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