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/smp_lock.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 68 #define DRV_VERSION "0.05" 69 70 static const struct i2c_device_id m41t80_id[] = { 71 { "m41t65", M41T80_FEATURE_HT | M41T80_FEATURE_WD }, 72 { "m41t80", M41T80_FEATURE_SQ }, 73 { "m41t81", M41T80_FEATURE_HT | M41T80_FEATURE_SQ}, 74 { "m41t81s", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 75 { "m41t82", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 76 { "m41t83", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 77 { "m41st84", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 78 { "m41st85", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 79 { "m41st87", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 80 { } 81 }; 82 MODULE_DEVICE_TABLE(i2c, m41t80_id); 83 84 struct m41t80_data { 85 u8 features; 86 struct rtc_device *rtc; 87 }; 88 89 static int m41t80_get_datetime(struct i2c_client *client, 90 struct rtc_time *tm) 91 { 92 u8 buf[M41T80_DATETIME_REG_SIZE], dt_addr[1] = { M41T80_REG_SEC }; 93 struct i2c_msg msgs[] = { 94 { 95 .addr = client->addr, 96 .flags = 0, 97 .len = 1, 98 .buf = dt_addr, 99 }, 100 { 101 .addr = client->addr, 102 .flags = I2C_M_RD, 103 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC, 104 .buf = buf + M41T80_REG_SEC, 105 }, 106 }; 107 108 if (i2c_transfer(client->adapter, msgs, 2) < 0) { 109 dev_err(&client->dev, "read error\n"); 110 return -EIO; 111 } 112 113 tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f); 114 tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f); 115 tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f); 116 tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f); 117 tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07; 118 tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1; 119 120 /* assume 20YY not 19YY, and ignore the Century Bit */ 121 tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100; 122 return 0; 123 } 124 125 /* Sets the given date and time to the real time clock. */ 126 static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm) 127 { 128 u8 wbuf[1 + M41T80_DATETIME_REG_SIZE]; 129 u8 *buf = &wbuf[1]; 130 u8 dt_addr[1] = { M41T80_REG_SEC }; 131 struct i2c_msg msgs_in[] = { 132 { 133 .addr = client->addr, 134 .flags = 0, 135 .len = 1, 136 .buf = dt_addr, 137 }, 138 { 139 .addr = client->addr, 140 .flags = I2C_M_RD, 141 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC, 142 .buf = buf + M41T80_REG_SEC, 143 }, 144 }; 145 struct i2c_msg msgs[] = { 146 { 147 .addr = client->addr, 148 .flags = 0, 149 .len = 1 + M41T80_DATETIME_REG_SIZE, 150 .buf = wbuf, 151 }, 152 }; 153 154 /* Read current reg values into buf[1..7] */ 155 if (i2c_transfer(client->adapter, msgs_in, 2) < 0) { 156 dev_err(&client->dev, "read error\n"); 157 return -EIO; 158 } 159 160 wbuf[0] = 0; /* offset into rtc's regs */ 161 /* Merge time-data and register flags into buf[0..7] */ 162 buf[M41T80_REG_SSEC] = 0; 163 buf[M41T80_REG_SEC] = 164 bin2bcd(tm->tm_sec) | (buf[M41T80_REG_SEC] & ~0x7f); 165 buf[M41T80_REG_MIN] = 166 bin2bcd(tm->tm_min) | (buf[M41T80_REG_MIN] & ~0x7f); 167 buf[M41T80_REG_HOUR] = 168 bin2bcd(tm->tm_hour) | (buf[M41T80_REG_HOUR] & ~0x3f) ; 169 buf[M41T80_REG_WDAY] = 170 (tm->tm_wday & 0x07) | (buf[M41T80_REG_WDAY] & ~0x07); 171 buf[M41T80_REG_DAY] = 172 bin2bcd(tm->tm_mday) | (buf[M41T80_REG_DAY] & ~0x3f); 173 buf[M41T80_REG_MON] = 174 bin2bcd(tm->tm_mon + 1) | (buf[M41T80_REG_MON] & ~0x1f); 175 /* assume 20YY not 19YY */ 176 buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year % 100); 177 178 if (i2c_transfer(client->adapter, msgs, 1) != 1) { 179 dev_err(&client->dev, "write error\n"); 180 return -EIO; 181 } 182 return 0; 183 } 184 185 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE) 186 static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq) 187 { 188 struct i2c_client *client = to_i2c_client(dev); 189 struct m41t80_data *clientdata = i2c_get_clientdata(client); 190 u8 reg; 191 192 if (clientdata->features & M41T80_FEATURE_BL) { 193 reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 194 seq_printf(seq, "battery\t\t: %s\n", 195 (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok"); 196 } 197 return 0; 198 } 199 #else 200 #define m41t80_rtc_proc NULL 201 #endif 202 203 static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm) 204 { 205 return m41t80_get_datetime(to_i2c_client(dev), tm); 206 } 207 208 static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm) 209 { 210 return m41t80_set_datetime(to_i2c_client(dev), tm); 211 } 212 213 #if defined(CONFIG_RTC_INTF_DEV) || defined(CONFIG_RTC_INTF_DEV_MODULE) 214 static int 215 m41t80_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) 216 { 217 struct i2c_client *client = to_i2c_client(dev); 218 int rc; 219 220 switch (cmd) { 221 case RTC_AIE_OFF: 222 case RTC_AIE_ON: 223 break; 224 default: 225 return -ENOIOCTLCMD; 226 } 227 228 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); 229 if (rc < 0) 230 goto err; 231 switch (cmd) { 232 case RTC_AIE_OFF: 233 rc &= ~M41T80_ALMON_AFE; 234 break; 235 case RTC_AIE_ON: 236 rc |= M41T80_ALMON_AFE; 237 break; 238 } 239 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, rc) < 0) 240 goto err; 241 return 0; 242 err: 243 return -EIO; 244 } 245 #else 246 #define m41t80_rtc_ioctl NULL 247 #endif 248 249 static int m41t80_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *t) 250 { 251 struct i2c_client *client = to_i2c_client(dev); 252 u8 wbuf[1 + M41T80_ALARM_REG_SIZE]; 253 u8 *buf = &wbuf[1]; 254 u8 *reg = buf - M41T80_REG_ALARM_MON; 255 u8 dt_addr[1] = { M41T80_REG_ALARM_MON }; 256 struct i2c_msg msgs_in[] = { 257 { 258 .addr = client->addr, 259 .flags = 0, 260 .len = 1, 261 .buf = dt_addr, 262 }, 263 { 264 .addr = client->addr, 265 .flags = I2C_M_RD, 266 .len = M41T80_ALARM_REG_SIZE, 267 .buf = buf, 268 }, 269 }; 270 struct i2c_msg msgs[] = { 271 { 272 .addr = client->addr, 273 .flags = 0, 274 .len = 1 + M41T80_ALARM_REG_SIZE, 275 .buf = wbuf, 276 }, 277 }; 278 279 if (i2c_transfer(client->adapter, msgs_in, 2) < 0) { 280 dev_err(&client->dev, "read error\n"); 281 return -EIO; 282 } 283 reg[M41T80_REG_ALARM_MON] &= ~(0x1f | M41T80_ALMON_AFE); 284 reg[M41T80_REG_ALARM_DAY] = 0; 285 reg[M41T80_REG_ALARM_HOUR] &= ~(0x3f | 0x80); 286 reg[M41T80_REG_ALARM_MIN] = 0; 287 reg[M41T80_REG_ALARM_SEC] = 0; 288 289 wbuf[0] = M41T80_REG_ALARM_MON; /* offset into rtc's regs */ 290 reg[M41T80_REG_ALARM_SEC] |= t->time.tm_sec >= 0 ? 291 bin2bcd(t->time.tm_sec) : 0x80; 292 reg[M41T80_REG_ALARM_MIN] |= t->time.tm_min >= 0 ? 293 bin2bcd(t->time.tm_min) : 0x80; 294 reg[M41T80_REG_ALARM_HOUR] |= t->time.tm_hour >= 0 ? 295 bin2bcd(t->time.tm_hour) : 0x80; 296 reg[M41T80_REG_ALARM_DAY] |= t->time.tm_mday >= 0 ? 297 bin2bcd(t->time.tm_mday) : 0x80; 298 if (t->time.tm_mon >= 0) 299 reg[M41T80_REG_ALARM_MON] |= bin2bcd(t->time.tm_mon + 1); 300 else 301 reg[M41T80_REG_ALARM_DAY] |= 0x40; 302 303 if (i2c_transfer(client->adapter, msgs, 1) != 1) { 304 dev_err(&client->dev, "write error\n"); 305 return -EIO; 306 } 307 308 if (t->enabled) { 309 reg[M41T80_REG_ALARM_MON] |= M41T80_ALMON_AFE; 310 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 311 reg[M41T80_REG_ALARM_MON]) < 0) { 312 dev_err(&client->dev, "write error\n"); 313 return -EIO; 314 } 315 } 316 return 0; 317 } 318 319 static int m41t80_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *t) 320 { 321 struct i2c_client *client = to_i2c_client(dev); 322 u8 buf[M41T80_ALARM_REG_SIZE + 1]; /* all alarm regs and flags */ 323 u8 dt_addr[1] = { M41T80_REG_ALARM_MON }; 324 u8 *reg = buf - M41T80_REG_ALARM_MON; 325 struct i2c_msg msgs[] = { 326 { 327 .addr = client->addr, 328 .flags = 0, 329 .len = 1, 330 .buf = dt_addr, 331 }, 332 { 333 .addr = client->addr, 334 .flags = I2C_M_RD, 335 .len = M41T80_ALARM_REG_SIZE + 1, 336 .buf = buf, 337 }, 338 }; 339 340 if (i2c_transfer(client->adapter, msgs, 2) < 0) { 341 dev_err(&client->dev, "read error\n"); 342 return -EIO; 343 } 344 t->time.tm_sec = -1; 345 t->time.tm_min = -1; 346 t->time.tm_hour = -1; 347 t->time.tm_mday = -1; 348 t->time.tm_mon = -1; 349 if (!(reg[M41T80_REG_ALARM_SEC] & 0x80)) 350 t->time.tm_sec = bcd2bin(reg[M41T80_REG_ALARM_SEC] & 0x7f); 351 if (!(reg[M41T80_REG_ALARM_MIN] & 0x80)) 352 t->time.tm_min = bcd2bin(reg[M41T80_REG_ALARM_MIN] & 0x7f); 353 if (!(reg[M41T80_REG_ALARM_HOUR] & 0x80)) 354 t->time.tm_hour = bcd2bin(reg[M41T80_REG_ALARM_HOUR] & 0x3f); 355 if (!(reg[M41T80_REG_ALARM_DAY] & 0x80)) 356 t->time.tm_mday = bcd2bin(reg[M41T80_REG_ALARM_DAY] & 0x3f); 357 if (!(reg[M41T80_REG_ALARM_DAY] & 0x40)) 358 t->time.tm_mon = bcd2bin(reg[M41T80_REG_ALARM_MON] & 0x1f) - 1; 359 t->time.tm_year = -1; 360 t->time.tm_wday = -1; 361 t->time.tm_yday = -1; 362 t->time.tm_isdst = -1; 363 t->enabled = !!(reg[M41T80_REG_ALARM_MON] & M41T80_ALMON_AFE); 364 t->pending = !!(reg[M41T80_REG_FLAGS] & M41T80_FLAGS_AF); 365 return 0; 366 } 367 368 static struct rtc_class_ops m41t80_rtc_ops = { 369 .read_time = m41t80_rtc_read_time, 370 .set_time = m41t80_rtc_set_time, 371 .read_alarm = m41t80_rtc_read_alarm, 372 .set_alarm = m41t80_rtc_set_alarm, 373 .proc = m41t80_rtc_proc, 374 .ioctl = m41t80_rtc_ioctl, 375 }; 376 377 #if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE) 378 static ssize_t m41t80_sysfs_show_flags(struct device *dev, 379 struct device_attribute *attr, char *buf) 380 { 381 struct i2c_client *client = to_i2c_client(dev); 382 int val; 383 384 val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 385 if (val < 0) 386 return -EIO; 387 return sprintf(buf, "%#x\n", val); 388 } 389 static DEVICE_ATTR(flags, S_IRUGO, m41t80_sysfs_show_flags, NULL); 390 391 static ssize_t m41t80_sysfs_show_sqwfreq(struct device *dev, 392 struct device_attribute *attr, char *buf) 393 { 394 struct i2c_client *client = to_i2c_client(dev); 395 struct m41t80_data *clientdata = i2c_get_clientdata(client); 396 int val; 397 398 if (!(clientdata->features & M41T80_FEATURE_SQ)) 399 return -EINVAL; 400 401 val = i2c_smbus_read_byte_data(client, M41T80_REG_SQW); 402 if (val < 0) 403 return -EIO; 404 val = (val >> 4) & 0xf; 405 switch (val) { 406 case 0: 407 break; 408 case 1: 409 val = 32768; 410 break; 411 default: 412 val = 32768 >> val; 413 } 414 return sprintf(buf, "%d\n", val); 415 } 416 static ssize_t m41t80_sysfs_set_sqwfreq(struct device *dev, 417 struct device_attribute *attr, 418 const char *buf, size_t count) 419 { 420 struct i2c_client *client = to_i2c_client(dev); 421 struct m41t80_data *clientdata = i2c_get_clientdata(client); 422 int almon, sqw; 423 int val = simple_strtoul(buf, NULL, 0); 424 425 if (!(clientdata->features & M41T80_FEATURE_SQ)) 426 return -EINVAL; 427 428 if (val) { 429 if (!is_power_of_2(val)) 430 return -EINVAL; 431 val = ilog2(val); 432 if (val == 15) 433 val = 1; 434 else if (val < 14) 435 val = 15 - val; 436 else 437 return -EINVAL; 438 } 439 /* disable SQW, set SQW frequency & re-enable */ 440 almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); 441 if (almon < 0) 442 return -EIO; 443 sqw = i2c_smbus_read_byte_data(client, M41T80_REG_SQW); 444 if (sqw < 0) 445 return -EIO; 446 sqw = (sqw & 0x0f) | (val << 4); 447 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 448 almon & ~M41T80_ALMON_SQWE) < 0 || 449 i2c_smbus_write_byte_data(client, M41T80_REG_SQW, sqw) < 0) 450 return -EIO; 451 if (val && i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 452 almon | M41T80_ALMON_SQWE) < 0) 453 return -EIO; 454 return count; 455 } 456 static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR, 457 m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq); 458 459 static struct attribute *attrs[] = { 460 &dev_attr_flags.attr, 461 &dev_attr_sqwfreq.attr, 462 NULL, 463 }; 464 static struct attribute_group attr_group = { 465 .attrs = attrs, 466 }; 467 468 static int m41t80_sysfs_register(struct device *dev) 469 { 470 return sysfs_create_group(&dev->kobj, &attr_group); 471 } 472 #else 473 static int m41t80_sysfs_register(struct device *dev) 474 { 475 return 0; 476 } 477 #endif 478 479 #ifdef CONFIG_RTC_DRV_M41T80_WDT 480 /* 481 ***************************************************************************** 482 * 483 * Watchdog Driver 484 * 485 ***************************************************************************** 486 */ 487 static struct i2c_client *save_client; 488 489 /* Default margin */ 490 #define WD_TIMO 60 /* 1..31 seconds */ 491 492 static int wdt_margin = WD_TIMO; 493 module_param(wdt_margin, int, 0); 494 MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)"); 495 496 static unsigned long wdt_is_open; 497 static int boot_flag; 498 499 /** 500 * wdt_ping: 501 * 502 * Reload counter one with the watchdog timeout. We don't bother reloading 503 * the cascade counter. 504 */ 505 static void wdt_ping(void) 506 { 507 unsigned char i2c_data[2]; 508 struct i2c_msg msgs1[1] = { 509 { 510 .addr = save_client->addr, 511 .flags = 0, 512 .len = 2, 513 .buf = i2c_data, 514 }, 515 }; 516 struct m41t80_data *clientdata = i2c_get_clientdata(save_client); 517 518 i2c_data[0] = 0x09; /* watchdog register */ 519 520 if (wdt_margin > 31) 521 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */ 522 else 523 /* 524 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02) 525 */ 526 i2c_data[1] = wdt_margin<<2 | 0x82; 527 528 /* 529 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as 530 * that would be an invalid resolution. 531 */ 532 if (clientdata->features & M41T80_FEATURE_WD) 533 i2c_data[1] &= ~M41T80_WATCHDOG_RB2; 534 535 i2c_transfer(save_client->adapter, msgs1, 1); 536 } 537 538 /** 539 * wdt_disable: 540 * 541 * disables watchdog. 542 */ 543 static void wdt_disable(void) 544 { 545 unsigned char i2c_data[2], i2c_buf[0x10]; 546 struct i2c_msg msgs0[2] = { 547 { 548 .addr = save_client->addr, 549 .flags = 0, 550 .len = 1, 551 .buf = i2c_data, 552 }, 553 { 554 .addr = save_client->addr, 555 .flags = I2C_M_RD, 556 .len = 1, 557 .buf = i2c_buf, 558 }, 559 }; 560 struct i2c_msg msgs1[1] = { 561 { 562 .addr = save_client->addr, 563 .flags = 0, 564 .len = 2, 565 .buf = i2c_data, 566 }, 567 }; 568 569 i2c_data[0] = 0x09; 570 i2c_transfer(save_client->adapter, msgs0, 2); 571 572 i2c_data[0] = 0x09; 573 i2c_data[1] = 0x00; 574 i2c_transfer(save_client->adapter, msgs1, 1); 575 } 576 577 /** 578 * wdt_write: 579 * @file: file handle to the watchdog 580 * @buf: buffer to write (unused as data does not matter here 581 * @count: count of bytes 582 * @ppos: pointer to the position to write. No seeks allowed 583 * 584 * A write to a watchdog device is defined as a keepalive signal. Any 585 * write of data will do, as we we don't define content meaning. 586 */ 587 static ssize_t wdt_write(struct file *file, const char __user *buf, 588 size_t count, loff_t *ppos) 589 { 590 /* Can't seek (pwrite) on this device 591 if (ppos != &file->f_pos) 592 return -ESPIPE; 593 */ 594 if (count) { 595 wdt_ping(); 596 return 1; 597 } 598 return 0; 599 } 600 601 static 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 */ 618 static int wdt_ioctl(struct inode *inode, 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 } 670 671 /** 672 * wdt_open: 673 * @inode: inode of device 674 * @file: file handle to device 675 * 676 */ 677 static int wdt_open(struct inode *inode, struct file *file) 678 { 679 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) { 680 lock_kernel(); 681 if (test_and_set_bit(0, &wdt_is_open)) { 682 unlock_kernel(); 683 return -EBUSY; 684 } 685 /* 686 * Activate 687 */ 688 wdt_is_open = 1; 689 unlock_kernel(); 690 return 0; 691 } 692 return -ENODEV; 693 } 694 695 /** 696 * wdt_close: 697 * @inode: inode to board 698 * @file: file handle to board 699 * 700 */ 701 static int wdt_release(struct inode *inode, struct file *file) 702 { 703 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) 704 clear_bit(0, &wdt_is_open); 705 return 0; 706 } 707 708 /** 709 * notify_sys: 710 * @this: our notifier block 711 * @code: the event being reported 712 * @unused: unused 713 * 714 * Our notifier is called on system shutdowns. We want to turn the card 715 * off at reboot otherwise the machine will reboot again during memory 716 * test or worse yet during the following fsck. This would suck, in fact 717 * trust me - if it happens it does suck. 718 */ 719 static int wdt_notify_sys(struct notifier_block *this, unsigned long code, 720 void *unused) 721 { 722 if (code == SYS_DOWN || code == SYS_HALT) 723 /* Disable Watchdog */ 724 wdt_disable(); 725 return NOTIFY_DONE; 726 } 727 728 static const struct file_operations wdt_fops = { 729 .owner = THIS_MODULE, 730 .read = wdt_read, 731 .ioctl = wdt_ioctl, 732 .write = wdt_write, 733 .open = wdt_open, 734 .release = wdt_release, 735 }; 736 737 static struct miscdevice wdt_dev = { 738 .minor = WATCHDOG_MINOR, 739 .name = "watchdog", 740 .fops = &wdt_fops, 741 }; 742 743 /* 744 * The WDT card needs to learn about soft shutdowns in order to 745 * turn the timebomb registers off. 746 */ 747 static struct notifier_block wdt_notifier = { 748 .notifier_call = wdt_notify_sys, 749 }; 750 #endif /* CONFIG_RTC_DRV_M41T80_WDT */ 751 752 /* 753 ***************************************************************************** 754 * 755 * Driver Interface 756 * 757 ***************************************************************************** 758 */ 759 static int m41t80_probe(struct i2c_client *client, 760 const struct i2c_device_id *id) 761 { 762 int rc = 0; 763 struct rtc_device *rtc = NULL; 764 struct rtc_time tm; 765 struct m41t80_data *clientdata = NULL; 766 767 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C 768 | I2C_FUNC_SMBUS_BYTE_DATA)) { 769 rc = -ENODEV; 770 goto exit; 771 } 772 773 dev_info(&client->dev, 774 "chip found, driver version " DRV_VERSION "\n"); 775 776 clientdata = kzalloc(sizeof(*clientdata), GFP_KERNEL); 777 if (!clientdata) { 778 rc = -ENOMEM; 779 goto exit; 780 } 781 782 rtc = rtc_device_register(client->name, &client->dev, 783 &m41t80_rtc_ops, THIS_MODULE); 784 if (IS_ERR(rtc)) { 785 rc = PTR_ERR(rtc); 786 rtc = NULL; 787 goto exit; 788 } 789 790 clientdata->rtc = rtc; 791 clientdata->features = id->driver_data; 792 i2c_set_clientdata(client, clientdata); 793 794 /* Make sure HT (Halt Update) bit is cleared */ 795 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR); 796 if (rc < 0) 797 goto ht_err; 798 799 if (rc & M41T80_ALHOUR_HT) { 800 if (clientdata->features & M41T80_FEATURE_HT) { 801 m41t80_get_datetime(client, &tm); 802 dev_info(&client->dev, "HT bit was set!\n"); 803 dev_info(&client->dev, 804 "Power Down at " 805 "%04i-%02i-%02i %02i:%02i:%02i\n", 806 tm.tm_year + 1900, 807 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, 808 tm.tm_min, tm.tm_sec); 809 } 810 if (i2c_smbus_write_byte_data(client, 811 M41T80_REG_ALARM_HOUR, 812 rc & ~M41T80_ALHOUR_HT) < 0) 813 goto ht_err; 814 } 815 816 /* Make sure ST (stop) bit is cleared */ 817 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC); 818 if (rc < 0) 819 goto st_err; 820 821 if (rc & M41T80_SEC_ST) { 822 if (i2c_smbus_write_byte_data(client, M41T80_REG_SEC, 823 rc & ~M41T80_SEC_ST) < 0) 824 goto st_err; 825 } 826 827 rc = m41t80_sysfs_register(&client->dev); 828 if (rc) 829 goto exit; 830 831 #ifdef CONFIG_RTC_DRV_M41T80_WDT 832 if (clientdata->features & M41T80_FEATURE_HT) { 833 save_client = client; 834 rc = misc_register(&wdt_dev); 835 if (rc) 836 goto exit; 837 rc = register_reboot_notifier(&wdt_notifier); 838 if (rc) { 839 misc_deregister(&wdt_dev); 840 goto exit; 841 } 842 } 843 #endif 844 return 0; 845 846 st_err: 847 rc = -EIO; 848 dev_err(&client->dev, "Can't clear ST bit\n"); 849 goto exit; 850 ht_err: 851 rc = -EIO; 852 dev_err(&client->dev, "Can't clear HT bit\n"); 853 goto exit; 854 855 exit: 856 if (rtc) 857 rtc_device_unregister(rtc); 858 kfree(clientdata); 859 return rc; 860 } 861 862 static int m41t80_remove(struct i2c_client *client) 863 { 864 struct m41t80_data *clientdata = i2c_get_clientdata(client); 865 struct rtc_device *rtc = clientdata->rtc; 866 867 #ifdef CONFIG_RTC_DRV_M41T80_WDT 868 if (clientdata->features & M41T80_FEATURE_HT) { 869 misc_deregister(&wdt_dev); 870 unregister_reboot_notifier(&wdt_notifier); 871 } 872 #endif 873 if (rtc) 874 rtc_device_unregister(rtc); 875 kfree(clientdata); 876 877 return 0; 878 } 879 880 static struct i2c_driver m41t80_driver = { 881 .driver = { 882 .name = "rtc-m41t80", 883 }, 884 .probe = m41t80_probe, 885 .remove = m41t80_remove, 886 .id_table = m41t80_id, 887 }; 888 889 static int __init m41t80_rtc_init(void) 890 { 891 return i2c_add_driver(&m41t80_driver); 892 } 893 894 static void __exit m41t80_rtc_exit(void) 895 { 896 i2c_del_driver(&m41t80_driver); 897 } 898 899 MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>"); 900 MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver"); 901 MODULE_LICENSE("GPL"); 902 MODULE_VERSION(DRV_VERSION); 903 904 module_init(m41t80_rtc_init); 905 module_exit(m41t80_rtc_exit); 906