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->enabled = !!(rtc_read(OMAP_RTC_INTERRUPTS_REG) 283 & OMAP_RTC_INTERRUPTS_IT_ALARM); 284 285 return 0; 286 } 287 288 static int omap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm) 289 { 290 u8 reg; 291 292 /* Much userspace code uses RTC_ALM_SET, thus "don't care" for 293 * day/month/year specifies alarms up to 24 hours in the future. 294 * So we need to handle that ... but let's ignore the "don't care" 295 * values for hours/minutes/seconds. 296 */ 297 if (alm->time.tm_mday <= 0 298 && alm->time.tm_mon < 0 299 && alm->time.tm_year < 0) { 300 struct rtc_time tm; 301 unsigned long now, then; 302 303 omap_rtc_read_time(dev, &tm); 304 rtc_tm_to_time(&tm, &now); 305 306 alm->time.tm_mday = tm.tm_mday; 307 alm->time.tm_mon = tm.tm_mon; 308 alm->time.tm_year = tm.tm_year; 309 rtc_tm_to_time(&alm->time, &then); 310 311 /* sometimes the alarm wraps into tomorrow */ 312 if (then < now) { 313 rtc_time_to_tm(now + 24 * 60 * 60, &tm); 314 alm->time.tm_mday = tm.tm_mday; 315 alm->time.tm_mon = tm.tm_mon; 316 alm->time.tm_year = tm.tm_year; 317 } 318 } 319 320 if (tm2bcd(&alm->time) < 0) 321 return -EINVAL; 322 323 local_irq_disable(); 324 rtc_wait_not_busy(); 325 326 rtc_write(alm->time.tm_year, OMAP_RTC_ALARM_YEARS_REG); 327 rtc_write(alm->time.tm_mon, OMAP_RTC_ALARM_MONTHS_REG); 328 rtc_write(alm->time.tm_mday, OMAP_RTC_ALARM_DAYS_REG); 329 rtc_write(alm->time.tm_hour, OMAP_RTC_ALARM_HOURS_REG); 330 rtc_write(alm->time.tm_min, OMAP_RTC_ALARM_MINUTES_REG); 331 rtc_write(alm->time.tm_sec, OMAP_RTC_ALARM_SECONDS_REG); 332 333 reg = rtc_read(OMAP_RTC_INTERRUPTS_REG); 334 if (alm->enabled) 335 reg |= OMAP_RTC_INTERRUPTS_IT_ALARM; 336 else 337 reg &= ~OMAP_RTC_INTERRUPTS_IT_ALARM; 338 rtc_write(reg, OMAP_RTC_INTERRUPTS_REG); 339 340 local_irq_enable(); 341 342 return 0; 343 } 344 345 static struct rtc_class_ops omap_rtc_ops = { 346 .ioctl = omap_rtc_ioctl, 347 .read_time = omap_rtc_read_time, 348 .set_time = omap_rtc_set_time, 349 .read_alarm = omap_rtc_read_alarm, 350 .set_alarm = omap_rtc_set_alarm, 351 }; 352 353 static int omap_rtc_alarm; 354 static int omap_rtc_timer; 355 356 static int __devinit omap_rtc_probe(struct platform_device *pdev) 357 { 358 struct resource *res, *mem; 359 struct rtc_device *rtc; 360 u8 reg, new_ctrl; 361 362 omap_rtc_timer = platform_get_irq(pdev, 0); 363 if (omap_rtc_timer <= 0) { 364 pr_debug("%s: no update irq?\n", pdev->name); 365 return -ENOENT; 366 } 367 368 omap_rtc_alarm = platform_get_irq(pdev, 1); 369 if (omap_rtc_alarm <= 0) { 370 pr_debug("%s: no alarm irq?\n", pdev->name); 371 return -ENOENT; 372 } 373 374 /* NOTE: using static mapping for RTC registers */ 375 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 376 if (res && res->start != OMAP_RTC_BASE) { 377 pr_debug("%s: RTC registers at %08x, expected %08x\n", 378 pdev->name, (unsigned) res->start, OMAP_RTC_BASE); 379 return -ENOENT; 380 } 381 382 if (res) 383 mem = request_mem_region(res->start, 384 res->end - res->start + 1, 385 pdev->name); 386 else 387 mem = NULL; 388 if (!mem) { 389 pr_debug("%s: RTC registers at %08x are not free\n", 390 pdev->name, OMAP_RTC_BASE); 391 return -EBUSY; 392 } 393 394 rtc = rtc_device_register(pdev->name, &pdev->dev, 395 &omap_rtc_ops, THIS_MODULE); 396 if (IS_ERR(rtc)) { 397 pr_debug("%s: can't register RTC device, err %ld\n", 398 pdev->name, PTR_ERR(rtc)); 399 goto fail; 400 } 401 platform_set_drvdata(pdev, rtc); 402 class_set_devdata(&rtc->class_dev, mem); 403 404 /* clear pending irqs, and set 1/second periodic, 405 * which we'll use instead of update irqs 406 */ 407 rtc_write(0, OMAP_RTC_INTERRUPTS_REG); 408 409 /* clear old status */ 410 reg = rtc_read(OMAP_RTC_STATUS_REG); 411 if (reg & (u8) OMAP_RTC_STATUS_POWER_UP) { 412 pr_info("%s: RTC power up reset detected\n", 413 pdev->name); 414 rtc_write(OMAP_RTC_STATUS_POWER_UP, OMAP_RTC_STATUS_REG); 415 } 416 if (reg & (u8) OMAP_RTC_STATUS_ALARM) 417 rtc_write(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG); 418 419 /* handle periodic and alarm irqs */ 420 if (request_irq(omap_rtc_timer, rtc_irq, IRQF_DISABLED, 421 rtc->class_dev.class_id, &rtc->class_dev)) { 422 pr_debug("%s: RTC timer interrupt IRQ%d already claimed\n", 423 pdev->name, omap_rtc_timer); 424 goto fail0; 425 } 426 if (request_irq(omap_rtc_alarm, rtc_irq, IRQF_DISABLED, 427 rtc->class_dev.class_id, &rtc->class_dev)) { 428 pr_debug("%s: RTC alarm interrupt IRQ%d already claimed\n", 429 pdev->name, omap_rtc_alarm); 430 goto fail1; 431 } 432 433 /* On boards with split power, RTC_ON_NOFF won't reset the RTC */ 434 reg = rtc_read(OMAP_RTC_CTRL_REG); 435 if (reg & (u8) OMAP_RTC_CTRL_STOP) 436 pr_info("%s: already running\n", pdev->name); 437 438 /* force to 24 hour mode */ 439 new_ctrl = reg & ~(OMAP_RTC_CTRL_SPLIT|OMAP_RTC_CTRL_AUTO_COMP); 440 new_ctrl |= OMAP_RTC_CTRL_STOP; 441 442 /* BOARD-SPECIFIC CUSTOMIZATION CAN GO HERE: 443 * 444 * - Boards wired so that RTC_WAKE_INT does something, and muxed 445 * right (W13_1610_RTC_WAKE_INT is the default after chip reset), 446 * should initialize the device wakeup flag appropriately. 447 * 448 * - Boards wired so RTC_ON_nOFF is used as the reset signal, 449 * rather than nPWRON_RESET, should forcibly enable split 450 * power mode. (Some chip errata report that RTC_CTRL_SPLIT 451 * is write-only, and always reads as zero...) 452 */ 453 device_init_wakeup(&pdev->dev, 0); 454 455 if (new_ctrl & (u8) OMAP_RTC_CTRL_SPLIT) 456 pr_info("%s: split power mode\n", pdev->name); 457 458 if (reg != new_ctrl) 459 rtc_write(new_ctrl, OMAP_RTC_CTRL_REG); 460 461 return 0; 462 463 fail1: 464 free_irq(omap_rtc_timer, NULL); 465 fail0: 466 rtc_device_unregister(rtc); 467 fail: 468 release_resource(mem); 469 return -EIO; 470 } 471 472 static int __devexit omap_rtc_remove(struct platform_device *pdev) 473 { 474 struct rtc_device *rtc = platform_get_drvdata(pdev);; 475 476 device_init_wakeup(&pdev->dev, 0); 477 478 /* leave rtc running, but disable irqs */ 479 rtc_write(0, OMAP_RTC_INTERRUPTS_REG); 480 481 free_irq(omap_rtc_timer, rtc); 482 free_irq(omap_rtc_alarm, rtc); 483 484 release_resource(class_get_devdata(&rtc->class_dev)); 485 rtc_device_unregister(rtc); 486 return 0; 487 } 488 489 #ifdef CONFIG_PM 490 491 static struct timespec rtc_delta; 492 static u8 irqstat; 493 494 static int omap_rtc_suspend(struct platform_device *pdev, pm_message_t state) 495 { 496 struct rtc_time rtc_tm; 497 struct timespec time; 498 499 time.tv_nsec = 0; 500 omap_rtc_read_time(NULL, &rtc_tm); 501 rtc_tm_to_time(&rtc_tm, &time.tv_sec); 502 503 save_time_delta(&rtc_delta, &time); 504 irqstat = rtc_read(OMAP_RTC_INTERRUPTS_REG); 505 506 /* FIXME the RTC alarm is not currently acting as a wakeup event 507 * source, and in fact this enable() call is just saving a flag 508 * that's never used... 509 */ 510 if (device_may_wakeup(&pdev->dev)) 511 enable_irq_wake(omap_rtc_alarm); 512 else 513 rtc_write(0, OMAP_RTC_INTERRUPTS_REG); 514 515 return 0; 516 } 517 518 static int omap_rtc_resume(struct platform_device *pdev) 519 { 520 struct rtc_time rtc_tm; 521 struct timespec time; 522 523 time.tv_nsec = 0; 524 omap_rtc_read_time(NULL, &rtc_tm); 525 rtc_tm_to_time(&rtc_tm, &time.tv_sec); 526 527 restore_time_delta(&rtc_delta, &time); 528 if (device_may_wakeup(&pdev->dev)) 529 disable_irq_wake(omap_rtc_alarm); 530 else 531 rtc_write(irqstat, OMAP_RTC_INTERRUPTS_REG); 532 return 0; 533 } 534 535 #else 536 #define omap_rtc_suspend NULL 537 #define omap_rtc_resume NULL 538 #endif 539 540 static void omap_rtc_shutdown(struct platform_device *pdev) 541 { 542 rtc_write(0, OMAP_RTC_INTERRUPTS_REG); 543 } 544 545 MODULE_ALIAS("omap_rtc"); 546 static struct platform_driver omap_rtc_driver = { 547 .probe = omap_rtc_probe, 548 .remove = __devexit_p(omap_rtc_remove), 549 .suspend = omap_rtc_suspend, 550 .resume = omap_rtc_resume, 551 .shutdown = omap_rtc_shutdown, 552 .driver = { 553 .name = "omap_rtc", 554 .owner = THIS_MODULE, 555 }, 556 }; 557 558 static int __init rtc_init(void) 559 { 560 return platform_driver_register(&omap_rtc_driver); 561 } 562 module_init(rtc_init); 563 564 static void __exit rtc_exit(void) 565 { 566 platform_driver_unregister(&omap_rtc_driver); 567 } 568 module_exit(rtc_exit); 569 570 MODULE_AUTHOR("George G. Davis (and others)"); 571 MODULE_LICENSE("GPL"); 572