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(): %ptR\n", __func__, tm); 151 152 return 0; 153 } 154 155 /* 156 * Set current time and date in RTC 157 */ 158 static int at91_rtc_settime(struct device *dev, struct rtc_time *tm) 159 { 160 unsigned long cr; 161 162 dev_dbg(dev, "%s(): %ptR\n", __func__, tm); 163 164 wait_for_completion(&at91_rtc_upd_rdy); 165 166 /* Stop Time/Calendar from counting */ 167 cr = at91_rtc_read(AT91_RTC_CR); 168 at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM); 169 170 at91_rtc_write_ier(AT91_RTC_ACKUPD); 171 wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */ 172 at91_rtc_write_idr(AT91_RTC_ACKUPD); 173 174 at91_rtc_write(AT91_RTC_TIMR, 175 bin2bcd(tm->tm_sec) << 0 176 | bin2bcd(tm->tm_min) << 8 177 | bin2bcd(tm->tm_hour) << 16); 178 179 at91_rtc_write(AT91_RTC_CALR, 180 bin2bcd((tm->tm_year + 1900) / 100) /* century */ 181 | bin2bcd(tm->tm_year % 100) << 8 /* year */ 182 | bin2bcd(tm->tm_mon + 1) << 16 /* tm_mon starts at zero */ 183 | bin2bcd(tm->tm_wday + 1) << 21 /* day of the week [0-6], Sunday=0 */ 184 | bin2bcd(tm->tm_mday) << 24); 185 186 /* Restart Time/Calendar */ 187 cr = at91_rtc_read(AT91_RTC_CR); 188 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_SECEV); 189 at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM)); 190 at91_rtc_write_ier(AT91_RTC_SECEV); 191 192 return 0; 193 } 194 195 /* 196 * Read alarm time and date in RTC 197 */ 198 static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm) 199 { 200 struct rtc_time *tm = &alrm->time; 201 202 at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm); 203 tm->tm_year = -1; 204 205 alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM) 206 ? 1 : 0; 207 208 dev_dbg(dev, "%s(): %ptR %sabled\n", __func__, tm, 209 alrm->enabled ? "en" : "dis"); 210 211 return 0; 212 } 213 214 /* 215 * Set alarm time and date in RTC 216 */ 217 static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm) 218 { 219 struct rtc_time tm; 220 221 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm); 222 223 tm.tm_mon = alrm->time.tm_mon; 224 tm.tm_mday = alrm->time.tm_mday; 225 tm.tm_hour = alrm->time.tm_hour; 226 tm.tm_min = alrm->time.tm_min; 227 tm.tm_sec = alrm->time.tm_sec; 228 229 at91_rtc_write_idr(AT91_RTC_ALARM); 230 at91_rtc_write(AT91_RTC_TIMALR, 231 bin2bcd(tm.tm_sec) << 0 232 | bin2bcd(tm.tm_min) << 8 233 | bin2bcd(tm.tm_hour) << 16 234 | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN); 235 at91_rtc_write(AT91_RTC_CALALR, 236 bin2bcd(tm.tm_mon + 1) << 16 /* tm_mon starts at zero */ 237 | bin2bcd(tm.tm_mday) << 24 238 | AT91_RTC_DATEEN | AT91_RTC_MTHEN); 239 240 if (alrm->enabled) { 241 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM); 242 at91_rtc_write_ier(AT91_RTC_ALARM); 243 } 244 245 dev_dbg(dev, "%s(): %ptR\n", __func__, &tm); 246 247 return 0; 248 } 249 250 static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) 251 { 252 dev_dbg(dev, "%s(): cmd=%08x\n", __func__, enabled); 253 254 if (enabled) { 255 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM); 256 at91_rtc_write_ier(AT91_RTC_ALARM); 257 } else 258 at91_rtc_write_idr(AT91_RTC_ALARM); 259 260 return 0; 261 } 262 /* 263 * Provide additional RTC information in /proc/driver/rtc 264 */ 265 static int at91_rtc_proc(struct device *dev, struct seq_file *seq) 266 { 267 unsigned long imr = at91_rtc_read_imr(); 268 269 seq_printf(seq, "update_IRQ\t: %s\n", 270 (imr & AT91_RTC_ACKUPD) ? "yes" : "no"); 271 seq_printf(seq, "periodic_IRQ\t: %s\n", 272 (imr & AT91_RTC_SECEV) ? "yes" : "no"); 273 274 return 0; 275 } 276 277 /* 278 * IRQ handler for the RTC 279 */ 280 static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id) 281 { 282 struct platform_device *pdev = dev_id; 283 struct rtc_device *rtc = platform_get_drvdata(pdev); 284 unsigned int rtsr; 285 unsigned long events = 0; 286 int ret = IRQ_NONE; 287 288 spin_lock(&suspended_lock); 289 rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr(); 290 if (rtsr) { /* this interrupt is shared! Is it ours? */ 291 if (rtsr & AT91_RTC_ALARM) 292 events |= (RTC_AF | RTC_IRQF); 293 if (rtsr & AT91_RTC_SECEV) { 294 complete(&at91_rtc_upd_rdy); 295 at91_rtc_write_idr(AT91_RTC_SECEV); 296 } 297 if (rtsr & AT91_RTC_ACKUPD) 298 complete(&at91_rtc_updated); 299 300 at91_rtc_write(AT91_RTC_SCCR, rtsr); /* clear status reg */ 301 302 if (!suspended) { 303 rtc_update_irq(rtc, 1, events); 304 305 dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n", 306 __func__, events >> 8, events & 0x000000FF); 307 } else { 308 cached_events |= events; 309 at91_rtc_write_idr(at91_rtc_imr); 310 pm_system_wakeup(); 311 } 312 313 ret = IRQ_HANDLED; 314 } 315 spin_unlock(&suspended_lock); 316 317 return ret; 318 } 319 320 static const struct at91_rtc_config at91rm9200_config = { 321 }; 322 323 static const struct at91_rtc_config at91sam9x5_config = { 324 .use_shadow_imr = true, 325 }; 326 327 #ifdef CONFIG_OF 328 static const struct of_device_id at91_rtc_dt_ids[] = { 329 { 330 .compatible = "atmel,at91rm9200-rtc", 331 .data = &at91rm9200_config, 332 }, { 333 .compatible = "atmel,at91sam9x5-rtc", 334 .data = &at91sam9x5_config, 335 }, { 336 /* sentinel */ 337 } 338 }; 339 MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids); 340 #endif 341 342 static const struct at91_rtc_config * 343 at91_rtc_get_config(struct platform_device *pdev) 344 { 345 const struct of_device_id *match; 346 347 if (pdev->dev.of_node) { 348 match = of_match_node(at91_rtc_dt_ids, pdev->dev.of_node); 349 if (!match) 350 return NULL; 351 return (const struct at91_rtc_config *)match->data; 352 } 353 354 return &at91rm9200_config; 355 } 356 357 static const struct rtc_class_ops at91_rtc_ops = { 358 .read_time = at91_rtc_readtime, 359 .set_time = at91_rtc_settime, 360 .read_alarm = at91_rtc_readalarm, 361 .set_alarm = at91_rtc_setalarm, 362 .proc = at91_rtc_proc, 363 .alarm_irq_enable = at91_rtc_alarm_irq_enable, 364 }; 365 366 /* 367 * Initialize and install RTC driver 368 */ 369 static int __init at91_rtc_probe(struct platform_device *pdev) 370 { 371 struct rtc_device *rtc; 372 struct resource *regs; 373 int ret = 0; 374 375 at91_rtc_config = at91_rtc_get_config(pdev); 376 if (!at91_rtc_config) 377 return -ENODEV; 378 379 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); 380 if (!regs) { 381 dev_err(&pdev->dev, "no mmio resource defined\n"); 382 return -ENXIO; 383 } 384 385 irq = platform_get_irq(pdev, 0); 386 if (irq < 0) { 387 dev_err(&pdev->dev, "no irq resource defined\n"); 388 return -ENXIO; 389 } 390 391 at91_rtc_regs = devm_ioremap(&pdev->dev, regs->start, 392 resource_size(regs)); 393 if (!at91_rtc_regs) { 394 dev_err(&pdev->dev, "failed to map registers, aborting.\n"); 395 return -ENOMEM; 396 } 397 398 rtc = devm_rtc_allocate_device(&pdev->dev); 399 if (IS_ERR(rtc)) 400 return PTR_ERR(rtc); 401 platform_set_drvdata(pdev, rtc); 402 403 sclk = devm_clk_get(&pdev->dev, NULL); 404 if (IS_ERR(sclk)) 405 return PTR_ERR(sclk); 406 407 ret = clk_prepare_enable(sclk); 408 if (ret) { 409 dev_err(&pdev->dev, "Could not enable slow clock\n"); 410 return ret; 411 } 412 413 at91_rtc_write(AT91_RTC_CR, 0); 414 at91_rtc_write(AT91_RTC_MR, 0); /* 24 hour mode */ 415 416 /* Disable all interrupts */ 417 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM | 418 AT91_RTC_SECEV | AT91_RTC_TIMEV | 419 AT91_RTC_CALEV); 420 421 ret = devm_request_irq(&pdev->dev, irq, at91_rtc_interrupt, 422 IRQF_SHARED | IRQF_COND_SUSPEND, 423 "at91_rtc", pdev); 424 if (ret) { 425 dev_err(&pdev->dev, "IRQ %d already in use.\n", irq); 426 goto err_clk; 427 } 428 429 /* cpu init code should really have flagged this device as 430 * being wake-capable; if it didn't, do that here. 431 */ 432 if (!device_can_wakeup(&pdev->dev)) 433 device_init_wakeup(&pdev->dev, 1); 434 435 rtc->ops = &at91_rtc_ops; 436 rtc->range_min = RTC_TIMESTAMP_BEGIN_1900; 437 rtc->range_max = RTC_TIMESTAMP_END_2099; 438 ret = rtc_register_device(rtc); 439 if (ret) 440 goto err_clk; 441 442 /* enable SECEV interrupt in order to initialize at91_rtc_upd_rdy 443 * completion. 444 */ 445 at91_rtc_write_ier(AT91_RTC_SECEV); 446 447 dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n"); 448 return 0; 449 450 err_clk: 451 clk_disable_unprepare(sclk); 452 453 return ret; 454 } 455 456 /* 457 * Disable and remove the RTC driver 458 */ 459 static int __exit at91_rtc_remove(struct platform_device *pdev) 460 { 461 /* Disable all interrupts */ 462 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM | 463 AT91_RTC_SECEV | AT91_RTC_TIMEV | 464 AT91_RTC_CALEV); 465 466 clk_disable_unprepare(sclk); 467 468 return 0; 469 } 470 471 static void at91_rtc_shutdown(struct platform_device *pdev) 472 { 473 /* Disable all interrupts */ 474 at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM | 475 AT91_RTC_SECEV | AT91_RTC_TIMEV | 476 AT91_RTC_CALEV); 477 } 478 479 #ifdef CONFIG_PM_SLEEP 480 481 /* AT91RM9200 RTC Power management control */ 482 483 static int at91_rtc_suspend(struct device *dev) 484 { 485 /* this IRQ is shared with DBGU and other hardware which isn't 486 * necessarily doing PM like we are... 487 */ 488 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM); 489 490 at91_rtc_imr = at91_rtc_read_imr() 491 & (AT91_RTC_ALARM|AT91_RTC_SECEV); 492 if (at91_rtc_imr) { 493 if (device_may_wakeup(dev)) { 494 unsigned long flags; 495 496 enable_irq_wake(irq); 497 498 spin_lock_irqsave(&suspended_lock, flags); 499 suspended = true; 500 spin_unlock_irqrestore(&suspended_lock, flags); 501 } else { 502 at91_rtc_write_idr(at91_rtc_imr); 503 } 504 } 505 return 0; 506 } 507 508 static int at91_rtc_resume(struct device *dev) 509 { 510 struct rtc_device *rtc = dev_get_drvdata(dev); 511 512 if (at91_rtc_imr) { 513 if (device_may_wakeup(dev)) { 514 unsigned long flags; 515 516 spin_lock_irqsave(&suspended_lock, flags); 517 518 if (cached_events) { 519 rtc_update_irq(rtc, 1, cached_events); 520 cached_events = 0; 521 } 522 523 suspended = false; 524 spin_unlock_irqrestore(&suspended_lock, flags); 525 526 disable_irq_wake(irq); 527 } 528 at91_rtc_write_ier(at91_rtc_imr); 529 } 530 return 0; 531 } 532 #endif 533 534 static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume); 535 536 static struct platform_driver at91_rtc_driver = { 537 .remove = __exit_p(at91_rtc_remove), 538 .shutdown = at91_rtc_shutdown, 539 .driver = { 540 .name = "at91_rtc", 541 .pm = &at91_rtc_pm_ops, 542 .of_match_table = of_match_ptr(at91_rtc_dt_ids), 543 }, 544 }; 545 546 module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe); 547 548 MODULE_AUTHOR("Rick Bronson"); 549 MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200"); 550 MODULE_LICENSE("GPL"); 551 MODULE_ALIAS("platform:at91_rtc"); 552