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 0 36#define M41T80_REG_SEC 1 37#define M41T80_REG_MIN 2 38#define M41T80_REG_HOUR 3 39#define M41T80_REG_WDAY 4 40#define M41T80_REG_DAY 5 41#define M41T80_REG_MON 6 42#define M41T80_REG_YEAR 7 43#define M41T80_REG_ALARM_MON 0xa 44#define M41T80_REG_ALARM_DAY 0xb 45#define M41T80_REG_ALARM_HOUR 0xc 46#define M41T80_REG_ALARM_MIN 0xd 47#define M41T80_REG_ALARM_SEC 0xe 48#define M41T80_REG_FLAGS 0xf 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 (1 << 7) /* ST: Stop Bit */ 56#define M41T80_ALMON_AFE (1 << 7) /* AFE: AF Enable Bit */ 57#define M41T80_ALMON_SQWE (1 << 6) /* SQWE: SQW Enable Bit */ 58#define M41T80_ALHOUR_HT (1 << 6) /* HT: Halt Update Bit */ 59#define M41T80_FLAGS_AF (1 << 6) /* AF: Alarm Flag Bit */ 60#define M41T80_FLAGS_BATT_LOW (1 << 4) /* BL: Battery Low Bit */ 61#define M41T80_WATCHDOG_RB2 (1 << 7) /* RB: Watchdog resolution */ 62#define M41T80_WATCHDOG_RB1 (1 << 1) /* RB: Watchdog resolution */ 63#define M41T80_WATCHDOG_RB0 (1 << 0) /* RB: Watchdog resolution */ 64 65#define M41T80_FEATURE_HT (1 << 0) /* Halt feature */ 66#define M41T80_FEATURE_BL (1 << 1) /* Battery low indicator */ 67#define M41T80_FEATURE_SQ (1 << 2) /* Squarewave feature */ 68#define M41T80_FEATURE_WD (1 << 3) /* Extra watchdog resolution */ 69#define M41T80_FEATURE_SQ_ALT (1 << 4) /* RSx bits are in reg 4 */ 70 71static DEFINE_MUTEX(m41t80_rtc_mutex); 72static 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 { "rv4162", M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT }, 84 { } 85}; 86MODULE_DEVICE_TABLE(i2c, m41t80_id); 87 88struct m41t80_data { 89 u8 features; 90 struct rtc_device *rtc; 91}; 92 93static int m41t80_get_datetime(struct i2c_client *client, 94 struct rtc_time *tm) 95{ 96 u8 buf[M41T80_DATETIME_REG_SIZE], dt_addr[1] = { M41T80_REG_SEC }; 97 struct i2c_msg msgs[] = { 98 { 99 .addr = client->addr, 100 .flags = 0, 101 .len = 1, 102 .buf = dt_addr, 103 }, 104 { 105 .addr = client->addr, 106 .flags = I2C_M_RD, 107 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC, 108 .buf = buf + M41T80_REG_SEC, 109 }, 110 }; 111 112 if (i2c_transfer(client->adapter, msgs, 2) < 0) { 113 dev_err(&client->dev, "read error\n"); 114 return -EIO; 115 } 116 117 tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f); 118 tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f); 119 tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f); 120 tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f); 121 tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07; 122 tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1; 123 124 /* assume 20YY not 19YY, and ignore the Century Bit */ 125 tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100; 126 return rtc_valid_tm(tm); 127} 128 129/* Sets the given date and time to the real time clock. */ 130static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm) 131{ 132 u8 wbuf[1 + M41T80_DATETIME_REG_SIZE]; 133 u8 *buf = &wbuf[1]; 134 u8 dt_addr[1] = { M41T80_REG_SEC }; 135 struct i2c_msg msgs_in[] = { 136 { 137 .addr = client->addr, 138 .flags = 0, 139 .len = 1, 140 .buf = dt_addr, 141 }, 142 { 143 .addr = client->addr, 144 .flags = I2C_M_RD, 145 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC, 146 .buf = buf + M41T80_REG_SEC, 147 }, 148 }; 149 struct i2c_msg msgs[] = { 150 { 151 .addr = client->addr, 152 .flags = 0, 153 .len = 1 + M41T80_DATETIME_REG_SIZE, 154 .buf = wbuf, 155 }, 156 }; 157 158 /* Read current reg values into buf[1..7] */ 159 if (i2c_transfer(client->adapter, msgs_in, 2) < 0) { 160 dev_err(&client->dev, "read error\n"); 161 return -EIO; 162 } 163 164 wbuf[0] = 0; /* offset into rtc's regs */ 165 /* Merge time-data and register flags into buf[0..7] */ 166 buf[M41T80_REG_SSEC] = 0; 167 buf[M41T80_REG_SEC] = 168 bin2bcd(tm->tm_sec) | (buf[M41T80_REG_SEC] & ~0x7f); 169 buf[M41T80_REG_MIN] = 170 bin2bcd(tm->tm_min) | (buf[M41T80_REG_MIN] & ~0x7f); 171 buf[M41T80_REG_HOUR] = 172 bin2bcd(tm->tm_hour) | (buf[M41T80_REG_HOUR] & ~0x3f); 173 buf[M41T80_REG_WDAY] = 174 (tm->tm_wday & 0x07) | (buf[M41T80_REG_WDAY] & ~0x07); 175 buf[M41T80_REG_DAY] = 176 bin2bcd(tm->tm_mday) | (buf[M41T80_REG_DAY] & ~0x3f); 177 buf[M41T80_REG_MON] = 178 bin2bcd(tm->tm_mon + 1) | (buf[M41T80_REG_MON] & ~0x1f); 179 /* assume 20YY not 19YY */ 180 buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year % 100); 181 182 if (i2c_transfer(client->adapter, msgs, 1) != 1) { 183 dev_err(&client->dev, "write error\n"); 184 return -EIO; 185 } 186 return 0; 187} 188 189#if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE) 190static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq) 191{ 192 struct i2c_client *client = to_i2c_client(dev); 193 struct m41t80_data *clientdata = i2c_get_clientdata(client); 194 u8 reg; 195 196 if (clientdata->features & M41T80_FEATURE_BL) { 197 reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 198 seq_printf(seq, "battery\t\t: %s\n", 199 (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok"); 200 } 201 return 0; 202} 203#else 204#define m41t80_rtc_proc NULL 205#endif 206 207static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm) 208{ 209 return m41t80_get_datetime(to_i2c_client(dev), tm); 210} 211 212static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm) 213{ 214 return m41t80_set_datetime(to_i2c_client(dev), tm); 215} 216 217/* 218 * XXX - m41t80 alarm functionality is reported broken. 219 * until it is fixed, don't register alarm functions. 220 */ 221static struct rtc_class_ops m41t80_rtc_ops = { 222 .read_time = m41t80_rtc_read_time, 223 .set_time = m41t80_rtc_set_time, 224 .proc = m41t80_rtc_proc, 225}; 226 227#if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE) 228static ssize_t m41t80_sysfs_show_flags(struct device *dev, 229 struct device_attribute *attr, char *buf) 230{ 231 struct i2c_client *client = to_i2c_client(dev); 232 int val; 233 234 val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 235 if (val < 0) 236 return val; 237 return sprintf(buf, "%#x\n", val); 238} 239static DEVICE_ATTR(flags, S_IRUGO, m41t80_sysfs_show_flags, NULL); 240 241static ssize_t m41t80_sysfs_show_sqwfreq(struct device *dev, 242 struct device_attribute *attr, char *buf) 243{ 244 struct i2c_client *client = to_i2c_client(dev); 245 struct m41t80_data *clientdata = i2c_get_clientdata(client); 246 int val, reg_sqw; 247 248 if (!(clientdata->features & M41T80_FEATURE_SQ)) 249 return -EINVAL; 250 251 reg_sqw = M41T80_REG_SQW; 252 if (clientdata->features & M41T80_FEATURE_SQ_ALT) 253 reg_sqw = M41T80_REG_WDAY; 254 val = i2c_smbus_read_byte_data(client, reg_sqw); 255 if (val < 0) 256 return val; 257 val = (val >> 4) & 0xf; 258 switch (val) { 259 case 0: 260 break; 261 case 1: 262 val = 32768; 263 break; 264 default: 265 val = 32768 >> val; 266 } 267 return sprintf(buf, "%d\n", val); 268} 269static ssize_t m41t80_sysfs_set_sqwfreq(struct device *dev, 270 struct device_attribute *attr, 271 const char *buf, size_t count) 272{ 273 struct i2c_client *client = to_i2c_client(dev); 274 struct m41t80_data *clientdata = i2c_get_clientdata(client); 275 int almon, sqw, reg_sqw, rc; 276 int val = simple_strtoul(buf, NULL, 0); 277 278 if (!(clientdata->features & M41T80_FEATURE_SQ)) 279 return -EINVAL; 280 281 if (val) { 282 if (!is_power_of_2(val)) 283 return -EINVAL; 284 val = ilog2(val); 285 if (val == 15) 286 val = 1; 287 else if (val < 14) 288 val = 15 - val; 289 else 290 return -EINVAL; 291 } 292 /* disable SQW, set SQW frequency & re-enable */ 293 almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); 294 if (almon < 0) 295 return almon; 296 reg_sqw = M41T80_REG_SQW; 297 if (clientdata->features & M41T80_FEATURE_SQ_ALT) 298 reg_sqw = M41T80_REG_WDAY; 299 sqw = i2c_smbus_read_byte_data(client, reg_sqw); 300 if (sqw < 0) 301 return sqw; 302 sqw = (sqw & 0x0f) | (val << 4); 303 304 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 305 almon & ~M41T80_ALMON_SQWE); 306 if (rc < 0) 307 return rc; 308 309 if (val) { 310 rc = i2c_smbus_write_byte_data(client, reg_sqw, sqw); 311 if (rc < 0) 312 return rc; 313 314 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 315 almon | M41T80_ALMON_SQWE); 316 if (rc <0) 317 return rc; 318 } 319 return count; 320} 321static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR, 322 m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq); 323 324static struct attribute *attrs[] = { 325 &dev_attr_flags.attr, 326 &dev_attr_sqwfreq.attr, 327 NULL, 328}; 329static struct attribute_group attr_group = { 330 .attrs = attrs, 331}; 332 333static int m41t80_sysfs_register(struct device *dev) 334{ 335 return sysfs_create_group(&dev->kobj, &attr_group); 336} 337#else 338static int m41t80_sysfs_register(struct device *dev) 339{ 340 return 0; 341} 342#endif 343 344#ifdef CONFIG_RTC_DRV_M41T80_WDT 345/* 346 ***************************************************************************** 347 * 348 * Watchdog Driver 349 * 350 ***************************************************************************** 351 */ 352static struct i2c_client *save_client; 353 354/* Default margin */ 355#define WD_TIMO 60 /* 1..31 seconds */ 356 357static int wdt_margin = WD_TIMO; 358module_param(wdt_margin, int, 0); 359MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)"); 360 361static unsigned long wdt_is_open; 362static int boot_flag; 363 364/** 365 * wdt_ping: 366 * 367 * Reload counter one with the watchdog timeout. We don't bother reloading 368 * the cascade counter. 369 */ 370static void wdt_ping(void) 371{ 372 unsigned char i2c_data[2]; 373 struct i2c_msg msgs1[1] = { 374 { 375 .addr = save_client->addr, 376 .flags = 0, 377 .len = 2, 378 .buf = i2c_data, 379 }, 380 }; 381 struct m41t80_data *clientdata = i2c_get_clientdata(save_client); 382 383 i2c_data[0] = 0x09; /* watchdog register */ 384 385 if (wdt_margin > 31) 386 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */ 387 else 388 /* 389 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02) 390 */ 391 i2c_data[1] = wdt_margin<<2 | 0x82; 392 393 /* 394 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as 395 * that would be an invalid resolution. 396 */ 397 if (clientdata->features & M41T80_FEATURE_WD) 398 i2c_data[1] &= ~M41T80_WATCHDOG_RB2; 399 400 i2c_transfer(save_client->adapter, msgs1, 1); 401} 402 403/** 404 * wdt_disable: 405 * 406 * disables watchdog. 407 */ 408static void wdt_disable(void) 409{ 410 unsigned char i2c_data[2], i2c_buf[0x10]; 411 struct i2c_msg msgs0[2] = { 412 { 413 .addr = save_client->addr, 414 .flags = 0, 415 .len = 1, 416 .buf = i2c_data, 417 }, 418 { 419 .addr = save_client->addr, 420 .flags = I2C_M_RD, 421 .len = 1, 422 .buf = i2c_buf, 423 }, 424 }; 425 struct i2c_msg msgs1[1] = { 426 { 427 .addr = save_client->addr, 428 .flags = 0, 429 .len = 2, 430 .buf = i2c_data, 431 }, 432 }; 433 434 i2c_data[0] = 0x09; 435 i2c_transfer(save_client->adapter, msgs0, 2); 436 437 i2c_data[0] = 0x09; 438 i2c_data[1] = 0x00; 439 i2c_transfer(save_client->adapter, msgs1, 1); 440} 441 442/** 443 * wdt_write: 444 * @file: file handle to the watchdog 445 * @buf: buffer to write (unused as data does not matter here 446 * @count: count of bytes 447 * @ppos: pointer to the position to write. No seeks allowed 448 * 449 * A write to a watchdog device is defined as a keepalive signal. Any 450 * write of data will do, as we we don't define content meaning. 451 */ 452static ssize_t wdt_write(struct file *file, const char __user *buf, 453 size_t count, loff_t *ppos) 454{ 455 if (count) { 456 wdt_ping(); 457 return 1; 458 } 459 return 0; 460} 461 462static ssize_t wdt_read(struct file *file, char __user *buf, 463 size_t count, loff_t *ppos) 464{ 465 return 0; 466} 467 468/** 469 * wdt_ioctl: 470 * @inode: inode of the device 471 * @file: file handle to the device 472 * @cmd: watchdog command 473 * @arg: argument pointer 474 * 475 * The watchdog API defines a common set of functions for all watchdogs 476 * according to their available features. We only actually usefully support 477 * querying capabilities and current status. 478 */ 479static int wdt_ioctl(struct file *file, unsigned int cmd, 480 unsigned long arg) 481{ 482 int new_margin, rv; 483 static struct watchdog_info ident = { 484 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING | 485 WDIOF_SETTIMEOUT, 486 .firmware_version = 1, 487 .identity = "M41T80 WTD" 488 }; 489 490 switch (cmd) { 491 case WDIOC_GETSUPPORT: 492 return copy_to_user((struct watchdog_info __user *)arg, &ident, 493 sizeof(ident)) ? -EFAULT : 0; 494 495 case WDIOC_GETSTATUS: 496 case WDIOC_GETBOOTSTATUS: 497 return put_user(boot_flag, (int __user *)arg); 498 case WDIOC_KEEPALIVE: 499 wdt_ping(); 500 return 0; 501 case WDIOC_SETTIMEOUT: 502 if (get_user(new_margin, (int __user *)arg)) 503 return -EFAULT; 504 /* Arbitrary, can't find the card's limits */ 505 if (new_margin < 1 || new_margin > 124) 506 return -EINVAL; 507 wdt_margin = new_margin; 508 wdt_ping(); 509 /* Fall */ 510 case WDIOC_GETTIMEOUT: 511 return put_user(wdt_margin, (int __user *)arg); 512 513 case WDIOC_SETOPTIONS: 514 if (copy_from_user(&rv, (int __user *)arg, sizeof(int))) 515 return -EFAULT; 516 517 if (rv & WDIOS_DISABLECARD) { 518 pr_info("disable watchdog\n"); 519 wdt_disable(); 520 } 521 522 if (rv & WDIOS_ENABLECARD) { 523 pr_info("enable watchdog\n"); 524 wdt_ping(); 525 } 526 527 return -EINVAL; 528 } 529 return -ENOTTY; 530} 531 532static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd, 533 unsigned long arg) 534{ 535 int ret; 536 537 mutex_lock(&m41t80_rtc_mutex); 538 ret = wdt_ioctl(file, cmd, arg); 539 mutex_unlock(&m41t80_rtc_mutex); 540 541 return ret; 542} 543 544/** 545 * wdt_open: 546 * @inode: inode of device 547 * @file: file handle to device 548 * 549 */ 550static int wdt_open(struct inode *inode, struct file *file) 551{ 552 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) { 553 mutex_lock(&m41t80_rtc_mutex); 554 if (test_and_set_bit(0, &wdt_is_open)) { 555 mutex_unlock(&m41t80_rtc_mutex); 556 return -EBUSY; 557 } 558 /* 559 * Activate 560 */ 561 wdt_is_open = 1; 562 mutex_unlock(&m41t80_rtc_mutex); 563 return nonseekable_open(inode, file); 564 } 565 return -ENODEV; 566} 567 568/** 569 * wdt_close: 570 * @inode: inode to board 571 * @file: file handle to board 572 * 573 */ 574static int wdt_release(struct inode *inode, struct file *file) 575{ 576 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) 577 clear_bit(0, &wdt_is_open); 578 return 0; 579} 580 581/** 582 * notify_sys: 583 * @this: our notifier block 584 * @code: the event being reported 585 * @unused: unused 586 * 587 * Our notifier is called on system shutdowns. We want to turn the card 588 * off at reboot otherwise the machine will reboot again during memory 589 * test or worse yet during the following fsck. This would suck, in fact 590 * trust me - if it happens it does suck. 591 */ 592static int wdt_notify_sys(struct notifier_block *this, unsigned long code, 593 void *unused) 594{ 595 if (code == SYS_DOWN || code == SYS_HALT) 596 /* Disable Watchdog */ 597 wdt_disable(); 598 return NOTIFY_DONE; 599} 600 601static const struct file_operations wdt_fops = { 602 .owner = THIS_MODULE, 603 .read = wdt_read, 604 .unlocked_ioctl = wdt_unlocked_ioctl, 605 .write = wdt_write, 606 .open = wdt_open, 607 .release = wdt_release, 608 .llseek = no_llseek, 609}; 610 611static struct miscdevice wdt_dev = { 612 .minor = WATCHDOG_MINOR, 613 .name = "watchdog", 614 .fops = &wdt_fops, 615}; 616 617/* 618 * The WDT card needs to learn about soft shutdowns in order to 619 * turn the timebomb registers off. 620 */ 621static struct notifier_block wdt_notifier = { 622 .notifier_call = wdt_notify_sys, 623}; 624#endif /* CONFIG_RTC_DRV_M41T80_WDT */ 625 626/* 627 ***************************************************************************** 628 * 629 * Driver Interface 630 * 631 ***************************************************************************** 632 */ 633static int m41t80_probe(struct i2c_client *client, 634 const struct i2c_device_id *id) 635{ 636 int rc = 0; 637 struct rtc_device *rtc = NULL; 638 struct rtc_time tm; 639 struct m41t80_data *clientdata = NULL; 640 641 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C 642 | I2C_FUNC_SMBUS_BYTE_DATA)) 643 return -ENODEV; 644 645 clientdata = devm_kzalloc(&client->dev, sizeof(*clientdata), 646 GFP_KERNEL); 647 if (!clientdata) 648 return -ENOMEM; 649 650 clientdata->features = id->driver_data; 651 i2c_set_clientdata(client, clientdata); 652 653 rtc = devm_rtc_device_register(&client->dev, client->name, 654 &m41t80_rtc_ops, THIS_MODULE); 655 if (IS_ERR(rtc)) 656 return PTR_ERR(rtc); 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); 662 663 if (rc >= 0 && rc & M41T80_ALHOUR_HT) { 664 if (clientdata->features & M41T80_FEATURE_HT) { 665 m41t80_get_datetime(client, &tm); 666 dev_info(&client->dev, "HT bit was set!\n"); 667 dev_info(&client->dev, 668 "Power Down at " 669 "%04i-%02i-%02i %02i:%02i:%02i\n", 670 tm.tm_year + 1900, 671 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, 672 tm.tm_min, tm.tm_sec); 673 } 674 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_HOUR, 675 rc & ~M41T80_ALHOUR_HT); 676 } 677 678 if (rc < 0) { 679 dev_err(&client->dev, "Can't clear HT bit\n"); 680 return rc; 681 } 682 683 /* Make sure ST (stop) bit is cleared */ 684 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC); 685 686 if (rc >= 0 && rc & M41T80_SEC_ST) 687 rc = i2c_smbus_write_byte_data(client, M41T80_REG_SEC, 688 rc & ~M41T80_SEC_ST); 689 if (rc < 0) { 690 dev_err(&client->dev, "Can't clear ST bit\n"); 691 return rc; 692 } 693 694 rc = m41t80_sysfs_register(&client->dev); 695 if (rc) 696 return rc; 697 698#ifdef CONFIG_RTC_DRV_M41T80_WDT 699 if (clientdata->features & M41T80_FEATURE_HT) { 700 save_client = client; 701 rc = misc_register(&wdt_dev); 702 if (rc) 703 return rc; 704 rc = register_reboot_notifier(&wdt_notifier); 705 if (rc) { 706 misc_deregister(&wdt_dev); 707 return rc; 708 } 709 } 710#endif 711 return 0; 712} 713 714static int m41t80_remove(struct i2c_client *client) 715{ 716#ifdef CONFIG_RTC_DRV_M41T80_WDT 717 struct m41t80_data *clientdata = i2c_get_clientdata(client); 718 719 if (clientdata->features & M41T80_FEATURE_HT) { 720 misc_deregister(&wdt_dev); 721 unregister_reboot_notifier(&wdt_notifier); 722 } 723#endif 724 725 return 0; 726} 727 728static struct i2c_driver m41t80_driver = { 729 .driver = { 730 .name = "rtc-m41t80", 731 }, 732 .probe = m41t80_probe, 733 .remove = m41t80_remove, 734 .id_table = m41t80_id, 735}; 736 737module_i2c_driver(m41t80_driver); 738 739MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>"); 740MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver"); 741MODULE_LICENSE("GPL"); 742