1 /* 2 * I2C client/driver for the ST M41T80 family of i2c rtc chips. 3 * 4 * Author: Alexander Bigga <ab@mycable.de> 5 * 6 * Based on m41t00.c by Mark A. Greer <mgreer@mvista.com> 7 * 8 * 2006 (c) mycable GmbH 9 * 10 * This program is free software; you can redistribute it and/or modify 11 * it under the terms of the GNU General Public License version 2 as 12 * published by the Free Software Foundation. 13 * 14 */ 15 16 #include <linux/bcd.h> 17 #include <linux/i2c.h> 18 #include <linux/init.h> 19 #include <linux/kernel.h> 20 #include <linux/module.h> 21 #include <linux/rtc.h> 22 #include <linux/slab.h> 23 #include <linux/mutex.h> 24 #include <linux/string.h> 25 #ifdef CONFIG_RTC_DRV_M41T80_WDT 26 #include <linux/fs.h> 27 #include <linux/ioctl.h> 28 #include <linux/miscdevice.h> 29 #include <linux/reboot.h> 30 #include <linux/watchdog.h> 31 #endif 32 33 #define M41T80_REG_SSEC 0 34 #define M41T80_REG_SEC 1 35 #define M41T80_REG_MIN 2 36 #define M41T80_REG_HOUR 3 37 #define M41T80_REG_WDAY 4 38 #define M41T80_REG_DAY 5 39 #define M41T80_REG_MON 6 40 #define M41T80_REG_YEAR 7 41 #define M41T80_REG_ALARM_MON 0xa 42 #define M41T80_REG_ALARM_DAY 0xb 43 #define M41T80_REG_ALARM_HOUR 0xc 44 #define M41T80_REG_ALARM_MIN 0xd 45 #define M41T80_REG_ALARM_SEC 0xe 46 #define M41T80_REG_FLAGS 0xf 47 #define M41T80_REG_SQW 0x13 48 49 #define M41T80_DATETIME_REG_SIZE (M41T80_REG_YEAR + 1) 50 #define M41T80_ALARM_REG_SIZE \ 51 (M41T80_REG_ALARM_SEC + 1 - M41T80_REG_ALARM_MON) 52 53 #define M41T80_SEC_ST (1 << 7) /* ST: Stop Bit */ 54 #define M41T80_ALMON_AFE (1 << 7) /* AFE: AF Enable Bit */ 55 #define M41T80_ALMON_SQWE (1 << 6) /* SQWE: SQW Enable Bit */ 56 #define M41T80_ALHOUR_HT (1 << 6) /* HT: Halt Update Bit */ 57 #define M41T80_FLAGS_AF (1 << 6) /* AF: Alarm Flag Bit */ 58 #define M41T80_FLAGS_BATT_LOW (1 << 4) /* BL: Battery Low Bit */ 59 #define M41T80_WATCHDOG_RB2 (1 << 7) /* RB: Watchdog resolution */ 60 #define M41T80_WATCHDOG_RB1 (1 << 1) /* RB: Watchdog resolution */ 61 #define M41T80_WATCHDOG_RB0 (1 << 0) /* RB: Watchdog resolution */ 62 63 #define M41T80_FEATURE_HT (1 << 0) /* Halt feature */ 64 #define M41T80_FEATURE_BL (1 << 1) /* Battery low indicator */ 65 #define M41T80_FEATURE_SQ (1 << 2) /* Squarewave feature */ 66 #define M41T80_FEATURE_WD (1 << 3) /* Extra watchdog resolution */ 67 #define M41T80_FEATURE_SQ_ALT (1 << 4) /* RSx bits are in reg 4 */ 68 69 #define DRV_VERSION "0.05" 70 71 static DEFINE_MUTEX(m41t80_rtc_mutex); 72 static const struct i2c_device_id m41t80_id[] = { 73 { "m41t62", M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT }, 74 { "m41t65", M41T80_FEATURE_HT | M41T80_FEATURE_WD }, 75 { "m41t80", M41T80_FEATURE_SQ }, 76 { "m41t81", M41T80_FEATURE_HT | M41T80_FEATURE_SQ}, 77 { "m41t81s", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 78 { "m41t82", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 79 { "m41t83", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 80 { "m41st84", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 81 { "m41st85", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 82 { "m41st87", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 83 { } 84 }; 85 MODULE_DEVICE_TABLE(i2c, m41t80_id); 86 87 struct m41t80_data { 88 u8 features; 89 struct rtc_device *rtc; 90 }; 91 92 static int m41t80_get_datetime(struct i2c_client *client, 93 struct rtc_time *tm) 94 { 95 u8 buf[M41T80_DATETIME_REG_SIZE], dt_addr[1] = { M41T80_REG_SEC }; 96 struct i2c_msg msgs[] = { 97 { 98 .addr = client->addr, 99 .flags = 0, 100 .len = 1, 101 .buf = dt_addr, 102 }, 103 { 104 .addr = client->addr, 105 .flags = I2C_M_RD, 106 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC, 107 .buf = buf + M41T80_REG_SEC, 108 }, 109 }; 110 111 if (i2c_transfer(client->adapter, msgs, 2) < 0) { 112 dev_err(&client->dev, "read error\n"); 113 return -EIO; 114 } 115 116 tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f); 117 tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f); 118 tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f); 119 tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f); 120 tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07; 121 tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1; 122 123 /* assume 20YY not 19YY, and ignore the Century Bit */ 124 tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100; 125 return rtc_valid_tm(tm); 126 } 127 128 /* Sets the given date and time to the real time clock. */ 129 static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm) 130 { 131 u8 wbuf[1 + M41T80_DATETIME_REG_SIZE]; 132 u8 *buf = &wbuf[1]; 133 u8 dt_addr[1] = { M41T80_REG_SEC }; 134 struct i2c_msg msgs_in[] = { 135 { 136 .addr = client->addr, 137 .flags = 0, 138 .len = 1, 139 .buf = dt_addr, 140 }, 141 { 142 .addr = client->addr, 143 .flags = I2C_M_RD, 144 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC, 145 .buf = buf + M41T80_REG_SEC, 146 }, 147 }; 148 struct i2c_msg msgs[] = { 149 { 150 .addr = client->addr, 151 .flags = 0, 152 .len = 1 + M41T80_DATETIME_REG_SIZE, 153 .buf = wbuf, 154 }, 155 }; 156 157 /* Read current reg values into buf[1..7] */ 158 if (i2c_transfer(client->adapter, msgs_in, 2) < 0) { 159 dev_err(&client->dev, "read error\n"); 160 return -EIO; 161 } 162 163 wbuf[0] = 0; /* offset into rtc's regs */ 164 /* Merge time-data and register flags into buf[0..7] */ 165 buf[M41T80_REG_SSEC] = 0; 166 buf[M41T80_REG_SEC] = 167 bin2bcd(tm->tm_sec) | (buf[M41T80_REG_SEC] & ~0x7f); 168 buf[M41T80_REG_MIN] = 169 bin2bcd(tm->tm_min) | (buf[M41T80_REG_MIN] & ~0x7f); 170 buf[M41T80_REG_HOUR] = 171 bin2bcd(tm->tm_hour) | (buf[M41T80_REG_HOUR] & ~0x3f) ; 172 buf[M41T80_REG_WDAY] = 173 (tm->tm_wday & 0x07) | (buf[M41T80_REG_WDAY] & ~0x07); 174 buf[M41T80_REG_DAY] = 175 bin2bcd(tm->tm_mday) | (buf[M41T80_REG_DAY] & ~0x3f); 176 buf[M41T80_REG_MON] = 177 bin2bcd(tm->tm_mon + 1) | (buf[M41T80_REG_MON] & ~0x1f); 178 /* assume 20YY not 19YY */ 179 buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year % 100); 180 181 if (i2c_transfer(client->adapter, msgs, 1) != 1) { 182 dev_err(&client->dev, "write error\n"); 183 return -EIO; 184 } 185 return 0; 186 } 187 188 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE) 189 static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq) 190 { 191 struct i2c_client *client = to_i2c_client(dev); 192 struct m41t80_data *clientdata = i2c_get_clientdata(client); 193 u8 reg; 194 195 if (clientdata->features & M41T80_FEATURE_BL) { 196 reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 197 seq_printf(seq, "battery\t\t: %s\n", 198 (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok"); 199 } 200 return 0; 201 } 202 #else 203 #define m41t80_rtc_proc NULL 204 #endif 205 206 static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm) 207 { 208 return m41t80_get_datetime(to_i2c_client(dev), tm); 209 } 210 211 static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm) 212 { 213 return m41t80_set_datetime(to_i2c_client(dev), tm); 214 } 215 216 static 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; 234 err: 235 return -EIO; 236 } 237 238 static 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 } 307 308 static 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 } 356 357 static struct rtc_class_ops m41t80_rtc_ops = { 358 .read_time = m41t80_rtc_read_time, 359 .set_time = m41t80_rtc_set_time, 360 .read_alarm = m41t80_rtc_read_alarm, 361 .set_alarm = m41t80_rtc_set_alarm, 362 .proc = m41t80_rtc_proc, 363 .alarm_irq_enable = m41t80_rtc_alarm_irq_enable, 364 }; 365 366 #if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE) 367 static ssize_t m41t80_sysfs_show_flags(struct device *dev, 368 struct device_attribute *attr, char *buf) 369 { 370 struct i2c_client *client = to_i2c_client(dev); 371 int val; 372 373 val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 374 if (val < 0) 375 return -EIO; 376 return sprintf(buf, "%#x\n", val); 377 } 378 static DEVICE_ATTR(flags, S_IRUGO, m41t80_sysfs_show_flags, NULL); 379 380 static ssize_t m41t80_sysfs_show_sqwfreq(struct device *dev, 381 struct device_attribute *attr, char *buf) 382 { 383 struct i2c_client *client = to_i2c_client(dev); 384 struct m41t80_data *clientdata = i2c_get_clientdata(client); 385 int val, reg_sqw; 386 387 if (!(clientdata->features & M41T80_FEATURE_SQ)) 388 return -EINVAL; 389 390 reg_sqw = M41T80_REG_SQW; 391 if (clientdata->features & M41T80_FEATURE_SQ_ALT) 392 reg_sqw = M41T80_REG_WDAY; 393 val = i2c_smbus_read_byte_data(client, reg_sqw); 394 if (val < 0) 395 return -EIO; 396 val = (val >> 4) & 0xf; 397 switch (val) { 398 case 0: 399 break; 400 case 1: 401 val = 32768; 402 break; 403 default: 404 val = 32768 >> val; 405 } 406 return sprintf(buf, "%d\n", val); 407 } 408 static ssize_t m41t80_sysfs_set_sqwfreq(struct device *dev, 409 struct device_attribute *attr, 410 const char *buf, size_t count) 411 { 412 struct i2c_client *client = to_i2c_client(dev); 413 struct m41t80_data *clientdata = i2c_get_clientdata(client); 414 int almon, sqw, reg_sqw; 415 int val = simple_strtoul(buf, NULL, 0); 416 417 if (!(clientdata->features & M41T80_FEATURE_SQ)) 418 return -EINVAL; 419 420 if (val) { 421 if (!is_power_of_2(val)) 422 return -EINVAL; 423 val = ilog2(val); 424 if (val == 15) 425 val = 1; 426 else if (val < 14) 427 val = 15 - val; 428 else 429 return -EINVAL; 430 } 431 /* disable SQW, set SQW frequency & re-enable */ 432 almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); 433 if (almon < 0) 434 return -EIO; 435 reg_sqw = M41T80_REG_SQW; 436 if (clientdata->features & M41T80_FEATURE_SQ_ALT) 437 reg_sqw = M41T80_REG_WDAY; 438 sqw = i2c_smbus_read_byte_data(client, reg_sqw); 439 if (sqw < 0) 440 return -EIO; 441 sqw = (sqw & 0x0f) | (val << 4); 442 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 443 almon & ~M41T80_ALMON_SQWE) < 0 || 444 i2c_smbus_write_byte_data(client, reg_sqw, sqw) < 0) 445 return -EIO; 446 if (val && i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 447 almon | M41T80_ALMON_SQWE) < 0) 448 return -EIO; 449 return count; 450 } 451 static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR, 452 m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq); 453 454 static struct attribute *attrs[] = { 455 &dev_attr_flags.attr, 456 &dev_attr_sqwfreq.attr, 457 NULL, 458 }; 459 static struct attribute_group attr_group = { 460 .attrs = attrs, 461 }; 462 463 static int m41t80_sysfs_register(struct device *dev) 464 { 465 return sysfs_create_group(&dev->kobj, &attr_group); 466 } 467 #else 468 static int m41t80_sysfs_register(struct device *dev) 469 { 470 return 0; 471 } 472 #endif 473 474 #ifdef CONFIG_RTC_DRV_M41T80_WDT 475 /* 476 ***************************************************************************** 477 * 478 * Watchdog Driver 479 * 480 ***************************************************************************** 481 */ 482 static struct i2c_client *save_client; 483 484 /* Default margin */ 485 #define WD_TIMO 60 /* 1..31 seconds */ 486 487 static int wdt_margin = WD_TIMO; 488 module_param(wdt_margin, int, 0); 489 MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)"); 490 491 static unsigned long wdt_is_open; 492 static int boot_flag; 493 494 /** 495 * wdt_ping: 496 * 497 * Reload counter one with the watchdog timeout. We don't bother reloading 498 * the cascade counter. 499 */ 500 static void wdt_ping(void) 501 { 502 unsigned char i2c_data[2]; 503 struct i2c_msg msgs1[1] = { 504 { 505 .addr = save_client->addr, 506 .flags = 0, 507 .len = 2, 508 .buf = i2c_data, 509 }, 510 }; 511 struct m41t80_data *clientdata = i2c_get_clientdata(save_client); 512 513 i2c_data[0] = 0x09; /* watchdog register */ 514 515 if (wdt_margin > 31) 516 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */ 517 else 518 /* 519 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02) 520 */ 521 i2c_data[1] = wdt_margin<<2 | 0x82; 522 523 /* 524 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as 525 * that would be an invalid resolution. 526 */ 527 if (clientdata->features & M41T80_FEATURE_WD) 528 i2c_data[1] &= ~M41T80_WATCHDOG_RB2; 529 530 i2c_transfer(save_client->adapter, msgs1, 1); 531 } 532 533 /** 534 * wdt_disable: 535 * 536 * disables watchdog. 537 */ 538 static void wdt_disable(void) 539 { 540 unsigned char i2c_data[2], i2c_buf[0x10]; 541 struct i2c_msg msgs0[2] = { 542 { 543 .addr = save_client->addr, 544 .flags = 0, 545 .len = 1, 546 .buf = i2c_data, 547 }, 548 { 549 .addr = save_client->addr, 550 .flags = I2C_M_RD, 551 .len = 1, 552 .buf = i2c_buf, 553 }, 554 }; 555 struct i2c_msg msgs1[1] = { 556 { 557 .addr = save_client->addr, 558 .flags = 0, 559 .len = 2, 560 .buf = i2c_data, 561 }, 562 }; 563 564 i2c_data[0] = 0x09; 565 i2c_transfer(save_client->adapter, msgs0, 2); 566 567 i2c_data[0] = 0x09; 568 i2c_data[1] = 0x00; 569 i2c_transfer(save_client->adapter, msgs1, 1); 570 } 571 572 /** 573 * wdt_write: 574 * @file: file handle to the watchdog 575 * @buf: buffer to write (unused as data does not matter here 576 * @count: count of bytes 577 * @ppos: pointer to the position to write. No seeks allowed 578 * 579 * A write to a watchdog device is defined as a keepalive signal. Any 580 * write of data will do, as we we don't define content meaning. 581 */ 582 static ssize_t wdt_write(struct file *file, const char __user *buf, 583 size_t count, loff_t *ppos) 584 { 585 if (count) { 586 wdt_ping(); 587 return 1; 588 } 589 return 0; 590 } 591 592 static ssize_t wdt_read(struct file *file, char __user *buf, 593 size_t count, loff_t *ppos) 594 { 595 return 0; 596 } 597 598 /** 599 * wdt_ioctl: 600 * @inode: inode of the device 601 * @file: file handle to the device 602 * @cmd: watchdog command 603 * @arg: argument pointer 604 * 605 * The watchdog API defines a common set of functions for all watchdogs 606 * according to their available features. We only actually usefully support 607 * querying capabilities and current status. 608 */ 609 static int wdt_ioctl(struct file *file, unsigned int cmd, 610 unsigned long arg) 611 { 612 int new_margin, rv; 613 static struct watchdog_info ident = { 614 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING | 615 WDIOF_SETTIMEOUT, 616 .firmware_version = 1, 617 .identity = "M41T80 WTD" 618 }; 619 620 switch (cmd) { 621 case WDIOC_GETSUPPORT: 622 return copy_to_user((struct watchdog_info __user *)arg, &ident, 623 sizeof(ident)) ? -EFAULT : 0; 624 625 case WDIOC_GETSTATUS: 626 case WDIOC_GETBOOTSTATUS: 627 return put_user(boot_flag, (int __user *)arg); 628 case WDIOC_KEEPALIVE: 629 wdt_ping(); 630 return 0; 631 case WDIOC_SETTIMEOUT: 632 if (get_user(new_margin, (int __user *)arg)) 633 return -EFAULT; 634 /* Arbitrary, can't find the card's limits */ 635 if (new_margin < 1 || new_margin > 124) 636 return -EINVAL; 637 wdt_margin = new_margin; 638 wdt_ping(); 639 /* Fall */ 640 case WDIOC_GETTIMEOUT: 641 return put_user(wdt_margin, (int __user *)arg); 642 643 case WDIOC_SETOPTIONS: 644 if (copy_from_user(&rv, (int __user *)arg, sizeof(int))) 645 return -EFAULT; 646 647 if (rv & WDIOS_DISABLECARD) { 648 pr_info("rtc-m41t80: disable watchdog\n"); 649 wdt_disable(); 650 } 651 652 if (rv & WDIOS_ENABLECARD) { 653 pr_info("rtc-m41t80: enable watchdog\n"); 654 wdt_ping(); 655 } 656 657 return -EINVAL; 658 } 659 return -ENOTTY; 660 } 661 662 static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd, 663 unsigned long arg) 664 { 665 int ret; 666 667 mutex_lock(&m41t80_rtc_mutex); 668 ret = wdt_ioctl(file, cmd, arg); 669 mutex_unlock(&m41t80_rtc_mutex); 670 671 return ret; 672 } 673 674 /** 675 * wdt_open: 676 * @inode: inode of device 677 * @file: file handle to device 678 * 679 */ 680 static int wdt_open(struct inode *inode, struct file *file) 681 { 682 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) { 683 mutex_lock(&m41t80_rtc_mutex); 684 if (test_and_set_bit(0, &wdt_is_open)) { 685 mutex_unlock(&m41t80_rtc_mutex); 686 return -EBUSY; 687 } 688 /* 689 * Activate 690 */ 691 wdt_is_open = 1; 692 mutex_unlock(&m41t80_rtc_mutex); 693 return nonseekable_open(inode, file); 694 } 695 return -ENODEV; 696 } 697 698 /** 699 * wdt_close: 700 * @inode: inode to board 701 * @file: file handle to board 702 * 703 */ 704 static int wdt_release(struct inode *inode, struct file *file) 705 { 706 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) 707 clear_bit(0, &wdt_is_open); 708 return 0; 709 } 710 711 /** 712 * notify_sys: 713 * @this: our notifier block 714 * @code: the event being reported 715 * @unused: unused 716 * 717 * Our notifier is called on system shutdowns. We want to turn the card 718 * off at reboot otherwise the machine will reboot again during memory 719 * test or worse yet during the following fsck. This would suck, in fact 720 * trust me - if it happens it does suck. 721 */ 722 static int wdt_notify_sys(struct notifier_block *this, unsigned long code, 723 void *unused) 724 { 725 if (code == SYS_DOWN || code == SYS_HALT) 726 /* Disable Watchdog */ 727 wdt_disable(); 728 return NOTIFY_DONE; 729 } 730 731 static const struct file_operations wdt_fops = { 732 .owner = THIS_MODULE, 733 .read = wdt_read, 734 .unlocked_ioctl = wdt_unlocked_ioctl, 735 .write = wdt_write, 736 .open = wdt_open, 737 .release = wdt_release, 738 .llseek = no_llseek, 739 }; 740 741 static struct miscdevice wdt_dev = { 742 .minor = WATCHDOG_MINOR, 743 .name = "watchdog", 744 .fops = &wdt_fops, 745 }; 746 747 /* 748 * The WDT card needs to learn about soft shutdowns in order to 749 * turn the timebomb registers off. 750 */ 751 static struct notifier_block wdt_notifier = { 752 .notifier_call = wdt_notify_sys, 753 }; 754 #endif /* CONFIG_RTC_DRV_M41T80_WDT */ 755 756 /* 757 ***************************************************************************** 758 * 759 * Driver Interface 760 * 761 ***************************************************************************** 762 */ 763 static int m41t80_probe(struct i2c_client *client, 764 const struct i2c_device_id *id) 765 { 766 int rc = 0; 767 struct rtc_device *rtc = NULL; 768 struct rtc_time tm; 769 struct m41t80_data *clientdata = NULL; 770 771 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C 772 | I2C_FUNC_SMBUS_BYTE_DATA)) { 773 rc = -ENODEV; 774 goto exit; 775 } 776 777 dev_info(&client->dev, 778 "chip found, driver version " DRV_VERSION "\n"); 779 780 clientdata = kzalloc(sizeof(*clientdata), GFP_KERNEL); 781 if (!clientdata) { 782 rc = -ENOMEM; 783 goto exit; 784 } 785 786 rtc = rtc_device_register(client->name, &client->dev, 787 &m41t80_rtc_ops, THIS_MODULE); 788 if (IS_ERR(rtc)) { 789 rc = PTR_ERR(rtc); 790 rtc = NULL; 791 goto exit; 792 } 793 794 clientdata->rtc = rtc; 795 clientdata->features = id->driver_data; 796 i2c_set_clientdata(client, clientdata); 797 798 /* Make sure HT (Halt Update) bit is cleared */ 799 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR); 800 if (rc < 0) 801 goto ht_err; 802 803 if (rc & M41T80_ALHOUR_HT) { 804 if (clientdata->features & M41T80_FEATURE_HT) { 805 m41t80_get_datetime(client, &tm); 806 dev_info(&client->dev, "HT bit was set!\n"); 807 dev_info(&client->dev, 808 "Power Down at " 809 "%04i-%02i-%02i %02i:%02i:%02i\n", 810 tm.tm_year + 1900, 811 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, 812 tm.tm_min, tm.tm_sec); 813 } 814 if (i2c_smbus_write_byte_data(client, 815 M41T80_REG_ALARM_HOUR, 816 rc & ~M41T80_ALHOUR_HT) < 0) 817 goto ht_err; 818 } 819 820 /* Make sure ST (stop) bit is cleared */ 821 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC); 822 if (rc < 0) 823 goto st_err; 824 825 if (rc & M41T80_SEC_ST) { 826 if (i2c_smbus_write_byte_data(client, M41T80_REG_SEC, 827 rc & ~M41T80_SEC_ST) < 0) 828 goto st_err; 829 } 830 831 rc = m41t80_sysfs_register(&client->dev); 832 if (rc) 833 goto exit; 834 835 #ifdef CONFIG_RTC_DRV_M41T80_WDT 836 if (clientdata->features & M41T80_FEATURE_HT) { 837 save_client = client; 838 rc = misc_register(&wdt_dev); 839 if (rc) 840 goto exit; 841 rc = register_reboot_notifier(&wdt_notifier); 842 if (rc) { 843 misc_deregister(&wdt_dev); 844 goto exit; 845 } 846 } 847 #endif 848 return 0; 849 850 st_err: 851 rc = -EIO; 852 dev_err(&client->dev, "Can't clear ST bit\n"); 853 goto exit; 854 ht_err: 855 rc = -EIO; 856 dev_err(&client->dev, "Can't clear HT bit\n"); 857 goto exit; 858 859 exit: 860 if (rtc) 861 rtc_device_unregister(rtc); 862 kfree(clientdata); 863 return rc; 864 } 865 866 static int m41t80_remove(struct i2c_client *client) 867 { 868 struct m41t80_data *clientdata = i2c_get_clientdata(client); 869 struct rtc_device *rtc = clientdata->rtc; 870 871 #ifdef CONFIG_RTC_DRV_M41T80_WDT 872 if (clientdata->features & M41T80_FEATURE_HT) { 873 misc_deregister(&wdt_dev); 874 unregister_reboot_notifier(&wdt_notifier); 875 } 876 #endif 877 if (rtc) 878 rtc_device_unregister(rtc); 879 kfree(clientdata); 880 881 return 0; 882 } 883 884 static struct i2c_driver m41t80_driver = { 885 .driver = { 886 .name = "rtc-m41t80", 887 }, 888 .probe = m41t80_probe, 889 .remove = m41t80_remove, 890 .id_table = m41t80_id, 891 }; 892 893 static int __init m41t80_rtc_init(void) 894 { 895 return i2c_add_driver(&m41t80_driver); 896 } 897 898 static void __exit m41t80_rtc_exit(void) 899 { 900 i2c_del_driver(&m41t80_driver); 901 } 902 903 MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>"); 904 MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver"); 905 MODULE_LICENSE("GPL"); 906 MODULE_VERSION(DRV_VERSION); 907 908 module_init(m41t80_rtc_init); 909 module_exit(m41t80_rtc_exit); 910