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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 17 18 #include <linux/bcd.h> 19 #include <linux/i2c.h> 20 #include <linux/init.h> 21 #include <linux/kernel.h> 22 #include <linux/module.h> 23 #include <linux/of_device.h> 24 #include <linux/rtc.h> 25 #include <linux/slab.h> 26 #include <linux/mutex.h> 27 #include <linux/string.h> 28 #ifdef CONFIG_RTC_DRV_M41T80_WDT 29 #include <linux/fs.h> 30 #include <linux/ioctl.h> 31 #include <linux/miscdevice.h> 32 #include <linux/reboot.h> 33 #include <linux/watchdog.h> 34 #endif 35 36 #define M41T80_REG_SSEC 0x00 37 #define M41T80_REG_SEC 0x01 38 #define M41T80_REG_MIN 0x02 39 #define M41T80_REG_HOUR 0x03 40 #define M41T80_REG_WDAY 0x04 41 #define M41T80_REG_DAY 0x05 42 #define M41T80_REG_MON 0x06 43 #define M41T80_REG_YEAR 0x07 44 #define M41T80_REG_ALARM_MON 0x0a 45 #define M41T80_REG_ALARM_DAY 0x0b 46 #define M41T80_REG_ALARM_HOUR 0x0c 47 #define M41T80_REG_ALARM_MIN 0x0d 48 #define M41T80_REG_ALARM_SEC 0x0e 49 #define M41T80_REG_FLAGS 0x0f 50 #define M41T80_REG_SQW 0x13 51 52 #define M41T80_DATETIME_REG_SIZE (M41T80_REG_YEAR + 1) 53 #define M41T80_ALARM_REG_SIZE \ 54 (M41T80_REG_ALARM_SEC + 1 - M41T80_REG_ALARM_MON) 55 56 #define M41T80_SEC_ST BIT(7) /* ST: Stop Bit */ 57 #define M41T80_ALMON_AFE BIT(7) /* AFE: AF Enable Bit */ 58 #define M41T80_ALMON_SQWE BIT(6) /* SQWE: SQW Enable Bit */ 59 #define M41T80_ALHOUR_HT BIT(6) /* HT: Halt Update Bit */ 60 #define M41T80_FLAGS_OF BIT(2) /* OF: Oscillator Failure Bit */ 61 #define M41T80_FLAGS_AF BIT(6) /* AF: Alarm Flag Bit */ 62 #define M41T80_FLAGS_BATT_LOW BIT(4) /* BL: Battery Low Bit */ 63 #define M41T80_WATCHDOG_RB2 BIT(7) /* RB: Watchdog resolution */ 64 #define M41T80_WATCHDOG_RB1 BIT(1) /* RB: Watchdog resolution */ 65 #define M41T80_WATCHDOG_RB0 BIT(0) /* RB: Watchdog resolution */ 66 67 #define M41T80_FEATURE_HT BIT(0) /* Halt feature */ 68 #define M41T80_FEATURE_BL BIT(1) /* Battery low indicator */ 69 #define M41T80_FEATURE_SQ BIT(2) /* Squarewave feature */ 70 #define M41T80_FEATURE_WD BIT(3) /* Extra watchdog resolution */ 71 #define M41T80_FEATURE_SQ_ALT BIT(4) /* RSx bits are in reg 4 */ 72 73 static DEFINE_MUTEX(m41t80_rtc_mutex); 74 static const struct i2c_device_id m41t80_id[] = { 75 { "m41t62", M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT }, 76 { "m41t65", M41T80_FEATURE_HT | M41T80_FEATURE_WD }, 77 { "m41t80", M41T80_FEATURE_SQ }, 78 { "m41t81", M41T80_FEATURE_HT | M41T80_FEATURE_SQ}, 79 { "m41t81s", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 80 { "m41t82", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 81 { "m41t83", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 82 { "m41st84", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 83 { "m41st85", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 84 { "m41st87", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, 85 { "rv4162", M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT }, 86 { } 87 }; 88 MODULE_DEVICE_TABLE(i2c, m41t80_id); 89 90 static const struct of_device_id m41t80_of_match[] = { 91 { 92 .compatible = "st,m41t62", 93 .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT) 94 }, 95 { 96 .compatible = "st,m41t65", 97 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_WD) 98 }, 99 { 100 .compatible = "st,m41t80", 101 .data = (void *)(M41T80_FEATURE_SQ) 102 }, 103 { 104 .compatible = "st,m41t81", 105 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_SQ) 106 }, 107 { 108 .compatible = "st,m41t81s", 109 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ) 110 }, 111 { 112 .compatible = "st,m41t82", 113 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ) 114 }, 115 { 116 .compatible = "st,m41t83", 117 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ) 118 }, 119 { 120 .compatible = "st,m41t84", 121 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ) 122 }, 123 { 124 .compatible = "st,m41t85", 125 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ) 126 }, 127 { 128 .compatible = "st,m41t87", 129 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ) 130 }, 131 { 132 .compatible = "microcrystal,rv4162", 133 .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT) 134 }, 135 /* DT compatibility only, do not use compatibles below: */ 136 { 137 .compatible = "st,rv4162", 138 .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT) 139 }, 140 { 141 .compatible = "rv4162", 142 .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT) 143 }, 144 { } 145 }; 146 MODULE_DEVICE_TABLE(of, m41t80_of_match); 147 148 struct m41t80_data { 149 unsigned long features; 150 struct rtc_device *rtc; 151 }; 152 153 static irqreturn_t m41t80_handle_irq(int irq, void *dev_id) 154 { 155 struct i2c_client *client = dev_id; 156 struct m41t80_data *m41t80 = i2c_get_clientdata(client); 157 struct mutex *lock = &m41t80->rtc->ops_lock; 158 unsigned long events = 0; 159 int flags, flags_afe; 160 161 mutex_lock(lock); 162 163 flags_afe = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); 164 if (flags_afe < 0) { 165 mutex_unlock(lock); 166 return IRQ_NONE; 167 } 168 169 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 170 if (flags <= 0) { 171 mutex_unlock(lock); 172 return IRQ_NONE; 173 } 174 175 if (flags & M41T80_FLAGS_AF) { 176 flags &= ~M41T80_FLAGS_AF; 177 flags_afe &= ~M41T80_ALMON_AFE; 178 events |= RTC_AF; 179 } 180 181 if (events) { 182 rtc_update_irq(m41t80->rtc, 1, events); 183 i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS, flags); 184 i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 185 flags_afe); 186 } 187 188 mutex_unlock(lock); 189 190 return IRQ_HANDLED; 191 } 192 193 static int m41t80_get_datetime(struct i2c_client *client, 194 struct rtc_time *tm) 195 { 196 unsigned char buf[8]; 197 int err, flags; 198 199 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 200 if (flags < 0) 201 return flags; 202 203 if (flags & M41T80_FLAGS_OF) { 204 dev_err(&client->dev, "Oscillator failure, data is invalid.\n"); 205 return -EINVAL; 206 } 207 208 err = i2c_smbus_read_i2c_block_data(client, M41T80_REG_SSEC, 209 sizeof(buf), buf); 210 if (err < 0) { 211 dev_err(&client->dev, "Unable to read date\n"); 212 return -EIO; 213 } 214 215 tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f); 216 tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f); 217 tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f); 218 tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f); 219 tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07; 220 tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1; 221 222 /* assume 20YY not 19YY, and ignore the Century Bit */ 223 tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100; 224 return rtc_valid_tm(tm); 225 } 226 227 /* Sets the given date and time to the real time clock. */ 228 static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm) 229 { 230 unsigned char buf[8]; 231 int err, flags; 232 233 if (tm->tm_year < 100 || tm->tm_year > 199) 234 return -EINVAL; 235 236 buf[M41T80_REG_SSEC] = 0; 237 buf[M41T80_REG_SEC] = bin2bcd(tm->tm_sec); 238 buf[M41T80_REG_MIN] = bin2bcd(tm->tm_min); 239 buf[M41T80_REG_HOUR] = bin2bcd(tm->tm_hour); 240 buf[M41T80_REG_DAY] = bin2bcd(tm->tm_mday); 241 buf[M41T80_REG_MON] = bin2bcd(tm->tm_mon + 1); 242 buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year - 100); 243 buf[M41T80_REG_WDAY] = tm->tm_wday; 244 245 err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_SSEC, 246 sizeof(buf), buf); 247 if (err < 0) { 248 dev_err(&client->dev, "Unable to write to date registers\n"); 249 return err; 250 } 251 252 /* Clear the OF bit of Flags Register */ 253 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 254 if (flags < 0) 255 return flags; 256 257 if (i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS, 258 flags & ~M41T80_FLAGS_OF)) { 259 dev_err(&client->dev, "Unable to write flags register\n"); 260 return -EIO; 261 } 262 263 return err; 264 } 265 266 static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq) 267 { 268 struct i2c_client *client = to_i2c_client(dev); 269 struct m41t80_data *clientdata = i2c_get_clientdata(client); 270 u8 reg; 271 272 if (clientdata->features & M41T80_FEATURE_BL) { 273 reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 274 seq_printf(seq, "battery\t\t: %s\n", 275 (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok"); 276 } 277 return 0; 278 } 279 280 static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm) 281 { 282 return m41t80_get_datetime(to_i2c_client(dev), tm); 283 } 284 285 static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm) 286 { 287 return m41t80_set_datetime(to_i2c_client(dev), tm); 288 } 289 290 static int m41t80_alarm_irq_enable(struct device *dev, unsigned int enabled) 291 { 292 struct i2c_client *client = to_i2c_client(dev); 293 int flags, retval; 294 295 flags = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); 296 if (flags < 0) 297 return flags; 298 299 if (enabled) 300 flags |= M41T80_ALMON_AFE; 301 else 302 flags &= ~M41T80_ALMON_AFE; 303 304 retval = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, flags); 305 if (retval < 0) { 306 dev_err(dev, "Unable to enable alarm IRQ %d\n", retval); 307 return retval; 308 } 309 return 0; 310 } 311 312 static int m41t80_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 313 { 314 struct i2c_client *client = to_i2c_client(dev); 315 u8 alarmvals[5]; 316 int ret, err; 317 318 alarmvals[0] = bin2bcd(alrm->time.tm_mon + 1); 319 alarmvals[1] = bin2bcd(alrm->time.tm_mday); 320 alarmvals[2] = bin2bcd(alrm->time.tm_hour); 321 alarmvals[3] = bin2bcd(alrm->time.tm_min); 322 alarmvals[4] = bin2bcd(alrm->time.tm_sec); 323 324 /* Clear AF and AFE flags */ 325 ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); 326 if (ret < 0) 327 return ret; 328 err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 329 ret & ~(M41T80_ALMON_AFE)); 330 if (err < 0) { 331 dev_err(dev, "Unable to clear AFE bit\n"); 332 return err; 333 } 334 335 ret = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 336 if (ret < 0) 337 return ret; 338 339 err = i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS, 340 ret & ~(M41T80_FLAGS_AF)); 341 if (err < 0) { 342 dev_err(dev, "Unable to clear AF bit\n"); 343 return err; 344 } 345 346 /* Write the alarm */ 347 err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_ALARM_MON, 348 5, alarmvals); 349 if (err) 350 return err; 351 352 /* Enable the alarm interrupt */ 353 if (alrm->enabled) { 354 alarmvals[0] |= M41T80_ALMON_AFE; 355 err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 356 alarmvals[0]); 357 if (err) 358 return err; 359 } 360 361 return 0; 362 } 363 364 static int m41t80_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 365 { 366 struct i2c_client *client = to_i2c_client(dev); 367 u8 alarmvals[5]; 368 int flags, ret; 369 370 ret = i2c_smbus_read_i2c_block_data(client, M41T80_REG_ALARM_MON, 371 5, alarmvals); 372 if (ret != 5) 373 return ret < 0 ? ret : -EIO; 374 375 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 376 if (flags < 0) 377 return flags; 378 379 alrm->time.tm_sec = bcd2bin(alarmvals[4] & 0x7f); 380 alrm->time.tm_min = bcd2bin(alarmvals[3] & 0x7f); 381 alrm->time.tm_hour = bcd2bin(alarmvals[2] & 0x3f); 382 alrm->time.tm_mday = bcd2bin(alarmvals[1] & 0x3f); 383 alrm->time.tm_mon = bcd2bin(alarmvals[0] & 0x3f); 384 385 alrm->enabled = !!(alarmvals[0] & M41T80_ALMON_AFE); 386 alrm->pending = (flags & M41T80_FLAGS_AF) && alrm->enabled; 387 388 return 0; 389 } 390 391 static struct rtc_class_ops m41t80_rtc_ops = { 392 .read_time = m41t80_rtc_read_time, 393 .set_time = m41t80_rtc_set_time, 394 .proc = m41t80_rtc_proc, 395 }; 396 397 #ifdef CONFIG_PM_SLEEP 398 static int m41t80_suspend(struct device *dev) 399 { 400 struct i2c_client *client = to_i2c_client(dev); 401 402 if (client->irq >= 0 && device_may_wakeup(dev)) 403 enable_irq_wake(client->irq); 404 405 return 0; 406 } 407 408 static int m41t80_resume(struct device *dev) 409 { 410 struct i2c_client *client = to_i2c_client(dev); 411 412 if (client->irq >= 0 && device_may_wakeup(dev)) 413 disable_irq_wake(client->irq); 414 415 return 0; 416 } 417 #endif 418 419 static SIMPLE_DEV_PM_OPS(m41t80_pm, m41t80_suspend, m41t80_resume); 420 421 static ssize_t flags_show(struct device *dev, 422 struct device_attribute *attr, char *buf) 423 { 424 struct i2c_client *client = to_i2c_client(dev); 425 int val; 426 427 val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); 428 if (val < 0) 429 return val; 430 return sprintf(buf, "%#x\n", val); 431 } 432 static DEVICE_ATTR_RO(flags); 433 434 static ssize_t sqwfreq_show(struct device *dev, 435 struct device_attribute *attr, char *buf) 436 { 437 struct i2c_client *client = to_i2c_client(dev); 438 struct m41t80_data *clientdata = i2c_get_clientdata(client); 439 int val, reg_sqw; 440 441 if (!(clientdata->features & M41T80_FEATURE_SQ)) 442 return -EINVAL; 443 444 reg_sqw = M41T80_REG_SQW; 445 if (clientdata->features & M41T80_FEATURE_SQ_ALT) 446 reg_sqw = M41T80_REG_WDAY; 447 val = i2c_smbus_read_byte_data(client, reg_sqw); 448 if (val < 0) 449 return val; 450 val = (val >> 4) & 0xf; 451 switch (val) { 452 case 0: 453 break; 454 case 1: 455 val = 32768; 456 break; 457 default: 458 val = 32768 >> val; 459 } 460 return sprintf(buf, "%d\n", val); 461 } 462 463 static ssize_t sqwfreq_store(struct device *dev, 464 struct device_attribute *attr, 465 const char *buf, size_t count) 466 { 467 struct i2c_client *client = to_i2c_client(dev); 468 struct m41t80_data *clientdata = i2c_get_clientdata(client); 469 int almon, sqw, reg_sqw, rc; 470 unsigned long val; 471 472 rc = kstrtoul(buf, 0, &val); 473 if (rc < 0) 474 return rc; 475 476 if (!(clientdata->features & M41T80_FEATURE_SQ)) 477 return -EINVAL; 478 479 if (val) { 480 if (!is_power_of_2(val)) 481 return -EINVAL; 482 val = ilog2(val); 483 if (val == 15) 484 val = 1; 485 else if (val < 14) 486 val = 15 - val; 487 else 488 return -EINVAL; 489 } 490 /* disable SQW, set SQW frequency & re-enable */ 491 almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); 492 if (almon < 0) 493 return almon; 494 reg_sqw = M41T80_REG_SQW; 495 if (clientdata->features & M41T80_FEATURE_SQ_ALT) 496 reg_sqw = M41T80_REG_WDAY; 497 sqw = i2c_smbus_read_byte_data(client, reg_sqw); 498 if (sqw < 0) 499 return sqw; 500 sqw = (sqw & 0x0f) | (val << 4); 501 502 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 503 almon & ~M41T80_ALMON_SQWE); 504 if (rc < 0) 505 return rc; 506 507 if (val) { 508 rc = i2c_smbus_write_byte_data(client, reg_sqw, sqw); 509 if (rc < 0) 510 return rc; 511 512 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, 513 almon | M41T80_ALMON_SQWE); 514 if (rc < 0) 515 return rc; 516 } 517 return count; 518 } 519 static DEVICE_ATTR_RW(sqwfreq); 520 521 static struct attribute *attrs[] = { 522 &dev_attr_flags.attr, 523 &dev_attr_sqwfreq.attr, 524 NULL, 525 }; 526 527 static struct attribute_group attr_group = { 528 .attrs = attrs, 529 }; 530 531 #ifdef CONFIG_RTC_DRV_M41T80_WDT 532 /* 533 ***************************************************************************** 534 * 535 * Watchdog Driver 536 * 537 ***************************************************************************** 538 */ 539 static struct i2c_client *save_client; 540 541 /* Default margin */ 542 #define WD_TIMO 60 /* 1..31 seconds */ 543 544 static int wdt_margin = WD_TIMO; 545 module_param(wdt_margin, int, 0); 546 MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)"); 547 548 static unsigned long wdt_is_open; 549 static int boot_flag; 550 551 /** 552 * wdt_ping: 553 * 554 * Reload counter one with the watchdog timeout. We don't bother reloading 555 * the cascade counter. 556 */ 557 static void wdt_ping(void) 558 { 559 unsigned char i2c_data[2]; 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 struct m41t80_data *clientdata = i2c_get_clientdata(save_client); 569 570 i2c_data[0] = 0x09; /* watchdog register */ 571 572 if (wdt_margin > 31) 573 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */ 574 else 575 /* 576 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02) 577 */ 578 i2c_data[1] = wdt_margin << 2 | 0x82; 579 580 /* 581 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as 582 * that would be an invalid resolution. 583 */ 584 if (clientdata->features & M41T80_FEATURE_WD) 585 i2c_data[1] &= ~M41T80_WATCHDOG_RB2; 586 587 i2c_transfer(save_client->adapter, msgs1, 1); 588 } 589 590 /** 591 * wdt_disable: 592 * 593 * disables watchdog. 594 */ 595 static void wdt_disable(void) 596 { 597 unsigned char i2c_data[2], i2c_buf[0x10]; 598 struct i2c_msg msgs0[2] = { 599 { 600 .addr = save_client->addr, 601 .flags = 0, 602 .len = 1, 603 .buf = i2c_data, 604 }, 605 { 606 .addr = save_client->addr, 607 .flags = I2C_M_RD, 608 .len = 1, 609 .buf = i2c_buf, 610 }, 611 }; 612 struct i2c_msg msgs1[1] = { 613 { 614 .addr = save_client->addr, 615 .flags = 0, 616 .len = 2, 617 .buf = i2c_data, 618 }, 619 }; 620 621 i2c_data[0] = 0x09; 622 i2c_transfer(save_client->adapter, msgs0, 2); 623 624 i2c_data[0] = 0x09; 625 i2c_data[1] = 0x00; 626 i2c_transfer(save_client->adapter, msgs1, 1); 627 } 628 629 /** 630 * wdt_write: 631 * @file: file handle to the watchdog 632 * @buf: buffer to write (unused as data does not matter here 633 * @count: count of bytes 634 * @ppos: pointer to the position to write. No seeks allowed 635 * 636 * A write to a watchdog device is defined as a keepalive signal. Any 637 * write of data will do, as we we don't define content meaning. 638 */ 639 static ssize_t wdt_write(struct file *file, const char __user *buf, 640 size_t count, loff_t *ppos) 641 { 642 if (count) { 643 wdt_ping(); 644 return 1; 645 } 646 return 0; 647 } 648 649 static ssize_t wdt_read(struct file *file, char __user *buf, 650 size_t count, loff_t *ppos) 651 { 652 return 0; 653 } 654 655 /** 656 * wdt_ioctl: 657 * @inode: inode of the device 658 * @file: file handle to the device 659 * @cmd: watchdog command 660 * @arg: argument pointer 661 * 662 * The watchdog API defines a common set of functions for all watchdogs 663 * according to their available features. We only actually usefully support 664 * querying capabilities and current status. 665 */ 666 static int wdt_ioctl(struct file *file, unsigned int cmd, 667 unsigned long arg) 668 { 669 int new_margin, rv; 670 static struct watchdog_info ident = { 671 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING | 672 WDIOF_SETTIMEOUT, 673 .firmware_version = 1, 674 .identity = "M41T80 WTD" 675 }; 676 677 switch (cmd) { 678 case WDIOC_GETSUPPORT: 679 return copy_to_user((struct watchdog_info __user *)arg, &ident, 680 sizeof(ident)) ? -EFAULT : 0; 681 682 case WDIOC_GETSTATUS: 683 case WDIOC_GETBOOTSTATUS: 684 return put_user(boot_flag, (int __user *)arg); 685 case WDIOC_KEEPALIVE: 686 wdt_ping(); 687 return 0; 688 case WDIOC_SETTIMEOUT: 689 if (get_user(new_margin, (int __user *)arg)) 690 return -EFAULT; 691 /* Arbitrary, can't find the card's limits */ 692 if (new_margin < 1 || new_margin > 124) 693 return -EINVAL; 694 wdt_margin = new_margin; 695 wdt_ping(); 696 /* Fall */ 697 case WDIOC_GETTIMEOUT: 698 return put_user(wdt_margin, (int __user *)arg); 699 700 case WDIOC_SETOPTIONS: 701 if (copy_from_user(&rv, (int __user *)arg, sizeof(int))) 702 return -EFAULT; 703 704 if (rv & WDIOS_DISABLECARD) { 705 pr_info("disable watchdog\n"); 706 wdt_disable(); 707 } 708 709 if (rv & WDIOS_ENABLECARD) { 710 pr_info("enable watchdog\n"); 711 wdt_ping(); 712 } 713 714 return -EINVAL; 715 } 716 return -ENOTTY; 717 } 718 719 static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd, 720 unsigned long arg) 721 { 722 int ret; 723 724 mutex_lock(&m41t80_rtc_mutex); 725 ret = wdt_ioctl(file, cmd, arg); 726 mutex_unlock(&m41t80_rtc_mutex); 727 728 return ret; 729 } 730 731 /** 732 * wdt_open: 733 * @inode: inode of device 734 * @file: file handle to device 735 * 736 */ 737 static int wdt_open(struct inode *inode, struct file *file) 738 { 739 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) { 740 mutex_lock(&m41t80_rtc_mutex); 741 if (test_and_set_bit(0, &wdt_is_open)) { 742 mutex_unlock(&m41t80_rtc_mutex); 743 return -EBUSY; 744 } 745 /* 746 * Activate 747 */ 748 wdt_is_open = 1; 749 mutex_unlock(&m41t80_rtc_mutex); 750 return nonseekable_open(inode, file); 751 } 752 return -ENODEV; 753 } 754 755 /** 756 * wdt_close: 757 * @inode: inode to board 758 * @file: file handle to board 759 * 760 */ 761 static int wdt_release(struct inode *inode, struct file *file) 762 { 763 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) 764 clear_bit(0, &wdt_is_open); 765 return 0; 766 } 767 768 /** 769 * notify_sys: 770 * @this: our notifier block 771 * @code: the event being reported 772 * @unused: unused 773 * 774 * Our notifier is called on system shutdowns. We want to turn the card 775 * off at reboot otherwise the machine will reboot again during memory 776 * test or worse yet during the following fsck. This would suck, in fact 777 * trust me - if it happens it does suck. 778 */ 779 static int wdt_notify_sys(struct notifier_block *this, unsigned long code, 780 void *unused) 781 { 782 if (code == SYS_DOWN || code == SYS_HALT) 783 /* Disable Watchdog */ 784 wdt_disable(); 785 return NOTIFY_DONE; 786 } 787 788 static const struct file_operations wdt_fops = { 789 .owner = THIS_MODULE, 790 .read = wdt_read, 791 .unlocked_ioctl = wdt_unlocked_ioctl, 792 .write = wdt_write, 793 .open = wdt_open, 794 .release = wdt_release, 795 .llseek = no_llseek, 796 }; 797 798 static struct miscdevice wdt_dev = { 799 .minor = WATCHDOG_MINOR, 800 .name = "watchdog", 801 .fops = &wdt_fops, 802 }; 803 804 /* 805 * The WDT card needs to learn about soft shutdowns in order to 806 * turn the timebomb registers off. 807 */ 808 static struct notifier_block wdt_notifier = { 809 .notifier_call = wdt_notify_sys, 810 }; 811 #endif /* CONFIG_RTC_DRV_M41T80_WDT */ 812 813 /* 814 ***************************************************************************** 815 * 816 * Driver Interface 817 * 818 ***************************************************************************** 819 */ 820 821 static void m41t80_remove_sysfs_group(void *_dev) 822 { 823 struct device *dev = _dev; 824 825 sysfs_remove_group(&dev->kobj, &attr_group); 826 } 827 828 static int m41t80_probe(struct i2c_client *client, 829 const struct i2c_device_id *id) 830 { 831 struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent); 832 int rc = 0; 833 struct rtc_device *rtc = NULL; 834 struct rtc_time tm; 835 struct m41t80_data *m41t80_data = NULL; 836 837 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK | 838 I2C_FUNC_SMBUS_BYTE_DATA)) { 839 dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n"); 840 return -ENODEV; 841 } 842 843 m41t80_data = devm_kzalloc(&client->dev, sizeof(*m41t80_data), 844 GFP_KERNEL); 845 if (!m41t80_data) 846 return -ENOMEM; 847 848 if (client->dev.of_node) 849 m41t80_data->features = (unsigned long) 850 of_device_get_match_data(&client->dev); 851 else 852 m41t80_data->features = id->driver_data; 853 i2c_set_clientdata(client, m41t80_data); 854 855 if (client->irq > 0) { 856 rc = devm_request_threaded_irq(&client->dev, client->irq, 857 NULL, m41t80_handle_irq, 858 IRQF_TRIGGER_LOW | IRQF_ONESHOT, 859 "m41t80", client); 860 if (rc) { 861 dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n"); 862 client->irq = 0; 863 } else { 864 m41t80_rtc_ops.read_alarm = m41t80_read_alarm; 865 m41t80_rtc_ops.set_alarm = m41t80_set_alarm; 866 m41t80_rtc_ops.alarm_irq_enable = m41t80_alarm_irq_enable; 867 /* Enable the wakealarm */ 868 device_init_wakeup(&client->dev, true); 869 } 870 } 871 872 rtc = devm_rtc_device_register(&client->dev, client->name, 873 &m41t80_rtc_ops, THIS_MODULE); 874 if (IS_ERR(rtc)) 875 return PTR_ERR(rtc); 876 877 m41t80_data->rtc = rtc; 878 879 /* Make sure HT (Halt Update) bit is cleared */ 880 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR); 881 882 if (rc >= 0 && rc & M41T80_ALHOUR_HT) { 883 if (m41t80_data->features & M41T80_FEATURE_HT) { 884 m41t80_get_datetime(client, &tm); 885 dev_info(&client->dev, "HT bit was set!\n"); 886 dev_info(&client->dev, 887 "Power Down at %04i-%02i-%02i %02i:%02i:%02i\n", 888 tm.tm_year + 1900, 889 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, 890 tm.tm_min, tm.tm_sec); 891 } 892 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_HOUR, 893 rc & ~M41T80_ALHOUR_HT); 894 } 895 896 if (rc < 0) { 897 dev_err(&client->dev, "Can't clear HT bit\n"); 898 return rc; 899 } 900 901 /* Make sure ST (stop) bit is cleared */ 902 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC); 903 904 if (rc >= 0 && rc & M41T80_SEC_ST) 905 rc = i2c_smbus_write_byte_data(client, M41T80_REG_SEC, 906 rc & ~M41T80_SEC_ST); 907 if (rc < 0) { 908 dev_err(&client->dev, "Can't clear ST bit\n"); 909 return rc; 910 } 911 912 /* Export sysfs entries */ 913 rc = sysfs_create_group(&(&client->dev)->kobj, &attr_group); 914 if (rc) { 915 dev_err(&client->dev, "Failed to create sysfs group: %d\n", rc); 916 return rc; 917 } 918 919 rc = devm_add_action_or_reset(&client->dev, m41t80_remove_sysfs_group, 920 &client->dev); 921 if (rc) { 922 dev_err(&client->dev, 923 "Failed to add sysfs cleanup action: %d\n", rc); 924 return rc; 925 } 926 927 #ifdef CONFIG_RTC_DRV_M41T80_WDT 928 if (m41t80_data->features & M41T80_FEATURE_HT) { 929 save_client = client; 930 rc = misc_register(&wdt_dev); 931 if (rc) 932 return rc; 933 rc = register_reboot_notifier(&wdt_notifier); 934 if (rc) { 935 misc_deregister(&wdt_dev); 936 return rc; 937 } 938 } 939 #endif 940 return 0; 941 } 942 943 static int m41t80_remove(struct i2c_client *client) 944 { 945 #ifdef CONFIG_RTC_DRV_M41T80_WDT 946 struct m41t80_data *clientdata = i2c_get_clientdata(client); 947 948 if (clientdata->features & M41T80_FEATURE_HT) { 949 misc_deregister(&wdt_dev); 950 unregister_reboot_notifier(&wdt_notifier); 951 } 952 #endif 953 954 return 0; 955 } 956 957 static struct i2c_driver m41t80_driver = { 958 .driver = { 959 .name = "rtc-m41t80", 960 .of_match_table = of_match_ptr(m41t80_of_match), 961 .pm = &m41t80_pm, 962 }, 963 .probe = m41t80_probe, 964 .remove = m41t80_remove, 965 .id_table = m41t80_id, 966 }; 967 968 module_i2c_driver(m41t80_driver); 969 970 MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>"); 971 MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver"); 972 MODULE_LICENSE("GPL"); 973