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 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 { } 84}; 85MODULE_DEVICE_TABLE(i2c, m41t80_id); 86 87struct m41t80_data { 88 u8 features; 89 struct rtc_device *rtc; 90}; 91 92static 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. */ 129static 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) 189static 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 206static 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 211static 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 216static int m41t80_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) 217{ 218 struct i2c_client *client = to_i2c_client(dev); 219 int rc; 220 221 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); 222 if (rc < 0) 223 goto err; 224 225 if (enabled) 226 rc |= M41T80_ALMON_AFE; 227 else 228 rc &= ~M41T80_ALMON_AFE; 229 230 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, rc) < 0) 231 goto err; 232 233 return 0; 234err: 235 return -EIO; 236} 237 238static int m41t80_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *t) 239{ 240 struct i2c_client *client = to_i2c_client(dev); 241 u8 wbuf[1 + M41T80_ALARM_REG_SIZE]; 242 u8 *buf = &wbuf[1]; 243 u8 *reg = buf - M41T80_REG_ALARM_MON; 244 u8 dt_addr[1] = { M41T80_REG_ALARM_MON }; 245 struct i2c_msg msgs_in[] = { 246 { 247 .addr = client->addr, 248 .flags = 0, 249 .len = 1, 250 .buf = dt_addr, 251 }, 252 { 253 .addr = client->addr, 254 .flags = I2C_M_RD, 255 .len = M41T80_ALARM_REG_SIZE, 256 .buf = buf, 257 }, 258 }; 259 struct i2c_msg msgs[] = { 260 { 261 .addr = client->addr, 262 .flags = 0, 263 .len = 1 + M41T80_ALARM_REG_SIZE, 264 .buf = wbuf, 265 }, 266 }; 267 268 if (i2c_transfer(client->adapter, msgs_in, 2) < 0) { 269 dev_err(&client->dev, "read error\n"); 270 return -EIO; 271 } 272 reg[M41T80_REG_ALARM_MON] &= ~(0x1f | M41T80_ALMON_AFE); 273 reg[M41T80_REG_ALARM_DAY] = 0; 274 reg[M41T80_REG_ALARM_HOUR] &= ~(0x3f | 0x80); 275 reg[M41T80_REG_ALARM_MIN] = 0; 276 reg[M41T80_REG_ALARM_SEC] = 0; 277 278 wbuf[0] = M41T80_REG_ALARM_MON; /* offset into rtc's regs */ 279 reg[M41T80_REG_ALARM_SEC] |= t->time.tm_sec >= 0 ? 280 bin2bcd(t->time.tm_sec) : 0x80; 281 reg[M41T80_REG_ALARM_MIN] |= t->time.tm_min >= 0 ? 282 bin2bcd(t->time.tm_min) : 0x80; 283 reg[M41T80_REG_ALARM_HOUR] |= t->time.tm_hour >= 0 ? 284 bin2bcd(t->time.tm_hour) : 0x80; 285 reg[M41T80_REG_ALARM_DAY] |= t->time.tm_mday >= 0 ? 286 bin2bcd(t->time.tm_mday) : 0x80; 287 if (t->time.tm_mon >= 0) 288 reg[M41T80_REG_ALARM_MON] |= bin2bcd(t->time.tm_mon + 1); 289 else 290 reg[M41T80_REG_ALARM_DAY] |= 0x40; 291 292 if (i2c_transfer(client->adapter, msgs, 1) != 1) { 293 dev_err(&client->dev, "write error\n"); 294 return -EIO; 295 } 296 297 if (t->enabled) { 298 reg[M41T80_REG_ALARM_MON] |= M41T80_ALMON_AFE; 299 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 300 reg[M41T80_REG_ALARM_MON]) < 0) { 301 dev_err(&client->dev, "write error\n"); 302 return -EIO; 303 } 304 } 305 return 0; 306} 307 308static int m41t80_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *t) 309{ 310 struct i2c_client *client = to_i2c_client(dev); 311 u8 buf[M41T80_ALARM_REG_SIZE + 1]; /* all alarm regs and flags */ 312 u8 dt_addr[1] = { M41T80_REG_ALARM_MON }; 313 u8 *reg = buf - M41T80_REG_ALARM_MON; 314 struct i2c_msg msgs[] = { 315 { 316 .addr = client->addr, 317 .flags = 0, 318 .len = 1, 319 .buf = dt_addr, 320 }, 321 { 322 .addr = client->addr, 323 .flags = I2C_M_RD, 324 .len = M41T80_ALARM_REG_SIZE + 1, 325 .buf = buf, 326 }, 327 }; 328 329 if (i2c_transfer(client->adapter, msgs, 2) < 0) { 330 dev_err(&client->dev, "read error\n"); 331 return -EIO; 332 } 333 t->time.tm_sec = -1; 334 t->time.tm_min = -1; 335 t->time.tm_hour = -1; 336 t->time.tm_mday = -1; 337 t->time.tm_mon = -1; 338 if (!(reg[M41T80_REG_ALARM_SEC] & 0x80)) 339 t->time.tm_sec = bcd2bin(reg[M41T80_REG_ALARM_SEC] & 0x7f); 340 if (!(reg[M41T80_REG_ALARM_MIN] & 0x80)) 341 t->time.tm_min = bcd2bin(reg[M41T80_REG_ALARM_MIN] & 0x7f); 342 if (!(reg[M41T80_REG_ALARM_HOUR] & 0x80)) 343 t->time.tm_hour = bcd2bin(reg[M41T80_REG_ALARM_HOUR] & 0x3f); 344 if (!(reg[M41T80_REG_ALARM_DAY] & 0x80)) 345 t->time.tm_mday = bcd2bin(reg[M41T80_REG_ALARM_DAY] & 0x3f); 346 if (!(reg[M41T80_REG_ALARM_DAY] & 0x40)) 347 t->time.tm_mon = bcd2bin(reg[M41T80_REG_ALARM_MON] & 0x1f) - 1; 348 t->time.tm_year = -1; 349 t->time.tm_wday = -1; 350 t->time.tm_yday = -1; 351 t->time.tm_isdst = -1; 352 t->enabled = !!(reg[M41T80_REG_ALARM_MON] & M41T80_ALMON_AFE); 353 t->pending = !!(reg[M41T80_REG_FLAGS] & M41T80_FLAGS_AF); 354 return 0; 355} 356 357static struct rtc_class_ops m41t80_rtc_ops = { 358 .read_time = m41t80_rtc_read_time, 359 .set_time = m41t80_rtc_set_time, 360 /* 361 * XXX - m41t80 alarm functionality is reported broken. 362 * until it is fixed, don't register alarm functions. 363 * 364 .read_alarm = m41t80_rtc_read_alarm, 365 .set_alarm = m41t80_rtc_set_alarm, 366 */ 367 .proc = m41t80_rtc_proc, 368 /* 369 * See above comment on broken alarm 370 * 371 .alarm_irq_enable = m41t80_rtc_alarm_irq_enable, 372 */ 373}; 374 375#if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE) 376static ssize_t m41t80_sysfs_show_flags(struct device *dev, 377 struct device_attribute *attr, char *buf) 378{ 379 struct i2c_client *client = to_i2c_client(dev); 380 int val; 381 382 val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 383 if (val < 0) 384 return -EIO; 385 return sprintf(buf, "%#x\n", val); 386} 387static DEVICE_ATTR(flags, S_IRUGO, m41t80_sysfs_show_flags, NULL); 388 389static ssize_t m41t80_sysfs_show_sqwfreq(struct device *dev, 390 struct device_attribute *attr, char *buf) 391{ 392 struct i2c_client *client = to_i2c_client(dev); 393 struct m41t80_data *clientdata = i2c_get_clientdata(client); 394 int val, reg_sqw; 395 396 if (!(clientdata->features & M41T80_FEATURE_SQ)) 397 return -EINVAL; 398 399 reg_sqw = M41T80_REG_SQW; 400 if (clientdata->features & M41T80_FEATURE_SQ_ALT) 401 reg_sqw = M41T80_REG_WDAY; 402 val = i2c_smbus_read_byte_data(client, reg_sqw); 403 if (val < 0) 404 return -EIO; 405 val = (val >> 4) & 0xf; 406 switch (val) { 407 case 0: 408 break; 409 case 1: 410 val = 32768; 411 break; 412 default: 413 val = 32768 >> val; 414 } 415 return sprintf(buf, "%d\n", val); 416} 417static ssize_t m41t80_sysfs_set_sqwfreq(struct device *dev, 418 struct device_attribute *attr, 419 const char *buf, size_t count) 420{ 421 struct i2c_client *client = to_i2c_client(dev); 422 struct m41t80_data *clientdata = i2c_get_clientdata(client); 423 int almon, sqw, reg_sqw; 424 int val = simple_strtoul(buf, NULL, 0); 425 426 if (!(clientdata->features & M41T80_FEATURE_SQ)) 427 return -EINVAL; 428 429 if (val) { 430 if (!is_power_of_2(val)) 431 return -EINVAL; 432 val = ilog2(val); 433 if (val == 15) 434 val = 1; 435 else if (val < 14) 436 val = 15 - val; 437 else 438 return -EINVAL; 439 } 440 /* disable SQW, set SQW frequency & re-enable */ 441 almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); 442 if (almon < 0) 443 return -EIO; 444 reg_sqw = M41T80_REG_SQW; 445 if (clientdata->features & M41T80_FEATURE_SQ_ALT) 446 reg_sqw = M41T80_REG_WDAY; 447 sqw = i2c_smbus_read_byte_data(client, reg_sqw); 448 if (sqw < 0) 449 return -EIO; 450 sqw = (sqw & 0x0f) | (val << 4); 451 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 452 almon & ~M41T80_ALMON_SQWE) < 0 || 453 i2c_smbus_write_byte_data(client, reg_sqw, sqw) < 0) 454 return -EIO; 455 if (val && i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 456 almon | M41T80_ALMON_SQWE) < 0) 457 return -EIO; 458 return count; 459} 460static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR, 461 m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq); 462 463static struct attribute *attrs[] = { 464 &dev_attr_flags.attr, 465 &dev_attr_sqwfreq.attr, 466 NULL, 467}; 468static struct attribute_group attr_group = { 469 .attrs = attrs, 470}; 471 472static int m41t80_sysfs_register(struct device *dev) 473{ 474 return sysfs_create_group(&dev->kobj, &attr_group); 475} 476#else 477static int m41t80_sysfs_register(struct device *dev) 478{ 479 return 0; 480} 481#endif 482 483#ifdef CONFIG_RTC_DRV_M41T80_WDT 484/* 485 ***************************************************************************** 486 * 487 * Watchdog Driver 488 * 489 ***************************************************************************** 490 */ 491static struct i2c_client *save_client; 492 493/* Default margin */ 494#define WD_TIMO 60 /* 1..31 seconds */ 495 496static int wdt_margin = WD_TIMO; 497module_param(wdt_margin, int, 0); 498MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)"); 499 500static unsigned long wdt_is_open; 501static int boot_flag; 502 503/** 504 * wdt_ping: 505 * 506 * Reload counter one with the watchdog timeout. We don't bother reloading 507 * the cascade counter. 508 */ 509static void wdt_ping(void) 510{ 511 unsigned char i2c_data[2]; 512 struct i2c_msg msgs1[1] = { 513 { 514 .addr = save_client->addr, 515 .flags = 0, 516 .len = 2, 517 .buf = i2c_data, 518 }, 519 }; 520 struct m41t80_data *clientdata = i2c_get_clientdata(save_client); 521 522 i2c_data[0] = 0x09; /* watchdog register */ 523 524 if (wdt_margin > 31) 525 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */ 526 else 527 /* 528 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02) 529 */ 530 i2c_data[1] = wdt_margin<<2 | 0x82; 531 532 /* 533 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as 534 * that would be an invalid resolution. 535 */ 536 if (clientdata->features & M41T80_FEATURE_WD) 537 i2c_data[1] &= ~M41T80_WATCHDOG_RB2; 538 539 i2c_transfer(save_client->adapter, msgs1, 1); 540} 541 542/** 543 * wdt_disable: 544 * 545 * disables watchdog. 546 */ 547static void wdt_disable(void) 548{ 549 unsigned char i2c_data[2], i2c_buf[0x10]; 550 struct i2c_msg msgs0[2] = { 551 { 552 .addr = save_client->addr, 553 .flags = 0, 554 .len = 1, 555 .buf = i2c_data, 556 }, 557 { 558 .addr = save_client->addr, 559 .flags = I2C_M_RD, 560 .len = 1, 561 .buf = i2c_buf, 562 }, 563 }; 564 struct i2c_msg msgs1[1] = { 565 { 566 .addr = save_client->addr, 567 .flags = 0, 568 .len = 2, 569 .buf = i2c_data, 570 }, 571 }; 572 573 i2c_data[0] = 0x09; 574 i2c_transfer(save_client->adapter, msgs0, 2); 575 576 i2c_data[0] = 0x09; 577 i2c_data[1] = 0x00; 578 i2c_transfer(save_client->adapter, msgs1, 1); 579} 580 581/** 582 * wdt_write: 583 * @file: file handle to the watchdog 584 * @buf: buffer to write (unused as data does not matter here 585 * @count: count of bytes 586 * @ppos: pointer to the position to write. No seeks allowed 587 * 588 * A write to a watchdog device is defined as a keepalive signal. Any 589 * write of data will do, as we we don't define content meaning. 590 */ 591static ssize_t wdt_write(struct file *file, const char __user *buf, 592 size_t count, loff_t *ppos) 593{ 594 if (count) { 595 wdt_ping(); 596 return 1; 597 } 598 return 0; 599} 600 601static ssize_t wdt_read(struct file *file, char __user *buf, 602 size_t count, loff_t *ppos) 603{ 604 return 0; 605} 606 607/** 608 * wdt_ioctl: 609 * @inode: inode of the device 610 * @file: file handle to the device 611 * @cmd: watchdog command 612 * @arg: argument pointer 613 * 614 * The watchdog API defines a common set of functions for all watchdogs 615 * according to their available features. We only actually usefully support 616 * querying capabilities and current status. 617 */ 618static int wdt_ioctl(struct file *file, unsigned int cmd, 619 unsigned long arg) 620{ 621 int new_margin, rv; 622 static struct watchdog_info ident = { 623 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING | 624 WDIOF_SETTIMEOUT, 625 .firmware_version = 1, 626 .identity = "M41T80 WTD" 627 }; 628 629 switch (cmd) { 630 case WDIOC_GETSUPPORT: 631 return copy_to_user((struct watchdog_info __user *)arg, &ident, 632 sizeof(ident)) ? -EFAULT : 0; 633 634 case WDIOC_GETSTATUS: 635 case WDIOC_GETBOOTSTATUS: 636 return put_user(boot_flag, (int __user *)arg); 637 case WDIOC_KEEPALIVE: 638 wdt_ping(); 639 return 0; 640 case WDIOC_SETTIMEOUT: 641 if (get_user(new_margin, (int __user *)arg)) 642 return -EFAULT; 643 /* Arbitrary, can't find the card's limits */ 644 if (new_margin < 1 || new_margin > 124) 645 return -EINVAL; 646 wdt_margin = new_margin; 647 wdt_ping(); 648 /* Fall */ 649 case WDIOC_GETTIMEOUT: 650 return put_user(wdt_margin, (int __user *)arg); 651 652 case WDIOC_SETOPTIONS: 653 if (copy_from_user(&rv, (int __user *)arg, sizeof(int))) 654 return -EFAULT; 655 656 if (rv & WDIOS_DISABLECARD) { 657 pr_info("rtc-m41t80: disable watchdog\n"); 658 wdt_disable(); 659 } 660 661 if (rv & WDIOS_ENABLECARD) { 662 pr_info("rtc-m41t80: enable watchdog\n"); 663 wdt_ping(); 664 } 665 666 return -EINVAL; 667 } 668 return -ENOTTY; 669} 670 671static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd, 672 unsigned long arg) 673{ 674 int ret; 675 676 mutex_lock(&m41t80_rtc_mutex); 677 ret = wdt_ioctl(file, cmd, arg); 678 mutex_unlock(&m41t80_rtc_mutex); 679 680 return ret; 681} 682 683/** 684 * wdt_open: 685 * @inode: inode of device 686 * @file: file handle to device 687 * 688 */ 689static int wdt_open(struct inode *inode, struct file *file) 690{ 691 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) { 692 mutex_lock(&m41t80_rtc_mutex); 693 if (test_and_set_bit(0, &wdt_is_open)) { 694 mutex_unlock(&m41t80_rtc_mutex); 695 return -EBUSY; 696 } 697 /* 698 * Activate 699 */ 700 wdt_is_open = 1; 701 mutex_unlock(&m41t80_rtc_mutex); 702 return nonseekable_open(inode, file); 703 } 704 return -ENODEV; 705} 706 707/** 708 * wdt_close: 709 * @inode: inode to board 710 * @file: file handle to board 711 * 712 */ 713static int wdt_release(struct inode *inode, struct file *file) 714{ 715 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) 716 clear_bit(0, &wdt_is_open); 717 return 0; 718} 719 720/** 721 * notify_sys: 722 * @this: our notifier block 723 * @code: the event being reported 724 * @unused: unused 725 * 726 * Our notifier is called on system shutdowns. We want to turn the card 727 * off at reboot otherwise the machine will reboot again during memory 728 * test or worse yet during the following fsck. This would suck, in fact 729 * trust me - if it happens it does suck. 730 */ 731static int wdt_notify_sys(struct notifier_block *this, unsigned long code, 732 void *unused) 733{ 734 if (code == SYS_DOWN || code == SYS_HALT) 735 /* Disable Watchdog */ 736 wdt_disable(); 737 return NOTIFY_DONE; 738} 739 740static const struct file_operations wdt_fops = { 741 .owner = THIS_MODULE, 742 .read = wdt_read, 743 .unlocked_ioctl = wdt_unlocked_ioctl, 744 .write = wdt_write, 745 .open = wdt_open, 746 .release = wdt_release, 747 .llseek = no_llseek, 748}; 749 750static struct miscdevice wdt_dev = { 751 .minor = WATCHDOG_MINOR, 752 .name = "watchdog", 753 .fops = &wdt_fops, 754}; 755 756/* 757 * The WDT card needs to learn about soft shutdowns in order to 758 * turn the timebomb registers off. 759 */ 760static struct notifier_block wdt_notifier = { 761 .notifier_call = wdt_notify_sys, 762}; 763#endif /* CONFIG_RTC_DRV_M41T80_WDT */ 764 765/* 766 ***************************************************************************** 767 * 768 * Driver Interface 769 * 770 ***************************************************************************** 771 */ 772static int m41t80_probe(struct i2c_client *client, 773 const struct i2c_device_id *id) 774{ 775 int rc = 0; 776 struct rtc_device *rtc = NULL; 777 struct rtc_time tm; 778 struct m41t80_data *clientdata = NULL; 779 780 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C 781 | I2C_FUNC_SMBUS_BYTE_DATA)) { 782 rc = -ENODEV; 783 goto exit; 784 } 785 786 dev_info(&client->dev, 787 "chip found, driver version " DRV_VERSION "\n"); 788 789 clientdata = kzalloc(sizeof(*clientdata), GFP_KERNEL); 790 if (!clientdata) { 791 rc = -ENOMEM; 792 goto exit; 793 } 794 795 clientdata->features = id->driver_data; 796 i2c_set_clientdata(client, clientdata); 797 798 rtc = rtc_device_register(client->name, &client->dev, 799 &m41t80_rtc_ops, THIS_MODULE); 800 if (IS_ERR(rtc)) { 801 rc = PTR_ERR(rtc); 802 rtc = NULL; 803 goto exit; 804 } 805 806 clientdata->rtc = rtc; 807 808 /* Make sure HT (Halt Update) bit is cleared */ 809 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR); 810 if (rc < 0) 811 goto ht_err; 812 813 if (rc & M41T80_ALHOUR_HT) { 814 if (clientdata->features & M41T80_FEATURE_HT) { 815 m41t80_get_datetime(client, &tm); 816 dev_info(&client->dev, "HT bit was set!\n"); 817 dev_info(&client->dev, 818 "Power Down at " 819 "%04i-%02i-%02i %02i:%02i:%02i\n", 820 tm.tm_year + 1900, 821 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, 822 tm.tm_min, tm.tm_sec); 823 } 824 if (i2c_smbus_write_byte_data(client, 825 M41T80_REG_ALARM_HOUR, 826 rc & ~M41T80_ALHOUR_HT) < 0) 827 goto ht_err; 828 } 829 830 /* Make sure ST (stop) bit is cleared */ 831 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC); 832 if (rc < 0) 833 goto st_err; 834 835 if (rc & M41T80_SEC_ST) { 836 if (i2c_smbus_write_byte_data(client, M41T80_REG_SEC, 837 rc & ~M41T80_SEC_ST) < 0) 838 goto st_err; 839 } 840 841 rc = m41t80_sysfs_register(&client->dev); 842 if (rc) 843 goto exit; 844 845#ifdef CONFIG_RTC_DRV_M41T80_WDT 846 if (clientdata->features & M41T80_FEATURE_HT) { 847 save_client = client; 848 rc = misc_register(&wdt_dev); 849 if (rc) 850 goto exit; 851 rc = register_reboot_notifier(&wdt_notifier); 852 if (rc) { 853 misc_deregister(&wdt_dev); 854 goto exit; 855 } 856 } 857#endif 858 return 0; 859 860st_err: 861 rc = -EIO; 862 dev_err(&client->dev, "Can't clear ST bit\n"); 863 goto exit; 864ht_err: 865 rc = -EIO; 866 dev_err(&client->dev, "Can't clear HT bit\n"); 867 goto exit; 868 869exit: 870 if (rtc) 871 rtc_device_unregister(rtc); 872 kfree(clientdata); 873 return rc; 874} 875 876static int m41t80_remove(struct i2c_client *client) 877{ 878 struct m41t80_data *clientdata = i2c_get_clientdata(client); 879 struct rtc_device *rtc = clientdata->rtc; 880 881#ifdef CONFIG_RTC_DRV_M41T80_WDT 882 if (clientdata->features & M41T80_FEATURE_HT) { 883 misc_deregister(&wdt_dev); 884 unregister_reboot_notifier(&wdt_notifier); 885 } 886#endif 887 if (rtc) 888 rtc_device_unregister(rtc); 889 kfree(clientdata); 890 891 return 0; 892} 893 894static struct i2c_driver m41t80_driver = { 895 .driver = { 896 .name = "rtc-m41t80", 897 }, 898 .probe = m41t80_probe, 899 .remove = m41t80_remove, 900 .id_table = m41t80_id, 901}; 902 903module_i2c_driver(m41t80_driver); 904 905MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>"); 906MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver"); 907MODULE_LICENSE("GPL"); 908MODULE_VERSION(DRV_VERSION); 909