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 #if defined(CONFIG_RTC_INTF_DEV) || defined(CONFIG_RTC_INTF_DEV_MODULE) 217 static int 218 m41t80_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) 219 { 220 struct i2c_client *client = to_i2c_client(dev); 221 int rc; 222 223 switch (cmd) { 224 case RTC_AIE_OFF: 225 case RTC_AIE_ON: 226 break; 227 default: 228 return -ENOIOCTLCMD; 229 } 230 231 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); 232 if (rc < 0) 233 goto err; 234 switch (cmd) { 235 case RTC_AIE_OFF: 236 rc &= ~M41T80_ALMON_AFE; 237 break; 238 case RTC_AIE_ON: 239 rc |= M41T80_ALMON_AFE; 240 break; 241 } 242 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, rc) < 0) 243 goto err; 244 return 0; 245 err: 246 return -EIO; 247 } 248 #else 249 #define m41t80_rtc_ioctl NULL 250 #endif 251 252 static int m41t80_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *t) 253 { 254 struct i2c_client *client = to_i2c_client(dev); 255 u8 wbuf[1 + M41T80_ALARM_REG_SIZE]; 256 u8 *buf = &wbuf[1]; 257 u8 *reg = buf - M41T80_REG_ALARM_MON; 258 u8 dt_addr[1] = { M41T80_REG_ALARM_MON }; 259 struct i2c_msg msgs_in[] = { 260 { 261 .addr = client->addr, 262 .flags = 0, 263 .len = 1, 264 .buf = dt_addr, 265 }, 266 { 267 .addr = client->addr, 268 .flags = I2C_M_RD, 269 .len = M41T80_ALARM_REG_SIZE, 270 .buf = buf, 271 }, 272 }; 273 struct i2c_msg msgs[] = { 274 { 275 .addr = client->addr, 276 .flags = 0, 277 .len = 1 + M41T80_ALARM_REG_SIZE, 278 .buf = wbuf, 279 }, 280 }; 281 282 if (i2c_transfer(client->adapter, msgs_in, 2) < 0) { 283 dev_err(&client->dev, "read error\n"); 284 return -EIO; 285 } 286 reg[M41T80_REG_ALARM_MON] &= ~(0x1f | M41T80_ALMON_AFE); 287 reg[M41T80_REG_ALARM_DAY] = 0; 288 reg[M41T80_REG_ALARM_HOUR] &= ~(0x3f | 0x80); 289 reg[M41T80_REG_ALARM_MIN] = 0; 290 reg[M41T80_REG_ALARM_SEC] = 0; 291 292 wbuf[0] = M41T80_REG_ALARM_MON; /* offset into rtc's regs */ 293 reg[M41T80_REG_ALARM_SEC] |= t->time.tm_sec >= 0 ? 294 bin2bcd(t->time.tm_sec) : 0x80; 295 reg[M41T80_REG_ALARM_MIN] |= t->time.tm_min >= 0 ? 296 bin2bcd(t->time.tm_min) : 0x80; 297 reg[M41T80_REG_ALARM_HOUR] |= t->time.tm_hour >= 0 ? 298 bin2bcd(t->time.tm_hour) : 0x80; 299 reg[M41T80_REG_ALARM_DAY] |= t->time.tm_mday >= 0 ? 300 bin2bcd(t->time.tm_mday) : 0x80; 301 if (t->time.tm_mon >= 0) 302 reg[M41T80_REG_ALARM_MON] |= bin2bcd(t->time.tm_mon + 1); 303 else 304 reg[M41T80_REG_ALARM_DAY] |= 0x40; 305 306 if (i2c_transfer(client->adapter, msgs, 1) != 1) { 307 dev_err(&client->dev, "write error\n"); 308 return -EIO; 309 } 310 311 if (t->enabled) { 312 reg[M41T80_REG_ALARM_MON] |= M41T80_ALMON_AFE; 313 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 314 reg[M41T80_REG_ALARM_MON]) < 0) { 315 dev_err(&client->dev, "write error\n"); 316 return -EIO; 317 } 318 } 319 return 0; 320 } 321 322 static int m41t80_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *t) 323 { 324 struct i2c_client *client = to_i2c_client(dev); 325 u8 buf[M41T80_ALARM_REG_SIZE + 1]; /* all alarm regs and flags */ 326 u8 dt_addr[1] = { M41T80_REG_ALARM_MON }; 327 u8 *reg = buf - M41T80_REG_ALARM_MON; 328 struct i2c_msg msgs[] = { 329 { 330 .addr = client->addr, 331 .flags = 0, 332 .len = 1, 333 .buf = dt_addr, 334 }, 335 { 336 .addr = client->addr, 337 .flags = I2C_M_RD, 338 .len = M41T80_ALARM_REG_SIZE + 1, 339 .buf = buf, 340 }, 341 }; 342 343 if (i2c_transfer(client->adapter, msgs, 2) < 0) { 344 dev_err(&client->dev, "read error\n"); 345 return -EIO; 346 } 347 t->time.tm_sec = -1; 348 t->time.tm_min = -1; 349 t->time.tm_hour = -1; 350 t->time.tm_mday = -1; 351 t->time.tm_mon = -1; 352 if (!(reg[M41T80_REG_ALARM_SEC] & 0x80)) 353 t->time.tm_sec = bcd2bin(reg[M41T80_REG_ALARM_SEC] & 0x7f); 354 if (!(reg[M41T80_REG_ALARM_MIN] & 0x80)) 355 t->time.tm_min = bcd2bin(reg[M41T80_REG_ALARM_MIN] & 0x7f); 356 if (!(reg[M41T80_REG_ALARM_HOUR] & 0x80)) 357 t->time.tm_hour = bcd2bin(reg[M41T80_REG_ALARM_HOUR] & 0x3f); 358 if (!(reg[M41T80_REG_ALARM_DAY] & 0x80)) 359 t->time.tm_mday = bcd2bin(reg[M41T80_REG_ALARM_DAY] & 0x3f); 360 if (!(reg[M41T80_REG_ALARM_DAY] & 0x40)) 361 t->time.tm_mon = bcd2bin(reg[M41T80_REG_ALARM_MON] & 0x1f) - 1; 362 t->time.tm_year = -1; 363 t->time.tm_wday = -1; 364 t->time.tm_yday = -1; 365 t->time.tm_isdst = -1; 366 t->enabled = !!(reg[M41T80_REG_ALARM_MON] & M41T80_ALMON_AFE); 367 t->pending = !!(reg[M41T80_REG_FLAGS] & M41T80_FLAGS_AF); 368 return 0; 369 } 370 371 static struct rtc_class_ops m41t80_rtc_ops = { 372 .read_time = m41t80_rtc_read_time, 373 .set_time = m41t80_rtc_set_time, 374 .read_alarm = m41t80_rtc_read_alarm, 375 .set_alarm = m41t80_rtc_set_alarm, 376 .proc = m41t80_rtc_proc, 377 .ioctl = m41t80_rtc_ioctl, 378 }; 379 380 #if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE) 381 static ssize_t m41t80_sysfs_show_flags(struct device *dev, 382 struct device_attribute *attr, char *buf) 383 { 384 struct i2c_client *client = to_i2c_client(dev); 385 int val; 386 387 val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 388 if (val < 0) 389 return -EIO; 390 return sprintf(buf, "%#x\n", val); 391 } 392 static DEVICE_ATTR(flags, S_IRUGO, m41t80_sysfs_show_flags, NULL); 393 394 static ssize_t m41t80_sysfs_show_sqwfreq(struct device *dev, 395 struct device_attribute *attr, char *buf) 396 { 397 struct i2c_client *client = to_i2c_client(dev); 398 struct m41t80_data *clientdata = i2c_get_clientdata(client); 399 int val, reg_sqw; 400 401 if (!(clientdata->features & M41T80_FEATURE_SQ)) 402 return -EINVAL; 403 404 reg_sqw = M41T80_REG_SQW; 405 if (clientdata->features & M41T80_FEATURE_SQ_ALT) 406 reg_sqw = M41T80_REG_WDAY; 407 val = i2c_smbus_read_byte_data(client, reg_sqw); 408 if (val < 0) 409 return -EIO; 410 val = (val >> 4) & 0xf; 411 switch (val) { 412 case 0: 413 break; 414 case 1: 415 val = 32768; 416 break; 417 default: 418 val = 32768 >> val; 419 } 420 return sprintf(buf, "%d\n", val); 421 } 422 static ssize_t m41t80_sysfs_set_sqwfreq(struct device *dev, 423 struct device_attribute *attr, 424 const char *buf, size_t count) 425 { 426 struct i2c_client *client = to_i2c_client(dev); 427 struct m41t80_data *clientdata = i2c_get_clientdata(client); 428 int almon, sqw, reg_sqw; 429 int val = simple_strtoul(buf, NULL, 0); 430 431 if (!(clientdata->features & M41T80_FEATURE_SQ)) 432 return -EINVAL; 433 434 if (val) { 435 if (!is_power_of_2(val)) 436 return -EINVAL; 437 val = ilog2(val); 438 if (val == 15) 439 val = 1; 440 else if (val < 14) 441 val = 15 - val; 442 else 443 return -EINVAL; 444 } 445 /* disable SQW, set SQW frequency & re-enable */ 446 almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); 447 if (almon < 0) 448 return -EIO; 449 reg_sqw = M41T80_REG_SQW; 450 if (clientdata->features & M41T80_FEATURE_SQ_ALT) 451 reg_sqw = M41T80_REG_WDAY; 452 sqw = i2c_smbus_read_byte_data(client, reg_sqw); 453 if (sqw < 0) 454 return -EIO; 455 sqw = (sqw & 0x0f) | (val << 4); 456 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 457 almon & ~M41T80_ALMON_SQWE) < 0 || 458 i2c_smbus_write_byte_data(client, reg_sqw, sqw) < 0) 459 return -EIO; 460 if (val && i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 461 almon | M41T80_ALMON_SQWE) < 0) 462 return -EIO; 463 return count; 464 } 465 static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR, 466 m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq); 467 468 static struct attribute *attrs[] = { 469 &dev_attr_flags.attr, 470 &dev_attr_sqwfreq.attr, 471 NULL, 472 }; 473 static struct attribute_group attr_group = { 474 .attrs = attrs, 475 }; 476 477 static int m41t80_sysfs_register(struct device *dev) 478 { 479 return sysfs_create_group(&dev->kobj, &attr_group); 480 } 481 #else 482 static int m41t80_sysfs_register(struct device *dev) 483 { 484 return 0; 485 } 486 #endif 487 488 #ifdef CONFIG_RTC_DRV_M41T80_WDT 489 /* 490 ***************************************************************************** 491 * 492 * Watchdog Driver 493 * 494 ***************************************************************************** 495 */ 496 static struct i2c_client *save_client; 497 498 /* Default margin */ 499 #define WD_TIMO 60 /* 1..31 seconds */ 500 501 static int wdt_margin = WD_TIMO; 502 module_param(wdt_margin, int, 0); 503 MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)"); 504 505 static unsigned long wdt_is_open; 506 static int boot_flag; 507 508 /** 509 * wdt_ping: 510 * 511 * Reload counter one with the watchdog timeout. We don't bother reloading 512 * the cascade counter. 513 */ 514 static void wdt_ping(void) 515 { 516 unsigned char i2c_data[2]; 517 struct i2c_msg msgs1[1] = { 518 { 519 .addr = save_client->addr, 520 .flags = 0, 521 .len = 2, 522 .buf = i2c_data, 523 }, 524 }; 525 struct m41t80_data *clientdata = i2c_get_clientdata(save_client); 526 527 i2c_data[0] = 0x09; /* watchdog register */ 528 529 if (wdt_margin > 31) 530 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */ 531 else 532 /* 533 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02) 534 */ 535 i2c_data[1] = wdt_margin<<2 | 0x82; 536 537 /* 538 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as 539 * that would be an invalid resolution. 540 */ 541 if (clientdata->features & M41T80_FEATURE_WD) 542 i2c_data[1] &= ~M41T80_WATCHDOG_RB2; 543 544 i2c_transfer(save_client->adapter, msgs1, 1); 545 } 546 547 /** 548 * wdt_disable: 549 * 550 * disables watchdog. 551 */ 552 static void wdt_disable(void) 553 { 554 unsigned char i2c_data[2], i2c_buf[0x10]; 555 struct i2c_msg msgs0[2] = { 556 { 557 .addr = save_client->addr, 558 .flags = 0, 559 .len = 1, 560 .buf = i2c_data, 561 }, 562 { 563 .addr = save_client->addr, 564 .flags = I2C_M_RD, 565 .len = 1, 566 .buf = i2c_buf, 567 }, 568 }; 569 struct i2c_msg msgs1[1] = { 570 { 571 .addr = save_client->addr, 572 .flags = 0, 573 .len = 2, 574 .buf = i2c_data, 575 }, 576 }; 577 578 i2c_data[0] = 0x09; 579 i2c_transfer(save_client->adapter, msgs0, 2); 580 581 i2c_data[0] = 0x09; 582 i2c_data[1] = 0x00; 583 i2c_transfer(save_client->adapter, msgs1, 1); 584 } 585 586 /** 587 * wdt_write: 588 * @file: file handle to the watchdog 589 * @buf: buffer to write (unused as data does not matter here 590 * @count: count of bytes 591 * @ppos: pointer to the position to write. No seeks allowed 592 * 593 * A write to a watchdog device is defined as a keepalive signal. Any 594 * write of data will do, as we we don't define content meaning. 595 */ 596 static ssize_t wdt_write(struct file *file, const char __user *buf, 597 size_t count, loff_t *ppos) 598 { 599 if (count) { 600 wdt_ping(); 601 return 1; 602 } 603 return 0; 604 } 605 606 static ssize_t wdt_read(struct file *file, char __user *buf, 607 size_t count, loff_t *ppos) 608 { 609 return 0; 610 } 611 612 /** 613 * wdt_ioctl: 614 * @inode: inode of the device 615 * @file: file handle to the device 616 * @cmd: watchdog command 617 * @arg: argument pointer 618 * 619 * The watchdog API defines a common set of functions for all watchdogs 620 * according to their available features. We only actually usefully support 621 * querying capabilities and current status. 622 */ 623 static int wdt_ioctl(struct file *file, unsigned int cmd, 624 unsigned long arg) 625 { 626 int new_margin, rv; 627 static struct watchdog_info ident = { 628 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING | 629 WDIOF_SETTIMEOUT, 630 .firmware_version = 1, 631 .identity = "M41T80 WTD" 632 }; 633 634 switch (cmd) { 635 case WDIOC_GETSUPPORT: 636 return copy_to_user((struct watchdog_info __user *)arg, &ident, 637 sizeof(ident)) ? -EFAULT : 0; 638 639 case WDIOC_GETSTATUS: 640 case WDIOC_GETBOOTSTATUS: 641 return put_user(boot_flag, (int __user *)arg); 642 case WDIOC_KEEPALIVE: 643 wdt_ping(); 644 return 0; 645 case WDIOC_SETTIMEOUT: 646 if (get_user(new_margin, (int __user *)arg)) 647 return -EFAULT; 648 /* Arbitrary, can't find the card's limits */ 649 if (new_margin < 1 || new_margin > 124) 650 return -EINVAL; 651 wdt_margin = new_margin; 652 wdt_ping(); 653 /* Fall */ 654 case WDIOC_GETTIMEOUT: 655 return put_user(wdt_margin, (int __user *)arg); 656 657 case WDIOC_SETOPTIONS: 658 if (copy_from_user(&rv, (int __user *)arg, sizeof(int))) 659 return -EFAULT; 660 661 if (rv & WDIOS_DISABLECARD) { 662 pr_info("rtc-m41t80: disable watchdog\n"); 663 wdt_disable(); 664 } 665 666 if (rv & WDIOS_ENABLECARD) { 667 pr_info("rtc-m41t80: enable watchdog\n"); 668 wdt_ping(); 669 } 670 671 return -EINVAL; 672 } 673 return -ENOTTY; 674 } 675 676 static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd, 677 unsigned long arg) 678 { 679 int ret; 680 681 mutex_lock(&m41t80_rtc_mutex); 682 ret = wdt_ioctl(file, cmd, arg); 683 mutex_unlock(&m41t80_rtc_mutex); 684 685 return ret; 686 } 687 688 /** 689 * wdt_open: 690 * @inode: inode of device 691 * @file: file handle to device 692 * 693 */ 694 static int wdt_open(struct inode *inode, struct file *file) 695 { 696 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) { 697 mutex_lock(&m41t80_rtc_mutex); 698 if (test_and_set_bit(0, &wdt_is_open)) { 699 mutex_unlock(&m41t80_rtc_mutex); 700 return -EBUSY; 701 } 702 /* 703 * Activate 704 */ 705 wdt_is_open = 1; 706 mutex_unlock(&m41t80_rtc_mutex); 707 return nonseekable_open(inode, file); 708 } 709 return -ENODEV; 710 } 711 712 /** 713 * wdt_close: 714 * @inode: inode to board 715 * @file: file handle to board 716 * 717 */ 718 static int wdt_release(struct inode *inode, struct file *file) 719 { 720 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) 721 clear_bit(0, &wdt_is_open); 722 return 0; 723 } 724 725 /** 726 * notify_sys: 727 * @this: our notifier block 728 * @code: the event being reported 729 * @unused: unused 730 * 731 * Our notifier is called on system shutdowns. We want to turn the card 732 * off at reboot otherwise the machine will reboot again during memory 733 * test or worse yet during the following fsck. This would suck, in fact 734 * trust me - if it happens it does suck. 735 */ 736 static int wdt_notify_sys(struct notifier_block *this, unsigned long code, 737 void *unused) 738 { 739 if (code == SYS_DOWN || code == SYS_HALT) 740 /* Disable Watchdog */ 741 wdt_disable(); 742 return NOTIFY_DONE; 743 } 744 745 static const struct file_operations wdt_fops = { 746 .owner = THIS_MODULE, 747 .read = wdt_read, 748 .unlocked_ioctl = wdt_unlocked_ioctl, 749 .write = wdt_write, 750 .open = wdt_open, 751 .release = wdt_release, 752 .llseek = no_llseek, 753 }; 754 755 static struct miscdevice wdt_dev = { 756 .minor = WATCHDOG_MINOR, 757 .name = "watchdog", 758 .fops = &wdt_fops, 759 }; 760 761 /* 762 * The WDT card needs to learn about soft shutdowns in order to 763 * turn the timebomb registers off. 764 */ 765 static struct notifier_block wdt_notifier = { 766 .notifier_call = wdt_notify_sys, 767 }; 768 #endif /* CONFIG_RTC_DRV_M41T80_WDT */ 769 770 /* 771 ***************************************************************************** 772 * 773 * Driver Interface 774 * 775 ***************************************************************************** 776 */ 777 static int m41t80_probe(struct i2c_client *client, 778 const struct i2c_device_id *id) 779 { 780 int rc = 0; 781 struct rtc_device *rtc = NULL; 782 struct rtc_time tm; 783 struct m41t80_data *clientdata = NULL; 784 785 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C 786 | I2C_FUNC_SMBUS_BYTE_DATA)) { 787 rc = -ENODEV; 788 goto exit; 789 } 790 791 dev_info(&client->dev, 792 "chip found, driver version " DRV_VERSION "\n"); 793 794 clientdata = kzalloc(sizeof(*clientdata), GFP_KERNEL); 795 if (!clientdata) { 796 rc = -ENOMEM; 797 goto exit; 798 } 799 800 rtc = rtc_device_register(client->name, &client->dev, 801 &m41t80_rtc_ops, THIS_MODULE); 802 if (IS_ERR(rtc)) { 803 rc = PTR_ERR(rtc); 804 rtc = NULL; 805 goto exit; 806 } 807 808 clientdata->rtc = rtc; 809 clientdata->features = id->driver_data; 810 i2c_set_clientdata(client, clientdata); 811 812 /* Make sure HT (Halt Update) bit is cleared */ 813 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR); 814 if (rc < 0) 815 goto ht_err; 816 817 if (rc & M41T80_ALHOUR_HT) { 818 if (clientdata->features & M41T80_FEATURE_HT) { 819 m41t80_get_datetime(client, &tm); 820 dev_info(&client->dev, "HT bit was set!\n"); 821 dev_info(&client->dev, 822 "Power Down at " 823 "%04i-%02i-%02i %02i:%02i:%02i\n", 824 tm.tm_year + 1900, 825 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, 826 tm.tm_min, tm.tm_sec); 827 } 828 if (i2c_smbus_write_byte_data(client, 829 M41T80_REG_ALARM_HOUR, 830 rc & ~M41T80_ALHOUR_HT) < 0) 831 goto ht_err; 832 } 833 834 /* Make sure ST (stop) bit is cleared */ 835 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC); 836 if (rc < 0) 837 goto st_err; 838 839 if (rc & M41T80_SEC_ST) { 840 if (i2c_smbus_write_byte_data(client, M41T80_REG_SEC, 841 rc & ~M41T80_SEC_ST) < 0) 842 goto st_err; 843 } 844 845 rc = m41t80_sysfs_register(&client->dev); 846 if (rc) 847 goto exit; 848 849 #ifdef CONFIG_RTC_DRV_M41T80_WDT 850 if (clientdata->features & M41T80_FEATURE_HT) { 851 save_client = client; 852 rc = misc_register(&wdt_dev); 853 if (rc) 854 goto exit; 855 rc = register_reboot_notifier(&wdt_notifier); 856 if (rc) { 857 misc_deregister(&wdt_dev); 858 goto exit; 859 } 860 } 861 #endif 862 return 0; 863 864 st_err: 865 rc = -EIO; 866 dev_err(&client->dev, "Can't clear ST bit\n"); 867 goto exit; 868 ht_err: 869 rc = -EIO; 870 dev_err(&client->dev, "Can't clear HT bit\n"); 871 goto exit; 872 873 exit: 874 if (rtc) 875 rtc_device_unregister(rtc); 876 kfree(clientdata); 877 return rc; 878 } 879 880 static int m41t80_remove(struct i2c_client *client) 881 { 882 struct m41t80_data *clientdata = i2c_get_clientdata(client); 883 struct rtc_device *rtc = clientdata->rtc; 884 885 #ifdef CONFIG_RTC_DRV_M41T80_WDT 886 if (clientdata->features & M41T80_FEATURE_HT) { 887 misc_deregister(&wdt_dev); 888 unregister_reboot_notifier(&wdt_notifier); 889 } 890 #endif 891 if (rtc) 892 rtc_device_unregister(rtc); 893 kfree(clientdata); 894 895 return 0; 896 } 897 898 static struct i2c_driver m41t80_driver = { 899 .driver = { 900 .name = "rtc-m41t80", 901 }, 902 .probe = m41t80_probe, 903 .remove = m41t80_remove, 904 .id_table = m41t80_id, 905 }; 906 907 static int __init m41t80_rtc_init(void) 908 { 909 return i2c_add_driver(&m41t80_driver); 910 } 911 912 static void __exit m41t80_rtc_exit(void) 913 { 914 i2c_del_driver(&m41t80_driver); 915 } 916 917 MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>"); 918 MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver"); 919 MODULE_LICENSE("GPL"); 920 MODULE_VERSION(DRV_VERSION); 921 922 module_init(m41t80_rtc_init); 923 module_exit(m41t80_rtc_exit); 924