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 #define DRV_VERSION "0.05" 70 71 static DEFINE_MUTEX(m41t80_rtc_mutex); 72 static const struct i2c_device_id m41t80_id[] = { 73 { "m41t62", M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT }, 74 { "m41t65", M41T80_FEATURE_HT | M41T80_FEATURE_WD }, 75 { "m41t80", M41T80_FEATURE_SQ }, 76 { "m41t81", M41T80_FEATURE_HT | M41T80_FEATURE_SQ}, 77 { "m41t81s", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 78 { "m41t82", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 79 { "m41t83", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 80 { "m41st84", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 81 { "m41st85", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 82 { "m41st87", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 83 { } 84 }; 85 MODULE_DEVICE_TABLE(i2c, m41t80_id); 86 87 struct m41t80_data { 88 u8 features; 89 struct rtc_device *rtc; 90 }; 91 92 static int m41t80_get_datetime(struct i2c_client *client, 93 struct rtc_time *tm) 94 { 95 u8 buf[M41T80_DATETIME_REG_SIZE], dt_addr[1] = { M41T80_REG_SEC }; 96 struct i2c_msg msgs[] = { 97 { 98 .addr = client->addr, 99 .flags = 0, 100 .len = 1, 101 .buf = dt_addr, 102 }, 103 { 104 .addr = client->addr, 105 .flags = I2C_M_RD, 106 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC, 107 .buf = buf + M41T80_REG_SEC, 108 }, 109 }; 110 111 if (i2c_transfer(client->adapter, msgs, 2) < 0) { 112 dev_err(&client->dev, "read error\n"); 113 return -EIO; 114 } 115 116 tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f); 117 tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f); 118 tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f); 119 tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f); 120 tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07; 121 tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1; 122 123 /* assume 20YY not 19YY, and ignore the Century Bit */ 124 tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100; 125 return rtc_valid_tm(tm); 126 } 127 128 /* Sets the given date and time to the real time clock. */ 129 static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm) 130 { 131 u8 wbuf[1 + M41T80_DATETIME_REG_SIZE]; 132 u8 *buf = &wbuf[1]; 133 u8 dt_addr[1] = { M41T80_REG_SEC }; 134 struct i2c_msg msgs_in[] = { 135 { 136 .addr = client->addr, 137 .flags = 0, 138 .len = 1, 139 .buf = dt_addr, 140 }, 141 { 142 .addr = client->addr, 143 .flags = I2C_M_RD, 144 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC, 145 .buf = buf + M41T80_REG_SEC, 146 }, 147 }; 148 struct i2c_msg msgs[] = { 149 { 150 .addr = client->addr, 151 .flags = 0, 152 .len = 1 + M41T80_DATETIME_REG_SIZE, 153 .buf = wbuf, 154 }, 155 }; 156 157 /* Read current reg values into buf[1..7] */ 158 if (i2c_transfer(client->adapter, msgs_in, 2) < 0) { 159 dev_err(&client->dev, "read error\n"); 160 return -EIO; 161 } 162 163 wbuf[0] = 0; /* offset into rtc's regs */ 164 /* Merge time-data and register flags into buf[0..7] */ 165 buf[M41T80_REG_SSEC] = 0; 166 buf[M41T80_REG_SEC] = 167 bin2bcd(tm->tm_sec) | (buf[M41T80_REG_SEC] & ~0x7f); 168 buf[M41T80_REG_MIN] = 169 bin2bcd(tm->tm_min) | (buf[M41T80_REG_MIN] & ~0x7f); 170 buf[M41T80_REG_HOUR] = 171 bin2bcd(tm->tm_hour) | (buf[M41T80_REG_HOUR] & ~0x3f); 172 buf[M41T80_REG_WDAY] = 173 (tm->tm_wday & 0x07) | (buf[M41T80_REG_WDAY] & ~0x07); 174 buf[M41T80_REG_DAY] = 175 bin2bcd(tm->tm_mday) | (buf[M41T80_REG_DAY] & ~0x3f); 176 buf[M41T80_REG_MON] = 177 bin2bcd(tm->tm_mon + 1) | (buf[M41T80_REG_MON] & ~0x1f); 178 /* assume 20YY not 19YY */ 179 buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year % 100); 180 181 if (i2c_transfer(client->adapter, msgs, 1) != 1) { 182 dev_err(&client->dev, "write error\n"); 183 return -EIO; 184 } 185 return 0; 186 } 187 188 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE) 189 static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq) 190 { 191 struct i2c_client *client = to_i2c_client(dev); 192 struct m41t80_data *clientdata = i2c_get_clientdata(client); 193 u8 reg; 194 195 if (clientdata->features & M41T80_FEATURE_BL) { 196 reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 197 seq_printf(seq, "battery\t\t: %s\n", 198 (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok"); 199 } 200 return 0; 201 } 202 #else 203 #define m41t80_rtc_proc NULL 204 #endif 205 206 static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm) 207 { 208 return m41t80_get_datetime(to_i2c_client(dev), tm); 209 } 210 211 static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm) 212 { 213 return m41t80_set_datetime(to_i2c_client(dev), tm); 214 } 215 216 /* 217 * XXX - m41t80 alarm functionality is reported broken. 218 * until it is fixed, don't register alarm functions. 219 */ 220 static struct rtc_class_ops m41t80_rtc_ops = { 221 .read_time = m41t80_rtc_read_time, 222 .set_time = m41t80_rtc_set_time, 223 .proc = m41t80_rtc_proc, 224 }; 225 226 #if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE) 227 static ssize_t m41t80_sysfs_show_flags(struct device *dev, 228 struct device_attribute *attr, char *buf) 229 { 230 struct i2c_client *client = to_i2c_client(dev); 231 int val; 232 233 val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 234 if (val < 0) 235 return -EIO; 236 return sprintf(buf, "%#x\n", val); 237 } 238 static DEVICE_ATTR(flags, S_IRUGO, m41t80_sysfs_show_flags, NULL); 239 240 static ssize_t m41t80_sysfs_show_sqwfreq(struct device *dev, 241 struct device_attribute *attr, char *buf) 242 { 243 struct i2c_client *client = to_i2c_client(dev); 244 struct m41t80_data *clientdata = i2c_get_clientdata(client); 245 int val, reg_sqw; 246 247 if (!(clientdata->features & M41T80_FEATURE_SQ)) 248 return -EINVAL; 249 250 reg_sqw = M41T80_REG_SQW; 251 if (clientdata->features & M41T80_FEATURE_SQ_ALT) 252 reg_sqw = M41T80_REG_WDAY; 253 val = i2c_smbus_read_byte_data(client, reg_sqw); 254 if (val < 0) 255 return -EIO; 256 val = (val >> 4) & 0xf; 257 switch (val) { 258 case 0: 259 break; 260 case 1: 261 val = 32768; 262 break; 263 default: 264 val = 32768 >> val; 265 } 266 return sprintf(buf, "%d\n", val); 267 } 268 static ssize_t m41t80_sysfs_set_sqwfreq(struct device *dev, 269 struct device_attribute *attr, 270 const char *buf, size_t count) 271 { 272 struct i2c_client *client = to_i2c_client(dev); 273 struct m41t80_data *clientdata = i2c_get_clientdata(client); 274 int almon, sqw, reg_sqw; 275 int val = simple_strtoul(buf, NULL, 0); 276 277 if (!(clientdata->features & M41T80_FEATURE_SQ)) 278 return -EINVAL; 279 280 if (val) { 281 if (!is_power_of_2(val)) 282 return -EINVAL; 283 val = ilog2(val); 284 if (val == 15) 285 val = 1; 286 else if (val < 14) 287 val = 15 - val; 288 else 289 return -EINVAL; 290 } 291 /* disable SQW, set SQW frequency & re-enable */ 292 almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); 293 if (almon < 0) 294 return -EIO; 295 reg_sqw = M41T80_REG_SQW; 296 if (clientdata->features & M41T80_FEATURE_SQ_ALT) 297 reg_sqw = M41T80_REG_WDAY; 298 sqw = i2c_smbus_read_byte_data(client, reg_sqw); 299 if (sqw < 0) 300 return -EIO; 301 sqw = (sqw & 0x0f) | (val << 4); 302 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 303 almon & ~M41T80_ALMON_SQWE) < 0 || 304 i2c_smbus_write_byte_data(client, reg_sqw, sqw) < 0) 305 return -EIO; 306 if (val && i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 307 almon | M41T80_ALMON_SQWE) < 0) 308 return -EIO; 309 return count; 310 } 311 static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR, 312 m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq); 313 314 static struct attribute *attrs[] = { 315 &dev_attr_flags.attr, 316 &dev_attr_sqwfreq.attr, 317 NULL, 318 }; 319 static struct attribute_group attr_group = { 320 .attrs = attrs, 321 }; 322 323 static int m41t80_sysfs_register(struct device *dev) 324 { 325 return sysfs_create_group(&dev->kobj, &attr_group); 326 } 327 #else 328 static int m41t80_sysfs_register(struct device *dev) 329 { 330 return 0; 331 } 332 #endif 333 334 #ifdef CONFIG_RTC_DRV_M41T80_WDT 335 /* 336 ***************************************************************************** 337 * 338 * Watchdog Driver 339 * 340 ***************************************************************************** 341 */ 342 static struct i2c_client *save_client; 343 344 /* Default margin */ 345 #define WD_TIMO 60 /* 1..31 seconds */ 346 347 static int wdt_margin = WD_TIMO; 348 module_param(wdt_margin, int, 0); 349 MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)"); 350 351 static unsigned long wdt_is_open; 352 static int boot_flag; 353 354 /** 355 * wdt_ping: 356 * 357 * Reload counter one with the watchdog timeout. We don't bother reloading 358 * the cascade counter. 359 */ 360 static void wdt_ping(void) 361 { 362 unsigned char i2c_data[2]; 363 struct i2c_msg msgs1[1] = { 364 { 365 .addr = save_client->addr, 366 .flags = 0, 367 .len = 2, 368 .buf = i2c_data, 369 }, 370 }; 371 struct m41t80_data *clientdata = i2c_get_clientdata(save_client); 372 373 i2c_data[0] = 0x09; /* watchdog register */ 374 375 if (wdt_margin > 31) 376 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */ 377 else 378 /* 379 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02) 380 */ 381 i2c_data[1] = wdt_margin<<2 | 0x82; 382 383 /* 384 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as 385 * that would be an invalid resolution. 386 */ 387 if (clientdata->features & M41T80_FEATURE_WD) 388 i2c_data[1] &= ~M41T80_WATCHDOG_RB2; 389 390 i2c_transfer(save_client->adapter, msgs1, 1); 391 } 392 393 /** 394 * wdt_disable: 395 * 396 * disables watchdog. 397 */ 398 static void wdt_disable(void) 399 { 400 unsigned char i2c_data[2], i2c_buf[0x10]; 401 struct i2c_msg msgs0[2] = { 402 { 403 .addr = save_client->addr, 404 .flags = 0, 405 .len = 1, 406 .buf = i2c_data, 407 }, 408 { 409 .addr = save_client->addr, 410 .flags = I2C_M_RD, 411 .len = 1, 412 .buf = i2c_buf, 413 }, 414 }; 415 struct i2c_msg msgs1[1] = { 416 { 417 .addr = save_client->addr, 418 .flags = 0, 419 .len = 2, 420 .buf = i2c_data, 421 }, 422 }; 423 424 i2c_data[0] = 0x09; 425 i2c_transfer(save_client->adapter, msgs0, 2); 426 427 i2c_data[0] = 0x09; 428 i2c_data[1] = 0x00; 429 i2c_transfer(save_client->adapter, msgs1, 1); 430 } 431 432 /** 433 * wdt_write: 434 * @file: file handle to the watchdog 435 * @buf: buffer to write (unused as data does not matter here 436 * @count: count of bytes 437 * @ppos: pointer to the position to write. No seeks allowed 438 * 439 * A write to a watchdog device is defined as a keepalive signal. Any 440 * write of data will do, as we we don't define content meaning. 441 */ 442 static ssize_t wdt_write(struct file *file, const char __user *buf, 443 size_t count, loff_t *ppos) 444 { 445 if (count) { 446 wdt_ping(); 447 return 1; 448 } 449 return 0; 450 } 451 452 static ssize_t wdt_read(struct file *file, char __user *buf, 453 size_t count, loff_t *ppos) 454 { 455 return 0; 456 } 457 458 /** 459 * wdt_ioctl: 460 * @inode: inode of the device 461 * @file: file handle to the device 462 * @cmd: watchdog command 463 * @arg: argument pointer 464 * 465 * The watchdog API defines a common set of functions for all watchdogs 466 * according to their available features. We only actually usefully support 467 * querying capabilities and current status. 468 */ 469 static int wdt_ioctl(struct file *file, unsigned int cmd, 470 unsigned long arg) 471 { 472 int new_margin, rv; 473 static struct watchdog_info ident = { 474 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING | 475 WDIOF_SETTIMEOUT, 476 .firmware_version = 1, 477 .identity = "M41T80 WTD" 478 }; 479 480 switch (cmd) { 481 case WDIOC_GETSUPPORT: 482 return copy_to_user((struct watchdog_info __user *)arg, &ident, 483 sizeof(ident)) ? -EFAULT : 0; 484 485 case WDIOC_GETSTATUS: 486 case WDIOC_GETBOOTSTATUS: 487 return put_user(boot_flag, (int __user *)arg); 488 case WDIOC_KEEPALIVE: 489 wdt_ping(); 490 return 0; 491 case WDIOC_SETTIMEOUT: 492 if (get_user(new_margin, (int __user *)arg)) 493 return -EFAULT; 494 /* Arbitrary, can't find the card's limits */ 495 if (new_margin < 1 || new_margin > 124) 496 return -EINVAL; 497 wdt_margin = new_margin; 498 wdt_ping(); 499 /* Fall */ 500 case WDIOC_GETTIMEOUT: 501 return put_user(wdt_margin, (int __user *)arg); 502 503 case WDIOC_SETOPTIONS: 504 if (copy_from_user(&rv, (int __user *)arg, sizeof(int))) 505 return -EFAULT; 506 507 if (rv & WDIOS_DISABLECARD) { 508 pr_info("rtc-m41t80: disable watchdog\n"); 509 wdt_disable(); 510 } 511 512 if (rv & WDIOS_ENABLECARD) { 513 pr_info("rtc-m41t80: enable watchdog\n"); 514 wdt_ping(); 515 } 516 517 return -EINVAL; 518 } 519 return -ENOTTY; 520 } 521 522 static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd, 523 unsigned long arg) 524 { 525 int ret; 526 527 mutex_lock(&m41t80_rtc_mutex); 528 ret = wdt_ioctl(file, cmd, arg); 529 mutex_unlock(&m41t80_rtc_mutex); 530 531 return ret; 532 } 533 534 /** 535 * wdt_open: 536 * @inode: inode of device 537 * @file: file handle to device 538 * 539 */ 540 static int wdt_open(struct inode *inode, struct file *file) 541 { 542 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) { 543 mutex_lock(&m41t80_rtc_mutex); 544 if (test_and_set_bit(0, &wdt_is_open)) { 545 mutex_unlock(&m41t80_rtc_mutex); 546 return -EBUSY; 547 } 548 /* 549 * Activate 550 */ 551 wdt_is_open = 1; 552 mutex_unlock(&m41t80_rtc_mutex); 553 return nonseekable_open(inode, file); 554 } 555 return -ENODEV; 556 } 557 558 /** 559 * wdt_close: 560 * @inode: inode to board 561 * @file: file handle to board 562 * 563 */ 564 static int wdt_release(struct inode *inode, struct file *file) 565 { 566 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) 567 clear_bit(0, &wdt_is_open); 568 return 0; 569 } 570 571 /** 572 * notify_sys: 573 * @this: our notifier block 574 * @code: the event being reported 575 * @unused: unused 576 * 577 * Our notifier is called on system shutdowns. We want to turn the card 578 * off at reboot otherwise the machine will reboot again during memory 579 * test or worse yet during the following fsck. This would suck, in fact 580 * trust me - if it happens it does suck. 581 */ 582 static int wdt_notify_sys(struct notifier_block *this, unsigned long code, 583 void *unused) 584 { 585 if (code == SYS_DOWN || code == SYS_HALT) 586 /* Disable Watchdog */ 587 wdt_disable(); 588 return NOTIFY_DONE; 589 } 590 591 static const struct file_operations wdt_fops = { 592 .owner = THIS_MODULE, 593 .read = wdt_read, 594 .unlocked_ioctl = wdt_unlocked_ioctl, 595 .write = wdt_write, 596 .open = wdt_open, 597 .release = wdt_release, 598 .llseek = no_llseek, 599 }; 600 601 static struct miscdevice wdt_dev = { 602 .minor = WATCHDOG_MINOR, 603 .name = "watchdog", 604 .fops = &wdt_fops, 605 }; 606 607 /* 608 * The WDT card needs to learn about soft shutdowns in order to 609 * turn the timebomb registers off. 610 */ 611 static struct notifier_block wdt_notifier = { 612 .notifier_call = wdt_notify_sys, 613 }; 614 #endif /* CONFIG_RTC_DRV_M41T80_WDT */ 615 616 /* 617 ***************************************************************************** 618 * 619 * Driver Interface 620 * 621 ***************************************************************************** 622 */ 623 static int m41t80_probe(struct i2c_client *client, 624 const struct i2c_device_id *id) 625 { 626 int rc = 0; 627 struct rtc_device *rtc = NULL; 628 struct rtc_time tm; 629 struct m41t80_data *clientdata = NULL; 630 631 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C 632 | I2C_FUNC_SMBUS_BYTE_DATA)) { 633 rc = -ENODEV; 634 goto exit; 635 } 636 637 dev_info(&client->dev, 638 "chip found, driver version " DRV_VERSION "\n"); 639 640 clientdata = devm_kzalloc(&client->dev, sizeof(*clientdata), 641 GFP_KERNEL); 642 if (!clientdata) { 643 rc = -ENOMEM; 644 goto exit; 645 } 646 647 clientdata->features = id->driver_data; 648 i2c_set_clientdata(client, clientdata); 649 650 rtc = devm_rtc_device_register(&client->dev, client->name, 651 &m41t80_rtc_ops, THIS_MODULE); 652 if (IS_ERR(rtc)) { 653 rc = PTR_ERR(rtc); 654 rtc = NULL; 655 goto exit; 656 } 657 658 clientdata->rtc = rtc; 659 660 /* Make sure HT (Halt Update) bit is cleared */ 661 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR); 662 if (rc < 0) 663 goto ht_err; 664 665 if (rc & M41T80_ALHOUR_HT) { 666 if (clientdata->features & M41T80_FEATURE_HT) { 667 m41t80_get_datetime(client, &tm); 668 dev_info(&client->dev, "HT bit was set!\n"); 669 dev_info(&client->dev, 670 "Power Down at " 671 "%04i-%02i-%02i %02i:%02i:%02i\n", 672 tm.tm_year + 1900, 673 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, 674 tm.tm_min, tm.tm_sec); 675 } 676 if (i2c_smbus_write_byte_data(client, 677 M41T80_REG_ALARM_HOUR, 678 rc & ~M41T80_ALHOUR_HT) < 0) 679 goto ht_err; 680 } 681 682 /* Make sure ST (stop) bit is cleared */ 683 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC); 684 if (rc < 0) 685 goto st_err; 686 687 if (rc & M41T80_SEC_ST) { 688 if (i2c_smbus_write_byte_data(client, M41T80_REG_SEC, 689 rc & ~M41T80_SEC_ST) < 0) 690 goto st_err; 691 } 692 693 rc = m41t80_sysfs_register(&client->dev); 694 if (rc) 695 goto exit; 696 697 #ifdef CONFIG_RTC_DRV_M41T80_WDT 698 if (clientdata->features & M41T80_FEATURE_HT) { 699 save_client = client; 700 rc = misc_register(&wdt_dev); 701 if (rc) 702 goto exit; 703 rc = register_reboot_notifier(&wdt_notifier); 704 if (rc) { 705 misc_deregister(&wdt_dev); 706 goto exit; 707 } 708 } 709 #endif 710 return 0; 711 712 st_err: 713 rc = -EIO; 714 dev_err(&client->dev, "Can't clear ST bit\n"); 715 goto exit; 716 ht_err: 717 rc = -EIO; 718 dev_err(&client->dev, "Can't clear HT bit\n"); 719 goto exit; 720 721 exit: 722 return rc; 723 } 724 725 static int m41t80_remove(struct i2c_client *client) 726 { 727 #ifdef CONFIG_RTC_DRV_M41T80_WDT 728 struct m41t80_data *clientdata = i2c_get_clientdata(client); 729 730 if (clientdata->features & M41T80_FEATURE_HT) { 731 misc_deregister(&wdt_dev); 732 unregister_reboot_notifier(&wdt_notifier); 733 } 734 #endif 735 736 return 0; 737 } 738 739 static struct i2c_driver m41t80_driver = { 740 .driver = { 741 .name = "rtc-m41t80", 742 }, 743 .probe = m41t80_probe, 744 .remove = m41t80_remove, 745 .id_table = m41t80_id, 746 }; 747 748 module_i2c_driver(m41t80_driver); 749 750 MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>"); 751 MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver"); 752 MODULE_LICENSE("GPL"); 753 MODULE_VERSION(DRV_VERSION); 754