1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Real Time Clock interface for Linux on Atmel AT91RM9200 4 * 5 * Copyright (C) 2002 Rick Bronson 6 * 7 * Converted to RTC class model by Andrew Victor 8 * 9 * Ported to Linux 2.6 by Steven Scholz 10 * Based on s3c2410-rtc.c Simtec Electronics 11 * 12 * Based on sa1100-rtc.c by Nils Faerber 13 * Based on rtc.c by Paul Gortmaker 14 */ 15 16 #include <linux/bcd.h> 17 #include <linux/clk.h> 18 #include <linux/completion.h> 19 #include <linux/interrupt.h> 20 #include <linux/ioctl.h> 21 #include <linux/io.h> 22 #include <linux/kernel.h> 23 #include <linux/module.h> 24 #include <linux/of_device.h> 25 #include <linux/of.h> 26 #include <linux/platform_device.h> 27 #include <linux/rtc.h> 28 #include <linux/spinlock.h> 29 #include <linux/suspend.h> 30 #include <linux/time.h> 31 #include <linux/uaccess.h> 32 33 #include "rtc-at91rm9200.h" 34 35 #define at91_rtc_read(field) \ 36 readl_relaxed(at91_rtc_regs + field) 37 #define at91_rtc_write(field, val) \ 38 writel_relaxed((val), at91_rtc_regs + field) 39 40 struct at91_rtc_config { 41 bool use_shadow_imr; 42 }; 43 44 static const struct at91_rtc_config *at91_rtc_config; 45 static DECLARE_COMPLETION(at91_rtc_updated); 46 static DECLARE_COMPLETION(at91_rtc_upd_rdy); 47 static void __iomem *at91_rtc_regs; 48 static int irq; 49 static DEFINE_SPINLOCK(at91_rtc_lock); 50 static u32 at91_rtc_shadow_imr; 51 static bool suspended; 52 static DEFINE_SPINLOCK(suspended_lock); 53 static unsigned long cached_events; 54 static u32 at91_rtc_imr; 55 static struct clk *sclk; 56 57 static void at91_rtc_write_ier(u32 mask) 58 { 59 unsigned long flags; 60 61 spin_lock_irqsave(&at91_rtc_lock, flags); 62 at91_rtc_shadow_imr |= mask; 63 at91_rtc_write(AT91_RTC_IER, mask); 64 spin_unlock_irqrestore(&at91_rtc_lock, flags); 65 } 66 67 static void at91_rtc_write_idr(u32 mask) 68 { 69 unsigned long flags; 70 71 spin_lock_irqsave(&at91_rtc_lock, flags); 72 at91_rtc_write(AT91_RTC_IDR, mask); 73 /* 74 * Register read back (of any RTC-register) needed to make sure 75 * IDR-register write has reached the peripheral before updating 76 * shadow mask. 77 * 78 * Note that there is still a possibility that the mask is updated 79 * before interrupts have actually been disabled in hardware. The only 80 * way to be certain would be to poll the IMR-register, which is is 81 * the very register we are trying to emulate. The register read back 82 * is a reasonable heuristic. 83 */ 84 at91_rtc_read(AT91_RTC_SR); 85 at91_rtc_shadow_imr &= ~mask; 86 spin_unlock_irqrestore(&at91_rtc_lock, flags); 87 } 88 89 static u32 at91_rtc_read_imr(void) 90 { 91 unsigned long flags; 92 u32 mask; 93 94 if (at91_rtc_config->use_shadow_imr) { 95 spin_lock_irqsave(&at91_rtc_lock, flags); 96 mask = at91_rtc_shadow_imr; 97 spin_unlock_irqrestore(&at91_rtc_lock, flags); 98 } else { 99 mask = at91_rtc_read(AT91_RTC_IMR); 100 } 101 102 return mask; 103 } 104 105 /* 106 * Decode time/date into rtc_time structure 107 */ 108 static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg, 109 struct rtc_time *tm) 110 { 111 unsigned int time, date; 112 113 /* must read twice in case it changes */ 114 do { 115 time = at91_rtc_read(timereg); 116 date = at91_rtc_read(calreg); 117 } while ((time != at91_rtc_read(timereg)) || 118 (date != at91_rtc_read(calreg))); 119 120 tm->tm_sec = bcd2bin((time & AT91_RTC_SEC) >> 0); 121 tm->tm_min = bcd2bin((time & AT91_RTC_MIN) >> 8); 122 tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16); 123 124 /* 125 * The Calendar Alarm register does not have a field for 126 * the year - so these will return an invalid value. 127 */ 128 tm->tm_year = bcd2bin(date & AT91_RTC_CENT) * 100; /* century */ 129 tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8); /* year */ 130 131 tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */ 132 tm->tm_mon = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1; 133 tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24); 134 } 135 136 /* 137 * Read current time and date in RTC 138 */ 139 static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm) 140 { 141 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm); 142 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year); 143 tm->tm_year = tm->tm_year - 1900; 144 145 dev_dbg(dev, "%s(): %ptR\n", __func__, tm); 146 147 return 0; 148 } 149 150 /* 151 * Set current time and date in RTC 152 */ 153 static int at91_rtc_settime(struct device *dev, struct rtc_time *tm) 154 { 155 unsigned long cr; 156 157 dev_dbg(dev, "%s(): %ptR\n", __func__, tm); 158 159 wait_for_completion(&at91_rtc_upd_rdy); 160 161 /* Stop Time/Calendar from counting */ 162 cr = at91_rtc_read(AT91_RTC_CR); 163 at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM); 164 165 at91_rtc_write_ier(AT91_RTC_ACKUPD); 166 wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */ 167 at91_rtc_write_idr(AT91_RTC_ACKUPD); 168 169 at91_rtc_write(AT91_RTC_TIMR, 170 bin2bcd(tm->tm_sec) << 0 171 | bin2bcd(tm->tm_min) << 8 172 | bin2bcd(tm->tm_hour) << 16); 173 174 at91_rtc_write(AT91_RTC_CALR, 175 bin2bcd((tm->tm_year + 1900) / 100) /* century */ 176 | bin2bcd(tm->tm_year % 100) << 8 /* year */ 177 | bin2bcd(tm->tm_mon + 1) << 16 /* tm_mon starts at zero */ 178 | bin2bcd(tm->tm_wday + 1) << 21 /* day of the week [0-6], Sunday=0 */ 179 | bin2bcd(tm->tm_mday) << 24); 180 181 /* Restart Time/Calendar */ 182 cr = at91_rtc_read(AT91_RTC_CR); 183 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_SECEV); 184 at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM)); 185 at91_rtc_write_ier(AT91_RTC_SECEV); 186 187 return 0; 188 } 189 190 /* 191 * Read alarm time and date in RTC 192 */ 193 static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm) 194 { 195 struct rtc_time *tm = &alrm->time; 196 197 at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm); 198 tm->tm_year = -1; 199 200 alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM) 201 ? 1 : 0; 202 203 dev_dbg(dev, "%s(): %ptR %sabled\n", __func__, tm, 204 alrm->enabled ? "en" : "dis"); 205 206 return 0; 207 } 208 209 /* 210 * Set alarm time and date in RTC 211 */ 212 static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm) 213 { 214 struct rtc_time tm; 215 216 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm); 217 218 tm.tm_mon = alrm->time.tm_mon; 219 tm.tm_mday = alrm->time.tm_mday; 220 tm.tm_hour = alrm->time.tm_hour; 221 tm.tm_min = alrm->time.tm_min; 222 tm.tm_sec = alrm->time.tm_sec; 223 224 at91_rtc_write_idr(AT91_RTC_ALARM); 225 at91_rtc_write(AT91_RTC_TIMALR, 226 bin2bcd(tm.tm_sec) << 0 227 | bin2bcd(tm.tm_min) << 8 228 | bin2bcd(tm.tm_hour) << 16 229 | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN); 230 at91_rtc_write(AT91_RTC_CALALR, 231 bin2bcd(tm.tm_mon + 1) << 16 /* tm_mon starts at zero */ 232 | bin2bcd(tm.tm_mday) << 24 233 | AT91_RTC_DATEEN | AT91_RTC_MTHEN); 234 235 if (alrm->enabled) { 236 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM); 237 at91_rtc_write_ier(AT91_RTC_ALARM); 238 } 239 240 dev_dbg(dev, "%s(): %ptR\n", __func__, &tm); 241 242 return 0; 243 } 244 245 static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) 246 { 247 dev_dbg(dev, "%s(): cmd=%08x\n", __func__, enabled); 248 249 if (enabled) { 250 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM); 251 at91_rtc_write_ier(AT91_RTC_ALARM); 252 } else 253 at91_rtc_write_idr(AT91_RTC_ALARM); 254 255 return 0; 256 } 257 /* 258 * Provide additional RTC information in /proc/driver/rtc 259 */ 260 static int at91_rtc_proc(struct device *dev, struct seq_file *seq) 261 { 262 unsigned long imr = at91_rtc_read_imr(); 263 264 seq_printf(seq, "update_IRQ\t: %s\n", 265 (imr & AT91_RTC_ACKUPD) ? "yes" : "no"); 266 seq_printf(seq, "periodic_IRQ\t: %s\n", 267 (imr & AT91_RTC_SECEV) ? "yes" : "no"); 268 269 return 0; 270 } 271 272 /* 273 * IRQ handler for the RTC 274 */ 275 static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id) 276 { 277 struct platform_device *pdev = dev_id; 278 struct rtc_device *rtc = platform_get_drvdata(pdev); 279 unsigned int rtsr; 280 unsigned long events = 0; 281 int ret = IRQ_NONE; 282 283 spin_lock(&suspended_lock); 284 rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr(); 285 if (rtsr) { /* this interrupt is shared! Is it ours? */ 286 if (rtsr & AT91_RTC_ALARM) 287 events |= (RTC_AF | RTC_IRQF); 288 if (rtsr & AT91_RTC_SECEV) { 289 complete(&at91_rtc_upd_rdy); 290 at91_rtc_write_idr(AT91_RTC_SECEV); 291 } 292 if (rtsr & AT91_RTC_ACKUPD) 293 complete(&at91_rtc_updated); 294 295 at91_rtc_write(AT91_RTC_SCCR, rtsr); /* clear status reg */ 296 297 if (!suspended) { 298 rtc_update_irq(rtc, 1, events); 299 300 dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n", 301 __func__, events >> 8, events & 0x000000FF); 302 } else { 303 cached_events |= events; 304 at91_rtc_write_idr(at91_rtc_imr); 305 pm_system_wakeup(); 306 } 307 308 ret = IRQ_HANDLED; 309 } 310 spin_unlock(&suspended_lock); 311 312 return ret; 313 } 314 315 static const struct at91_rtc_config at91rm9200_config = { 316 }; 317 318 static const struct at91_rtc_config at91sam9x5_config = { 319 .use_shadow_imr = true, 320 }; 321 322 static const struct of_device_id at91_rtc_dt_ids[] = { 323 { 324 .compatible = "atmel,at91rm9200-rtc", 325 .data = &at91rm9200_config, 326 }, { 327 .compatible = "atmel,at91sam9x5-rtc", 328 .data = &at91sam9x5_config, 329 }, { 330 /* sentinel */ 331 } 332 }; 333 MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids); 334 335 static const struct rtc_class_ops at91_rtc_ops = { 336 .read_time = at91_rtc_readtime, 337 .set_time = at91_rtc_settime, 338 .read_alarm = at91_rtc_readalarm, 339 .set_alarm = at91_rtc_setalarm, 340 .proc = at91_rtc_proc, 341 .alarm_irq_enable = at91_rtc_alarm_irq_enable, 342 }; 343 344 /* 345 * Initialize and install RTC driver 346 */ 347 static int __init at91_rtc_probe(struct platform_device *pdev) 348 { 349 struct rtc_device *rtc; 350 struct resource *regs; 351 int ret = 0; 352 353 at91_rtc_config = of_device_get_match_data(&pdev->dev); 354 if (!at91_rtc_config) 355 return -ENODEV; 356 357 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); 358 if (!regs) { 359 dev_err(&pdev->dev, "no mmio resource defined\n"); 360 return -ENXIO; 361 } 362 363 irq = platform_get_irq(pdev, 0); 364 if (irq < 0) 365 return -ENXIO; 366 367 at91_rtc_regs = devm_ioremap(&pdev->dev, regs->start, 368 resource_size(regs)); 369 if (!at91_rtc_regs) { 370 dev_err(&pdev->dev, "failed to map registers, aborting.\n"); 371 return -ENOMEM; 372 } 373 374 rtc = devm_rtc_allocate_device(&pdev->dev); 375 if (IS_ERR(rtc)) 376 return PTR_ERR(rtc); 377 platform_set_drvdata(pdev, rtc); 378 379 sclk = devm_clk_get(&pdev->dev, NULL); 380 if (IS_ERR(sclk)) 381 return PTR_ERR(sclk); 382 383 ret = clk_prepare_enable(sclk); 384 if (ret) { 385 dev_err(&pdev->dev, "Could not enable slow clock\n"); 386 return ret; 387 } 388 389 at91_rtc_write(AT91_RTC_CR, 0); 390 at91_rtc_write(AT91_RTC_MR, 0); /* 24 hour mode */ 391 392 /* Disable all interrupts */ 393 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM | 394 AT91_RTC_SECEV | AT91_RTC_TIMEV | 395 AT91_RTC_CALEV); 396 397 ret = devm_request_irq(&pdev->dev, irq, at91_rtc_interrupt, 398 IRQF_SHARED | IRQF_COND_SUSPEND, 399 "at91_rtc", pdev); 400 if (ret) { 401 dev_err(&pdev->dev, "IRQ %d already in use.\n", irq); 402 goto err_clk; 403 } 404 405 /* cpu init code should really have flagged this device as 406 * being wake-capable; if it didn't, do that here. 407 */ 408 if (!device_can_wakeup(&pdev->dev)) 409 device_init_wakeup(&pdev->dev, 1); 410 411 rtc->ops = &at91_rtc_ops; 412 rtc->range_min = RTC_TIMESTAMP_BEGIN_1900; 413 rtc->range_max = RTC_TIMESTAMP_END_2099; 414 ret = rtc_register_device(rtc); 415 if (ret) 416 goto err_clk; 417 418 /* enable SECEV interrupt in order to initialize at91_rtc_upd_rdy 419 * completion. 420 */ 421 at91_rtc_write_ier(AT91_RTC_SECEV); 422 423 dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n"); 424 return 0; 425 426 err_clk: 427 clk_disable_unprepare(sclk); 428 429 return ret; 430 } 431 432 /* 433 * Disable and remove the RTC driver 434 */ 435 static int __exit at91_rtc_remove(struct platform_device *pdev) 436 { 437 /* Disable all interrupts */ 438 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM | 439 AT91_RTC_SECEV | AT91_RTC_TIMEV | 440 AT91_RTC_CALEV); 441 442 clk_disable_unprepare(sclk); 443 444 return 0; 445 } 446 447 static void at91_rtc_shutdown(struct platform_device *pdev) 448 { 449 /* Disable all interrupts */ 450 at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM | 451 AT91_RTC_SECEV | AT91_RTC_TIMEV | 452 AT91_RTC_CALEV); 453 } 454 455 #ifdef CONFIG_PM_SLEEP 456 457 /* AT91RM9200 RTC Power management control */ 458 459 static int at91_rtc_suspend(struct device *dev) 460 { 461 /* this IRQ is shared with DBGU and other hardware which isn't 462 * necessarily doing PM like we are... 463 */ 464 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM); 465 466 at91_rtc_imr = at91_rtc_read_imr() 467 & (AT91_RTC_ALARM|AT91_RTC_SECEV); 468 if (at91_rtc_imr) { 469 if (device_may_wakeup(dev)) { 470 unsigned long flags; 471 472 enable_irq_wake(irq); 473 474 spin_lock_irqsave(&suspended_lock, flags); 475 suspended = true; 476 spin_unlock_irqrestore(&suspended_lock, flags); 477 } else { 478 at91_rtc_write_idr(at91_rtc_imr); 479 } 480 } 481 return 0; 482 } 483 484 static int at91_rtc_resume(struct device *dev) 485 { 486 struct rtc_device *rtc = dev_get_drvdata(dev); 487 488 if (at91_rtc_imr) { 489 if (device_may_wakeup(dev)) { 490 unsigned long flags; 491 492 spin_lock_irqsave(&suspended_lock, flags); 493 494 if (cached_events) { 495 rtc_update_irq(rtc, 1, cached_events); 496 cached_events = 0; 497 } 498 499 suspended = false; 500 spin_unlock_irqrestore(&suspended_lock, flags); 501 502 disable_irq_wake(irq); 503 } 504 at91_rtc_write_ier(at91_rtc_imr); 505 } 506 return 0; 507 } 508 #endif 509 510 static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume); 511 512 static struct platform_driver at91_rtc_driver = { 513 .remove = __exit_p(at91_rtc_remove), 514 .shutdown = at91_rtc_shutdown, 515 .driver = { 516 .name = "at91_rtc", 517 .pm = &at91_rtc_pm_ops, 518 .of_match_table = of_match_ptr(at91_rtc_dt_ids), 519 }, 520 }; 521 522 module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe); 523 524 MODULE_AUTHOR("Rick Bronson"); 525 MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200"); 526 MODULE_LICENSE("GPL"); 527 MODULE_ALIAS("platform:at91_rtc"); 528