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/bcd.h> 22 #include <linux/clk.h> 23 #include <linux/completion.h> 24 #include <linux/interrupt.h> 25 #include <linux/ioctl.h> 26 #include <linux/io.h> 27 #include <linux/kernel.h> 28 #include <linux/module.h> 29 #include <linux/of_device.h> 30 #include <linux/of.h> 31 #include <linux/platform_device.h> 32 #include <linux/rtc.h> 33 #include <linux/spinlock.h> 34 #include <linux/suspend.h> 35 #include <linux/time.h> 36 #include <linux/uaccess.h> 37 38 #include "rtc-at91rm9200.h" 39 40 #define at91_rtc_read(field) \ 41 readl_relaxed(at91_rtc_regs + field) 42 #define at91_rtc_write(field, val) \ 43 writel_relaxed((val), at91_rtc_regs + field) 44 45 struct at91_rtc_config { 46 bool use_shadow_imr; 47 }; 48 49 static const struct at91_rtc_config *at91_rtc_config; 50 static DECLARE_COMPLETION(at91_rtc_updated); 51 static DECLARE_COMPLETION(at91_rtc_upd_rdy); 52 static void __iomem *at91_rtc_regs; 53 static int irq; 54 static DEFINE_SPINLOCK(at91_rtc_lock); 55 static u32 at91_rtc_shadow_imr; 56 static bool suspended; 57 static DEFINE_SPINLOCK(suspended_lock); 58 static unsigned long cached_events; 59 static u32 at91_rtc_imr; 60 static struct clk *sclk; 61 62 static void at91_rtc_write_ier(u32 mask) 63 { 64 unsigned long flags; 65 66 spin_lock_irqsave(&at91_rtc_lock, flags); 67 at91_rtc_shadow_imr |= mask; 68 at91_rtc_write(AT91_RTC_IER, mask); 69 spin_unlock_irqrestore(&at91_rtc_lock, flags); 70 } 71 72 static void at91_rtc_write_idr(u32 mask) 73 { 74 unsigned long flags; 75 76 spin_lock_irqsave(&at91_rtc_lock, flags); 77 at91_rtc_write(AT91_RTC_IDR, mask); 78 /* 79 * Register read back (of any RTC-register) needed to make sure 80 * IDR-register write has reached the peripheral before updating 81 * shadow mask. 82 * 83 * Note that there is still a possibility that the mask is updated 84 * before interrupts have actually been disabled in hardware. The only 85 * way to be certain would be to poll the IMR-register, which is is 86 * the very register we are trying to emulate. The register read back 87 * is a reasonable heuristic. 88 */ 89 at91_rtc_read(AT91_RTC_SR); 90 at91_rtc_shadow_imr &= ~mask; 91 spin_unlock_irqrestore(&at91_rtc_lock, flags); 92 } 93 94 static u32 at91_rtc_read_imr(void) 95 { 96 unsigned long flags; 97 u32 mask; 98 99 if (at91_rtc_config->use_shadow_imr) { 100 spin_lock_irqsave(&at91_rtc_lock, flags); 101 mask = at91_rtc_shadow_imr; 102 spin_unlock_irqrestore(&at91_rtc_lock, flags); 103 } else { 104 mask = at91_rtc_read(AT91_RTC_IMR); 105 } 106 107 return mask; 108 } 109 110 /* 111 * Decode time/date into rtc_time structure 112 */ 113 static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg, 114 struct rtc_time *tm) 115 { 116 unsigned int time, date; 117 118 /* must read twice in case it changes */ 119 do { 120 time = at91_rtc_read(timereg); 121 date = at91_rtc_read(calreg); 122 } while ((time != at91_rtc_read(timereg)) || 123 (date != at91_rtc_read(calreg))); 124 125 tm->tm_sec = bcd2bin((time & AT91_RTC_SEC) >> 0); 126 tm->tm_min = bcd2bin((time & AT91_RTC_MIN) >> 8); 127 tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16); 128 129 /* 130 * The Calendar Alarm register does not have a field for 131 * the year - so these will return an invalid value. 132 */ 133 tm->tm_year = bcd2bin(date & AT91_RTC_CENT) * 100; /* century */ 134 tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8); /* year */ 135 136 tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */ 137 tm->tm_mon = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1; 138 tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24); 139 } 140 141 /* 142 * Read current time and date in RTC 143 */ 144 static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm) 145 { 146 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm); 147 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year); 148 tm->tm_year = tm->tm_year - 1900; 149 150 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__, 151 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday, 152 tm->tm_hour, tm->tm_min, tm->tm_sec); 153 154 return 0; 155 } 156 157 /* 158 * Set current time and date in RTC 159 */ 160 static int at91_rtc_settime(struct device *dev, struct rtc_time *tm) 161 { 162 unsigned long cr; 163 164 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__, 165 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday, 166 tm->tm_hour, tm->tm_min, tm->tm_sec); 167 168 wait_for_completion(&at91_rtc_upd_rdy); 169 170 /* Stop Time/Calendar from counting */ 171 cr = at91_rtc_read(AT91_RTC_CR); 172 at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM); 173 174 at91_rtc_write_ier(AT91_RTC_ACKUPD); 175 wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */ 176 at91_rtc_write_idr(AT91_RTC_ACKUPD); 177 178 at91_rtc_write(AT91_RTC_TIMR, 179 bin2bcd(tm->tm_sec) << 0 180 | bin2bcd(tm->tm_min) << 8 181 | bin2bcd(tm->tm_hour) << 16); 182 183 at91_rtc_write(AT91_RTC_CALR, 184 bin2bcd((tm->tm_year + 1900) / 100) /* century */ 185 | bin2bcd(tm->tm_year % 100) << 8 /* year */ 186 | bin2bcd(tm->tm_mon + 1) << 16 /* tm_mon starts at zero */ 187 | bin2bcd(tm->tm_wday + 1) << 21 /* day of the week [0-6], Sunday=0 */ 188 | bin2bcd(tm->tm_mday) << 24); 189 190 /* Restart Time/Calendar */ 191 cr = at91_rtc_read(AT91_RTC_CR); 192 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_SECEV); 193 at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM)); 194 at91_rtc_write_ier(AT91_RTC_SECEV); 195 196 return 0; 197 } 198 199 /* 200 * Read alarm time and date in RTC 201 */ 202 static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm) 203 { 204 struct rtc_time *tm = &alrm->time; 205 206 at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm); 207 tm->tm_year = -1; 208 209 alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM) 210 ? 1 : 0; 211 212 dev_dbg(dev, "%s(): %02d-%02d %02d:%02d:%02d %sabled\n", __func__, 213 tm->tm_mon, tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec, 214 alrm->enabled ? "en" : "dis"); 215 216 return 0; 217 } 218 219 /* 220 * Set alarm time and date in RTC 221 */ 222 static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm) 223 { 224 struct rtc_time tm; 225 226 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm); 227 228 tm.tm_mon = alrm->time.tm_mon; 229 tm.tm_mday = alrm->time.tm_mday; 230 tm.tm_hour = alrm->time.tm_hour; 231 tm.tm_min = alrm->time.tm_min; 232 tm.tm_sec = alrm->time.tm_sec; 233 234 at91_rtc_write_idr(AT91_RTC_ALARM); 235 at91_rtc_write(AT91_RTC_TIMALR, 236 bin2bcd(tm.tm_sec) << 0 237 | bin2bcd(tm.tm_min) << 8 238 | bin2bcd(tm.tm_hour) << 16 239 | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN); 240 at91_rtc_write(AT91_RTC_CALALR, 241 bin2bcd(tm.tm_mon + 1) << 16 /* tm_mon starts at zero */ 242 | bin2bcd(tm.tm_mday) << 24 243 | AT91_RTC_DATEEN | AT91_RTC_MTHEN); 244 245 if (alrm->enabled) { 246 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM); 247 at91_rtc_write_ier(AT91_RTC_ALARM); 248 } 249 250 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__, 251 tm.tm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour, 252 tm.tm_min, tm.tm_sec); 253 254 return 0; 255 } 256 257 static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) 258 { 259 dev_dbg(dev, "%s(): cmd=%08x\n", __func__, enabled); 260 261 if (enabled) { 262 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM); 263 at91_rtc_write_ier(AT91_RTC_ALARM); 264 } else 265 at91_rtc_write_idr(AT91_RTC_ALARM); 266 267 return 0; 268 } 269 /* 270 * Provide additional RTC information in /proc/driver/rtc 271 */ 272 static int at91_rtc_proc(struct device *dev, struct seq_file *seq) 273 { 274 unsigned long imr = at91_rtc_read_imr(); 275 276 seq_printf(seq, "update_IRQ\t: %s\n", 277 (imr & AT91_RTC_ACKUPD) ? "yes" : "no"); 278 seq_printf(seq, "periodic_IRQ\t: %s\n", 279 (imr & AT91_RTC_SECEV) ? "yes" : "no"); 280 281 return 0; 282 } 283 284 /* 285 * IRQ handler for the RTC 286 */ 287 static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id) 288 { 289 struct platform_device *pdev = dev_id; 290 struct rtc_device *rtc = platform_get_drvdata(pdev); 291 unsigned int rtsr; 292 unsigned long events = 0; 293 int ret = IRQ_NONE; 294 295 spin_lock(&suspended_lock); 296 rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr(); 297 if (rtsr) { /* this interrupt is shared! Is it ours? */ 298 if (rtsr & AT91_RTC_ALARM) 299 events |= (RTC_AF | RTC_IRQF); 300 if (rtsr & AT91_RTC_SECEV) { 301 complete(&at91_rtc_upd_rdy); 302 at91_rtc_write_idr(AT91_RTC_SECEV); 303 } 304 if (rtsr & AT91_RTC_ACKUPD) 305 complete(&at91_rtc_updated); 306 307 at91_rtc_write(AT91_RTC_SCCR, rtsr); /* clear status reg */ 308 309 if (!suspended) { 310 rtc_update_irq(rtc, 1, events); 311 312 dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n", 313 __func__, events >> 8, events & 0x000000FF); 314 } else { 315 cached_events |= events; 316 at91_rtc_write_idr(at91_rtc_imr); 317 pm_system_wakeup(); 318 } 319 320 ret = IRQ_HANDLED; 321 } 322 spin_unlock(&suspended_lock); 323 324 return ret; 325 } 326 327 static const struct at91_rtc_config at91rm9200_config = { 328 }; 329 330 static const struct at91_rtc_config at91sam9x5_config = { 331 .use_shadow_imr = true, 332 }; 333 334 #ifdef CONFIG_OF 335 static const struct of_device_id at91_rtc_dt_ids[] = { 336 { 337 .compatible = "atmel,at91rm9200-rtc", 338 .data = &at91rm9200_config, 339 }, { 340 .compatible = "atmel,at91sam9x5-rtc", 341 .data = &at91sam9x5_config, 342 }, { 343 /* sentinel */ 344 } 345 }; 346 MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids); 347 #endif 348 349 static const struct at91_rtc_config * 350 at91_rtc_get_config(struct platform_device *pdev) 351 { 352 const struct of_device_id *match; 353 354 if (pdev->dev.of_node) { 355 match = of_match_node(at91_rtc_dt_ids, pdev->dev.of_node); 356 if (!match) 357 return NULL; 358 return (const struct at91_rtc_config *)match->data; 359 } 360 361 return &at91rm9200_config; 362 } 363 364 static const struct rtc_class_ops at91_rtc_ops = { 365 .read_time = at91_rtc_readtime, 366 .set_time = at91_rtc_settime, 367 .read_alarm = at91_rtc_readalarm, 368 .set_alarm = at91_rtc_setalarm, 369 .proc = at91_rtc_proc, 370 .alarm_irq_enable = at91_rtc_alarm_irq_enable, 371 }; 372 373 /* 374 * Initialize and install RTC driver 375 */ 376 static int __init at91_rtc_probe(struct platform_device *pdev) 377 { 378 struct rtc_device *rtc; 379 struct resource *regs; 380 int ret = 0; 381 382 at91_rtc_config = at91_rtc_get_config(pdev); 383 if (!at91_rtc_config) 384 return -ENODEV; 385 386 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); 387 if (!regs) { 388 dev_err(&pdev->dev, "no mmio resource defined\n"); 389 return -ENXIO; 390 } 391 392 irq = platform_get_irq(pdev, 0); 393 if (irq < 0) { 394 dev_err(&pdev->dev, "no irq resource defined\n"); 395 return -ENXIO; 396 } 397 398 at91_rtc_regs = devm_ioremap(&pdev->dev, regs->start, 399 resource_size(regs)); 400 if (!at91_rtc_regs) { 401 dev_err(&pdev->dev, "failed to map registers, aborting.\n"); 402 return -ENOMEM; 403 } 404 405 rtc = devm_rtc_allocate_device(&pdev->dev); 406 if (IS_ERR(rtc)) 407 return PTR_ERR(rtc); 408 platform_set_drvdata(pdev, rtc); 409 410 sclk = devm_clk_get(&pdev->dev, NULL); 411 if (IS_ERR(sclk)) 412 return PTR_ERR(sclk); 413 414 ret = clk_prepare_enable(sclk); 415 if (ret) { 416 dev_err(&pdev->dev, "Could not enable slow clock\n"); 417 return ret; 418 } 419 420 at91_rtc_write(AT91_RTC_CR, 0); 421 at91_rtc_write(AT91_RTC_MR, 0); /* 24 hour mode */ 422 423 /* Disable all interrupts */ 424 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM | 425 AT91_RTC_SECEV | AT91_RTC_TIMEV | 426 AT91_RTC_CALEV); 427 428 ret = devm_request_irq(&pdev->dev, irq, at91_rtc_interrupt, 429 IRQF_SHARED | IRQF_COND_SUSPEND, 430 "at91_rtc", pdev); 431 if (ret) { 432 dev_err(&pdev->dev, "IRQ %d already in use.\n", irq); 433 goto err_clk; 434 } 435 436 /* cpu init code should really have flagged this device as 437 * being wake-capable; if it didn't, do that here. 438 */ 439 if (!device_can_wakeup(&pdev->dev)) 440 device_init_wakeup(&pdev->dev, 1); 441 442 rtc->ops = &at91_rtc_ops; 443 rtc->range_min = RTC_TIMESTAMP_BEGIN_1900; 444 rtc->range_max = RTC_TIMESTAMP_END_2099; 445 ret = rtc_register_device(rtc); 446 if (ret) 447 goto err_clk; 448 449 /* enable SECEV interrupt in order to initialize at91_rtc_upd_rdy 450 * completion. 451 */ 452 at91_rtc_write_ier(AT91_RTC_SECEV); 453 454 dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n"); 455 return 0; 456 457 err_clk: 458 clk_disable_unprepare(sclk); 459 460 return ret; 461 } 462 463 /* 464 * Disable and remove the RTC driver 465 */ 466 static int __exit at91_rtc_remove(struct platform_device *pdev) 467 { 468 /* Disable all interrupts */ 469 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM | 470 AT91_RTC_SECEV | AT91_RTC_TIMEV | 471 AT91_RTC_CALEV); 472 473 clk_disable_unprepare(sclk); 474 475 return 0; 476 } 477 478 static void at91_rtc_shutdown(struct platform_device *pdev) 479 { 480 /* Disable all interrupts */ 481 at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM | 482 AT91_RTC_SECEV | AT91_RTC_TIMEV | 483 AT91_RTC_CALEV); 484 } 485 486 #ifdef CONFIG_PM_SLEEP 487 488 /* AT91RM9200 RTC Power management control */ 489 490 static int at91_rtc_suspend(struct device *dev) 491 { 492 /* this IRQ is shared with DBGU and other hardware which isn't 493 * necessarily doing PM like we are... 494 */ 495 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM); 496 497 at91_rtc_imr = at91_rtc_read_imr() 498 & (AT91_RTC_ALARM|AT91_RTC_SECEV); 499 if (at91_rtc_imr) { 500 if (device_may_wakeup(dev)) { 501 unsigned long flags; 502 503 enable_irq_wake(irq); 504 505 spin_lock_irqsave(&suspended_lock, flags); 506 suspended = true; 507 spin_unlock_irqrestore(&suspended_lock, flags); 508 } else { 509 at91_rtc_write_idr(at91_rtc_imr); 510 } 511 } 512 return 0; 513 } 514 515 static int at91_rtc_resume(struct device *dev) 516 { 517 struct rtc_device *rtc = dev_get_drvdata(dev); 518 519 if (at91_rtc_imr) { 520 if (device_may_wakeup(dev)) { 521 unsigned long flags; 522 523 spin_lock_irqsave(&suspended_lock, flags); 524 525 if (cached_events) { 526 rtc_update_irq(rtc, 1, cached_events); 527 cached_events = 0; 528 } 529 530 suspended = false; 531 spin_unlock_irqrestore(&suspended_lock, flags); 532 533 disable_irq_wake(irq); 534 } 535 at91_rtc_write_ier(at91_rtc_imr); 536 } 537 return 0; 538 } 539 #endif 540 541 static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume); 542 543 static struct platform_driver at91_rtc_driver = { 544 .remove = __exit_p(at91_rtc_remove), 545 .shutdown = at91_rtc_shutdown, 546 .driver = { 547 .name = "at91_rtc", 548 .pm = &at91_rtc_pm_ops, 549 .of_match_table = of_match_ptr(at91_rtc_dt_ids), 550 }, 551 }; 552 553 module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe); 554 555 MODULE_AUTHOR("Rick Bronson"); 556 MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200"); 557 MODULE_LICENSE("GPL"); 558 MODULE_ALIAS("platform:at91_rtc"); 559