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 #include <linux/bcd.h> 17 #include <linux/i2c.h> 18 #include <linux/init.h> 19 #include <linux/kernel.h> 20 #include <linux/module.h> 21 #include <linux/rtc.h> 22 #include <linux/slab.h> 23 #include <linux/mutex.h> 24 #include <linux/string.h> 25 #ifdef CONFIG_RTC_DRV_M41T80_WDT 26 #include <linux/fs.h> 27 #include <linux/ioctl.h> 28 #include <linux/miscdevice.h> 29 #include <linux/reboot.h> 30 #include <linux/watchdog.h> 31 #endif 32 33 #define M41T80_REG_SSEC 0 34 #define M41T80_REG_SEC 1 35 #define M41T80_REG_MIN 2 36 #define M41T80_REG_HOUR 3 37 #define M41T80_REG_WDAY 4 38 #define M41T80_REG_DAY 5 39 #define M41T80_REG_MON 6 40 #define M41T80_REG_YEAR 7 41 #define M41T80_REG_ALARM_MON 0xa 42 #define M41T80_REG_ALARM_DAY 0xb 43 #define M41T80_REG_ALARM_HOUR 0xc 44 #define M41T80_REG_ALARM_MIN 0xd 45 #define M41T80_REG_ALARM_SEC 0xe 46 #define M41T80_REG_FLAGS 0xf 47 #define M41T80_REG_SQW 0x13 48 49 #define M41T80_DATETIME_REG_SIZE (M41T80_REG_YEAR + 1) 50 #define M41T80_ALARM_REG_SIZE \ 51 (M41T80_REG_ALARM_SEC + 1 - M41T80_REG_ALARM_MON) 52 53 #define M41T80_SEC_ST (1 << 7) /* ST: Stop Bit */ 54 #define M41T80_ALMON_AFE (1 << 7) /* AFE: AF Enable Bit */ 55 #define M41T80_ALMON_SQWE (1 << 6) /* SQWE: SQW Enable Bit */ 56 #define M41T80_ALHOUR_HT (1 << 6) /* HT: Halt Update Bit */ 57 #define M41T80_FLAGS_AF (1 << 6) /* AF: Alarm Flag Bit */ 58 #define M41T80_FLAGS_BATT_LOW (1 << 4) /* BL: Battery Low Bit */ 59 #define M41T80_WATCHDOG_RB2 (1 << 7) /* RB: Watchdog resolution */ 60 #define M41T80_WATCHDOG_RB1 (1 << 1) /* RB: Watchdog resolution */ 61 #define M41T80_WATCHDOG_RB0 (1 << 0) /* RB: Watchdog resolution */ 62 63 #define M41T80_FEATURE_HT (1 << 0) /* Halt feature */ 64 #define M41T80_FEATURE_BL (1 << 1) /* Battery low indicator */ 65 #define M41T80_FEATURE_SQ (1 << 2) /* Squarewave feature */ 66 #define M41T80_FEATURE_WD (1 << 3) /* Extra watchdog resolution */ 67 #define M41T80_FEATURE_SQ_ALT (1 << 4) /* RSx bits are in reg 4 */ 68 69 static DEFINE_MUTEX(m41t80_rtc_mutex); 70 static const struct i2c_device_id m41t80_id[] = { 71 { "m41t62", M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT }, 72 { "m41t65", M41T80_FEATURE_HT | M41T80_FEATURE_WD }, 73 { "m41t80", M41T80_FEATURE_SQ }, 74 { "m41t81", M41T80_FEATURE_HT | M41T80_FEATURE_SQ}, 75 { "m41t81s", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 76 { "m41t82", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 77 { "m41t83", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 78 { "m41st84", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 79 { "m41st85", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 80 { "m41st87", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 81 { "rv4162", M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT }, 82 { } 83 }; 84 MODULE_DEVICE_TABLE(i2c, m41t80_id); 85 86 struct m41t80_data { 87 u8 features; 88 struct rtc_device *rtc; 89 }; 90 91 static int m41t80_get_datetime(struct i2c_client *client, 92 struct rtc_time *tm) 93 { 94 u8 buf[M41T80_DATETIME_REG_SIZE], dt_addr[1] = { M41T80_REG_SEC }; 95 struct i2c_msg msgs[] = { 96 { 97 .addr = client->addr, 98 .flags = 0, 99 .len = 1, 100 .buf = dt_addr, 101 }, 102 { 103 .addr = client->addr, 104 .flags = I2C_M_RD, 105 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC, 106 .buf = buf + M41T80_REG_SEC, 107 }, 108 }; 109 110 if (i2c_transfer(client->adapter, msgs, 2) < 0) { 111 dev_err(&client->dev, "read error\n"); 112 return -EIO; 113 } 114 115 tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f); 116 tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f); 117 tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f); 118 tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f); 119 tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07; 120 tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1; 121 122 /* assume 20YY not 19YY, and ignore the Century Bit */ 123 tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100; 124 return rtc_valid_tm(tm); 125 } 126 127 /* Sets the given date and time to the real time clock. */ 128 static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm) 129 { 130 u8 wbuf[1 + M41T80_DATETIME_REG_SIZE]; 131 u8 *buf = &wbuf[1]; 132 u8 dt_addr[1] = { M41T80_REG_SEC }; 133 struct i2c_msg msgs_in[] = { 134 { 135 .addr = client->addr, 136 .flags = 0, 137 .len = 1, 138 .buf = dt_addr, 139 }, 140 { 141 .addr = client->addr, 142 .flags = I2C_M_RD, 143 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC, 144 .buf = buf + M41T80_REG_SEC, 145 }, 146 }; 147 struct i2c_msg msgs[] = { 148 { 149 .addr = client->addr, 150 .flags = 0, 151 .len = 1 + M41T80_DATETIME_REG_SIZE, 152 .buf = wbuf, 153 }, 154 }; 155 156 /* Read current reg values into buf[1..7] */ 157 if (i2c_transfer(client->adapter, msgs_in, 2) < 0) { 158 dev_err(&client->dev, "read error\n"); 159 return -EIO; 160 } 161 162 wbuf[0] = 0; /* offset into rtc's regs */ 163 /* Merge time-data and register flags into buf[0..7] */ 164 buf[M41T80_REG_SSEC] = 0; 165 buf[M41T80_REG_SEC] = 166 bin2bcd(tm->tm_sec) | (buf[M41T80_REG_SEC] & ~0x7f); 167 buf[M41T80_REG_MIN] = 168 bin2bcd(tm->tm_min) | (buf[M41T80_REG_MIN] & ~0x7f); 169 buf[M41T80_REG_HOUR] = 170 bin2bcd(tm->tm_hour) | (buf[M41T80_REG_HOUR] & ~0x3f); 171 buf[M41T80_REG_WDAY] = 172 (tm->tm_wday & 0x07) | (buf[M41T80_REG_WDAY] & ~0x07); 173 buf[M41T80_REG_DAY] = 174 bin2bcd(tm->tm_mday) | (buf[M41T80_REG_DAY] & ~0x3f); 175 buf[M41T80_REG_MON] = 176 bin2bcd(tm->tm_mon + 1) | (buf[M41T80_REG_MON] & ~0x1f); 177 /* assume 20YY not 19YY */ 178 buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year % 100); 179 180 if (i2c_transfer(client->adapter, msgs, 1) != 1) { 181 dev_err(&client->dev, "write error\n"); 182 return -EIO; 183 } 184 return 0; 185 } 186 187 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE) 188 static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq) 189 { 190 struct i2c_client *client = to_i2c_client(dev); 191 struct m41t80_data *clientdata = i2c_get_clientdata(client); 192 u8 reg; 193 194 if (clientdata->features & M41T80_FEATURE_BL) { 195 reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 196 seq_printf(seq, "battery\t\t: %s\n", 197 (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok"); 198 } 199 return 0; 200 } 201 #else 202 #define m41t80_rtc_proc NULL 203 #endif 204 205 static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm) 206 { 207 return m41t80_get_datetime(to_i2c_client(dev), tm); 208 } 209 210 static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm) 211 { 212 return m41t80_set_datetime(to_i2c_client(dev), tm); 213 } 214 215 /* 216 * XXX - m41t80 alarm functionality is reported broken. 217 * until it is fixed, don't register alarm functions. 218 */ 219 static struct rtc_class_ops m41t80_rtc_ops = { 220 .read_time = m41t80_rtc_read_time, 221 .set_time = m41t80_rtc_set_time, 222 .proc = m41t80_rtc_proc, 223 }; 224 225 #if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE) 226 static ssize_t m41t80_sysfs_show_flags(struct device *dev, 227 struct device_attribute *attr, char *buf) 228 { 229 struct i2c_client *client = to_i2c_client(dev); 230 int val; 231 232 val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 233 if (val < 0) 234 return val; 235 return sprintf(buf, "%#x\n", val); 236 } 237 static DEVICE_ATTR(flags, S_IRUGO, m41t80_sysfs_show_flags, NULL); 238 239 static ssize_t m41t80_sysfs_show_sqwfreq(struct device *dev, 240 struct device_attribute *attr, char *buf) 241 { 242 struct i2c_client *client = to_i2c_client(dev); 243 struct m41t80_data *clientdata = i2c_get_clientdata(client); 244 int val, reg_sqw; 245 246 if (!(clientdata->features & M41T80_FEATURE_SQ)) 247 return -EINVAL; 248 249 reg_sqw = M41T80_REG_SQW; 250 if (clientdata->features & M41T80_FEATURE_SQ_ALT) 251 reg_sqw = M41T80_REG_WDAY; 252 val = i2c_smbus_read_byte_data(client, reg_sqw); 253 if (val < 0) 254 return val; 255 val = (val >> 4) & 0xf; 256 switch (val) { 257 case 0: 258 break; 259 case 1: 260 val = 32768; 261 break; 262 default: 263 val = 32768 >> val; 264 } 265 return sprintf(buf, "%d\n", val); 266 } 267 static ssize_t m41t80_sysfs_set_sqwfreq(struct device *dev, 268 struct device_attribute *attr, 269 const char *buf, size_t count) 270 { 271 struct i2c_client *client = to_i2c_client(dev); 272 struct m41t80_data *clientdata = i2c_get_clientdata(client); 273 int almon, sqw, reg_sqw, rc; 274 int val = simple_strtoul(buf, NULL, 0); 275 276 if (!(clientdata->features & M41T80_FEATURE_SQ)) 277 return -EINVAL; 278 279 if (val) { 280 if (!is_power_of_2(val)) 281 return -EINVAL; 282 val = ilog2(val); 283 if (val == 15) 284 val = 1; 285 else if (val < 14) 286 val = 15 - val; 287 else 288 return -EINVAL; 289 } 290 /* disable SQW, set SQW frequency & re-enable */ 291 almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); 292 if (almon < 0) 293 return almon; 294 reg_sqw = M41T80_REG_SQW; 295 if (clientdata->features & M41T80_FEATURE_SQ_ALT) 296 reg_sqw = M41T80_REG_WDAY; 297 sqw = i2c_smbus_read_byte_data(client, reg_sqw); 298 if (sqw < 0) 299 return sqw; 300 sqw = (sqw & 0x0f) | (val << 4); 301 302 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 303 almon & ~M41T80_ALMON_SQWE); 304 if (rc < 0) 305 return rc; 306 307 if (val) { 308 rc = i2c_smbus_write_byte_data(client, reg_sqw, sqw); 309 if (rc < 0) 310 return rc; 311 312 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 313 almon | M41T80_ALMON_SQWE); 314 if (rc <0) 315 return rc; 316 } 317 return count; 318 } 319 static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR, 320 m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq); 321 322 static struct attribute *attrs[] = { 323 &dev_attr_flags.attr, 324 &dev_attr_sqwfreq.attr, 325 NULL, 326 }; 327 static struct attribute_group attr_group = { 328 .attrs = attrs, 329 }; 330 331 static int m41t80_sysfs_register(struct device *dev) 332 { 333 return sysfs_create_group(&dev->kobj, &attr_group); 334 } 335 #else 336 static int m41t80_sysfs_register(struct device *dev) 337 { 338 return 0; 339 } 340 #endif 341 342 #ifdef CONFIG_RTC_DRV_M41T80_WDT 343 /* 344 ***************************************************************************** 345 * 346 * Watchdog Driver 347 * 348 ***************************************************************************** 349 */ 350 static struct i2c_client *save_client; 351 352 /* Default margin */ 353 #define WD_TIMO 60 /* 1..31 seconds */ 354 355 static int wdt_margin = WD_TIMO; 356 module_param(wdt_margin, int, 0); 357 MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)"); 358 359 static unsigned long wdt_is_open; 360 static int boot_flag; 361 362 /** 363 * wdt_ping: 364 * 365 * Reload counter one with the watchdog timeout. We don't bother reloading 366 * the cascade counter. 367 */ 368 static void wdt_ping(void) 369 { 370 unsigned char i2c_data[2]; 371 struct i2c_msg msgs1[1] = { 372 { 373 .addr = save_client->addr, 374 .flags = 0, 375 .len = 2, 376 .buf = i2c_data, 377 }, 378 }; 379 struct m41t80_data *clientdata = i2c_get_clientdata(save_client); 380 381 i2c_data[0] = 0x09; /* watchdog register */ 382 383 if (wdt_margin > 31) 384 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */ 385 else 386 /* 387 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02) 388 */ 389 i2c_data[1] = wdt_margin<<2 | 0x82; 390 391 /* 392 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as 393 * that would be an invalid resolution. 394 */ 395 if (clientdata->features & M41T80_FEATURE_WD) 396 i2c_data[1] &= ~M41T80_WATCHDOG_RB2; 397 398 i2c_transfer(save_client->adapter, msgs1, 1); 399 } 400 401 /** 402 * wdt_disable: 403 * 404 * disables watchdog. 405 */ 406 static void wdt_disable(void) 407 { 408 unsigned char i2c_data[2], i2c_buf[0x10]; 409 struct i2c_msg msgs0[2] = { 410 { 411 .addr = save_client->addr, 412 .flags = 0, 413 .len = 1, 414 .buf = i2c_data, 415 }, 416 { 417 .addr = save_client->addr, 418 .flags = I2C_M_RD, 419 .len = 1, 420 .buf = i2c_buf, 421 }, 422 }; 423 struct i2c_msg msgs1[1] = { 424 { 425 .addr = save_client->addr, 426 .flags = 0, 427 .len = 2, 428 .buf = i2c_data, 429 }, 430 }; 431 432 i2c_data[0] = 0x09; 433 i2c_transfer(save_client->adapter, msgs0, 2); 434 435 i2c_data[0] = 0x09; 436 i2c_data[1] = 0x00; 437 i2c_transfer(save_client->adapter, msgs1, 1); 438 } 439 440 /** 441 * wdt_write: 442 * @file: file handle to the watchdog 443 * @buf: buffer to write (unused as data does not matter here 444 * @count: count of bytes 445 * @ppos: pointer to the position to write. No seeks allowed 446 * 447 * A write to a watchdog device is defined as a keepalive signal. Any 448 * write of data will do, as we we don't define content meaning. 449 */ 450 static ssize_t wdt_write(struct file *file, const char __user *buf, 451 size_t count, loff_t *ppos) 452 { 453 if (count) { 454 wdt_ping(); 455 return 1; 456 } 457 return 0; 458 } 459 460 static ssize_t wdt_read(struct file *file, char __user *buf, 461 size_t count, loff_t *ppos) 462 { 463 return 0; 464 } 465 466 /** 467 * wdt_ioctl: 468 * @inode: inode of the device 469 * @file: file handle to the device 470 * @cmd: watchdog command 471 * @arg: argument pointer 472 * 473 * The watchdog API defines a common set of functions for all watchdogs 474 * according to their available features. We only actually usefully support 475 * querying capabilities and current status. 476 */ 477 static int wdt_ioctl(struct file *file, unsigned int cmd, 478 unsigned long arg) 479 { 480 int new_margin, rv; 481 static struct watchdog_info ident = { 482 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING | 483 WDIOF_SETTIMEOUT, 484 .firmware_version = 1, 485 .identity = "M41T80 WTD" 486 }; 487 488 switch (cmd) { 489 case WDIOC_GETSUPPORT: 490 return copy_to_user((struct watchdog_info __user *)arg, &ident, 491 sizeof(ident)) ? -EFAULT : 0; 492 493 case WDIOC_GETSTATUS: 494 case WDIOC_GETBOOTSTATUS: 495 return put_user(boot_flag, (int __user *)arg); 496 case WDIOC_KEEPALIVE: 497 wdt_ping(); 498 return 0; 499 case WDIOC_SETTIMEOUT: 500 if (get_user(new_margin, (int __user *)arg)) 501 return -EFAULT; 502 /* Arbitrary, can't find the card's limits */ 503 if (new_margin < 1 || new_margin > 124) 504 return -EINVAL; 505 wdt_margin = new_margin; 506 wdt_ping(); 507 /* Fall */ 508 case WDIOC_GETTIMEOUT: 509 return put_user(wdt_margin, (int __user *)arg); 510 511 case WDIOC_SETOPTIONS: 512 if (copy_from_user(&rv, (int __user *)arg, sizeof(int))) 513 return -EFAULT; 514 515 if (rv & WDIOS_DISABLECARD) { 516 pr_info("rtc-m41t80: disable watchdog\n"); 517 wdt_disable(); 518 } 519 520 if (rv & WDIOS_ENABLECARD) { 521 pr_info("rtc-m41t80: enable watchdog\n"); 522 wdt_ping(); 523 } 524 525 return -EINVAL; 526 } 527 return -ENOTTY; 528 } 529 530 static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd, 531 unsigned long arg) 532 { 533 int ret; 534 535 mutex_lock(&m41t80_rtc_mutex); 536 ret = wdt_ioctl(file, cmd, arg); 537 mutex_unlock(&m41t80_rtc_mutex); 538 539 return ret; 540 } 541 542 /** 543 * wdt_open: 544 * @inode: inode of device 545 * @file: file handle to device 546 * 547 */ 548 static int wdt_open(struct inode *inode, struct file *file) 549 { 550 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) { 551 mutex_lock(&m41t80_rtc_mutex); 552 if (test_and_set_bit(0, &wdt_is_open)) { 553 mutex_unlock(&m41t80_rtc_mutex); 554 return -EBUSY; 555 } 556 /* 557 * Activate 558 */ 559 wdt_is_open = 1; 560 mutex_unlock(&m41t80_rtc_mutex); 561 return nonseekable_open(inode, file); 562 } 563 return -ENODEV; 564 } 565 566 /** 567 * wdt_close: 568 * @inode: inode to board 569 * @file: file handle to board 570 * 571 */ 572 static int wdt_release(struct inode *inode, struct file *file) 573 { 574 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) 575 clear_bit(0, &wdt_is_open); 576 return 0; 577 } 578 579 /** 580 * notify_sys: 581 * @this: our notifier block 582 * @code: the event being reported 583 * @unused: unused 584 * 585 * Our notifier is called on system shutdowns. We want to turn the card 586 * off at reboot otherwise the machine will reboot again during memory 587 * test or worse yet during the following fsck. This would suck, in fact 588 * trust me - if it happens it does suck. 589 */ 590 static int wdt_notify_sys(struct notifier_block *this, unsigned long code, 591 void *unused) 592 { 593 if (code == SYS_DOWN || code == SYS_HALT) 594 /* Disable Watchdog */ 595 wdt_disable(); 596 return NOTIFY_DONE; 597 } 598 599 static const struct file_operations wdt_fops = { 600 .owner = THIS_MODULE, 601 .read = wdt_read, 602 .unlocked_ioctl = wdt_unlocked_ioctl, 603 .write = wdt_write, 604 .open = wdt_open, 605 .release = wdt_release, 606 .llseek = no_llseek, 607 }; 608 609 static struct miscdevice wdt_dev = { 610 .minor = WATCHDOG_MINOR, 611 .name = "watchdog", 612 .fops = &wdt_fops, 613 }; 614 615 /* 616 * The WDT card needs to learn about soft shutdowns in order to 617 * turn the timebomb registers off. 618 */ 619 static struct notifier_block wdt_notifier = { 620 .notifier_call = wdt_notify_sys, 621 }; 622 #endif /* CONFIG_RTC_DRV_M41T80_WDT */ 623 624 /* 625 ***************************************************************************** 626 * 627 * Driver Interface 628 * 629 ***************************************************************************** 630 */ 631 static int m41t80_probe(struct i2c_client *client, 632 const struct i2c_device_id *id) 633 { 634 int rc = 0; 635 struct rtc_device *rtc = NULL; 636 struct rtc_time tm; 637 struct m41t80_data *clientdata = NULL; 638 639 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C 640 | I2C_FUNC_SMBUS_BYTE_DATA)) 641 return -ENODEV; 642 643 clientdata = devm_kzalloc(&client->dev, sizeof(*clientdata), 644 GFP_KERNEL); 645 if (!clientdata) 646 return -ENOMEM; 647 648 clientdata->features = id->driver_data; 649 i2c_set_clientdata(client, clientdata); 650 651 rtc = devm_rtc_device_register(&client->dev, client->name, 652 &m41t80_rtc_ops, THIS_MODULE); 653 if (IS_ERR(rtc)) 654 return PTR_ERR(rtc); 655 656 clientdata->rtc = rtc; 657 658 /* Make sure HT (Halt Update) bit is cleared */ 659 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR); 660 661 if (rc >= 0 && rc & M41T80_ALHOUR_HT) { 662 if (clientdata->features & M41T80_FEATURE_HT) { 663 m41t80_get_datetime(client, &tm); 664 dev_info(&client->dev, "HT bit was set!\n"); 665 dev_info(&client->dev, 666 "Power Down at " 667 "%04i-%02i-%02i %02i:%02i:%02i\n", 668 tm.tm_year + 1900, 669 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, 670 tm.tm_min, tm.tm_sec); 671 } 672 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_HOUR, 673 rc & ~M41T80_ALHOUR_HT); 674 } 675 676 if (rc < 0) { 677 dev_err(&client->dev, "Can't clear HT bit\n"); 678 return rc; 679 } 680 681 /* Make sure ST (stop) bit is cleared */ 682 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC); 683 684 if (rc >= 0 && rc & M41T80_SEC_ST) 685 rc = i2c_smbus_write_byte_data(client, M41T80_REG_SEC, 686 rc & ~M41T80_SEC_ST); 687 if (rc < 0) { 688 dev_err(&client->dev, "Can't clear ST bit\n"); 689 return rc; 690 } 691 692 rc = m41t80_sysfs_register(&client->dev); 693 if (rc) 694 return rc; 695 696 #ifdef CONFIG_RTC_DRV_M41T80_WDT 697 if (clientdata->features & M41T80_FEATURE_HT) { 698 save_client = client; 699 rc = misc_register(&wdt_dev); 700 if (rc) 701 return rc; 702 rc = register_reboot_notifier(&wdt_notifier); 703 if (rc) { 704 misc_deregister(&wdt_dev); 705 return rc; 706 } 707 } 708 #endif 709 return 0; 710 } 711 712 static int m41t80_remove(struct i2c_client *client) 713 { 714 #ifdef CONFIG_RTC_DRV_M41T80_WDT 715 struct m41t80_data *clientdata = i2c_get_clientdata(client); 716 717 if (clientdata->features & M41T80_FEATURE_HT) { 718 misc_deregister(&wdt_dev); 719 unregister_reboot_notifier(&wdt_notifier); 720 } 721 #endif 722 723 return 0; 724 } 725 726 static struct i2c_driver m41t80_driver = { 727 .driver = { 728 .name = "rtc-m41t80", 729 }, 730 .probe = m41t80_probe, 731 .remove = m41t80_remove, 732 .id_table = m41t80_id, 733 }; 734 735 module_i2c_driver(m41t80_driver); 736 737 MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>"); 738 MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver"); 739 MODULE_LICENSE("GPL"); 740