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 0x100 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 irq; 93 unsigned int irqen; 94 int alrm_sec; 95 int alrm_min; 96 int alrm_hour; 97 int alrm_mday; 98 spinlock_t lock; 99 }; 100 101 static DEFINE_SPINLOCK(ds1511_lock); 102 103 static __iomem char *ds1511_base; 104 static u32 reg_spacing = 1; 105 106 static noinline void 107 rtc_write(uint8_t val, uint32_t reg) 108 { 109 writeb(val, ds1511_base + (reg * reg_spacing)); 110 } 111 112 static inline void 113 rtc_write_alarm(uint8_t val, enum ds1511reg reg) 114 { 115 rtc_write((val | 0x80), reg); 116 } 117 118 static noinline uint8_t 119 rtc_read(enum ds1511reg reg) 120 { 121 return readb(ds1511_base + (reg * reg_spacing)); 122 } 123 124 static inline void 125 rtc_disable_update(void) 126 { 127 rtc_write((rtc_read(RTC_CMD) & ~RTC_TE), RTC_CMD); 128 } 129 130 static void 131 rtc_enable_update(void) 132 { 133 rtc_write((rtc_read(RTC_CMD) | RTC_TE), RTC_CMD); 134 } 135 136 /* 137 * #define DS1511_WDOG_RESET_SUPPORT 138 * 139 * Uncomment this if you want to use these routines in 140 * some platform code. 141 */ 142 #ifdef DS1511_WDOG_RESET_SUPPORT 143 /* 144 * just enough code to set the watchdog timer so that it 145 * will reboot the system 146 */ 147 void 148 ds1511_wdog_set(unsigned long deciseconds) 149 { 150 /* 151 * the wdog timer can take 99.99 seconds 152 */ 153 deciseconds %= 10000; 154 /* 155 * set the wdog values in the wdog registers 156 */ 157 rtc_write(bin2bcd(deciseconds % 100), DS1511_WD_MSEC); 158 rtc_write(bin2bcd(deciseconds / 100), DS1511_WD_SEC); 159 /* 160 * set wdog enable and wdog 'steering' bit to issue a reset 161 */ 162 rtc_write(rtc_read(RTC_CMD) | DS1511_WDE | DS1511_WDS, RTC_CMD); 163 } 164 165 void 166 ds1511_wdog_disable(void) 167 { 168 /* 169 * clear wdog enable and wdog 'steering' bits 170 */ 171 rtc_write(rtc_read(RTC_CMD) & ~(DS1511_WDE | DS1511_WDS), RTC_CMD); 172 /* 173 * clear the wdog counter 174 */ 175 rtc_write(0, DS1511_WD_MSEC); 176 rtc_write(0, DS1511_WD_SEC); 177 } 178 #endif 179 180 /* 181 * set the rtc chip's idea of the time. 182 * stupidly, some callers call with year unmolested; 183 * and some call with year = year - 1900. thanks. 184 */ 185 static int ds1511_rtc_set_time(struct device *dev, struct rtc_time *rtc_tm) 186 { 187 u8 mon, day, dow, hrs, min, sec, yrs, cen; 188 unsigned long flags; 189 190 /* 191 * won't have to change this for a while 192 */ 193 if (rtc_tm->tm_year < 1900) 194 rtc_tm->tm_year += 1900; 195 196 if (rtc_tm->tm_year < 1970) 197 return -EINVAL; 198 199 yrs = rtc_tm->tm_year % 100; 200 cen = rtc_tm->tm_year / 100; 201 mon = rtc_tm->tm_mon + 1; /* tm_mon starts at zero */ 202 day = rtc_tm->tm_mday; 203 dow = rtc_tm->tm_wday & 0x7; /* automatic BCD */ 204 hrs = rtc_tm->tm_hour; 205 min = rtc_tm->tm_min; 206 sec = rtc_tm->tm_sec; 207 208 if ((mon > 12) || (day == 0)) 209 return -EINVAL; 210 211 if (day > rtc_month_days(rtc_tm->tm_mon, rtc_tm->tm_year)) 212 return -EINVAL; 213 214 if ((hrs >= 24) || (min >= 60) || (sec >= 60)) 215 return -EINVAL; 216 217 /* 218 * each register is a different number of valid bits 219 */ 220 sec = bin2bcd(sec) & 0x7f; 221 min = bin2bcd(min) & 0x7f; 222 hrs = bin2bcd(hrs) & 0x3f; 223 day = bin2bcd(day) & 0x3f; 224 mon = bin2bcd(mon) & 0x1f; 225 yrs = bin2bcd(yrs) & 0xff; 226 cen = bin2bcd(cen) & 0xff; 227 228 spin_lock_irqsave(&ds1511_lock, flags); 229 rtc_disable_update(); 230 rtc_write(cen, RTC_CENTURY); 231 rtc_write(yrs, RTC_YEAR); 232 rtc_write((rtc_read(RTC_MON) & 0xe0) | mon, RTC_MON); 233 rtc_write(day, RTC_DOM); 234 rtc_write(hrs, RTC_HOUR); 235 rtc_write(min, RTC_MIN); 236 rtc_write(sec, RTC_SEC); 237 rtc_write(dow, RTC_DOW); 238 rtc_enable_update(); 239 spin_unlock_irqrestore(&ds1511_lock, flags); 240 241 return 0; 242 } 243 244 static int ds1511_rtc_read_time(struct device *dev, struct rtc_time *rtc_tm) 245 { 246 unsigned int century; 247 unsigned long flags; 248 249 spin_lock_irqsave(&ds1511_lock, flags); 250 rtc_disable_update(); 251 252 rtc_tm->tm_sec = rtc_read(RTC_SEC) & 0x7f; 253 rtc_tm->tm_min = rtc_read(RTC_MIN) & 0x7f; 254 rtc_tm->tm_hour = rtc_read(RTC_HOUR) & 0x3f; 255 rtc_tm->tm_mday = rtc_read(RTC_DOM) & 0x3f; 256 rtc_tm->tm_wday = rtc_read(RTC_DOW) & 0x7; 257 rtc_tm->tm_mon = rtc_read(RTC_MON) & 0x1f; 258 rtc_tm->tm_year = rtc_read(RTC_YEAR) & 0x7f; 259 century = rtc_read(RTC_CENTURY); 260 261 rtc_enable_update(); 262 spin_unlock_irqrestore(&ds1511_lock, flags); 263 264 rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec); 265 rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min); 266 rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour); 267 rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday); 268 rtc_tm->tm_wday = bcd2bin(rtc_tm->tm_wday); 269 rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon); 270 rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year); 271 century = bcd2bin(century) * 100; 272 273 /* 274 * Account for differences between how the RTC uses the values 275 * and how they are defined in a struct rtc_time; 276 */ 277 century += rtc_tm->tm_year; 278 rtc_tm->tm_year = century - 1900; 279 280 rtc_tm->tm_mon--; 281 282 if (rtc_valid_tm(rtc_tm) < 0) { 283 dev_err(dev, "retrieved date/time is not valid.\n"); 284 rtc_time_to_tm(0, rtc_tm); 285 } 286 return 0; 287 } 288 289 /* 290 * write the alarm register settings 291 * 292 * we only have the use to interrupt every second, otherwise 293 * known as the update interrupt, or the interrupt if the whole 294 * date/hours/mins/secs matches. the ds1511 has many more 295 * permutations, but the kernel doesn't. 296 */ 297 static void 298 ds1511_rtc_update_alarm(struct rtc_plat_data *pdata) 299 { 300 unsigned long flags; 301 302 spin_lock_irqsave(&pdata->lock, flags); 303 rtc_write(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ? 304 0x80 : bin2bcd(pdata->alrm_mday) & 0x3f, 305 RTC_ALARM_DATE); 306 rtc_write(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ? 307 0x80 : bin2bcd(pdata->alrm_hour) & 0x3f, 308 RTC_ALARM_HOUR); 309 rtc_write(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ? 310 0x80 : bin2bcd(pdata->alrm_min) & 0x7f, 311 RTC_ALARM_MIN); 312 rtc_write(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ? 313 0x80 : bin2bcd(pdata->alrm_sec) & 0x7f, 314 RTC_ALARM_SEC); 315 rtc_write(rtc_read(RTC_CMD) | (pdata->irqen ? RTC_TIE : 0), RTC_CMD); 316 rtc_read(RTC_CMD1); /* clear interrupts */ 317 spin_unlock_irqrestore(&pdata->lock, flags); 318 } 319 320 static int 321 ds1511_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 322 { 323 struct platform_device *pdev = to_platform_device(dev); 324 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 325 326 if (pdata->irq <= 0) 327 return -EINVAL; 328 329 pdata->alrm_mday = alrm->time.tm_mday; 330 pdata->alrm_hour = alrm->time.tm_hour; 331 pdata->alrm_min = alrm->time.tm_min; 332 pdata->alrm_sec = alrm->time.tm_sec; 333 if (alrm->enabled) 334 pdata->irqen |= RTC_AF; 335 336 ds1511_rtc_update_alarm(pdata); 337 return 0; 338 } 339 340 static int 341 ds1511_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 342 { 343 struct platform_device *pdev = to_platform_device(dev); 344 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 345 346 if (pdata->irq <= 0) 347 return -EINVAL; 348 349 alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday; 350 alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour; 351 alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min; 352 alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec; 353 alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0; 354 return 0; 355 } 356 357 static irqreturn_t 358 ds1511_interrupt(int irq, void *dev_id) 359 { 360 struct platform_device *pdev = dev_id; 361 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 362 unsigned long events = 0; 363 364 spin_lock(&pdata->lock); 365 /* 366 * read and clear interrupt 367 */ 368 if (rtc_read(RTC_CMD1) & DS1511_IRQF) { 369 events = RTC_IRQF; 370 if (rtc_read(RTC_ALARM_SEC) & 0x80) 371 events |= RTC_UF; 372 else 373 events |= RTC_AF; 374 rtc_update_irq(pdata->rtc, 1, events); 375 } 376 spin_unlock(&pdata->lock); 377 return events ? IRQ_HANDLED : IRQ_NONE; 378 } 379 380 static int ds1511_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) 381 { 382 struct platform_device *pdev = to_platform_device(dev); 383 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 384 385 if (pdata->irq <= 0) 386 return -EINVAL; 387 if (enabled) 388 pdata->irqen |= RTC_AF; 389 else 390 pdata->irqen &= ~RTC_AF; 391 ds1511_rtc_update_alarm(pdata); 392 return 0; 393 } 394 395 static const struct rtc_class_ops ds1511_rtc_ops = { 396 .read_time = ds1511_rtc_read_time, 397 .set_time = ds1511_rtc_set_time, 398 .read_alarm = ds1511_rtc_read_alarm, 399 .set_alarm = ds1511_rtc_set_alarm, 400 .alarm_irq_enable = ds1511_rtc_alarm_irq_enable, 401 }; 402 403 static ssize_t 404 ds1511_nvram_read(struct file *filp, struct kobject *kobj, 405 struct bin_attribute *ba, 406 char *buf, loff_t pos, size_t size) 407 { 408 ssize_t count; 409 410 rtc_write(pos, DS1511_RAMADDR_LSB); 411 for (count = 0; count < size; count++) 412 *buf++ = rtc_read(DS1511_RAMDATA); 413 414 return count; 415 } 416 417 static ssize_t 418 ds1511_nvram_write(struct file *filp, struct kobject *kobj, 419 struct bin_attribute *bin_attr, 420 char *buf, loff_t pos, size_t size) 421 { 422 ssize_t count; 423 424 rtc_write(pos, DS1511_RAMADDR_LSB); 425 for (count = 0; count < size; count++) 426 rtc_write(*buf++, DS1511_RAMDATA); 427 428 return count; 429 } 430 431 static struct bin_attribute ds1511_nvram_attr = { 432 .attr = { 433 .name = "nvram", 434 .mode = S_IRUGO | S_IWUSR, 435 }, 436 .size = DS1511_RAM_MAX, 437 .read = ds1511_nvram_read, 438 .write = ds1511_nvram_write, 439 }; 440 441 static int ds1511_rtc_probe(struct platform_device *pdev) 442 { 443 struct resource *res; 444 struct rtc_plat_data *pdata; 445 int ret = 0; 446 447 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); 448 if (!pdata) 449 return -ENOMEM; 450 451 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 452 ds1511_base = devm_ioremap_resource(&pdev->dev, res); 453 if (IS_ERR(ds1511_base)) 454 return PTR_ERR(ds1511_base); 455 pdata->ioaddr = ds1511_base; 456 pdata->irq = platform_get_irq(pdev, 0); 457 458 /* 459 * turn on the clock and the crystal, etc. 460 */ 461 rtc_write(DS1511_BME, RTC_CMD); 462 rtc_write(0, RTC_CMD1); 463 /* 464 * clear the wdog counter 465 */ 466 rtc_write(0, DS1511_WD_MSEC); 467 rtc_write(0, DS1511_WD_SEC); 468 /* 469 * start the clock 470 */ 471 rtc_enable_update(); 472 473 /* 474 * check for a dying bat-tree 475 */ 476 if (rtc_read(RTC_CMD1) & DS1511_BLF1) 477 dev_warn(&pdev->dev, "voltage-low detected.\n"); 478 479 spin_lock_init(&pdata->lock); 480 platform_set_drvdata(pdev, pdata); 481 482 pdata->rtc = devm_rtc_device_register(&pdev->dev, pdev->name, 483 &ds1511_rtc_ops, THIS_MODULE); 484 if (IS_ERR(pdata->rtc)) 485 return PTR_ERR(pdata->rtc); 486 487 /* 488 * if the platform has an interrupt in mind for this device, 489 * then by all means, set it 490 */ 491 if (pdata->irq > 0) { 492 rtc_read(RTC_CMD1); 493 if (devm_request_irq(&pdev->dev, pdata->irq, ds1511_interrupt, 494 IRQF_SHARED, pdev->name, pdev) < 0) { 495 496 dev_warn(&pdev->dev, "interrupt not available.\n"); 497 pdata->irq = 0; 498 } 499 } 500 501 ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr); 502 if (ret) 503 dev_err(&pdev->dev, "Unable to create sysfs entry: %s\n", 504 ds1511_nvram_attr.attr.name); 505 506 return 0; 507 } 508 509 static int ds1511_rtc_remove(struct platform_device *pdev) 510 { 511 struct rtc_plat_data *pdata = platform_get_drvdata(pdev); 512 513 sysfs_remove_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr); 514 if (pdata->irq > 0) { 515 /* 516 * disable the alarm interrupt 517 */ 518 rtc_write(rtc_read(RTC_CMD) & ~RTC_TIE, RTC_CMD); 519 rtc_read(RTC_CMD1); 520 } 521 return 0; 522 } 523 524 /* work with hotplug and coldplug */ 525 MODULE_ALIAS("platform:ds1511"); 526 527 static struct platform_driver ds1511_rtc_driver = { 528 .probe = ds1511_rtc_probe, 529 .remove = ds1511_rtc_remove, 530 .driver = { 531 .name = "ds1511", 532 }, 533 }; 534 535 module_platform_driver(ds1511_rtc_driver); 536 537 MODULE_AUTHOR("Andrew Sharp <andy.sharp@lsi.com>"); 538 MODULE_DESCRIPTION("Dallas DS1511 RTC driver"); 539 MODULE_LICENSE("GPL"); 540 MODULE_VERSION(DRV_VERSION); 541