shadow_imr) { 101 spin_lock_irqsave(&at91_rtc_lock, flags); 102 mask = at91_rtc_shadow_imr; 103 spin_unlock_irqrestore(&at91_rtc_lock, flags); 104 } else { 105 mask = at91_rtc_read(AT91_RTC_IMR); 106 } 107 108 return mask; 109 } 110 111 /* 112 * Decode time/date into rtc_time structure 113 */ 114 static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg, 115 struct rtc_time *tm) 116 { 117 unsigned int time, date; 118 119 /* must read twice in case it changes */ 120 do { 121 time = at91_rtc_read(timereg); 122 date = at91_rtc_read(calreg); 123 } while ((time != at91_rtc_read(timereg)) || 124 (date != at91_rtc_read(calreg))); 125 126 tm->tm_sec = bcd2bin((time & AT91_RTC_SEC) >> 0); 127 tm->tm_min = bcd2bin((time & AT91_RTC_MIN) >> 8); 128 tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16); 129 130 /* 131 * The Calendar Alarm register does not have a field for 132 * the year - so these will return an invalid value. When an 133 * alarm is set, at91_alarm_year will store the current year. 134 */ 135 tm->tm_year = bcd2bin(date & AT91_RTC_CENT) * 100; /* century */ 136 tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8); /* year */ 137 138 tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */ 139 tm->tm_mon = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1; 140 tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24); 141 } 142 143 /* 144 * Read current time and date in RTC 145 */ 146 static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm) 147 { 148 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm); 149 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year); 150 tm->tm_year = tm->tm_year - 1900; 151 152 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__, 153 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday, 154 tm->tm_hour, tm->tm_min, tm->tm_sec); 155 156 return 0; 157 } 158 159 /* 160 * Set current time and date in RTC 161 */ 162 static int at91_rtc_settime(struct device *dev, struct rtc_time *tm) 163 { 164 unsigned long cr; 165 166 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__, 167 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday, 168 tm->tm_hour, tm->tm_min, tm->tm_sec); 169 170 wait_for_completion(&at91_rtc_upd_rdy); 171 172 /* Stop Time/Calendar from counting */ 173 cr = at91_rtc_read(AT91_RTC_CR); 174 at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM); 175 176 at91_rtc_write_ier(AT91_RTC_ACKUPD); 177 wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */ 178 at91_rtc_write_idr(AT91_RTC_ACKUPD); 179 180 at91_rtc_write(AT91_RTC_TIMR, 181 bin2bcd(tm->tm_sec) << 0 182 | bin2bcd(tm->tm_min) << 8 183 | bin2bcd(tm->tm_hour) << 16); 184 185 at91_rtc_write(AT91_RTC_CALR, 186 bin2bcd((tm->tm_year + 1900) / 100) /* century */ 187 | bin2bcd(tm->tm_year % 100) << 8 /* year */ 188 | bin2bcd(tm->tm_mon + 1) << 16 /* tm_mon starts at zero */ 189 | bin2bcd(tm->tm_wday + 1) << 21 /* day of the week [0-6], Sunday=0 */ 190 | bin2bcd(tm->tm_mday) << 24); 191 192 /* Restart Time/Calendar */ 193 cr = at91_rtc_read(AT91_RTC_CR); 194 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_SECEV); 195 at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM)); 196 at91_rtc_write_ier(AT91_RTC_SECEV); 197 198 return 0; 199 } 200 201 /* 202 * Read alarm time and date in RTC 203 */ 204 static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm) 205 { 206 struct rtc_time *tm = &alrm->time; 207 208 at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm); 209 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year); 210 tm->tm_year = at91_alarm_year - 1900; 211 212 alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM) 213 ? 1 : 0; 214 215 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__, 216 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday, 217 tm->tm_hour, tm->tm_min, tm->tm_sec); 218 219 return 0; 220 } 221 222 /* 223 * Set alarm time and date in RTC 224 */ 225 static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm) 226 { 227 struct rtc_time tm; 228 229 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm); 230 231 at91_alarm_year = tm.tm_year; 232 233 tm.tm_mon = alrm->time.tm_mon; 234 tm.tm_mday = alrm->time.tm_mday; 235 tm.tm_hour = alrm->time.tm_hour; 236 tm.tm_min = alrm->time.tm_min; 237 tm.tm_sec = alrm->time.tm_sec; 238 239 at91_rtc_write_idr(AT91_RTC_ALARM); 240 at91_rtc_write(AT91_RTC_TIMALR, 241 bin2bcd(tm.tm_sec) << 0 242 | bin2bcd(tm.tm_min) << 8 243 | bin2bcd(tm.tm_hour) << 16 244 | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN); 245 at91_rtc_write(AT91_RTC_CALALR, 246 bin2bcd(tm.tm_mon + 1) << 16 /* tm_mon starts at zero */ 247 | bin2bcd(tm.tm_mday) << 24 248 | AT91_RTC_DATEEN | AT91_RTC_MTHEN); 249 250 if (alrm->enabled) { 251 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM); 252 at91_rtc_write_ier(AT91_RTC_ALARM); 253 } 254 255 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__, 256 at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour, 257 tm.tm_min, tm.tm_sec); 258 259 return 0; 260 } 261 262 static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) 263 { 264 dev_dbg(dev, "%s(): cmd=%08x\n", __func__, enabled); 265 266 if (enabled) { 267 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM); 268 at91_rtc_write_ier(AT91_RTC_ALARM); 269 } else 270 at91_rtc_write_idr(AT91_RTC_ALARM); 271 272 return 0; 273 } 274 /* 275 * Provide additional RTC information in /proc/driver/rtc 276 */ 277 static int at91_rtc_proc(struct device *dev, struct seq_file *seq) 278 { 279 unsigned long imr = at91_rtc_read_imr(); 280 281 seq_printf(seq, "update_IRQ\t: %s\n", 282 (imr & AT91_RTC_ACKUPD) ? "yes" : "no"); 283 seq_printf(seq, "periodic_IRQ\t: %s\n", 284 (imr & AT91_RTC_SECEV) ? "yes" : "no"); 285 286 return 0; 287 } 288 289 /* 290 * IRQ handler for the RTC 291 */ 292 static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id) 293 { 294 struct platform_device *pdev = dev_id; 295 struct rtc_device *rtc = platform_get_drvdata(pdev); 296 unsigned int rtsr; 297 unsigned long events = 0; 298 int ret = IRQ_NONE; 299 300 spin_lock(&suspended_lock); 301 rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr(); 302 if (rtsr) { /* this interrupt is shared! Is it ours? */ 303 if (rtsr & AT91_RTC_ALARM) 304 events |= (RTC_AF | RTC_IRQF); 305 if (rtsr & AT91_RTC_SECEV) { 306 complete(&at91_rtc_upd_rdy); 307 at91_rtc_write_idr(AT91_RTC_SECEV); 308 } 309 if (rtsr & AT91_RTC_ACKUPD) 310 complete(&at91_rtc_updated); 311 312 at91_rtc_write(AT91_RTC_SCCR, rtsr); /* clear status reg */ 313 314 if (!suspended) { 315 rtc_update_irq(rtc, 1, events); 316 317 dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n", 318 __func__, events >> 8, events & 0x000000FF); 319 } else { 320 cached_events |= events; 321 at91_rtc_write_idr(at91_rtc_imr); 322 pm_system_wakeup(); 323 } 324 325 ret = IRQ_HANDLED; 326 } 327 spin_lock(&suspended_lock); 328 329 return ret; 330 } 331 332 static const struct at91_rtc_config at91rm9200_config = { 333 }; 334 335 static const struct at91_rtc_config at91sam9x5_config = { 336 .use_shadow_imr = true, 337 }; 338 339 #ifdef CONFIG_OF 340 static const struct of_device_id at91_rtc_dt_ids[] = { 341 { 342 .compatible = "atmel,at91rm9200-rtc", 343 .data = &at91rm9200_config, 344 }, { 345 .compatible = "atmel,at91sam9x5-rtc", 346 .data = &at91sam9x5_config, 347 }, { 348 /* sentinel */ 349 } 350 }; 351 MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids); 352 #endif 353 354 static const struct at91_rtc_config * 355 at91_rtc_get_config(struct platform_device *pdev) 356 { 357 const struct of_device_id *match; 358 359 if (pdev->dev.of_node) { 360 match = of_match_node(at91_rtc_dt_ids, pdev->dev.of_node); 361 if (!match) 362 return NULL; 363 return (const struct at91_rtc_config *)match->data; 364 } 365 366 return &at91rm9200_config; 367 } 368 369 static const struct rtc_class_ops at91_rtc_ops = { 370 .read_time = at91_rtc_readtime, 371 .set_time = at91_rtc_settime, 372 .read_alarm = at91_rtc_readalarm, 373 .set_alarm = at91_rtc_setalarm, 374 .proc = at91_rtc_proc, 375 .alarm_irq_enable = at91_rtc_alarm_irq_enable, 376 }; 377 378 /* 379 * Initialize and install RTC driver 380 */ 381 static int __init at91_rtc_probe(struct platform_device *pdev) 382 { 383 struct rtc_device *rtc; 384 struct resource *regs; 385 int ret = 0; 386 387 at91_rtc_config = at91_rtc_get_config(pdev); 388 if (!at91_rtc_config) 389 return -ENODEV; 390 391 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); 392 if (!regs) { 393 dev_err(&pdev->dev, "no mmio resource defined\n"); 394 return -ENXIO; 395 } 396 397 irq = platform_get_irq(pdev, 0); 398 if (irq < 0) { 399 dev_err(&pdev->dev, "no irq resource defined\n"); 400 return -ENXIO; 401 } 402 403 at91_rtc_regs = devm_ioremap(&pdev->dev, regs->start, 404 resource_size(regs)); 405 if (!at91_rtc_regs) { 406 dev_err(&pdev->dev, "failed to map registers, aborting.\n"); 407 return -ENOMEM; 408 } 409 410 at91_rtc_write(AT91_RTC_CR, 0); 411 at91_rtc_write(AT91_RTC_MR, 0); /* 24 hour mode */ 412 413 /* Disable all interrupts */ 414 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM | 415 AT91_RTC_SECEV | AT91_RTC_TIMEV | 416 AT91_RTC_CALEV); 417 418 ret = devm_request_irq(&pdev->dev, irq, at91_rtc_interrupt, 419 IRQF_SHARED | IRQF_COND_SUSPEND, 420 "at91_rtc", pdev); 421 if (ret) { 422 dev_err(&pdev->dev, "IRQ %d already in use.\n", irq); 423 return ret; 424 } 425 426 /* cpu init code should really have flagged this device as 427 * being wake-capable; if it didn't, do that here. 428 */ 429 if (!device_can_wakeup(&pdev->dev)) 430 device_init_wakeup(&pdev->dev, 1); 431 432 rtc = devm_rtc_device_register(&pdev->dev, pdev->name, 433 &at91_rtc_ops, THIS_MODULE); 434 if (IS_ERR(rtc)) 435 return PTR_ERR(rtc); 436 platform_set_drvdata(pdev, rtc); 437 438 /* enable SECEV interrupt in order to initialize at91_rtc_upd_rdy 439 * completion. 440 */ 441 at91_rtc_write_ier(AT91_RTC_SECEV); 442 443 dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n"); 444 return 0; 445 } 446 447 /* 448 * Disable and remove the RTC driver 449 */ 450 static int __exit at91_rtc_remove(struct platform_device *pdev) 451 { 452 /* Disable all interrupts */ 453 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM | 454 AT91_RTC_SECEV | AT91_RTC_TIMEV | 455 AT91_RTC_CALEV); 456 457 return 0; 458 } 459 460 static void at91_rtc_shutdown(struct platform_device *pdev) 461 { 462 /* Disable all interrupts */ 463 at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM | 464 AT91_RTC_SECEV | AT91_RTC_TIMEV | 465 AT91_RTC_CALEV); 466 } 467 468 #ifdef CONFIG_PM_SLEEP 469 470 /* AT91RM9200 RTC Power management control */ 471 472 static int at91_rtc_suspend(struct device *dev) 473 { 474 /* this IRQ is shared with DBGU and other hardware which isn't 475 * necessarily doing PM like we are... 476 */ 477 at91_rtc_imr = at91_rtc_read_imr() 478 & (AT91_RTC_ALARM|AT91_RTC_SECEV); 479 if (at91_rtc_imr) { 480 if (device_may_wakeup(dev)) { 481 unsigned long flags; 482 483 enable_irq_wake(irq); 484 485 spin_lock_irqsave(&suspended_lock, flags); 486 suspended = true; 487 spin_unlock_irqrestore(&suspended_lock, flags); 488 } else { 489 at91_rtc_write_idr(at91_rtc_imr); 490 } 491 } 492 return 0; 493 } 494 495 static int at91_rtc_resume(struct device *dev) 496 { 497 struct rtc_device *rtc = dev_get_drvdata(dev); 498 499 if (at91_rtc_imr) { 500 if (device_may_wakeup(dev)) { 501 unsigned long flags; 502 503 spin_lock_irqsave(&suspended_lock, flags); 504 505 if (cached_events) { 506 rtc_update_irq(rtc, 1, cached_events); 507 cached_events = 0; 508 } 509 510 suspended = false; 511 spin_unlock_irqrestore(&suspended_lock, flags); 512 513 disable_irq_wake(irq); 514 } 515 at91_rtc_write_ier(at91_rtc_imr); 516 } 517 return 0; 518 } 519 #endif 520 521 static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume); 522 523 static struct platform_driver at91_rtc_driver = { 524 .remove = __exit_p(at91_rtc_remove), 525 .shutdown = at91_rtc_shutdown, 526 .driver = { 527 .name = "at91_rtc", 528 .pm = &at91_rtc_pm_ops, 529 .of_match_table = of_match_ptr(at91_rtc_dt_ids), 530 }, 531 }; 532 533 module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe); 534 535 MODULE_AUTHOR("Rick Bronson"); 536 MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200"); 537 MODULE_LICENSE("GPL"); 538 MODULE_ALIAS("platform:at91_rtc"); 539