1 /* 2 * TI OMAP1 Real Time Clock interface for Linux 3 * 4 * Copyright (C) 2003 MontaVista Software, Inc. 5 * Author: George G. Davis <gdavis@mvista.com> or <source@mvista.com> 6 * 7 * Copyright (C) 2006 David Brownell (new RTC framework) 8 * 9 * This program is free software; you can redistribute it and/or 10 * modify it under the terms of the GNU General Public License 11 * as published by the Free Software Foundation; either version 12 * 2 of the License, or (at your option) any later version. 13 */ 14 15 #include <linux/kernel.h> 16 #include <linux/init.h> 17 #include <linux/module.h> 18 #include <linux/ioport.h> 19 #include <linux/delay.h> 20 #include <linux/rtc.h> 21 #include <linux/bcd.h> 22 #include <linux/platform_device.h> 23 24 #include <asm/io.h> 25 #include <asm/mach/time.h> 26 27 28 /* The OMAP1 RTC is a year/month/day/hours/minutes/seconds BCD clock 29 * with century-range alarm matching, driven by the 32kHz clock. 30 * 31 * The main user-visible ways it differs from PC RTCs are by omitting 32 * "don't care" alarm fields and sub-second periodic IRQs, and having 33 * an autoadjust mechanism to calibrate to the true oscillator rate. 34 * 35 * Board-specific wiring options include using split power mode with 36 * RTC_OFF_NOFF used as the reset signal (so the RTC won't be reset), 37 * and wiring RTC_WAKE_INT (so the RTC alarm can wake the system from 38 * low power modes). See the BOARD-SPECIFIC CUSTOMIZATION comment. 39 */ 40 41 #define OMAP_RTC_BASE 0xfffb4800 42 43 /* RTC registers */ 44 #define OMAP_RTC_SECONDS_REG 0x00 45 #define OMAP_RTC_MINUTES_REG 0x04 46 #define OMAP_RTC_HOURS_REG 0x08 47 #define OMAP_RTC_DAYS_REG 0x0C 48 #define OMAP_RTC_MONTHS_REG 0x10 49 #define OMAP_RTC_YEARS_REG 0x14 50 #define OMAP_RTC_WEEKS_REG 0x18 51 52 #define OMAP_RTC_ALARM_SECONDS_REG 0x20 53 #define OMAP_RTC_ALARM_MINUTES_REG 0x24 54 #define OMAP_RTC_ALARM_HOURS_REG 0x28 55 #define OMAP_RTC_ALARM_DAYS_REG 0x2c 56 #define OMAP_RTC_ALARM_MONTHS_REG 0x30 57 #define OMAP_RTC_ALARM_YEARS_REG 0x34 58 59 #define OMAP_RTC_CTRL_REG 0x40 60 #define OMAP_RTC_STATUS_REG 0x44 61 #define OMAP_RTC_INTERRUPTS_REG 0x48 62 63 #define OMAP_RTC_COMP_LSB_REG 0x4c 64 #define OMAP_RTC_COMP_MSB_REG 0x50 65 #define OMAP_RTC_OSC_REG 0x54 66 67 /* OMAP_RTC_CTRL_REG bit fields: */ 68 #define OMAP_RTC_CTRL_SPLIT (1<<7) 69 #define OMAP_RTC_CTRL_DISABLE (1<<6) 70 #define OMAP_RTC_CTRL_SET_32_COUNTER (1<<5) 71 #define OMAP_RTC_CTRL_TEST (1<<4) 72 #define OMAP_RTC_CTRL_MODE_12_24 (1<<3) 73 #define OMAP_RTC_CTRL_AUTO_COMP (1<<2) 74 #define OMAP_RTC_CTRL_ROUND_30S (1<<1) 75 #define OMAP_RTC_CTRL_STOP (1<<0) 76 77 /* OMAP_RTC_STATUS_REG bit fields: */ 78 #define OMAP_RTC_STATUS_POWER_UP (1<<7) 79 #define OMAP_RTC_STATUS_ALARM (1<<6) 80 #define OMAP_RTC_STATUS_1D_EVENT (1<<5) 81 #define OMAP_RTC_STATUS_1H_EVENT (1<<4) 82 #define OMAP_RTC_STATUS_1M_EVENT (1<<3) 83 #define OMAP_RTC_STATUS_1S_EVENT (1<<2) 84 #define OMAP_RTC_STATUS_RUN (1<<1) 85 #define OMAP_RTC_STATUS_BUSY (1<<0) 86 87 /* OMAP_RTC_INTERRUPTS_REG bit fields: */ 88 #define OMAP_RTC_INTERRUPTS_IT_ALARM (1<<3) 89 #define OMAP_RTC_INTERRUPTS_IT_TIMER (1<<2) 90 91 92 #define rtc_read(addr) omap_readb(OMAP_RTC_BASE + (addr)) 93 #define rtc_write(val, addr) omap_writeb(val, OMAP_RTC_BASE + (addr)) 94 95 96 /* platform_bus isn't hotpluggable, so for static linkage it'd be safe 97 * to get rid of probe() and remove() code ... too bad the driver struct 98 * remembers probe(), that's about 25% of the runtime footprint!! 99 */ 100 #ifndef MODULE 101 #undef __devexit 102 #undef __devexit_p 103 #define __devexit __exit 104 #define __devexit_p __exit_p 105 #endif 106 107 108 /* we rely on the rtc framework to handle locking (rtc->ops_lock), 109 * so the only other requirement is that register accesses which 110 * require BUSY to be clear are made with IRQs locally disabled 111 */ 112 static void rtc_wait_not_busy(void) 113 { 114 int count = 0; 115 u8 status; 116 117 /* BUSY may stay active for 1/32768 second (~30 usec) */ 118 for (count = 0; count < 50; count++) { 119 status = rtc_read(OMAP_RTC_STATUS_REG); 120 if ((status & (u8)OMAP_RTC_STATUS_BUSY) == 0) 121 break; 122 udelay(1); 123 } 124 /* now we have ~15 usec to read/write various registers */ 125 } 126 127 static irqreturn_t rtc_irq(int irq, void *class_dev) 128 { 129 unsigned long events = 0; 130 u8 irq_data; 131 132 irq_data = rtc_read(OMAP_RTC_STATUS_REG); 133 134 /* alarm irq? */ 135 if (irq_data & OMAP_RTC_STATUS_ALARM) { 136 rtc_write(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG); 137 events |= RTC_IRQF | RTC_AF; 138 } 139 140 /* 1/sec periodic/update irq? */ 141 if (irq_data & OMAP_RTC_STATUS_1S_EVENT) 142 events |= RTC_IRQF | RTC_UF; 143 144 rtc_update_irq(class_dev, 1, events); 145 146 return IRQ_HANDLED; 147 } 148 149 #ifdef CONFIG_RTC_INTF_DEV 150 151 static int 152 omap_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) 153 { 154 u8 reg; 155 156 switch (cmd) { 157 case RTC_AIE_OFF: 158 case RTC_AIE_ON: 159 case RTC_UIE_OFF: 160 case RTC_UIE_ON: 161 break; 162 default: 163 return -ENOIOCTLCMD; 164 } 165 166 local_irq_disable(); 167 rtc_wait_not_busy(); 168 reg = rtc_read(OMAP_RTC_INTERRUPTS_REG); 169 switch (cmd) { 170 /* AIE = Alarm Interrupt Enable */ 171 case RTC_AIE_OFF: 172 reg &= ~OMAP_RTC_INTERRUPTS_IT_ALARM; 173 break; 174 case RTC_AIE_ON: 175 reg |= OMAP_RTC_INTERRUPTS_IT_ALARM; 176 break; 177 /* UIE = Update Interrupt Enable (1/second) */ 178 case RTC_UIE_OFF: 179 reg &= ~OMAP_RTC_INTERRUPTS_IT_TIMER; 180 break; 181 case RTC_UIE_ON: 182 reg |= OMAP_RTC_INTERRUPTS_IT_TIMER; 183 break; 184 } 185 rtc_wait_not_busy(); 186 rtc_write(reg, OMAP_RTC_INTERRUPTS_REG); 187 local_irq_enable(); 188 189 return 0; 190 } 191 192 #else 193 #define omap_rtc_ioctl NULL 194 #endif 195 196 /* this hardware doesn't support "don't care" alarm fields */ 197 static int tm2bcd(struct rtc_time *tm) 198 { 199 if (rtc_valid_tm(tm) != 0) 200 return -EINVAL; 201 202 tm->tm_sec = BIN2BCD(tm->tm_sec); 203 tm->tm_min = BIN2BCD(tm->tm_min); 204 tm->tm_hour = BIN2BCD(tm->tm_hour); 205 tm->tm_mday = BIN2BCD(tm->tm_mday); 206 207 tm->tm_mon = BIN2BCD(tm->tm_mon + 1); 208 209 /* epoch == 1900 */ 210 if (tm->tm_year < 100 || tm->tm_year > 199) 211 return -EINVAL; 212 tm->tm_year = BIN2BCD(tm->tm_year - 100); 213 214 return 0; 215 } 216 217 static void bcd2tm(struct rtc_time *tm) 218 { 219 tm->tm_sec = BCD2BIN(tm->tm_sec); 220 tm->tm_min = BCD2BIN(tm->tm_min); 221 tm->tm_hour = BCD2BIN(tm->tm_hour); 222 tm->tm_mday = BCD2BIN(tm->tm_mday); 223 tm->tm_mon = BCD2BIN(tm->tm_mon) - 1; 224 /* epoch == 1900 */ 225 tm->tm_year = BCD2BIN(tm->tm_year) + 100; 226 } 227 228 229 static int omap_rtc_read_time(struct device *dev, struct rtc_time *tm) 230 { 231 /* we don't report wday/yday/isdst ... */ 232 local_irq_disable(); 233 rtc_wait_not_busy(); 234 235 tm->tm_sec = rtc_read(OMAP_RTC_SECONDS_REG); 236 tm->tm_min = rtc_read(OMAP_RTC_MINUTES_REG); 237 tm->tm_hour = rtc_read(OMAP_RTC_HOURS_REG); 238 tm->tm_mday = rtc_read(OMAP_RTC_DAYS_REG); 239 tm->tm_mon = rtc_read(OMAP_RTC_MONTHS_REG); 240 tm->tm_year = rtc_read(OMAP_RTC_YEARS_REG); 241 242 local_irq_enable(); 243 244 bcd2tm(tm); 245 return 0; 246 } 247 248 static int omap_rtc_set_time(struct device *dev, struct rtc_time *tm) 249 { 250 if (tm2bcd(tm) < 0) 251 return -EINVAL; 252 local_irq_disable(); 253 rtc_wait_not_busy(); 254 255 rtc_write(tm->tm_year, OMAP_RTC_YEARS_REG); 256 rtc_write(tm->tm_mon, OMAP_RTC_MONTHS_REG); 257 rtc_write(tm->tm_mday, OMAP_RTC_DAYS_REG); 258 rtc_write(tm->tm_hour, OMAP_RTC_HOURS_REG); 259 rtc_write(tm->tm_min, OMAP_RTC_MINUTES_REG); 260 rtc_write(tm->tm_sec, OMAP_RTC_SECONDS_REG); 261 262 local_irq_enable(); 263 264 return 0; 265 } 266 267 static int omap_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm) 268 { 269 local_irq_disable(); 270 rtc_wait_not_busy(); 271 272 alm->time.tm_sec = rtc_read(OMAP_RTC_ALARM_SECONDS_REG); 273 alm->time.tm_min = rtc_read(OMAP_RTC_ALARM_MINUTES_REG); 274 alm->time.tm_hour = rtc_read(OMAP_RTC_ALARM_HOURS_REG); 275 alm->time.tm_mday = rtc_read(OMAP_RTC_ALARM_DAYS_REG); 276 alm->time.tm_mon = rtc_read(OMAP_RTC_ALARM_MONTHS_REG); 277 alm->time.tm_year = rtc_read(OMAP_RTC_ALARM_YEARS_REG); 278 279 local_irq_enable(); 280 281 bcd2tm(&alm->time); 282 alm->pending = !!(rtc_read(OMAP_RTC_INTERRUPTS_REG) 283 & OMAP_RTC_INTERRUPTS_IT_ALARM); 284 alm->enabled = alm->pending && device_may_wakeup(dev); 285 286 return 0; 287 } 288 289 static int omap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm) 290 { 291 u8 reg; 292 293 /* Much userspace code uses RTC_ALM_SET, thus "don't care" for 294 * day/month/year specifies alarms up to 24 hours in the future. 295 * So we need to handle that ... but let's ignore the "don't care" 296 * values for hours/minutes/seconds. 297 */ 298 if (alm->time.tm_mday <= 0 299 && alm->time.tm_mon < 0 300 && alm->time.tm_year < 0) { 301 struct rtc_time tm; 302 unsigned long now, then; 303 304 omap_rtc_read_time(dev, &tm); 305 rtc_tm_to_time(&tm, &now); 306 307 alm->time.tm_mday = tm.tm_mday; 308 alm->time.tm_mon = tm.tm_mon; 309 alm->time.tm_year = tm.tm_year; 310 rtc_tm_to_time(&alm->time, &then); 311 312 /* sometimes the alarm wraps into tomorrow */ 313 if (then < now) { 314 rtc_time_to_tm(now + 24 * 60 * 60, &tm); 315 alm->time.tm_mday = tm.tm_mday; 316 alm->time.tm_mon = tm.tm_mon; 317 alm->time.tm_year = tm.tm_year; 318 } 319 } 320 321 if (tm2bcd(&alm->time) < 0) 322 return -EINVAL; 323 324 local_irq_disable(); 325 rtc_wait_not_busy(); 326 327 rtc_write(alm->time.tm_year, OMAP_RTC_ALARM_YEARS_REG); 328 rtc_write(alm->time.tm_mon, OMAP_RTC_ALARM_MONTHS_REG); 329 rtc_write(alm->time.tm_mday, OMAP_RTC_ALARM_DAYS_REG); 330 rtc_write(alm->time.tm_hour, OMAP_RTC_ALARM_HOURS_REG); 331 rtc_write(alm->time.tm_min, OMAP_RTC_ALARM_MINUTES_REG); 332 rtc_write(alm->time.tm_sec, OMAP_RTC_ALARM_SECONDS_REG); 333 334 reg = rtc_read(OMAP_RTC_INTERRUPTS_REG); 335 if (alm->enabled) 336 reg |= OMAP_RTC_INTERRUPTS_IT_ALARM; 337 else 338 reg &= ~OMAP_RTC_INTERRUPTS_IT_ALARM; 339 rtc_write(reg, OMAP_RTC_INTERRUPTS_REG); 340 341 local_irq_enable(); 342 343 return 0; 344 } 345 346 static struct rtc_class_ops omap_rtc_ops = { 347 .ioctl = omap_rtc_ioctl, 348 .read_time = omap_rtc_read_time, 349 .set_time = omap_rtc_set_time, 350 .read_alarm = omap_rtc_read_alarm, 351 .set_alarm = omap_rtc_set_alarm, 352 }; 353 354 static int omap_rtc_alarm; 355 static int omap_rtc_timer; 356 357 static int __devinit omap_rtc_probe(struct platform_device *pdev) 358 { 359 struct resource *res, *mem; 360 struct rtc_device *rtc; 361 u8 reg, new_ctrl; 362 363 omap_rtc_timer = platform_get_irq(pdev, 0); 364 if (omap_rtc_timer <= 0) { 365 pr_debug("%s: no update irq?\n", pdev->name); 366 return -ENOENT; 367 } 368 369 omap_rtc_alarm = platform_get_irq(pdev, 1); 370 if (omap_rtc_alarm <= 0) { 371 pr_debug("%s: no alarm irq?\n", pdev->name); 372 return -ENOENT; 373 } 374 375 /* NOTE: using static mapping for RTC registers */ 376 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 377 if (res && res->start != OMAP_RTC_BASE) { 378 pr_debug("%s: RTC registers at %08x, expected %08x\n", 379 pdev->name, (unsigned) res->start, OMAP_RTC_BASE); 380 return -ENOENT; 381 } 382 383 if (res) 384 mem = request_mem_region(res->start, 385 res->end - res->start + 1, 386 pdev->name); 387 else 388 mem = NULL; 389 if (!mem) { 390 pr_debug("%s: RTC registers at %08x are not free\n", 391 pdev->name, OMAP_RTC_BASE); 392 return -EBUSY; 393 } 394 395 rtc = rtc_device_register(pdev->name, &pdev->dev, 396 &omap_rtc_ops, THIS_MODULE); 397 if (IS_ERR(rtc)) { 398 pr_debug("%s: can't register RTC device, err %ld\n", 399 pdev->name, PTR_ERR(rtc)); 400 goto fail; 401 } 402 platform_set_drvdata(pdev, rtc); 403 class_set_devdata(&rtc->class_dev, mem); 404 405 /* clear pending irqs, and set 1/second periodic, 406 * which we'll use instead of update irqs 407 */ 408 rtc_write(0, OMAP_RTC_INTERRUPTS_REG); 409 410 /* clear old status */ 411 reg = rtc_read(OMAP_RTC_STATUS_REG); 412 if (reg & (u8) OMAP_RTC_STATUS_POWER_UP) { 413 pr_info("%s: RTC power up reset detected\n", 414 pdev->name); 415 rtc_write(OMAP_RTC_STATUS_POWER_UP, OMAP_RTC_STATUS_REG); 416 } 417 if (reg & (u8) OMAP_RTC_STATUS_ALARM) 418 rtc_write(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG); 419 420 /* handle periodic and alarm irqs */ 421 if (request_irq(omap_rtc_timer, rtc_irq, SA_INTERRUPT, 422 rtc->class_dev.class_id, &rtc->class_dev)) { 423 pr_debug("%s: RTC timer interrupt IRQ%d already claimed\n", 424 pdev->name, omap_rtc_timer); 425 goto fail0; 426 } 427 if (request_irq(omap_rtc_alarm, rtc_irq, SA_INTERRUPT, 428 rtc->class_dev.class_id, &rtc->class_dev)) { 429 pr_debug("%s: RTC alarm interrupt IRQ%d already claimed\n", 430 pdev->name, omap_rtc_alarm); 431 goto fail1; 432 } 433 434 /* On boards with split power, RTC_ON_NOFF won't reset the RTC */ 435 reg = rtc_read(OMAP_RTC_CTRL_REG); 436 if (reg & (u8) OMAP_RTC_CTRL_STOP) 437 pr_info("%s: already running\n", pdev->name); 438 439 /* force to 24 hour mode */ 440 new_ctrl = reg & ~(OMAP_RTC_CTRL_SPLIT|OMAP_RTC_CTRL_AUTO_COMP); 441 new_ctrl |= OMAP_RTC_CTRL_STOP; 442 443 /* BOARD-SPECIFIC CUSTOMIZATION CAN GO HERE: 444 * 445 * - Boards wired so that RTC_WAKE_INT does something, and muxed 446 * right (W13_1610_RTC_WAKE_INT is the default after chip reset), 447 * should initialize the device wakeup flag appropriately. 448 * 449 * - Boards wired so RTC_ON_nOFF is used as the reset signal, 450 * rather than nPWRON_RESET, should forcibly enable split 451 * power mode. (Some chip errata report that RTC_CTRL_SPLIT 452 * is write-only, and always reads as zero...) 453 */ 454 device_init_wakeup(&pdev->dev, 0); 455 456 if (new_ctrl & (u8) OMAP_RTC_CTRL_SPLIT) 457 pr_info("%s: split power mode\n", pdev->name); 458 459 if (reg != new_ctrl) 460 rtc_write(new_ctrl, OMAP_RTC_CTRL_REG); 461 462 return 0; 463 464 fail1: 465 free_irq(omap_rtc_timer, NULL); 466 fail0: 467 rtc_device_unregister(rtc); 468 fail: 469 release_resource(mem); 470 return -EIO; 471 } 472 473 static int __devexit omap_rtc_remove(struct platform_device *pdev) 474 { 475 struct rtc_device *rtc = platform_get_drvdata(pdev);; 476 477 device_init_wakeup(&pdev->dev, 0); 478 479 /* leave rtc running, but disable irqs */ 480 rtc_write(0, OMAP_RTC_INTERRUPTS_REG); 481 482 free_irq(omap_rtc_timer, rtc); 483 free_irq(omap_rtc_alarm, rtc); 484 485 release_resource(class_get_devdata(&rtc->class_dev)); 486 rtc_device_unregister(rtc); 487 return 0; 488 } 489 490 #ifdef CONFIG_PM 491 492 static struct timespec rtc_delta; 493 static u8 irqstat; 494 495 static int omap_rtc_suspend(struct platform_device *pdev, pm_message_t state) 496 { 497 struct rtc_time rtc_tm; 498 struct timespec time; 499 500 time.tv_nsec = 0; 501 omap_rtc_read_time(NULL, &rtc_tm); 502 rtc_tm_to_time(&rtc_tm, &time.tv_sec); 503 504 save_time_delta(&rtc_delta, &time); 505 irqstat = rtc_read(OMAP_RTC_INTERRUPTS_REG); 506 507 /* FIXME the RTC alarm is not currently acting as a wakeup event 508 * source, and in fact this enable() call is just saving a flag 509 * that's never used... 510 */ 511 if (device_may_wakeup(&pdev->dev)) 512 enable_irq_wake(omap_rtc_alarm); 513 else 514 rtc_write(0, OMAP_RTC_INTERRUPTS_REG); 515 516 return 0; 517 } 518 519 static int omap_rtc_resume(struct platform_device *pdev) 520 { 521 struct rtc_time rtc_tm; 522 struct timespec time; 523 524 time.tv_nsec = 0; 525 omap_rtc_read_time(NULL, &rtc_tm); 526 rtc_tm_to_time(&rtc_tm, &time.tv_sec); 527 528 restore_time_delta(&rtc_delta, &time); 529 if (device_may_wakeup(&pdev->dev)) 530 disable_irq_wake(omap_rtc_alarm); 531 else 532 rtc_write(irqstat, OMAP_RTC_INTERRUPTS_REG); 533 return 0; 534 } 535 536 #else 537 #define omap_rtc_suspend NULL 538 #define omap_rtc_resume NULL 539 #endif 540 541 static void omap_rtc_shutdown(struct platform_device *pdev) 542 { 543 rtc_write(0, OMAP_RTC_INTERRUPTS_REG); 544 } 545 546 MODULE_ALIAS("omap_rtc"); 547 static struct platform_driver omap_rtc_driver = { 548 .probe = omap_rtc_probe, 549 .remove = __devexit_p(omap_rtc_remove), 550 .suspend = omap_rtc_suspend, 551 .resume = omap_rtc_resume, 552 .shutdown = omap_rtc_shutdown, 553 .driver = { 554 .name = "omap_rtc", 555 .owner = THIS_MODULE, 556 }, 557 }; 558 559 static int __init rtc_init(void) 560 { 561 return platform_driver_register(&omap_rtc_driver); 562 } 563 module_init(rtc_init); 564 565 static void __exit rtc_exit(void) 566 { 567 platform_driver_unregister(&omap_rtc_driver); 568 } 569 module_exit(rtc_exit); 570 571 MODULE_AUTHOR("George G. Davis (and others)"); 572 MODULE_LICENSE("GPL"); 573