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) for OMAP1 boards (OMAP-L138 has this built into 38 * the SoC). 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 static void __iomem *rtc_base; 92 93 #define rtc_read(addr) __raw_readb(rtc_base + (addr)) 94 #define rtc_write(val, addr) __raw_writeb(val, rtc_base + (addr)) 95 96 97 /* we rely on the rtc framework to handle locking (rtc->ops_lock), 98 * so the only other requirement is that register accesses which 99 * require BUSY to be clear are made with IRQs locally disabled 100 */ 101 static void rtc_wait_not_busy(void) 102 { 103 int count = 0; 104 u8 status; 105 106 /* BUSY may stay active for 1/32768 second (~30 usec) */ 107 for (count = 0; count < 50; count++) { 108 status = rtc_read(OMAP_RTC_STATUS_REG); 109 if ((status & (u8)OMAP_RTC_STATUS_BUSY) == 0) 110 break; 111 udelay(1); 112 } 113 /* now we have ~15 usec to read/write various registers */ 114 } 115 116 static irqreturn_t rtc_irq(int irq, void *rtc) 117 { 118 unsigned long events = 0; 119 u8 irq_data; 120 121 irq_data = rtc_read(OMAP_RTC_STATUS_REG); 122 123 /* alarm irq? */ 124 if (irq_data & OMAP_RTC_STATUS_ALARM) { 125 rtc_write(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG); 126 events |= RTC_IRQF | RTC_AF; 127 } 128 129 /* 1/sec periodic/update irq? */ 130 if (irq_data & OMAP_RTC_STATUS_1S_EVENT) 131 events |= RTC_IRQF | RTC_UF; 132 133 rtc_update_irq(rtc, 1, events); 134 135 return IRQ_HANDLED; 136 } 137 138 static int omap_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) 139 { 140 u8 reg; 141 142 local_irq_disable(); 143 rtc_wait_not_busy(); 144 reg = rtc_read(OMAP_RTC_INTERRUPTS_REG); 145 if (enabled) 146 reg |= OMAP_RTC_INTERRUPTS_IT_ALARM; 147 else 148 reg &= ~OMAP_RTC_INTERRUPTS_IT_ALARM; 149 rtc_wait_not_busy(); 150 rtc_write(reg, OMAP_RTC_INTERRUPTS_REG); 151 local_irq_enable(); 152 153 return 0; 154 } 155 156 /* this hardware doesn't support "don't care" alarm fields */ 157 static int tm2bcd(struct rtc_time *tm) 158 { 159 if (rtc_valid_tm(tm) != 0) 160 return -EINVAL; 161 162 tm->tm_sec = bin2bcd(tm->tm_sec); 163 tm->tm_min = bin2bcd(tm->tm_min); 164 tm->tm_hour = bin2bcd(tm->tm_hour); 165 tm->tm_mday = bin2bcd(tm->tm_mday); 166 167 tm->tm_mon = bin2bcd(tm->tm_mon + 1); 168 169 /* epoch == 1900 */ 170 if (tm->tm_year < 100 || tm->tm_year > 199) 171 return -EINVAL; 172 tm->tm_year = bin2bcd(tm->tm_year - 100); 173 174 return 0; 175 } 176 177 static void bcd2tm(struct rtc_time *tm) 178 { 179 tm->tm_sec = bcd2bin(tm->tm_sec); 180 tm->tm_min = bcd2bin(tm->tm_min); 181 tm->tm_hour = bcd2bin(tm->tm_hour); 182 tm->tm_mday = bcd2bin(tm->tm_mday); 183 tm->tm_mon = bcd2bin(tm->tm_mon) - 1; 184 /* epoch == 1900 */ 185 tm->tm_year = bcd2bin(tm->tm_year) + 100; 186 } 187 188 189 static int omap_rtc_read_time(struct device *dev, struct rtc_time *tm) 190 { 191 /* we don't report wday/yday/isdst ... */ 192 local_irq_disable(); 193 rtc_wait_not_busy(); 194 195 tm->tm_sec = rtc_read(OMAP_RTC_SECONDS_REG); 196 tm->tm_min = rtc_read(OMAP_RTC_MINUTES_REG); 197 tm->tm_hour = rtc_read(OMAP_RTC_HOURS_REG); 198 tm->tm_mday = rtc_read(OMAP_RTC_DAYS_REG); 199 tm->tm_mon = rtc_read(OMAP_RTC_MONTHS_REG); 200 tm->tm_year = rtc_read(OMAP_RTC_YEARS_REG); 201 202 local_irq_enable(); 203 204 bcd2tm(tm); 205 return 0; 206 } 207 208 static int omap_rtc_set_time(struct device *dev, struct rtc_time *tm) 209 { 210 if (tm2bcd(tm) < 0) 211 return -EINVAL; 212 local_irq_disable(); 213 rtc_wait_not_busy(); 214 215 rtc_write(tm->tm_year, OMAP_RTC_YEARS_REG); 216 rtc_write(tm->tm_mon, OMAP_RTC_MONTHS_REG); 217 rtc_write(tm->tm_mday, OMAP_RTC_DAYS_REG); 218 rtc_write(tm->tm_hour, OMAP_RTC_HOURS_REG); 219 rtc_write(tm->tm_min, OMAP_RTC_MINUTES_REG); 220 rtc_write(tm->tm_sec, OMAP_RTC_SECONDS_REG); 221 222 local_irq_enable(); 223 224 return 0; 225 } 226 227 static int omap_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm) 228 { 229 local_irq_disable(); 230 rtc_wait_not_busy(); 231 232 alm->time.tm_sec = rtc_read(OMAP_RTC_ALARM_SECONDS_REG); 233 alm->time.tm_min = rtc_read(OMAP_RTC_ALARM_MINUTES_REG); 234 alm->time.tm_hour = rtc_read(OMAP_RTC_ALARM_HOURS_REG); 235 alm->time.tm_mday = rtc_read(OMAP_RTC_ALARM_DAYS_REG); 236 alm->time.tm_mon = rtc_read(OMAP_RTC_ALARM_MONTHS_REG); 237 alm->time.tm_year = rtc_read(OMAP_RTC_ALARM_YEARS_REG); 238 239 local_irq_enable(); 240 241 bcd2tm(&alm->time); 242 alm->enabled = !!(rtc_read(OMAP_RTC_INTERRUPTS_REG) 243 & OMAP_RTC_INTERRUPTS_IT_ALARM); 244 245 return 0; 246 } 247 248 static int omap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm) 249 { 250 u8 reg; 251 252 if (tm2bcd(&alm->time) < 0) 253 return -EINVAL; 254 255 local_irq_disable(); 256 rtc_wait_not_busy(); 257 258 rtc_write(alm->time.tm_year, OMAP_RTC_ALARM_YEARS_REG); 259 rtc_write(alm->time.tm_mon, OMAP_RTC_ALARM_MONTHS_REG); 260 rtc_write(alm->time.tm_mday, OMAP_RTC_ALARM_DAYS_REG); 261 rtc_write(alm->time.tm_hour, OMAP_RTC_ALARM_HOURS_REG); 262 rtc_write(alm->time.tm_min, OMAP_RTC_ALARM_MINUTES_REG); 263 rtc_write(alm->time.tm_sec, OMAP_RTC_ALARM_SECONDS_REG); 264 265 reg = rtc_read(OMAP_RTC_INTERRUPTS_REG); 266 if (alm->enabled) 267 reg |= OMAP_RTC_INTERRUPTS_IT_ALARM; 268 else 269 reg &= ~OMAP_RTC_INTERRUPTS_IT_ALARM; 270 rtc_write(reg, OMAP_RTC_INTERRUPTS_REG); 271 272 local_irq_enable(); 273 274 return 0; 275 } 276 277 static struct rtc_class_ops omap_rtc_ops = { 278 .read_time = omap_rtc_read_time, 279 .set_time = omap_rtc_set_time, 280 .read_alarm = omap_rtc_read_alarm, 281 .set_alarm = omap_rtc_set_alarm, 282 .alarm_irq_enable = omap_rtc_alarm_irq_enable, 283 }; 284 285 static int omap_rtc_alarm; 286 static int omap_rtc_timer; 287 288 static int __init omap_rtc_probe(struct platform_device *pdev) 289 { 290 struct resource *res, *mem; 291 struct rtc_device *rtc; 292 u8 reg, new_ctrl; 293 294 omap_rtc_timer = platform_get_irq(pdev, 0); 295 if (omap_rtc_timer <= 0) { 296 pr_debug("%s: no update irq?\n", pdev->name); 297 return -ENOENT; 298 } 299 300 omap_rtc_alarm = platform_get_irq(pdev, 1); 301 if (omap_rtc_alarm <= 0) { 302 pr_debug("%s: no alarm irq?\n", pdev->name); 303 return -ENOENT; 304 } 305 306 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 307 if (!res) { 308 pr_debug("%s: RTC resource data missing\n", pdev->name); 309 return -ENOENT; 310 } 311 312 mem = request_mem_region(res->start, resource_size(res), pdev->name); 313 if (!mem) { 314 pr_debug("%s: RTC registers at %08x are not free\n", 315 pdev->name, res->start); 316 return -EBUSY; 317 } 318 319 rtc_base = ioremap(res->start, resource_size(res)); 320 if (!rtc_base) { 321 pr_debug("%s: RTC registers can't be mapped\n", pdev->name); 322 goto fail; 323 } 324 325 rtc = rtc_device_register(pdev->name, &pdev->dev, 326 &omap_rtc_ops, THIS_MODULE); 327 if (IS_ERR(rtc)) { 328 pr_debug("%s: can't register RTC device, err %ld\n", 329 pdev->name, PTR_ERR(rtc)); 330 goto fail0; 331 } 332 platform_set_drvdata(pdev, rtc); 333 dev_set_drvdata(&rtc->dev, mem); 334 335 /* clear pending irqs, and set 1/second periodic, 336 * which we'll use instead of update irqs 337 */ 338 rtc_write(0, OMAP_RTC_INTERRUPTS_REG); 339 340 /* clear old status */ 341 reg = rtc_read(OMAP_RTC_STATUS_REG); 342 if (reg & (u8) OMAP_RTC_STATUS_POWER_UP) { 343 pr_info("%s: RTC power up reset detected\n", 344 pdev->name); 345 rtc_write(OMAP_RTC_STATUS_POWER_UP, OMAP_RTC_STATUS_REG); 346 } 347 if (reg & (u8) OMAP_RTC_STATUS_ALARM) 348 rtc_write(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG); 349 350 /* handle periodic and alarm irqs */ 351 if (request_irq(omap_rtc_timer, rtc_irq, IRQF_DISABLED, 352 dev_name(&rtc->dev), rtc)) { 353 pr_debug("%s: RTC timer interrupt IRQ%d already claimed\n", 354 pdev->name, omap_rtc_timer); 355 goto fail1; 356 } 357 if ((omap_rtc_timer != omap_rtc_alarm) && 358 (request_irq(omap_rtc_alarm, rtc_irq, IRQF_DISABLED, 359 dev_name(&rtc->dev), rtc))) { 360 pr_debug("%s: RTC alarm interrupt IRQ%d already claimed\n", 361 pdev->name, omap_rtc_alarm); 362 goto fail2; 363 } 364 365 /* On boards with split power, RTC_ON_NOFF won't reset the RTC */ 366 reg = rtc_read(OMAP_RTC_CTRL_REG); 367 if (reg & (u8) OMAP_RTC_CTRL_STOP) 368 pr_info("%s: already running\n", pdev->name); 369 370 /* force to 24 hour mode */ 371 new_ctrl = reg & ~(OMAP_RTC_CTRL_SPLIT|OMAP_RTC_CTRL_AUTO_COMP); 372 new_ctrl |= OMAP_RTC_CTRL_STOP; 373 374 /* BOARD-SPECIFIC CUSTOMIZATION CAN GO HERE: 375 * 376 * - Device wake-up capability setting should come through chip 377 * init logic. OMAP1 boards should initialize the "wakeup capable" 378 * flag in the platform device if the board is wired right for 379 * being woken up by RTC alarm. For OMAP-L138, this capability 380 * is built into the SoC by the "Deep Sleep" capability. 381 * 382 * - Boards wired so RTC_ON_nOFF is used as the reset signal, 383 * rather than nPWRON_RESET, should forcibly enable split 384 * power mode. (Some chip errata report that RTC_CTRL_SPLIT 385 * is write-only, and always reads as zero...) 386 */ 387 388 if (new_ctrl & (u8) OMAP_RTC_CTRL_SPLIT) 389 pr_info("%s: split power mode\n", pdev->name); 390 391 if (reg != new_ctrl) 392 rtc_write(new_ctrl, OMAP_RTC_CTRL_REG); 393 394 return 0; 395 396 fail2: 397 free_irq(omap_rtc_timer, NULL); 398 fail1: 399 rtc_device_unregister(rtc); 400 fail0: 401 iounmap(rtc_base); 402 fail: 403 release_mem_region(mem->start, resource_size(mem)); 404 return -EIO; 405 } 406 407 static int __exit omap_rtc_remove(struct platform_device *pdev) 408 { 409 struct rtc_device *rtc = platform_get_drvdata(pdev); 410 struct resource *mem = dev_get_drvdata(&rtc->dev); 411 412 device_init_wakeup(&pdev->dev, 0); 413 414 /* leave rtc running, but disable irqs */ 415 rtc_write(0, OMAP_RTC_INTERRUPTS_REG); 416 417 free_irq(omap_rtc_timer, rtc); 418 419 if (omap_rtc_timer != omap_rtc_alarm) 420 free_irq(omap_rtc_alarm, rtc); 421 422 rtc_device_unregister(rtc); 423 iounmap(rtc_base); 424 release_mem_region(mem->start, resource_size(mem)); 425 return 0; 426 } 427 428 #ifdef CONFIG_PM 429 430 static u8 irqstat; 431 432 static int omap_rtc_suspend(struct platform_device *pdev, pm_message_t state) 433 { 434 irqstat = rtc_read(OMAP_RTC_INTERRUPTS_REG); 435 436 /* FIXME the RTC alarm is not currently acting as a wakeup event 437 * source, and in fact this enable() call is just saving a flag 438 * that's never used... 439 */ 440 if (device_may_wakeup(&pdev->dev)) 441 enable_irq_wake(omap_rtc_alarm); 442 else 443 rtc_write(0, OMAP_RTC_INTERRUPTS_REG); 444 445 return 0; 446 } 447 448 static int omap_rtc_resume(struct platform_device *pdev) 449 { 450 if (device_may_wakeup(&pdev->dev)) 451 disable_irq_wake(omap_rtc_alarm); 452 else 453 rtc_write(irqstat, OMAP_RTC_INTERRUPTS_REG); 454 return 0; 455 } 456 457 #else 458 #define omap_rtc_suspend NULL 459 #define omap_rtc_resume NULL 460 #endif 461 462 static void omap_rtc_shutdown(struct platform_device *pdev) 463 { 464 rtc_write(0, OMAP_RTC_INTERRUPTS_REG); 465 } 466 467 MODULE_ALIAS("platform:omap_rtc"); 468 static struct platform_driver omap_rtc_driver = { 469 .remove = __exit_p(omap_rtc_remove), 470 .suspend = omap_rtc_suspend, 471 .resume = omap_rtc_resume, 472 .shutdown = omap_rtc_shutdown, 473 .driver = { 474 .name = "omap_rtc", 475 .owner = THIS_MODULE, 476 }, 477 }; 478 479 static int __init rtc_init(void) 480 { 481 return platform_driver_probe(&omap_rtc_driver, omap_rtc_probe); 482 } 483 module_init(rtc_init); 484 485 static void __exit rtc_exit(void) 486 { 487 platform_driver_unregister(&omap_rtc_driver); 488 } 489 module_exit(rtc_exit); 490 491 MODULE_AUTHOR("George G. Davis (and others)"); 492 MODULE_LICENSE("GPL"); 493