1 /* 2 * An rtc driver for the Dallas DS1511 3 * 4 * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp> 5 * Copyright (C) 2007 Andrew Sharp <andy.sharp@lsi.com> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 * 11 * Real time clock driver for the Dallas 1511 chip, which also 12 * contains a watchdog timer. There is a tiny amount of code that 13 * platform code could use to mess with the watchdog device a little 14 * bit, but not a full watchdog driver. 15 */ 16 17 #include <linux/bcd.h> 18 #include <linux/init.h> 19 #include <linux/kernel.h> 20 #include <linux/gfp.h> 21 #include <linux/delay.h> 22 #include <linux/interrupt.h> 23 #include <linux/rtc.h> 24 #include <linux/platform_device.h> 25 #include <linux/io.h> 26 #include <linux/module.h> 27 28 #define DRV_VERSION "0.6" 29 30 enum ds1511reg { 31 DS1511_SEC = 0x0, 32 DS1511_MIN = 0x1, 33 DS1511_HOUR = 0x2, 34 DS1511_DOW = 0x3, 35 DS1511_DOM = 0x4, 36 DS1511_MONTH = 0x5, 37 DS1511_YEAR = 0x6, 38 DS1511_CENTURY = 0x7, 39 DS1511_AM1_SEC = 0x8, 40 DS1511_AM2_MIN = 0x9, 41 DS1511_AM3_HOUR = 0xa, 42 DS1511_AM4_DATE = 0xb, 43 DS1511_WD_MSEC = 0xc, 44 DS1511_WD_SEC = 0xd, 45 DS1511_CONTROL_A = 0xe, 46 DS1511_CONTROL_B = 0xf, 47 DS1511_RAMADDR_LSB = 0x10, 48 DS1511_RAMDATA = 0x13 49 }; 50 51 #define DS1511_BLF1 0x80 52 #define DS1511_BLF2 0x40 53 #define DS1511_PRS 0x20 54 #define DS1511_PAB 0x10 55 #define DS1511_TDF 0x08 56 #define DS1511_KSF 0x04 57 #define DS1511_WDF 0x02 58 #define DS1511_IRQF 0x01 59 #define DS1511_TE 0x80 60 #define DS1511_CS 0x40 61 #define DS1511_BME 0x20 62 #define DS1511_TPE 0x10 63 #define DS1511_TIE 0x08 64 #define DS1511_KIE 0x04 65 #define DS1511_WDE 0x02 66 #define DS1511_WDS 0x01 67 #define DS1511_RAM_MAX 0xff 68 69 #define RTC_CMD DS1511_CONTROL_B 70 #define RTC_CMD1 DS1511_CONTROL_A 71 72 #define RTC_ALARM_SEC DS1511_AM1_SEC 73 #define RTC_ALARM_MIN DS1511_AM2_MIN 74 #define RTC_ALARM_HOUR DS1511_AM3_HOUR 75 #define RTC_ALARM_DATE DS1511_AM4_DATE 76 77 #define RTC_SEC DS1511_SEC 78 #define RTC_MIN DS1511_MIN 79 #define RTC_HOUR DS1511_HOUR 80 #define RTC_DOW DS1511_DOW 81 #define RTC_DOM DS1511_DOM 82 #define RTC_MON DS1511_MONTH 83 #define RTC_YEAR DS1511_YEAR 84 #define RTC_CENTURY DS1511_CENTURY 85 86 #define RTC_TIE DS1511_TIE 87 #define RTC_TE DS1511_TE 88 89 struct rtc_plat_data { 90 struct rtc_device *rtc; 91 void __iomem *ioaddr; /* virtual base address */ 92 int size; /* amount of memory mapped */ 93 int irq; 94 unsigned int irqen; 95 int alrm_sec; 96 int alrm_min; 97 int alrm_hour; 98 int alrm_mday; 99 spinlock_t lock; 100 }; 101 102 static DEFINE_SPINLOCK(ds1511_lock); 103 104 static __iomem char *ds1511_base; 105 static u32 reg_spacing = 1; 106 107 static noinline void 108 rtc_write(uint8_t val, uint32_t reg) 109 { 110 writeb(val, ds1511_base + (reg * reg_spacing)); 111 } 112 113 static inline void 114 rtc_write_alarm(uint8_t val, enum ds1511reg reg) 115 { 116 rtc_write((val | 0x80), reg); 117 } 118 119 static noinline uint8_t 120 rtc_read(enum ds1511reg reg) 121 { 122 return readb(ds1511_base + (reg * reg_spacing)); 123 } 124 125 static inline void 126 rtc_disable_update(void) 127 { 128 rtc_write((rtc_read(RTC_CMD) & ~RTC_TE), RTC_CMD); 129 } 130 131 static void 132 rtc_enable_update(void) 133 { 134 rtc_write((rtc_read(RTC_CMD) | RTC_TE), RTC_CMD); 135 } 136 137 /* 138 * #define DS1511_WDOG_RESET_SUPPORT 139 * 140 * Uncomment this if you want to use these routines in 141 * some platform code. 142 */ 143 #ifdef DS1511_WDOG_RESET_SUPPORT 144 /* 145 * just enough code to set the watchdog timer so that it 146 * will reboot the system 147 */ 148 void 149 ds1511_wdog_set(unsigned long deciseconds) 150 { 151 /* 152 * the wdog timer can take 99.99 seconds 153 */ 154 deciseconds %= 10000; 155 /* 156 * set the wdog values in the wdog registers 157 */ 158 rtc_write(bin2bcd(deciseconds % 100), DS1511_WD_MSEC); 159 rtc_write(bin2bcd(deciseconds / 100), DS1511_WD_SEC); 160 /* 161 * set wdog enable and wdog 'steering' bit to issue a reset 162 */ 163 rtc_write(DS1511_WDE | DS1511_WDS, RTC_CMD); 164 } 165 166 void 167 ds1511_wdog_disable(void) 168 { 169 /* 170 * clear wdog enable and wdog 'steering' bits 171 */ 172 rtc_write(rtc_read(RTC_CMD) & ~(DS1511_WDE | DS1511_WDS), RTC_CMD); 173 /* 174 * clear the wdog counter 175 */ 176 rtc_write(0, DS1511_WD_MSEC); 177 rtc_write(0, DS1511_WD_SEC); 178 } 179 #endif 180 181 /* 182 * set the rtc chip's idea of the time. 183 * stupidly, some callers call with year unmolested; 184 * and some call with year = year - 1900. thanks. 185 */ 186 static int ds1511_rtc_set_time(struct device *dev, struct rtc_time *rtc_tm) 187 { 188 u8 mon, day, dow, hrs, min, sec, yrs, cen; 189 unsigned long flags; 190 191 /* 192 * won't have to change this for a while 193 */ 194 if (rtc_tm->tm_year < 1900) 195 rtc_tm->tm_year += 1900; 196 197 if (rtc_tm->tm_year < 1970) 198 return -EINVAL; 199 200 yrs = rtc_tm->tm_year % 100; 201 cen = rtc_tm->tm_year / 100; 202 mon = rtc_tm->tm_mon + 1; /* tm_mon starts at zero */ 203 day = rtc_tm->tm_mday; 204 dow = rtc_tm->tm_wday & 0x7; /* automatic BCD */ 205 hrs = rtc_tm->tm_hour; 206 min = rtc_tm->tm_min; 207 sec = rtc_tm->tm_sec; 208 209 if ((mon > 12) || (day == 0)) 210 return -EINVAL; 211 212 if (day > rtc_month_days(rtc_tm->tm_mon, rtc_tm->tm_year)) 213 return -EINVAL; 214 215 if ((hrs >= 24) || (min >= 60) || (sec >= 60)) 216 return -EINVAL; 217 218 /* 219 * each register is a different number of valid bits 220 */ 221 sec = bin2bcd(sec) & 0x7f; 222 min = bin2bcd(min) & 0x7f; 223 hrs = bin2bcd(hrs) & 0x3f; 224 day = bin2bcd(day) & 0x3f; 225 mon = bin2bcd(mon) & 0x1f; 226 yrs = bin2bcd(yrs) & 0xff; 227 cen = bin2bcd(cen) & 0xff; 228 229 spin_lock_irqsave(&ds1511_lock, flags); 230 rtc_disable_update(); 231 rtc_write(cen, RTC_CENTURY); 232 rtc_write(yrs, RTC_YEAR); 233 rtc_write((rtc_read(RTC_MON) & 0xe0) | mon, RTC_MON); 234 rtc_write(day, RTC_DOM); 235 rtc_write(hrs, RTC_HOUR); 236 rtc_write(min, RTC_MIN); 237 rtc_write(sec, RTC_SEC); 238 rtc_write(dow, RTC_DOW); 239 rtc_enable_update(); 240 spin_unlock_irqrestore(&ds1511_lock, flags); 241 242 return 0; 243 } 244 245 static int ds1511_rtc_read_time(struct device *dev, struct rtc_time *rtc_tm) 246 { 247 unsigned int century; 248 unsigned long flags; 249 250 spin_lock_irqsave(&ds1511_lock, flags); 251 rtc_disable_update(); 252 253 rtc_tm->tm_sec = rtc_read(RTC_SEC) & 0x7f; 254 rtc_tm->tm_min = rtc_read(RTC_MIN) & 0x7f; 255 rtc_tm->tm_hour = rtc_read(RTC_HOUR) & 0x3f; 256 rtc_tm->tm_mday = rtc_read(RTC_DOM) & 0x3f; 257 rtc_tm->tm_wday = rtc_read(RTC_DOW) & 0x7; 258 rtc_tm->tm_mon = rtc_read(RTC_MON) & 0x1f; 259 rtc_tm->tm_year = rtc_read(RTC_YEAR) & 0x7f; 260 century = rtc_read(RTC_CENTURY); 261 262 rtc_enable_update(); 263 spin_unlock_irqrestore(&ds1511_lock, flags); 264 265 rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec); 266 rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min); 267 rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour); 268 rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday); 269 rtc_tm->tm_wday = bcd2bin(rtc_tm->tm_wday); 270 rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon); 271 rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year); 272 century = bcd2bin(century) * 100; 273 274 /* 275 * Account for differences between how the RTC uses the values 276 * and how they are defined in a struct rtc_time; 277 */ 278 century += rtc_tm->tm_year; 279 rtc_tm->tm_year = century - 1900; 280 281 rtc_tm->tm_mon--; 282 283 if (rtc_valid_tm(rtc_tm) < 0) { 284 dev_err(dev, "retrieved date/time is not valid.\n"); 285 rtc_time_to_tm(0, rtc_tm); 286 } 287 return 0; 288 } 289 290 /* 291 * write the alarm register settings 292 * 293 * we only have the use to interrupt every second, otherwise 294 * known as the update interrupt, or the interrupt if the whole 295 * date/hours/mins/secs matches. the ds1511 has many more 296 * permutations, but the kernel doesn't. 297 */ 298 static void 299 ds1511_rtc_update_alarm(struct rtc_plat_data *pdata) 300 { 301 unsigned long flags; 302 303 spin_lock_irqsave(&pdata->lock, flags); 304 rtc_write(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ? 305 0x80 : bin2bcd(pdata->alrm_mday) & 0x3f, 306 RTC_ALARM_DATE); 307 rtc_write(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ? 308 0x80 : bin2bcd(pdata->alrm_hour) & 0x3f, 309 RTC_ALARM_HOUR); 310 rtc_write(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ? 311 0x80 : bin2bcd(pdata->alrm_min) & 0x7f, 312 RTC_ALARM_MIN); 313 rtc_write(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ? 314 0x80 : bin2bcd(pdata->alrm_sec) & 0x7f, 315 RTC_ALARM_SEC); 316 rtc_write(rtc_read(RTC_CMD) | (pdata->irqen ? RTC_TIE : 0), RTC_CMD); 317 rtc_read(RTC_CMD1); /* clear interrupts */ 318 spin_unlock_irqrestore(&pdata->lock, flags); 319 } 320 321 static int 322 ds1511_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 323 { 324 struct platform_device *pdev = to_platform_device(dev); 325 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 326 327 if (pdata->irq <= 0) 328 return -EINVAL; 329 330 pdata->alrm_mday = alrm->time.tm_mday; 331 pdata->alrm_hour = alrm->time.tm_hour; 332 pdata->alrm_min = alrm->time.tm_min; 333 pdata->alrm_sec = alrm->time.tm_sec; 334 if (alrm->enabled) 335 pdata->irqen |= RTC_AF; 336 337 ds1511_rtc_update_alarm(pdata); 338 return 0; 339 } 340 341 static int 342 ds1511_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 343 { 344 struct platform_device *pdev = to_platform_device(dev); 345 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 346 347 if (pdata->irq <= 0) 348 return -EINVAL; 349 350 alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday; 351 alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour; 352 alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min; 353 alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec; 354 alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0; 355 return 0; 356 } 357 358 static irqreturn_t 359 ds1511_interrupt(int irq, void *dev_id) 360 { 361 struct platform_device *pdev = dev_id; 362 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 363 unsigned long events = 0; 364 365 spin_lock(&pdata->lock); 366 /* 367 * read and clear interrupt 368 */ 369 if (rtc_read(RTC_CMD1) & DS1511_IRQF) { 370 events = RTC_IRQF; 371 if (rtc_read(RTC_ALARM_SEC) & 0x80) 372 events |= RTC_UF; 373 else 374 events |= RTC_AF; 375 if (likely(pdata->rtc)) 376 rtc_update_irq(pdata->rtc, 1, events); 377 } 378 spin_unlock(&pdata->lock); 379 return events ? IRQ_HANDLED : IRQ_NONE; 380 } 381 382 static int ds1511_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) 383 { 384 struct platform_device *pdev = to_platform_device(dev); 385 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 386 387 if (pdata->irq <= 0) 388 return -EINVAL; 389 if (enabled) 390 pdata->irqen |= RTC_AF; 391 else 392 pdata->irqen &= ~RTC_AF; 393 ds1511_rtc_update_alarm(pdata); 394 return 0; 395 } 396 397 static const struct rtc_class_ops ds1511_rtc_ops = { 398 .read_time = ds1511_rtc_read_time, 399 .set_time = ds1511_rtc_set_time, 400 .read_alarm = ds1511_rtc_read_alarm, 401 .set_alarm = ds1511_rtc_set_alarm, 402 .alarm_irq_enable = ds1511_rtc_alarm_irq_enable, 403 }; 404 405 static ssize_t 406 ds1511_nvram_read(struct file *filp, struct kobject *kobj, 407 struct bin_attribute *ba, 408 char *buf, loff_t pos, size_t size) 409 { 410 ssize_t count; 411 412 /* 413 * if count is more than one, turn on "burst" mode 414 * turn it off when you're done 415 */ 416 if (size > 1) 417 rtc_write((rtc_read(RTC_CMD) | DS1511_BME), RTC_CMD); 418 419 if (pos > DS1511_RAM_MAX) 420 pos = DS1511_RAM_MAX; 421 422 if (size + pos > DS1511_RAM_MAX + 1) 423 size = DS1511_RAM_MAX - pos + 1; 424 425 rtc_write(pos, DS1511_RAMADDR_LSB); 426 for (count = 0; size > 0; count++, size--) 427 *buf++ = rtc_read(DS1511_RAMDATA); 428 429 if (count > 1) 430 rtc_write((rtc_read(RTC_CMD) & ~DS1511_BME), RTC_CMD); 431 432 return count; 433 } 434 435 static ssize_t 436 ds1511_nvram_write(struct file *filp, struct kobject *kobj, 437 struct bin_attribute *bin_attr, 438 char *buf, loff_t pos, size_t size) 439 { 440 ssize_t count; 441 442 /* 443 * if count is more than one, turn on "burst" mode 444 * turn it off when you're done 445 */ 446 if (size > 1) 447 rtc_write((rtc_read(RTC_CMD) | DS1511_BME), RTC_CMD); 448 449 if (pos > DS1511_RAM_MAX) 450 pos = DS1511_RAM_MAX; 451 452 if (size + pos > DS1511_RAM_MAX + 1) 453 size = DS1511_RAM_MAX - pos + 1; 454 455 rtc_write(pos, DS1511_RAMADDR_LSB); 456 for (count = 0; size > 0; count++, size--) 457 rtc_write(*buf++, DS1511_RAMDATA); 458 459 if (count > 1) 460 rtc_write((rtc_read(RTC_CMD) & ~DS1511_BME), RTC_CMD); 461 462 return count; 463 } 464 465 static struct bin_attribute ds1511_nvram_attr = { 466 .attr = { 467 .name = "nvram", 468 .mode = S_IRUGO | S_IWUSR, 469 }, 470 .size = DS1511_RAM_MAX, 471 .read = ds1511_nvram_read, 472 .write = ds1511_nvram_write, 473 }; 474 475 static int ds1511_rtc_probe(struct platform_device *pdev) 476 { 477 struct rtc_device *rtc; 478 struct resource *res; 479 struct rtc_plat_data *pdata; 480 int ret = 0; 481 482 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 483 if (!res) 484 return -ENODEV; 485 486 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); 487 if (!pdata) 488 return -ENOMEM; 489 pdata->size = resource_size(res); 490 if (!devm_request_mem_region(&pdev->dev, res->start, pdata->size, 491 pdev->name)) 492 return -EBUSY; 493 ds1511_base = devm_ioremap(&pdev->dev, res->start, pdata->size); 494 if (!ds1511_base) 495 return -ENOMEM; 496 pdata->ioaddr = ds1511_base; 497 pdata->irq = platform_get_irq(pdev, 0); 498 499 /* 500 * turn on the clock and the crystal, etc. 501 */ 502 rtc_write(0, RTC_CMD); 503 rtc_write(0, RTC_CMD1); 504 /* 505 * clear the wdog counter 506 */ 507 rtc_write(0, DS1511_WD_MSEC); 508 rtc_write(0, DS1511_WD_SEC); 509 /* 510 * start the clock 511 */ 512 rtc_enable_update(); 513 514 /* 515 * check for a dying bat-tree 516 */ 517 if (rtc_read(RTC_CMD1) & DS1511_BLF1) 518 dev_warn(&pdev->dev, "voltage-low detected.\n"); 519 520 spin_lock_init(&pdata->lock); 521 platform_set_drvdata(pdev, pdata); 522 /* 523 * if the platform has an interrupt in mind for this device, 524 * then by all means, set it 525 */ 526 if (pdata->irq > 0) { 527 rtc_read(RTC_CMD1); 528 if (devm_request_irq(&pdev->dev, pdata->irq, ds1511_interrupt, 529 IRQF_SHARED, pdev->name, pdev) < 0) { 530 531 dev_warn(&pdev->dev, "interrupt not available.\n"); 532 pdata->irq = 0; 533 } 534 } 535 536 rtc = devm_rtc_device_register(&pdev->dev, pdev->name, &ds1511_rtc_ops, 537 THIS_MODULE); 538 if (IS_ERR(rtc)) 539 return PTR_ERR(rtc); 540 pdata->rtc = rtc; 541 542 ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr); 543 544 return ret; 545 } 546 547 static int ds1511_rtc_remove(struct platform_device *pdev) 548 { 549 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 550 551 sysfs_remove_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr); 552 if (pdata->irq > 0) { 553 /* 554 * disable the alarm interrupt 555 */ 556 rtc_write(rtc_read(RTC_CMD) & ~RTC_TIE, RTC_CMD); 557 rtc_read(RTC_CMD1); 558 } 559 return 0; 560 } 561 562 /* work with hotplug and coldplug */ 563 MODULE_ALIAS("platform:ds1511"); 564 565 static struct platform_driver ds1511_rtc_driver = { 566 .probe = ds1511_rtc_probe, 567 .remove = ds1511_rtc_remove, 568 .driver = { 569 .name = "ds1511", 570 .owner = THIS_MODULE, 571 }, 572 }; 573 574 module_platform_driver(ds1511_rtc_driver); 575 576 MODULE_AUTHOR("Andrew Sharp <andy.sharp@lsi.com>"); 577 MODULE_DESCRIPTION("Dallas DS1511 RTC driver"); 578 MODULE_LICENSE("GPL"); 579 MODULE_VERSION(DRV_VERSION); 580