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 #define M41T80_FEATURE_SQ_ALT (1 << 4) /* RSx bits are in reg 4 */ 68 69 #define DRV_VERSION "0.05" 70 71 static const struct i2c_device_id m41t80_id[] = { 72 { "m41t62", M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT }, 73 { "m41t65", M41T80_FEATURE_HT | M41T80_FEATURE_WD }, 74 { "m41t80", M41T80_FEATURE_SQ }, 75 { "m41t81", M41T80_FEATURE_HT | M41T80_FEATURE_SQ}, 76 { "m41t81s", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 77 { "m41t82", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 78 { "m41t83", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 79 { "m41st84", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 80 { "m41st85", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 81 { "m41st87", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 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 0; 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 #if defined(CONFIG_RTC_INTF_DEV) || defined(CONFIG_RTC_INTF_DEV_MODULE) 216 static int 217 m41t80_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) 218 { 219 struct i2c_client *client = to_i2c_client(dev); 220 int rc; 221 222 switch (cmd) { 223 case RTC_AIE_OFF: 224 case RTC_AIE_ON: 225 break; 226 default: 227 return -ENOIOCTLCMD; 228 } 229 230 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); 231 if (rc < 0) 232 goto err; 233 switch (cmd) { 234 case RTC_AIE_OFF: 235 rc &= ~M41T80_ALMON_AFE; 236 break; 237 case RTC_AIE_ON: 238 rc |= M41T80_ALMON_AFE; 239 break; 240 } 241 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, rc) < 0) 242 goto err; 243 return 0; 244 err: 245 return -EIO; 246 } 247 #else 248 #define m41t80_rtc_ioctl NULL 249 #endif 250 251 static int m41t80_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *t) 252 { 253 struct i2c_client *client = to_i2c_client(dev); 254 u8 wbuf[1 + M41T80_ALARM_REG_SIZE]; 255 u8 *buf = &wbuf[1]; 256 u8 *reg = buf - M41T80_REG_ALARM_MON; 257 u8 dt_addr[1] = { M41T80_REG_ALARM_MON }; 258 struct i2c_msg msgs_in[] = { 259 { 260 .addr = client->addr, 261 .flags = 0, 262 .len = 1, 263 .buf = dt_addr, 264 }, 265 { 266 .addr = client->addr, 267 .flags = I2C_M_RD, 268 .len = M41T80_ALARM_REG_SIZE, 269 .buf = buf, 270 }, 271 }; 272 struct i2c_msg msgs[] = { 273 { 274 .addr = client->addr, 275 .flags = 0, 276 .len = 1 + M41T80_ALARM_REG_SIZE, 277 .buf = wbuf, 278 }, 279 }; 280 281 if (i2c_transfer(client->adapter, msgs_in, 2) < 0) { 282 dev_err(&client->dev, "read error\n"); 283 return -EIO; 284 } 285 reg[M41T80_REG_ALARM_MON] &= ~(0x1f | M41T80_ALMON_AFE); 286 reg[M41T80_REG_ALARM_DAY] = 0; 287 reg[M41T80_REG_ALARM_HOUR] &= ~(0x3f | 0x80); 288 reg[M41T80_REG_ALARM_MIN] = 0; 289 reg[M41T80_REG_ALARM_SEC] = 0; 290 291 wbuf[0] = M41T80_REG_ALARM_MON; /* offset into rtc's regs */ 292 reg[M41T80_REG_ALARM_SEC] |= t->time.tm_sec >= 0 ? 293 bin2bcd(t->time.tm_sec) : 0x80; 294 reg[M41T80_REG_ALARM_MIN] |= t->time.tm_min >= 0 ? 295 bin2bcd(t->time.tm_min) : 0x80; 296 reg[M41T80_REG_ALARM_HOUR] |= t->time.tm_hour >= 0 ? 297 bin2bcd(t->time.tm_hour) : 0x80; 298 reg[M41T80_REG_ALARM_DAY] |= t->time.tm_mday >= 0 ? 299 bin2bcd(t->time.tm_mday) : 0x80; 300 if (t->time.tm_mon >= 0) 301 reg[M41T80_REG_ALARM_MON] |= bin2bcd(t->time.tm_mon + 1); 302 else 303 reg[M41T80_REG_ALARM_DAY] |= 0x40; 304 305 if (i2c_transfer(client->adapter, msgs, 1) != 1) { 306 dev_err(&client->dev, "write error\n"); 307 return -EIO; 308 } 309 310 if (t->enabled) { 311 reg[M41T80_REG_ALARM_MON] |= M41T80_ALMON_AFE; 312 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 313 reg[M41T80_REG_ALARM_MON]) < 0) { 314 dev_err(&client->dev, "write error\n"); 315 return -EIO; 316 } 317 } 318 return 0; 319 } 320 321 static int m41t80_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *t) 322 { 323 struct i2c_client *client = to_i2c_client(dev); 324 u8 buf[M41T80_ALARM_REG_SIZE + 1]; /* all alarm regs and flags */ 325 u8 dt_addr[1] = { M41T80_REG_ALARM_MON }; 326 u8 *reg = buf - M41T80_REG_ALARM_MON; 327 struct i2c_msg msgs[] = { 328 { 329 .addr = client->addr, 330 .flags = 0, 331 .len = 1, 332 .buf = dt_addr, 333 }, 334 { 335 .addr = client->addr, 336 .flags = I2C_M_RD, 337 .len = M41T80_ALARM_REG_SIZE + 1, 338 .buf = buf, 339 }, 340 }; 341 342 if (i2c_transfer(client->adapter, msgs, 2) < 0) { 343 dev_err(&client->dev, "read error\n"); 344 return -EIO; 345 } 346 t->time.tm_sec = -1; 347 t->time.tm_min = -1; 348 t->time.tm_hour = -1; 349 t->time.tm_mday = -1; 350 t->time.tm_mon = -1; 351 if (!(reg[M41T80_REG_ALARM_SEC] & 0x80)) 352 t->time.tm_sec = bcd2bin(reg[M41T80_REG_ALARM_SEC] & 0x7f); 353 if (!(reg[M41T80_REG_ALARM_MIN] & 0x80)) 354 t->time.tm_min = bcd2bin(reg[M41T80_REG_ALARM_MIN] & 0x7f); 355 if (!(reg[M41T80_REG_ALARM_HOUR] & 0x80)) 356 t->time.tm_hour = bcd2bin(reg[M41T80_REG_ALARM_HOUR] & 0x3f); 357 if (!(reg[M41T80_REG_ALARM_DAY] & 0x80)) 358 t->time.tm_mday = bcd2bin(reg[M41T80_REG_ALARM_DAY] & 0x3f); 359 if (!(reg[M41T80_REG_ALARM_DAY] & 0x40)) 360 t->time.tm_mon = bcd2bin(reg[M41T80_REG_ALARM_MON] & 0x1f) - 1; 361 t->time.tm_year = -1; 362 t->time.tm_wday = -1; 363 t->time.tm_yday = -1; 364 t->time.tm_isdst = -1; 365 t->enabled = !!(reg[M41T80_REG_ALARM_MON] & M41T80_ALMON_AFE); 366 t->pending = !!(reg[M41T80_REG_FLAGS] & M41T80_FLAGS_AF); 367 return 0; 368 } 369 370 static struct rtc_class_ops m41t80_rtc_ops = { 371 .read_time = m41t80_rtc_read_time, 372 .set_time = m41t80_rtc_set_time, 373 .read_alarm = m41t80_rtc_read_alarm, 374 .set_alarm = m41t80_rtc_set_alarm, 375 .proc = m41t80_rtc_proc, 376 .ioctl = m41t80_rtc_ioctl, 377 }; 378 379 #if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE) 380 static ssize_t m41t80_sysfs_show_flags(struct device *dev, 381 struct device_attribute *attr, char *buf) 382 { 383 struct i2c_client *client = to_i2c_client(dev); 384 int val; 385 386 val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 387 if (val < 0) 388 return -EIO; 389 return sprintf(buf, "%#x\n", val); 390 } 391 static DEVICE_ATTR(flags, S_IRUGO, m41t80_sysfs_show_flags, NULL); 392 393 static ssize_t m41t80_sysfs_show_sqwfreq(struct device *dev, 394 struct device_attribute *attr, char *buf) 395 { 396 struct i2c_client *client = to_i2c_client(dev); 397 struct m41t80_data *clientdata = i2c_get_clientdata(client); 398 int val, reg_sqw; 399 400 if (!(clientdata->features & M41T80_FEATURE_SQ)) 401 return -EINVAL; 402 403 reg_sqw = M41T80_REG_SQW; 404 if (clientdata->features & M41T80_FEATURE_SQ_ALT) 405 reg_sqw = M41T80_REG_WDAY; 406 val = i2c_smbus_read_byte_data(client, reg_sqw); 407 if (val < 0) 408 return -EIO; 409 val = (val >> 4) & 0xf; 410 switch (val) { 411 case 0: 412 break; 413 case 1: 414 val = 32768; 415 break; 416 default: 417 val = 32768 >> val; 418 } 419 return sprintf(buf, "%d\n", val); 420 } 421 static ssize_t m41t80_sysfs_set_sqwfreq(struct device *dev, 422 struct device_attribute *attr, 423 const char *buf, size_t count) 424 { 425 struct i2c_client *client = to_i2c_client(dev); 426 struct m41t80_data *clientdata = i2c_get_clientdata(client); 427 int almon, sqw, reg_sqw; 428 int val = simple_strtoul(buf, NULL, 0); 429 430 if (!(clientdata->features & M41T80_FEATURE_SQ)) 431 return -EINVAL; 432 433 if (val) { 434 if (!is_power_of_2(val)) 435 return -EINVAL; 436 val = ilog2(val); 437 if (val == 15) 438 val = 1; 439 else if (val < 14) 440 val = 15 - val; 441 else 442 return -EINVAL; 443 } 444 /* disable SQW, set SQW frequency & re-enable */ 445 almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); 446 if (almon < 0) 447 return -EIO; 448 reg_sqw = M41T80_REG_SQW; 449 if (clientdata->features & M41T80_FEATURE_SQ_ALT) 450 reg_sqw = M41T80_REG_WDAY; 451 sqw = i2c_smbus_read_byte_data(client, reg_sqw); 452 if (sqw < 0) 453 return -EIO; 454 sqw = (sqw & 0x0f) | (val << 4); 455 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 456 almon & ~M41T80_ALMON_SQWE) < 0 || 457 i2c_smbus_write_byte_data(client, reg_sqw, sqw) < 0) 458 return -EIO; 459 if (val && i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 460 almon | M41T80_ALMON_SQWE) < 0) 461 return -EIO; 462 return count; 463 } 464 static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR, 465 m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq); 466 467 static struct attribute *attrs[] = { 468 &dev_attr_flags.attr, 469 &dev_attr_sqwfreq.attr, 470 NULL, 471 }; 472 static struct attribute_group attr_group = { 473 .attrs = attrs, 474 }; 475 476 static int m41t80_sysfs_register(struct device *dev) 477 { 478 return sysfs_create_group(&dev->kobj, &attr_group); 479 } 480 #else 481 static int m41t80_sysfs_register(struct device *dev) 482 { 483 return 0; 484 } 485 #endif 486 487 #ifdef CONFIG_RTC_DRV_M41T80_WDT 488 /* 489 ***************************************************************************** 490 * 491 * Watchdog Driver 492 * 493 ***************************************************************************** 494 */ 495 static struct i2c_client *save_client; 496 497 /* Default margin */ 498 #define WD_TIMO 60 /* 1..31 seconds */ 499 500 static int wdt_margin = WD_TIMO; 501 module_param(wdt_margin, int, 0); 502 MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)"); 503 504 static unsigned long wdt_is_open; 505 static int boot_flag; 506 507 /** 508 * wdt_ping: 509 * 510 * Reload counter one with the watchdog timeout. We don't bother reloading 511 * the cascade counter. 512 */ 513 static void wdt_ping(void) 514 { 515 unsigned char i2c_data[2]; 516 struct i2c_msg msgs1[1] = { 517 { 518 .addr = save_client->addr, 519 .flags = 0, 520 .len = 2, 521 .buf = i2c_data, 522 }, 523 }; 524 struct m41t80_data *clientdata = i2c_get_clientdata(save_client); 525 526 i2c_data[0] = 0x09; /* watchdog register */ 527 528 if (wdt_margin > 31) 529 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */ 530 else 531 /* 532 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02) 533 */ 534 i2c_data[1] = wdt_margin<<2 | 0x82; 535 536 /* 537 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as 538 * that would be an invalid resolution. 539 */ 540 if (clientdata->features & M41T80_FEATURE_WD) 541 i2c_data[1] &= ~M41T80_WATCHDOG_RB2; 542 543 i2c_transfer(save_client->adapter, msgs1, 1); 544 } 545 546 /** 547 * wdt_disable: 548 * 549 * disables watchdog. 550 */ 551 static void wdt_disable(void) 552 { 553 unsigned char i2c_data[2], i2c_buf[0x10]; 554 struct i2c_msg msgs0[2] = { 555 { 556 .addr = save_client->addr, 557 .flags = 0, 558 .len = 1, 559 .buf = i2c_data, 560 }, 561 { 562 .addr = save_client->addr, 563 .flags = I2C_M_RD, 564 .len = 1, 565 .buf = i2c_buf, 566 }, 567 }; 568 struct i2c_msg msgs1[1] = { 569 { 570 .addr = save_client->addr, 571 .flags = 0, 572 .len = 2, 573 .buf = i2c_data, 574 }, 575 }; 576 577 i2c_data[0] = 0x09; 578 i2c_transfer(save_client->adapter, msgs0, 2); 579 580 i2c_data[0] = 0x09; 581 i2c_data[1] = 0x00; 582 i2c_transfer(save_client->adapter, msgs1, 1); 583 } 584 585 /** 586 * wdt_write: 587 * @file: file handle to the watchdog 588 * @buf: buffer to write (unused as data does not matter here 589 * @count: count of bytes 590 * @ppos: pointer to the position to write. No seeks allowed 591 * 592 * A write to a watchdog device is defined as a keepalive signal. Any 593 * write of data will do, as we we don't define content meaning. 594 */ 595 static ssize_t wdt_write(struct file *file, const char __user *buf, 596 size_t count, loff_t *ppos) 597 { 598 /* Can't seek (pwrite) on this device 599 if (ppos != &file->f_pos) 600 return -ESPIPE; 601 */ 602 if (count) { 603 wdt_ping(); 604 return 1; 605 } 606 return 0; 607 } 608 609 static ssize_t wdt_read(struct file *file, char __user *buf, 610 size_t count, loff_t *ppos) 611 { 612 return 0; 613 } 614 615 /** 616 * wdt_ioctl: 617 * @inode: inode of the device 618 * @file: file handle to the device 619 * @cmd: watchdog command 620 * @arg: argument pointer 621 * 622 * The watchdog API defines a common set of functions for all watchdogs 623 * according to their available features. We only actually usefully support 624 * querying capabilities and current status. 625 */ 626 static int wdt_ioctl(struct file *file, unsigned int cmd, 627 unsigned long arg) 628 { 629 int new_margin, rv; 630 static struct watchdog_info ident = { 631 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING | 632 WDIOF_SETTIMEOUT, 633 .firmware_version = 1, 634 .identity = "M41T80 WTD" 635 }; 636 637 switch (cmd) { 638 case WDIOC_GETSUPPORT: 639 return copy_to_user((struct watchdog_info __user *)arg, &ident, 640 sizeof(ident)) ? -EFAULT : 0; 641 642 case WDIOC_GETSTATUS: 643 case WDIOC_GETBOOTSTATUS: 644 return put_user(boot_flag, (int __user *)arg); 645 case WDIOC_KEEPALIVE: 646 wdt_ping(); 647 return 0; 648 case WDIOC_SETTIMEOUT: 649 if (get_user(new_margin, (int __user *)arg)) 650 return -EFAULT; 651 /* Arbitrary, can't find the card's limits */ 652 if (new_margin < 1 || new_margin > 124) 653 return -EINVAL; 654 wdt_margin = new_margin; 655 wdt_ping(); 656 /* Fall */ 657 case WDIOC_GETTIMEOUT: 658 return put_user(wdt_margin, (int __user *)arg); 659 660 case WDIOC_SETOPTIONS: 661 if (copy_from_user(&rv, (int __user *)arg, sizeof(int))) 662 return -EFAULT; 663 664 if (rv & WDIOS_DISABLECARD) { 665 pr_info("rtc-m41t80: disable watchdog\n"); 666 wdt_disable(); 667 } 668 669 if (rv & WDIOS_ENABLECARD) { 670 pr_info("rtc-m41t80: enable watchdog\n"); 671 wdt_ping(); 672 } 673 674 return -EINVAL; 675 } 676 return -ENOTTY; 677 } 678 679 static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd, 680 unsigned long arg) 681 { 682 int ret; 683 684 lock_kernel(); 685 ret = wdt_ioctl(file, cmd, arg); 686 unlock_kernel(); 687 688 return ret; 689 } 690 691 /** 692 * wdt_open: 693 * @inode: inode of device 694 * @file: file handle to device 695 * 696 */ 697 static int wdt_open(struct inode *inode, struct file *file) 698 { 699 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) { 700 lock_kernel(); 701 if (test_and_set_bit(0, &wdt_is_open)) { 702 unlock_kernel(); 703 return -EBUSY; 704 } 705 /* 706 * Activate 707 */ 708 wdt_is_open = 1; 709 unlock_kernel(); 710 return 0; 711 } 712 return -ENODEV; 713 } 714 715 /** 716 * wdt_close: 717 * @inode: inode to board 718 * @file: file handle to board 719 * 720 */ 721 static int wdt_release(struct inode *inode, struct file *file) 722 { 723 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) 724 clear_bit(0, &wdt_is_open); 725 return 0; 726 } 727 728 /** 729 * notify_sys: 730 * @this: our notifier block 731 * @code: the event being reported 732 * @unused: unused 733 * 734 * Our notifier is called on system shutdowns. We want to turn the card 735 * off at reboot otherwise the machine will reboot again during memory 736 * test or worse yet during the following fsck. This would suck, in fact 737 * trust me - if it happens it does suck. 738 */ 739 static int wdt_notify_sys(struct notifier_block *this, unsigned long code, 740 void *unused) 741 { 742 if (code == SYS_DOWN || code == SYS_HALT) 743 /* Disable Watchdog */ 744 wdt_disable(); 745 return NOTIFY_DONE; 746 } 747 748 static const struct file_operations wdt_fops = { 749 .owner = THIS_MODULE, 750 .read = wdt_read, 751 .unlocked_ioctl = wdt_unlocked_ioctl, 752 .write = wdt_write, 753 .open = wdt_open, 754 .release = wdt_release, 755 }; 756 757 static struct miscdevice wdt_dev = { 758 .minor = WATCHDOG_MINOR, 759 .name = "watchdog", 760 .fops = &wdt_fops, 761 }; 762 763 /* 764 * The WDT card needs to learn about soft shutdowns in order to 765 * turn the timebomb registers off. 766 */ 767 static struct notifier_block wdt_notifier = { 768 .notifier_call = wdt_notify_sys, 769 }; 770 #endif /* CONFIG_RTC_DRV_M41T80_WDT */ 771 772 /* 773 ***************************************************************************** 774 * 775 * Driver Interface 776 * 777 ***************************************************************************** 778 */ 779 static int m41t80_probe(struct i2c_client *client, 780 const struct i2c_device_id *id) 781 { 782 int rc = 0; 783 struct rtc_device *rtc = NULL; 784 struct rtc_time tm; 785 struct m41t80_data *clientdata = NULL; 786 787 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C 788 | I2C_FUNC_SMBUS_BYTE_DATA)) { 789 rc = -ENODEV; 790 goto exit; 791 } 792 793 dev_info(&client->dev, 794 "chip found, driver version " DRV_VERSION "\n"); 795 796 clientdata = kzalloc(sizeof(*clientdata), GFP_KERNEL); 797 if (!clientdata) { 798 rc = -ENOMEM; 799 goto exit; 800 } 801 802 rtc = rtc_device_register(client->name, &client->dev, 803 &m41t80_rtc_ops, THIS_MODULE); 804 if (IS_ERR(rtc)) { 805 rc = PTR_ERR(rtc); 806 rtc = NULL; 807 goto exit; 808 } 809 810 clientdata->rtc = rtc; 811 clientdata->features = id->driver_data; 812 i2c_set_clientdata(client, clientdata); 813 814 /* Make sure HT (Halt Update) bit is cleared */ 815 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR); 816 if (rc < 0) 817 goto ht_err; 818 819 if (rc & M41T80_ALHOUR_HT) { 820 if (clientdata->features & M41T80_FEATURE_HT) { 821 m41t80_get_datetime(client, &tm); 822 dev_info(&client->dev, "HT bit was set!\n"); 823 dev_info(&client->dev, 824 "Power Down at " 825 "%04i-%02i-%02i %02i:%02i:%02i\n", 826 tm.tm_year + 1900, 827 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, 828 tm.tm_min, tm.tm_sec); 829 } 830 if (i2c_smbus_write_byte_data(client, 831 M41T80_REG_ALARM_HOUR, 832 rc & ~M41T80_ALHOUR_HT) < 0) 833 goto ht_err; 834 } 835 836 /* Make sure ST (stop) bit is cleared */ 837 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC); 838 if (rc < 0) 839 goto st_err; 840 841 if (rc & M41T80_SEC_ST) { 842 if (i2c_smbus_write_byte_data(client, M41T80_REG_SEC, 843 rc & ~M41T80_SEC_ST) < 0) 844 goto st_err; 845 } 846 847 rc = m41t80_sysfs_register(&client->dev); 848 if (rc) 849 goto exit; 850 851 #ifdef CONFIG_RTC_DRV_M41T80_WDT 852 if (clientdata->features & M41T80_FEATURE_HT) { 853 save_client = client; 854 rc = misc_register(&wdt_dev); 855 if (rc) 856 goto exit; 857 rc = register_reboot_notifier(&wdt_notifier); 858 if (rc) { 859 misc_deregister(&wdt_dev); 860 goto exit; 861 } 862 } 863 #endif 864 return 0; 865 866 st_err: 867 rc = -EIO; 868 dev_err(&client->dev, "Can't clear ST bit\n"); 869 goto exit; 870 ht_err: 871 rc = -EIO; 872 dev_err(&client->dev, "Can't clear HT bit\n"); 873 goto exit; 874 875 exit: 876 if (rtc) 877 rtc_device_unregister(rtc); 878 kfree(clientdata); 879 return rc; 880 } 881 882 static int m41t80_remove(struct i2c_client *client) 883 { 884 struct m41t80_data *clientdata = i2c_get_clientdata(client); 885 struct rtc_device *rtc = clientdata->rtc; 886 887 #ifdef CONFIG_RTC_DRV_M41T80_WDT 888 if (clientdata->features & M41T80_FEATURE_HT) { 889 misc_deregister(&wdt_dev); 890 unregister_reboot_notifier(&wdt_notifier); 891 } 892 #endif 893 if (rtc) 894 rtc_device_unregister(rtc); 895 kfree(clientdata); 896 897 return 0; 898 } 899 900 static struct i2c_driver m41t80_driver = { 901 .driver = { 902 .name = "rtc-m41t80", 903 }, 904 .probe = m41t80_probe, 905 .remove = m41t80_remove, 906 .id_table = m41t80_id, 907 }; 908 909 static int __init m41t80_rtc_init(void) 910 { 911 return i2c_add_driver(&m41t80_driver); 912 } 913 914 static void __exit m41t80_rtc_exit(void) 915 { 916 i2c_del_driver(&m41t80_driver); 917 } 918 919 MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>"); 920 MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver"); 921 MODULE_LICENSE("GPL"); 922 MODULE_VERSION(DRV_VERSION); 923 924 module_init(m41t80_rtc_init); 925 module_exit(m41t80_rtc_exit); 926