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/module.h> 22 #include <linux/kernel.h> 23 #include <linux/platform_device.h> 24 #include <linux/time.h> 25 #include <linux/rtc.h> 26 #include <linux/bcd.h> 27 #include <linux/interrupt.h> 28 #include <linux/spinlock.h> 29 #include <linux/ioctl.h> 30 #include <linux/completion.h> 31 #include <linux/io.h> 32 #include <linux/of.h> 33 #include <linux/of_device.h> 34 #include <linux/uaccess.h> 35 36 #include "rtc-at91rm9200.h" 37 38 #define at91_rtc_read(field) \ 39 __raw_readl(at91_rtc_regs + field) 40 #define at91_rtc_write(field, val) \ 41 __raw_writel((val), at91_rtc_regs + field) 42 43 #define AT91_RTC_EPOCH 1900UL /* just like arch/arm/common/rtctime.c */ 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 unsigned int at91_alarm_year = AT91_RTC_EPOCH; 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 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. When an 127 * alarm is set, at91_alarm_year will store the current year. 128 */ 129 tm->tm_year = bcd2bin(date & AT91_RTC_CENT) * 100; /* century */ 130 tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8); /* year */ 131 132 tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */ 133 tm->tm_mon = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1; 134 tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24); 135 } 136 137 /* 138 * Read current time and date in RTC 139 */ 140 static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm) 141 { 142 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm); 143 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year); 144 tm->tm_year = tm->tm_year - 1900; 145 146 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__, 147 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday, 148 tm->tm_hour, tm->tm_min, tm->tm_sec); 149 150 return 0; 151 } 152 153 /* 154 * Set current time and date in RTC 155 */ 156 static int at91_rtc_settime(struct device *dev, struct rtc_time *tm) 157 { 158 unsigned long cr; 159 160 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__, 161 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday, 162 tm->tm_hour, tm->tm_min, tm->tm_sec); 163 164 /* Stop Time/Calendar from counting */ 165 cr = at91_rtc_read(AT91_RTC_CR); 166 at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM); 167 168 at91_rtc_write_ier(AT91_RTC_ACKUPD); 169 wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */ 170 at91_rtc_write_idr(AT91_RTC_ACKUPD); 171 172 at91_rtc_write(AT91_RTC_TIMR, 173 bin2bcd(tm->tm_sec) << 0 174 | bin2bcd(tm->tm_min) << 8 175 | bin2bcd(tm->tm_hour) << 16); 176 177 at91_rtc_write(AT91_RTC_CALR, 178 bin2bcd((tm->tm_year + 1900) / 100) /* century */ 179 | bin2bcd(tm->tm_year % 100) << 8 /* year */ 180 | bin2bcd(tm->tm_mon + 1) << 16 /* tm_mon starts at zero */ 181 | bin2bcd(tm->tm_wday + 1) << 21 /* day of the week [0-6], Sunday=0 */ 182 | bin2bcd(tm->tm_mday) << 24); 183 184 /* Restart Time/Calendar */ 185 cr = at91_rtc_read(AT91_RTC_CR); 186 at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM)); 187 188 return 0; 189 } 190 191 /* 192 * Read alarm time and date in RTC 193 */ 194 static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm) 195 { 196 struct rtc_time *tm = &alrm->time; 197 198 at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm); 199 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year); 200 tm->tm_year = at91_alarm_year - 1900; 201 202 alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM) 203 ? 1 : 0; 204 205 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__, 206 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday, 207 tm->tm_hour, tm->tm_min, tm->tm_sec); 208 209 return 0; 210 } 211 212 /* 213 * Set alarm time and date in RTC 214 */ 215 static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm) 216 { 217 struct rtc_time tm; 218 219 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm); 220 221 at91_alarm_year = tm.tm_year; 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(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__, 246 at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour, 247 tm.tm_min, tm.tm_sec); 248 249 return 0; 250 } 251 252 static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) 253 { 254 dev_dbg(dev, "%s(): cmd=%08x\n", __func__, enabled); 255 256 if (enabled) { 257 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM); 258 at91_rtc_write_ier(AT91_RTC_ALARM); 259 } else 260 at91_rtc_write_idr(AT91_RTC_ALARM); 261 262 return 0; 263 } 264 /* 265 * Provide additional RTC information in /proc/driver/rtc 266 */ 267 static int at91_rtc_proc(struct device *dev, struct seq_file *seq) 268 { 269 unsigned long imr = at91_rtc_read_imr(); 270 271 seq_printf(seq, "update_IRQ\t: %s\n", 272 (imr & AT91_RTC_ACKUPD) ? "yes" : "no"); 273 seq_printf(seq, "periodic_IRQ\t: %s\n", 274 (imr & AT91_RTC_SECEV) ? "yes" : "no"); 275 276 return 0; 277 } 278 279 /* 280 * IRQ handler for the RTC 281 */ 282 static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id) 283 { 284 struct platform_device *pdev = dev_id; 285 struct rtc_device *rtc = platform_get_drvdata(pdev); 286 unsigned int rtsr; 287 unsigned long events = 0; 288 289 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 events |= (RTC_UF | RTC_IRQF); 295 if (rtsr & AT91_RTC_ACKUPD) 296 complete(&at91_rtc_updated); 297 298 at91_rtc_write(AT91_RTC_SCCR, rtsr); /* clear status reg */ 299 300 rtc_update_irq(rtc, 1, events); 301 302 dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n", __func__, 303 events >> 8, events & 0x000000FF); 304 305 return IRQ_HANDLED; 306 } 307 return IRQ_NONE; /* not handled */ 308 } 309 310 static const struct at91_rtc_config at91rm9200_config = { 311 }; 312 313 static const struct at91_rtc_config at91sam9x5_config = { 314 .use_shadow_imr = true, 315 }; 316 317 #ifdef CONFIG_OF 318 static const struct of_device_id at91_rtc_dt_ids[] = { 319 { 320 .compatible = "atmel,at91rm9200-rtc", 321 .data = &at91rm9200_config, 322 }, { 323 .compatible = "atmel,at91sam9x5-rtc", 324 .data = &at91sam9x5_config, 325 }, { 326 /* sentinel */ 327 } 328 }; 329 MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids); 330 #endif 331 332 static const struct at91_rtc_config * 333 at91_rtc_get_config(struct platform_device *pdev) 334 { 335 const struct of_device_id *match; 336 337 if (pdev->dev.of_node) { 338 match = of_match_node(at91_rtc_dt_ids, pdev->dev.of_node); 339 if (!match) 340 return NULL; 341 return (const struct at91_rtc_config *)match->data; 342 } 343 344 return &at91rm9200_config; 345 } 346 347 static const struct rtc_class_ops at91_rtc_ops = { 348 .read_time = at91_rtc_readtime, 349 .set_time = at91_rtc_settime, 350 .read_alarm = at91_rtc_readalarm, 351 .set_alarm = at91_rtc_setalarm, 352 .proc = at91_rtc_proc, 353 .alarm_irq_enable = at91_rtc_alarm_irq_enable, 354 }; 355 356 /* 357 * Initialize and install RTC driver 358 */ 359 static int __init at91_rtc_probe(struct platform_device *pdev) 360 { 361 struct rtc_device *rtc; 362 struct resource *regs; 363 int ret = 0; 364 365 at91_rtc_config = at91_rtc_get_config(pdev); 366 if (!at91_rtc_config) 367 return -ENODEV; 368 369 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); 370 if (!regs) { 371 dev_err(&pdev->dev, "no mmio resource defined\n"); 372 return -ENXIO; 373 } 374 375 irq = platform_get_irq(pdev, 0); 376 if (irq < 0) { 377 dev_err(&pdev->dev, "no irq resource defined\n"); 378 return -ENXIO; 379 } 380 381 at91_rtc_regs = devm_ioremap(&pdev->dev, regs->start, 382 resource_size(regs)); 383 if (!at91_rtc_regs) { 384 dev_err(&pdev->dev, "failed to map registers, aborting.\n"); 385 return -ENOMEM; 386 } 387 388 at91_rtc_write(AT91_RTC_CR, 0); 389 at91_rtc_write(AT91_RTC_MR, 0); /* 24 hour mode */ 390 391 /* Disable all interrupts */ 392 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM | 393 AT91_RTC_SECEV | AT91_RTC_TIMEV | 394 AT91_RTC_CALEV); 395 396 ret = devm_request_irq(&pdev->dev, irq, at91_rtc_interrupt, 397 IRQF_SHARED, 398 "at91_rtc", pdev); 399 if (ret) { 400 dev_err(&pdev->dev, "IRQ %d already in use.\n", irq); 401 return ret; 402 } 403 404 /* cpu init code should really have flagged this device as 405 * being wake-capable; if it didn't, do that here. 406 */ 407 if (!device_can_wakeup(&pdev->dev)) 408 device_init_wakeup(&pdev->dev, 1); 409 410 rtc = devm_rtc_device_register(&pdev->dev, pdev->name, 411 &at91_rtc_ops, THIS_MODULE); 412 if (IS_ERR(rtc)) 413 return PTR_ERR(rtc); 414 platform_set_drvdata(pdev, rtc); 415 416 dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n"); 417 return 0; 418 } 419 420 /* 421 * Disable and remove the RTC driver 422 */ 423 static int __exit at91_rtc_remove(struct platform_device *pdev) 424 { 425 /* Disable all interrupts */ 426 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM | 427 AT91_RTC_SECEV | AT91_RTC_TIMEV | 428 AT91_RTC_CALEV); 429 430 return 0; 431 } 432 433 static void at91_rtc_shutdown(struct platform_device *pdev) 434 { 435 /* Disable all interrupts */ 436 at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM | 437 AT91_RTC_SECEV | AT91_RTC_TIMEV | 438 AT91_RTC_CALEV); 439 } 440 441 #ifdef CONFIG_PM_SLEEP 442 443 /* AT91RM9200 RTC Power management control */ 444 445 static u32 at91_rtc_imr; 446 447 static int at91_rtc_suspend(struct device *dev) 448 { 449 /* this IRQ is shared with DBGU and other hardware which isn't 450 * necessarily doing PM like we are... 451 */ 452 at91_rtc_imr = at91_rtc_read_imr() 453 & (AT91_RTC_ALARM|AT91_RTC_SECEV); 454 if (at91_rtc_imr) { 455 if (device_may_wakeup(dev)) 456 enable_irq_wake(irq); 457 else 458 at91_rtc_write_idr(at91_rtc_imr); 459 } 460 return 0; 461 } 462 463 static int at91_rtc_resume(struct device *dev) 464 { 465 if (at91_rtc_imr) { 466 if (device_may_wakeup(dev)) 467 disable_irq_wake(irq); 468 else 469 at91_rtc_write_ier(at91_rtc_imr); 470 } 471 return 0; 472 } 473 #endif 474 475 static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume); 476 477 static struct platform_driver at91_rtc_driver = { 478 .remove = __exit_p(at91_rtc_remove), 479 .shutdown = at91_rtc_shutdown, 480 .driver = { 481 .name = "at91_rtc", 482 .owner = THIS_MODULE, 483 .pm = &at91_rtc_pm_ops, 484 .of_match_table = of_match_ptr(at91_rtc_dt_ids), 485 }, 486 }; 487 488 module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe); 489 490 MODULE_AUTHOR("Rick Bronson"); 491 MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200"); 492 MODULE_LICENSE("GPL"); 493 MODULE_ALIAS("platform:at91_rtc"); 494