1 /* 2 * I2C client/driver for the ST M41T80 family of i2c rtc chips. 3 * 4 * Author: Alexander Bigga <ab@mycable.de> 5 * 6 * Based on m41t00.c by Mark A. Greer <mgreer@mvista.com> 7 * 8 * 2006 (c) mycable GmbH 9 * 10 * This program is free software; you can redistribute it and/or modify 11 * it under the terms of the GNU General Public License version 2 as 12 * published by the Free Software Foundation. 13 * 14 */ 15 16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 17 18 #include <linux/bcd.h> 19 #include <linux/i2c.h> 20 #include <linux/init.h> 21 #include <linux/kernel.h> 22 #include <linux/module.h> 23 #include <linux/rtc.h> 24 #include <linux/slab.h> 25 #include <linux/mutex.h> 26 #include <linux/string.h> 27 #ifdef CONFIG_RTC_DRV_M41T80_WDT 28 #include <linux/fs.h> 29 #include <linux/ioctl.h> 30 #include <linux/miscdevice.h> 31 #include <linux/reboot.h> 32 #include <linux/watchdog.h> 33 #endif 34 35 #define M41T80_REG_SSEC 0x00 36 #define M41T80_REG_SEC 0x01 37 #define M41T80_REG_MIN 0x02 38 #define M41T80_REG_HOUR 0x03 39 #define M41T80_REG_WDAY 0x04 40 #define M41T80_REG_DAY 0x05 41 #define M41T80_REG_MON 0x06 42 #define M41T80_REG_YEAR 0x07 43 #define M41T80_REG_ALARM_MON 0x0a 44 #define M41T80_REG_ALARM_DAY 0x0b 45 #define M41T80_REG_ALARM_HOUR 0x0c 46 #define M41T80_REG_ALARM_MIN 0x0d 47 #define M41T80_REG_ALARM_SEC 0x0e 48 #define M41T80_REG_FLAGS 0x0f 49 #define M41T80_REG_SQW 0x13 50 51 #define M41T80_DATETIME_REG_SIZE (M41T80_REG_YEAR + 1) 52 #define M41T80_ALARM_REG_SIZE \ 53 (M41T80_REG_ALARM_SEC + 1 - M41T80_REG_ALARM_MON) 54 55 #define M41T80_SEC_ST BIT(7) /* ST: Stop Bit */ 56 #define M41T80_ALMON_AFE BIT(7) /* AFE: AF Enable Bit */ 57 #define M41T80_ALMON_SQWE BIT(6) /* SQWE: SQW Enable Bit */ 58 #define M41T80_ALHOUR_HT BIT(6) /* HT: Halt Update Bit */ 59 #define M41T80_FLAGS_OF BIT(2) /* OF: Oscillator Failure Bit */ 60 #define M41T80_FLAGS_AF BIT(6) /* AF: Alarm Flag Bit */ 61 #define M41T80_FLAGS_BATT_LOW BIT(4) /* BL: Battery Low Bit */ 62 #define M41T80_WATCHDOG_RB2 BIT(7) /* RB: Watchdog resolution */ 63 #define M41T80_WATCHDOG_RB1 BIT(1) /* RB: Watchdog resolution */ 64 #define M41T80_WATCHDOG_RB0 BIT(0) /* RB: Watchdog resolution */ 65 66 #define M41T80_FEATURE_HT BIT(0) /* Halt feature */ 67 #define M41T80_FEATURE_BL BIT(1) /* Battery low indicator */ 68 #define M41T80_FEATURE_SQ BIT(2) /* Squarewave feature */ 69 #define M41T80_FEATURE_WD BIT(3) /* Extra watchdog resolution */ 70 #define M41T80_FEATURE_SQ_ALT BIT(4) /* RSx bits are in reg 4 */ 71 72 static DEFINE_MUTEX(m41t80_rtc_mutex); 73 static const struct i2c_device_id m41t80_id[] = { 74 { "m41t62", M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT }, 75 { "m41t65", M41T80_FEATURE_HT | M41T80_FEATURE_WD }, 76 { "m41t80", M41T80_FEATURE_SQ }, 77 { "m41t81", M41T80_FEATURE_HT | M41T80_FEATURE_SQ}, 78 { "m41t81s", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 79 { "m41t82", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 80 { "m41t83", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 81 { "m41st84", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 82 { "m41st85", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 83 { "m41st87", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 84 { "rv4162", M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT }, 85 { } 86 }; 87 MODULE_DEVICE_TABLE(i2c, m41t80_id); 88 89 struct m41t80_data { 90 u8 features; 91 struct rtc_device *rtc; 92 }; 93 94 static irqreturn_t m41t80_handle_irq(int irq, void *dev_id) 95 { 96 struct i2c_client *client = dev_id; 97 struct m41t80_data *m41t80 = i2c_get_clientdata(client); 98 struct mutex *lock = &m41t80->rtc->ops_lock; 99 unsigned long events = 0; 100 int flags, flags_afe; 101 102 mutex_lock(lock); 103 104 flags_afe = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); 105 if (flags_afe < 0) { 106 mutex_unlock(lock); 107 return IRQ_NONE; 108 } 109 110 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 111 if (flags <= 0) { 112 mutex_unlock(lock); 113 return IRQ_NONE; 114 } 115 116 if (flags & M41T80_FLAGS_AF) { 117 flags &= ~M41T80_FLAGS_AF; 118 flags_afe &= ~M41T80_ALMON_AFE; 119 events |= RTC_AF; 120 } 121 122 if (events) { 123 rtc_update_irq(m41t80->rtc, 1, events); 124 i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS, flags); 125 i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 126 flags_afe); 127 } 128 129 mutex_unlock(lock); 130 131 return IRQ_HANDLED; 132 } 133 134 static int m41t80_get_datetime(struct i2c_client *client, 135 struct rtc_time *tm) 136 { 137 unsigned char buf[8]; 138 int err, flags; 139 140 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 141 if (flags < 0) 142 return flags; 143 144 if (flags & M41T80_FLAGS_OF) { 145 dev_err(&client->dev, "Oscillator failure, data is invalid.\n"); 146 return -EINVAL; 147 } 148 149 err = i2c_smbus_read_i2c_block_data(client, M41T80_REG_SSEC, 150 sizeof(buf), buf); 151 if (err < 0) { 152 dev_err(&client->dev, "Unable to read date\n"); 153 return -EIO; 154 } 155 156 tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f); 157 tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f); 158 tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f); 159 tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f); 160 tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07; 161 tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1; 162 163 /* assume 20YY not 19YY, and ignore the Century Bit */ 164 tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100; 165 return rtc_valid_tm(tm); 166 } 167 168 /* Sets the given date and time to the real time clock. */ 169 static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm) 170 { 171 unsigned char buf[8]; 172 int err, flags; 173 174 if (tm->tm_year < 100 || tm->tm_year > 199) 175 return -EINVAL; 176 177 buf[M41T80_REG_SSEC] = 0; 178 buf[M41T80_REG_SEC] = bin2bcd(tm->tm_sec); 179 buf[M41T80_REG_MIN] = bin2bcd(tm->tm_min); 180 buf[M41T80_REG_HOUR] = bin2bcd(tm->tm_hour); 181 buf[M41T80_REG_DAY] = bin2bcd(tm->tm_mday); 182 buf[M41T80_REG_MON] = bin2bcd(tm->tm_mon + 1); 183 buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year - 100); 184 buf[M41T80_REG_WDAY] = tm->tm_wday; 185 186 err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_SSEC, 187 sizeof(buf), buf); 188 if (err < 0) { 189 dev_err(&client->dev, "Unable to write to date registers\n"); 190 return err; 191 } 192 193 /* Clear the OF bit of Flags Register */ 194 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 195 if (flags < 0) 196 return flags; 197 198 if (i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS, 199 flags & ~M41T80_FLAGS_OF)) { 200 dev_err(&client->dev, "Unable to write flags register\n"); 201 return -EIO; 202 } 203 204 return err; 205 } 206 207 static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq) 208 { 209 struct i2c_client *client = to_i2c_client(dev); 210 struct m41t80_data *clientdata = i2c_get_clientdata(client); 211 u8 reg; 212 213 if (clientdata->features & M41T80_FEATURE_BL) { 214 reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 215 seq_printf(seq, "battery\t\t: %s\n", 216 (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok"); 217 } 218 return 0; 219 } 220 221 static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm) 222 { 223 return m41t80_get_datetime(to_i2c_client(dev), tm); 224 } 225 226 static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm) 227 { 228 return m41t80_set_datetime(to_i2c_client(dev), tm); 229 } 230 231 static int m41t80_alarm_irq_enable(struct device *dev, unsigned int enabled) 232 { 233 struct i2c_client *client = to_i2c_client(dev); 234 int flags, retval; 235 236 flags = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); 237 if (flags < 0) 238 return flags; 239 240 if (enabled) 241 flags |= M41T80_ALMON_AFE; 242 else 243 flags &= ~M41T80_ALMON_AFE; 244 245 retval = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, flags); 246 if (retval < 0) { 247 dev_info(dev, "Unable to enable alarm IRQ %d\n", retval); 248 return retval; 249 } 250 return 0; 251 } 252 253 static int m41t80_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 254 { 255 struct i2c_client *client = to_i2c_client(dev); 256 u8 alarmvals[5]; 257 int ret, err; 258 259 alarmvals[0] = bin2bcd(alrm->time.tm_mon + 1); 260 alarmvals[1] = bin2bcd(alrm->time.tm_mday); 261 alarmvals[2] = bin2bcd(alrm->time.tm_hour); 262 alarmvals[3] = bin2bcd(alrm->time.tm_min); 263 alarmvals[4] = bin2bcd(alrm->time.tm_sec); 264 265 /* Clear AF and AFE flags */ 266 ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); 267 if (ret < 0) 268 return ret; 269 err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 270 ret & ~(M41T80_ALMON_AFE)); 271 if (err < 0) { 272 dev_err(dev, "Unable to clear AFE bit\n"); 273 return err; 274 } 275 276 ret = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 277 if (ret < 0) 278 return ret; 279 280 err = i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS, 281 ret & ~(M41T80_FLAGS_AF)); 282 if (err < 0) { 283 dev_err(dev, "Unable to clear AF bit\n"); 284 return err; 285 } 286 287 /* Write the alarm */ 288 err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_ALARM_MON, 289 5, alarmvals); 290 if (err) 291 return err; 292 293 /* Enable the alarm interrupt */ 294 if (alrm->enabled) { 295 alarmvals[0] |= M41T80_ALMON_AFE; 296 err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 297 alarmvals[0]); 298 if (err) 299 return err; 300 } 301 302 return 0; 303 } 304 305 static int m41t80_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 306 { 307 struct i2c_client *client = to_i2c_client(dev); 308 u8 alarmvals[5]; 309 int flags, ret; 310 311 ret = i2c_smbus_read_i2c_block_data(client, M41T80_REG_ALARM_MON, 312 5, alarmvals); 313 if (ret != 5) 314 return ret < 0 ? ret : -EIO; 315 316 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 317 if (flags < 0) 318 return flags; 319 320 alrm->time.tm_sec = bcd2bin(alarmvals[4] & 0x7f); 321 alrm->time.tm_min = bcd2bin(alarmvals[3] & 0x7f); 322 alrm->time.tm_hour = bcd2bin(alarmvals[2] & 0x3f); 323 alrm->time.tm_wday = -1; 324 alrm->time.tm_mday = bcd2bin(alarmvals[1] & 0x3f); 325 alrm->time.tm_mon = bcd2bin(alarmvals[0] & 0x3f); 326 alrm->time.tm_year = -1; 327 328 alrm->enabled = !!(alarmvals[0] & M41T80_ALMON_AFE); 329 alrm->pending = (flags & M41T80_FLAGS_AF) && alrm->enabled; 330 331 return 0; 332 } 333 334 static struct rtc_class_ops m41t80_rtc_ops = { 335 .read_time = m41t80_rtc_read_time, 336 .set_time = m41t80_rtc_set_time, 337 .proc = m41t80_rtc_proc, 338 }; 339 340 static ssize_t flags_show(struct device *dev, 341 struct device_attribute *attr, char *buf) 342 { 343 struct i2c_client *client = to_i2c_client(dev); 344 int val; 345 346 val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 347 if (val < 0) 348 return val; 349 return sprintf(buf, "%#x\n", val); 350 } 351 static DEVICE_ATTR_RO(flags); 352 353 static ssize_t sqwfreq_show(struct device *dev, 354 struct device_attribute *attr, char *buf) 355 { 356 struct i2c_client *client = to_i2c_client(dev); 357 struct m41t80_data *clientdata = i2c_get_clientdata(client); 358 int val, reg_sqw; 359 360 if (!(clientdata->features & M41T80_FEATURE_SQ)) 361 return -EINVAL; 362 363 reg_sqw = M41T80_REG_SQW; 364 if (clientdata->features & M41T80_FEATURE_SQ_ALT) 365 reg_sqw = M41T80_REG_WDAY; 366 val = i2c_smbus_read_byte_data(client, reg_sqw); 367 if (val < 0) 368 return val; 369 val = (val >> 4) & 0xf; 370 switch (val) { 371 case 0: 372 break; 373 case 1: 374 val = 32768; 375 break; 376 default: 377 val = 32768 >> val; 378 } 379 return sprintf(buf, "%d\n", val); 380 } 381 382 static ssize_t sqwfreq_store(struct device *dev, 383 struct device_attribute *attr, 384 const char *buf, size_t count) 385 { 386 struct i2c_client *client = to_i2c_client(dev); 387 struct m41t80_data *clientdata = i2c_get_clientdata(client); 388 int almon, sqw, reg_sqw, rc; 389 unsigned long val; 390 391 rc = kstrtoul(buf, 0, &val); 392 if (rc < 0) 393 return rc; 394 395 if (!(clientdata->features & M41T80_FEATURE_SQ)) 396 return -EINVAL; 397 398 if (val) { 399 if (!is_power_of_2(val)) 400 return -EINVAL; 401 val = ilog2(val); 402 if (val == 15) 403 val = 1; 404 else if (val < 14) 405 val = 15 - val; 406 else 407 return -EINVAL; 408 } 409 /* disable SQW, set SQW frequency & re-enable */ 410 almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); 411 if (almon < 0) 412 return almon; 413 reg_sqw = M41T80_REG_SQW; 414 if (clientdata->features & M41T80_FEATURE_SQ_ALT) 415 reg_sqw = M41T80_REG_WDAY; 416 sqw = i2c_smbus_read_byte_data(client, reg_sqw); 417 if (sqw < 0) 418 return sqw; 419 sqw = (sqw & 0x0f) | (val << 4); 420 421 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 422 almon & ~M41T80_ALMON_SQWE); 423 if (rc < 0) 424 return rc; 425 426 if (val) { 427 rc = i2c_smbus_write_byte_data(client, reg_sqw, sqw); 428 if (rc < 0) 429 return rc; 430 431 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 432 almon | M41T80_ALMON_SQWE); 433 if (rc < 0) 434 return rc; 435 } 436 return count; 437 } 438 static DEVICE_ATTR_RW(sqwfreq); 439 440 static struct attribute *attrs[] = { 441 &dev_attr_flags.attr, 442 &dev_attr_sqwfreq.attr, 443 NULL, 444 }; 445 446 static struct attribute_group attr_group = { 447 .attrs = attrs, 448 }; 449 450 #ifdef CONFIG_RTC_DRV_M41T80_WDT 451 /* 452 ***************************************************************************** 453 * 454 * Watchdog Driver 455 * 456 ***************************************************************************** 457 */ 458 static struct i2c_client *save_client; 459 460 /* Default margin */ 461 #define WD_TIMO 60 /* 1..31 seconds */ 462 463 static int wdt_margin = WD_TIMO; 464 module_param(wdt_margin, int, 0); 465 MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)"); 466 467 static unsigned long wdt_is_open; 468 static int boot_flag; 469 470 /** 471 * wdt_ping: 472 * 473 * Reload counter one with the watchdog timeout. We don't bother reloading 474 * the cascade counter. 475 */ 476 static void wdt_ping(void) 477 { 478 unsigned char i2c_data[2]; 479 struct i2c_msg msgs1[1] = { 480 { 481 .addr = save_client->addr, 482 .flags = 0, 483 .len = 2, 484 .buf = i2c_data, 485 }, 486 }; 487 struct m41t80_data *clientdata = i2c_get_clientdata(save_client); 488 489 i2c_data[0] = 0x09; /* watchdog register */ 490 491 if (wdt_margin > 31) 492 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */ 493 else 494 /* 495 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02) 496 */ 497 i2c_data[1] = wdt_margin << 2 | 0x82; 498 499 /* 500 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as 501 * that would be an invalid resolution. 502 */ 503 if (clientdata->features & M41T80_FEATURE_WD) 504 i2c_data[1] &= ~M41T80_WATCHDOG_RB2; 505 506 i2c_transfer(save_client->adapter, msgs1, 1); 507 } 508 509 /** 510 * wdt_disable: 511 * 512 * disables watchdog. 513 */ 514 static void wdt_disable(void) 515 { 516 unsigned char i2c_data[2], i2c_buf[0x10]; 517 struct i2c_msg msgs0[2] = { 518 { 519 .addr = save_client->addr, 520 .flags = 0, 521 .len = 1, 522 .buf = i2c_data, 523 }, 524 { 525 .addr = save_client->addr, 526 .flags = I2C_M_RD, 527 .len = 1, 528 .buf = i2c_buf, 529 }, 530 }; 531 struct i2c_msg msgs1[1] = { 532 { 533 .addr = save_client->addr, 534 .flags = 0, 535 .len = 2, 536 .buf = i2c_data, 537 }, 538 }; 539 540 i2c_data[0] = 0x09; 541 i2c_transfer(save_client->adapter, msgs0, 2); 542 543 i2c_data[0] = 0x09; 544 i2c_data[1] = 0x00; 545 i2c_transfer(save_client->adapter, msgs1, 1); 546 } 547 548 /** 549 * wdt_write: 550 * @file: file handle to the watchdog 551 * @buf: buffer to write (unused as data does not matter here 552 * @count: count of bytes 553 * @ppos: pointer to the position to write. No seeks allowed 554 * 555 * A write to a watchdog device is defined as a keepalive signal. Any 556 * write of data will do, as we we don't define content meaning. 557 */ 558 static ssize_t wdt_write(struct file *file, const char __user *buf, 559 size_t count, loff_t *ppos) 560 { 561 if (count) { 562 wdt_ping(); 563 return 1; 564 } 565 return 0; 566 } 567 568 static ssize_t wdt_read(struct file *file, char __user *buf, 569 size_t count, loff_t *ppos) 570 { 571 return 0; 572 } 573 574 /** 575 * wdt_ioctl: 576 * @inode: inode of the device 577 * @file: file handle to the device 578 * @cmd: watchdog command 579 * @arg: argument pointer 580 * 581 * The watchdog API defines a common set of functions for all watchdogs 582 * according to their available features. We only actually usefully support 583 * querying capabilities and current status. 584 */ 585 static int wdt_ioctl(struct file *file, unsigned int cmd, 586 unsigned long arg) 587 { 588 int new_margin, rv; 589 static struct watchdog_info ident = { 590 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING | 591 WDIOF_SETTIMEOUT, 592 .firmware_version = 1, 593 .identity = "M41T80 WTD" 594 }; 595 596 switch (cmd) { 597 case WDIOC_GETSUPPORT: 598 return copy_to_user((struct watchdog_info __user *)arg, &ident, 599 sizeof(ident)) ? -EFAULT : 0; 600 601 case WDIOC_GETSTATUS: 602 case WDIOC_GETBOOTSTATUS: 603 return put_user(boot_flag, (int __user *)arg); 604 case WDIOC_KEEPALIVE: 605 wdt_ping(); 606 return 0; 607 case WDIOC_SETTIMEOUT: 608 if (get_user(new_margin, (int __user *)arg)) 609 return -EFAULT; 610 /* Arbitrary, can't find the card's limits */ 611 if (new_margin < 1 || new_margin > 124) 612 return -EINVAL; 613 wdt_margin = new_margin; 614 wdt_ping(); 615 /* Fall */ 616 case WDIOC_GETTIMEOUT: 617 return put_user(wdt_margin, (int __user *)arg); 618 619 case WDIOC_SETOPTIONS: 620 if (copy_from_user(&rv, (int __user *)arg, sizeof(int))) 621 return -EFAULT; 622 623 if (rv & WDIOS_DISABLECARD) { 624 pr_info("disable watchdog\n"); 625 wdt_disable(); 626 } 627 628 if (rv & WDIOS_ENABLECARD) { 629 pr_info("enable watchdog\n"); 630 wdt_ping(); 631 } 632 633 return -EINVAL; 634 } 635 return -ENOTTY; 636 } 637 638 static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd, 639 unsigned long arg) 640 { 641 int ret; 642 643 mutex_lock(&m41t80_rtc_mutex); 644 ret = wdt_ioctl(file, cmd, arg); 645 mutex_unlock(&m41t80_rtc_mutex); 646 647 return ret; 648 } 649 650 /** 651 * wdt_open: 652 * @inode: inode of device 653 * @file: file handle to device 654 * 655 */ 656 static int wdt_open(struct inode *inode, struct file *file) 657 { 658 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) { 659 mutex_lock(&m41t80_rtc_mutex); 660 if (test_and_set_bit(0, &wdt_is_open)) { 661 mutex_unlock(&m41t80_rtc_mutex); 662 return -EBUSY; 663 } 664 /* 665 * Activate 666 */ 667 wdt_is_open = 1; 668 mutex_unlock(&m41t80_rtc_mutex); 669 return nonseekable_open(inode, file); 670 } 671 return -ENODEV; 672 } 673 674 /** 675 * wdt_close: 676 * @inode: inode to board 677 * @file: file handle to board 678 * 679 */ 680 static int wdt_release(struct inode *inode, struct file *file) 681 { 682 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) 683 clear_bit(0, &wdt_is_open); 684 return 0; 685 } 686 687 /** 688 * notify_sys: 689 * @this: our notifier block 690 * @code: the event being reported 691 * @unused: unused 692 * 693 * Our notifier is called on system shutdowns. We want to turn the card 694 * off at reboot otherwise the machine will reboot again during memory 695 * test or worse yet during the following fsck. This would suck, in fact 696 * trust me - if it happens it does suck. 697 */ 698 static int wdt_notify_sys(struct notifier_block *this, unsigned long code, 699 void *unused) 700 { 701 if (code == SYS_DOWN || code == SYS_HALT) 702 /* Disable Watchdog */ 703 wdt_disable(); 704 return NOTIFY_DONE; 705 } 706 707 static const struct file_operations wdt_fops = { 708 .owner = THIS_MODULE, 709 .read = wdt_read, 710 .unlocked_ioctl = wdt_unlocked_ioctl, 711 .write = wdt_write, 712 .open = wdt_open, 713 .release = wdt_release, 714 .llseek = no_llseek, 715 }; 716 717 static struct miscdevice wdt_dev = { 718 .minor = WATCHDOG_MINOR, 719 .name = "watchdog", 720 .fops = &wdt_fops, 721 }; 722 723 /* 724 * The WDT card needs to learn about soft shutdowns in order to 725 * turn the timebomb registers off. 726 */ 727 static struct notifier_block wdt_notifier = { 728 .notifier_call = wdt_notify_sys, 729 }; 730 #endif /* CONFIG_RTC_DRV_M41T80_WDT */ 731 732 /* 733 ***************************************************************************** 734 * 735 * Driver Interface 736 * 737 ***************************************************************************** 738 */ 739 740 static void m41t80_remove_sysfs_group(void *_dev) 741 { 742 struct device *dev = _dev; 743 744 sysfs_remove_group(&dev->kobj, &attr_group); 745 } 746 747 static int m41t80_probe(struct i2c_client *client, 748 const struct i2c_device_id *id) 749 { 750 struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent); 751 int rc = 0; 752 struct rtc_device *rtc = NULL; 753 struct rtc_time tm; 754 struct m41t80_data *m41t80_data = NULL; 755 756 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK | 757 I2C_FUNC_SMBUS_BYTE_DATA)) { 758 dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n"); 759 return -ENODEV; 760 } 761 762 m41t80_data = devm_kzalloc(&client->dev, sizeof(*m41t80_data), 763 GFP_KERNEL); 764 if (!m41t80_data) 765 return -ENOMEM; 766 767 m41t80_data->features = id->driver_data; 768 i2c_set_clientdata(client, m41t80_data); 769 770 if (client->irq > 0) { 771 rc = devm_request_threaded_irq(&client->dev, client->irq, 772 NULL, m41t80_handle_irq, 773 IRQF_TRIGGER_LOW | IRQF_ONESHOT, 774 "m41t80", client); 775 if (rc) { 776 dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n"); 777 client->irq = 0; 778 } else { 779 m41t80_rtc_ops.read_alarm = m41t80_read_alarm; 780 m41t80_rtc_ops.set_alarm = m41t80_set_alarm; 781 m41t80_rtc_ops.alarm_irq_enable = m41t80_alarm_irq_enable; 782 /* Enable the wakealarm */ 783 device_init_wakeup(&client->dev, true); 784 } 785 } 786 787 rtc = devm_rtc_device_register(&client->dev, client->name, 788 &m41t80_rtc_ops, THIS_MODULE); 789 if (IS_ERR(rtc)) 790 return PTR_ERR(rtc); 791 792 m41t80_data->rtc = rtc; 793 794 /* Make sure HT (Halt Update) bit is cleared */ 795 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR); 796 797 if (rc >= 0 && rc & M41T80_ALHOUR_HT) { 798 if (m41t80_data->features & M41T80_FEATURE_HT) { 799 m41t80_get_datetime(client, &tm); 800 dev_info(&client->dev, "HT bit was set!\n"); 801 dev_info(&client->dev, 802 "Power Down at %04i-%02i-%02i %02i:%02i:%02i\n", 803 tm.tm_year + 1900, 804 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, 805 tm.tm_min, tm.tm_sec); 806 } 807 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_HOUR, 808 rc & ~M41T80_ALHOUR_HT); 809 } 810 811 if (rc < 0) { 812 dev_err(&client->dev, "Can't clear HT bit\n"); 813 return rc; 814 } 815 816 /* Make sure ST (stop) bit is cleared */ 817 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC); 818 819 if (rc >= 0 && rc & M41T80_SEC_ST) 820 rc = i2c_smbus_write_byte_data(client, M41T80_REG_SEC, 821 rc & ~M41T80_SEC_ST); 822 if (rc < 0) { 823 dev_err(&client->dev, "Can't clear ST bit\n"); 824 return rc; 825 } 826 827 /* Export sysfs entries */ 828 rc = sysfs_create_group(&(&client->dev)->kobj, &attr_group); 829 if (rc) { 830 dev_err(&client->dev, "Failed to create sysfs group: %d\n", rc); 831 return rc; 832 } 833 834 rc = devm_add_action(&client->dev, m41t80_remove_sysfs_group, 835 &client->dev); 836 if (rc) { 837 m41t80_remove_sysfs_group(&client->dev); 838 dev_err(&client->dev, 839 "Failed to add sysfs cleanup action: %d\n", rc); 840 return rc; 841 } 842 843 #ifdef CONFIG_RTC_DRV_M41T80_WDT 844 if (m41t80_data->features & M41T80_FEATURE_HT) { 845 save_client = client; 846 rc = misc_register(&wdt_dev); 847 if (rc) 848 return rc; 849 rc = register_reboot_notifier(&wdt_notifier); 850 if (rc) { 851 misc_deregister(&wdt_dev); 852 return rc; 853 } 854 } 855 #endif 856 return 0; 857 } 858 859 static int m41t80_remove(struct i2c_client *client) 860 { 861 #ifdef CONFIG_RTC_DRV_M41T80_WDT 862 struct m41t80_data *clientdata = i2c_get_clientdata(client); 863 864 if (clientdata->features & M41T80_FEATURE_HT) { 865 misc_deregister(&wdt_dev); 866 unregister_reboot_notifier(&wdt_notifier); 867 } 868 #endif 869 870 return 0; 871 } 872 873 static struct i2c_driver m41t80_driver = { 874 .driver = { 875 .name = "rtc-m41t80", 876 }, 877 .probe = m41t80_probe, 878 .remove = m41t80_remove, 879 .id_table = m41t80_id, 880 }; 881 882 module_i2c_driver(m41t80_driver); 883 884 MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>"); 885 MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver"); 886 MODULE_LICENSE("GPL"); 887