drivers/rtc/rtc-m41t80.c

   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/rtc.h>
  24 #include <linux/slab.h>
  25 #include <linux/mutex.h>
  26 #include <linux/string.h>
  27 #ifdef CONFIG_RTC_DRV_M41T80_WDT
  28 #include <linux/fs.h>
  29 #include <linux/ioctl.h>
  30 #include <linux/miscdevice.h>
  31 #include <linux/reboot.h>
  32 #include <linux/watchdog.h>
  33 #endif
  34
  35 #define M41T80_REG_SSEC         0x00
  36 #define M41T80_REG_SEC          0x01
  37 #define M41T80_REG_MIN          0x02
  38 #define M41T80_REG_HOUR         0x03
  39 #define M41T80_REG_WDAY         0x04
  40 #define M41T80_REG_DAY          0x05
  41 #define M41T80_REG_MON          0x06
  42 #define M41T80_REG_YEAR         0x07
  43 #define M41T80_REG_ALARM_MON    0x0a
  44 #define M41T80_REG_ALARM_DAY    0x0b
  45 #define M41T80_REG_ALARM_HOUR   0x0c
  46 #define M41T80_REG_ALARM_MIN    0x0d
  47 #define M41T80_REG_ALARM_SEC    0x0e
  48 #define M41T80_REG_FLAGS        0x0f
  49 #define M41T80_REG_SQW          0x13
  50
  51 #define M41T80_DATETIME_REG_SIZE        (M41T80_REG_YEAR + 1)
  52 #define M41T80_ALARM_REG_SIZE   \
  53         (M41T80_REG_ALARM_SEC + 1 - M41T80_REG_ALARM_MON)
  54
  55 #define M41T80_SEC_ST           BIT(7)  /* ST: Stop Bit */
  56 #define M41T80_ALMON_AFE        BIT(7)  /* AFE: AF Enable Bit */
  57 #define M41T80_ALMON_SQWE       BIT(6)  /* SQWE: SQW Enable Bit */
  58 #define M41T80_ALHOUR_HT        BIT(6)  /* HT: Halt Update Bit */
  59 #define M41T80_FLAGS_AF         BIT(6)  /* AF: Alarm Flag Bit */
  60 #define M41T80_FLAGS_BATT_LOW   BIT(4)  /* BL: Battery Low Bit */
  61 #define M41T80_WATCHDOG_RB2     BIT(7)  /* RB: Watchdog resolution */
  62 #define M41T80_WATCHDOG_RB1     BIT(1)  /* RB: Watchdog resolution */
  63 #define M41T80_WATCHDOG_RB0     BIT(0)  /* RB: Watchdog resolution */
  64
  65 #define M41T80_FEATURE_HT       BIT(0)  /* Halt feature */
  66 #define M41T80_FEATURE_BL       BIT(1)  /* Battery low indicator */
  67 #define M41T80_FEATURE_SQ       BIT(2)  /* Squarewave feature */
  68 #define M41T80_FEATURE_WD       BIT(3)  /* Extra watchdog resolution */
  69 #define M41T80_FEATURE_SQ_ALT   BIT(4)  /* RSx bits are in reg 4 */
  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         { "rv4162", M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT },
  84         { }
  85 };
  86 MODULE_DEVICE_TABLE(i2c, m41t80_id);
  87
  88 struct m41t80_data {
  89         u8 features;
  90         struct rtc_device *rtc;
  91 };
  92
  93 static irqreturn_t m41t80_handle_irq(int irq, void *dev_id)
  94 {
  95         struct i2c_client *client = dev_id;
  96         struct m41t80_data *m41t80 = i2c_get_clientdata(client);
  97         struct mutex *lock = &m41t80->rtc->ops_lock;
  98         unsigned long events = 0;
  99         int flags, flags_afe;
 100
 101         mutex_lock(lock);
 102
 103         flags_afe = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
 104         if (flags_afe < 0) {
 105                 mutex_unlock(lock);
 106                 return IRQ_NONE;
 107         }
 108
 109         flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
 110         if (flags <= 0) {
 111                 mutex_unlock(lock);
 112                 return IRQ_NONE;
 113         }
 114
 115         if (flags & M41T80_FLAGS_AF) {
 116                 flags &= ~M41T80_FLAGS_AF;
 117                 flags_afe &= ~M41T80_ALMON_AFE;
 118                 events |= RTC_AF;
 119         }
 120
 121         if (events) {
 122                 rtc_update_irq(m41t80->rtc, 1, events);
 123                 i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS, flags);
 124                 i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
 125                                           flags_afe);
 126         }
 127
 128         mutex_unlock(lock);
 129
 130         return IRQ_HANDLED;
 131 }
 132
 133 static int m41t80_get_datetime(struct i2c_client *client,
 134                                struct rtc_time *tm)
 135 {
 136         unsigned char buf[8];
 137         int err;
 138
 139         err = i2c_smbus_read_i2c_block_data(client, M41T80_REG_SSEC,
 140                                             sizeof(buf), buf);
 141         if (err < 0) {
 142                 dev_err(&client->dev, "Unable to read date\n");
 143                 return -EIO;
 144         }
 145
 146         tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f);
 147         tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f);
 148         tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f);
 149         tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f);
 150         tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07;
 151         tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1;
 152
 153         /* assume 20YY not 19YY, and ignore the Century Bit */
 154         tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100;
 155         return rtc_valid_tm(tm);
 156 }
 157
 158 /* Sets the given date and time to the real time clock. */
 159 static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm)
 160 {
 161         unsigned char buf[8];
 162         int err;
 163
 164         if (tm->tm_year < 100 || tm->tm_year > 199)
 165                 return -EINVAL;
 166
 167         buf[M41T80_REG_SSEC] = 0;
 168         buf[M41T80_REG_SEC] = bin2bcd(tm->tm_sec);
 169         buf[M41T80_REG_MIN] = bin2bcd(tm->tm_min);
 170         buf[M41T80_REG_HOUR] = bin2bcd(tm->tm_hour);
 171         buf[M41T80_REG_DAY] = bin2bcd(tm->tm_mday);
 172         buf[M41T80_REG_MON] = bin2bcd(tm->tm_mon + 1);
 173         buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year - 100);
 174         buf[M41T80_REG_WDAY] = tm->tm_wday;
 175
 176         err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_SSEC,
 177                                              sizeof(buf), buf);
 178         if (err < 0) {
 179                 dev_err(&client->dev, "Unable to write to date registers\n");
 180                 return err;
 181         }
 182
 183         return err;
 184 }
 185
 186 static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq)
 187 {
 188         struct i2c_client *client = to_i2c_client(dev);
 189         struct m41t80_data *clientdata = i2c_get_clientdata(client);
 190         u8 reg;
 191
 192         if (clientdata->features & M41T80_FEATURE_BL) {
 193                 reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
 194                 seq_printf(seq, "battery\t\t: %s\n",
 195                            (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok");
 196         }
 197         return 0;
 198 }
 199
 200 static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm)
 201 {
 202         return m41t80_get_datetime(to_i2c_client(dev), tm);
 203 }
 204
 205 static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm)
 206 {
 207         return m41t80_set_datetime(to_i2c_client(dev), tm);
 208 }
 209
 210 static int m41t80_alarm_irq_enable(struct device *dev, unsigned int enabled)
 211 {
 212         struct i2c_client *client = to_i2c_client(dev);
 213         int flags, retval;
 214
 215         flags = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
 216         if (flags < 0)
 217                 return flags;
 218
 219         if (enabled)
 220                 flags |= M41T80_ALMON_AFE;
 221         else
 222                 flags &= ~M41T80_ALMON_AFE;
 223
 224         retval = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, flags);
 225         if (retval < 0) {
 226                 dev_info(dev, "Unable to enable alarm IRQ %d\n", retval);
 227                 return retval;
 228         }
 229         return 0;
 230 }
 231
 232 static int m41t80_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 233 {
 234         struct i2c_client *client = to_i2c_client(dev);
 235         u8 alarmvals[5];
 236         int ret, err;
 237
 238         alarmvals[0] = bin2bcd(alrm->time.tm_mon + 1);
 239         alarmvals[1] = bin2bcd(alrm->time.tm_mday);
 240         alarmvals[2] = bin2bcd(alrm->time.tm_hour);
 241         alarmvals[3] = bin2bcd(alrm->time.tm_min);
 242         alarmvals[4] = bin2bcd(alrm->time.tm_sec);
 243
 244         /* Clear AF and AFE flags */
 245         ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
 246         if (ret < 0)
 247                 return ret;
 248         err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
 249                                         ret & ~(M41T80_ALMON_AFE));
 250         if (err < 0) {
 251                 dev_err(dev, "Unable to clear AFE bit\n");
 252                 return err;
 253         }
 254
 255         ret = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
 256         if (ret < 0)
 257                 return ret;
 258
 259         err = i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS,
 260                                         ret & ~(M41T80_FLAGS_AF));
 261         if (err < 0) {
 262                 dev_err(dev, "Unable to clear AF bit\n");
 263                 return err;
 264         }
 265
 266         /* Write the alarm */
 267         err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_ALARM_MON,
 268                                              5, alarmvals);
 269         if (err)
 270                 return err;
 271
 272         /* Enable the alarm interrupt */
 273         if (alrm->enabled) {
 274                 alarmvals[0] |= M41T80_ALMON_AFE;
 275                 err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
 276                                                 alarmvals[0]);
 277                 if (err)
 278                         return err;
 279         }
 280
 281         return 0;
 282 }
 283
 284 static int m41t80_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 285 {
 286         struct i2c_client *client = to_i2c_client(dev);
 287         u8 alarmvals[5];
 288         int flags, ret;
 289
 290         ret = i2c_smbus_read_i2c_block_data(client, M41T80_REG_ALARM_MON,
 291                                             5, alarmvals);
 292         if (ret != 5)
 293                 return ret < 0 ? ret : -EIO;
 294
 295         flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
 296         if (flags < 0)
 297                 return flags;
 298
 299         alrm->time.tm_sec  = bcd2bin(alarmvals[4] & 0x7f);
 300         alrm->time.tm_min  = bcd2bin(alarmvals[3] & 0x7f);
 301         alrm->time.tm_hour = bcd2bin(alarmvals[2] & 0x3f);
 302         alrm->time.tm_wday = -1;
 303         alrm->time.tm_mday = bcd2bin(alarmvals[1] & 0x3f);
 304         alrm->time.tm_mon  = bcd2bin(alarmvals[0] & 0x3f);
 305         alrm->time.tm_year = -1;
 306
 307         alrm->enabled = !!(alarmvals[0] & M41T80_ALMON_AFE);
 308         alrm->pending = (flags & M41T80_FLAGS_AF) && alrm->enabled;
 309
 310         return 0;
 311 }
 312
 313 static struct rtc_class_ops m41t80_rtc_ops = {
 314         .read_time = m41t80_rtc_read_time,
 315         .set_time = m41t80_rtc_set_time,
 316         .proc = m41t80_rtc_proc,
 317 };
 318
 319 static ssize_t flags_show(struct device *dev,
 320                           struct device_attribute *attr, char *buf)
 321 {
 322         struct i2c_client *client = to_i2c_client(dev);
 323         int val;
 324
 325         val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
 326         if (val < 0)
 327                 return val;
 328         return sprintf(buf, "%#x\n", val);
 329 }
 330 static DEVICE_ATTR_RO(flags);
 331
 332 static ssize_t sqwfreq_show(struct device *dev,
 333                             struct device_attribute *attr, char *buf)
 334 {
 335         struct i2c_client *client = to_i2c_client(dev);
 336         struct m41t80_data *clientdata = i2c_get_clientdata(client);
 337         int val, reg_sqw;
 338
 339         if (!(clientdata->features & M41T80_FEATURE_SQ))
 340                 return -EINVAL;
 341
 342         reg_sqw = M41T80_REG_SQW;
 343         if (clientdata->features & M41T80_FEATURE_SQ_ALT)
 344                 reg_sqw = M41T80_REG_WDAY;
 345         val = i2c_smbus_read_byte_data(client, reg_sqw);
 346         if (val < 0)
 347                 return val;
 348         val = (val >> 4) & 0xf;
 349         switch (val) {
 350         case 0:
 351                 break;
 352         case 1:
 353                 val = 32768;
 354                 break;
 355         default:
 356                 val = 32768 >> val;
 357         }
 358         return sprintf(buf, "%d\n", val);
 359 }
 360
 361 static ssize_t sqwfreq_store(struct device *dev,
 362                              struct device_attribute *attr,
 363                              const char *buf, size_t count)
 364 {
 365         struct i2c_client *client = to_i2c_client(dev);
 366         struct m41t80_data *clientdata = i2c_get_clientdata(client);
 367         int almon, sqw, reg_sqw, rc;
 368         unsigned long val;
 369
 370         rc = kstrtoul(buf, 0, &val);
 371         if (rc < 0)
 372                 return rc;
 373
 374         if (!(clientdata->features & M41T80_FEATURE_SQ))
 375                 return -EINVAL;
 376
 377         if (val) {
 378                 if (!is_power_of_2(val))
 379                         return -EINVAL;
 380                 val = ilog2(val);
 381                 if (val == 15)
 382                         val = 1;
 383                 else if (val < 14)
 384                         val = 15 - val;
 385                 else
 386                         return -EINVAL;
 387         }
 388         /* disable SQW, set SQW frequency & re-enable */
 389         almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
 390         if (almon < 0)
 391                 return almon;
 392         reg_sqw = M41T80_REG_SQW;
 393         if (clientdata->features & M41T80_FEATURE_SQ_ALT)
 394                 reg_sqw = M41T80_REG_WDAY;
 395         sqw = i2c_smbus_read_byte_data(client, reg_sqw);
 396         if (sqw < 0)
 397                 return sqw;
 398         sqw = (sqw & 0x0f) | (val << 4);
 399
 400         rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
 401                                        almon & ~M41T80_ALMON_SQWE);
 402         if (rc < 0)
 403                 return rc;
 404
 405         if (val) {
 406                 rc = i2c_smbus_write_byte_data(client, reg_sqw, sqw);
 407                 if (rc < 0)
 408                         return rc;
 409
 410                 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
 411                                                almon | M41T80_ALMON_SQWE);
 412                 if (rc < 0)
 413                         return rc;
 414         }
 415         return count;
 416 }
 417 static DEVICE_ATTR_RW(sqwfreq);
 418
 419 static struct attribute *attrs[] = {
 420         &dev_attr_flags.attr,
 421         &dev_attr_sqwfreq.attr,
 422         NULL,
 423 };
 424
 425 static struct attribute_group attr_group = {
 426         .attrs = attrs,
 427 };
 428
 429 #ifdef CONFIG_RTC_DRV_M41T80_WDT
 430 /*
 431  *****************************************************************************
 432  *
 433  * Watchdog Driver
 434  *
 435  *****************************************************************************
 436  */
 437 static struct i2c_client *save_client;
 438
 439 /* Default margin */
 440 #define WD_TIMO 60              /* 1..31 seconds */
 441
 442 static int wdt_margin = WD_TIMO;
 443 module_param(wdt_margin, int, 0);
 444 MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)");
 445
 446 static unsigned long wdt_is_open;
 447 static int boot_flag;
 448
 449 /**
 450  *      wdt_ping:
 451  *
 452  *      Reload counter one with the watchdog timeout. We don't bother reloading
 453  *      the cascade counter.
 454  */
 455 static void wdt_ping(void)
 456 {
 457         unsigned char i2c_data[2];
 458         struct i2c_msg msgs1[1] = {
 459                 {
 460                         .addr   = save_client->addr,
 461                         .flags  = 0,
 462                         .len    = 2,
 463                         .buf    = i2c_data,
 464                 },
 465         };
 466         struct m41t80_data *clientdata = i2c_get_clientdata(save_client);
 467
 468         i2c_data[0] = 0x09;             /* watchdog register */
 469
 470         if (wdt_margin > 31)
 471                 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */
 472         else
 473                 /*
 474                  * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02)
 475                  */
 476                 i2c_data[1] = wdt_margin << 2 | 0x82;
 477
 478         /*
 479          * M41T65 has three bits for watchdog resolution.  Don't set bit 7, as
 480          * that would be an invalid resolution.
 481          */
 482         if (clientdata->features & M41T80_FEATURE_WD)
 483                 i2c_data[1] &= ~M41T80_WATCHDOG_RB2;
 484
 485         i2c_transfer(save_client->adapter, msgs1, 1);
 486 }
 487
 488 /**
 489  *      wdt_disable:
 490  *
 491  *      disables watchdog.
 492  */
 493 static void wdt_disable(void)
 494 {
 495         unsigned char i2c_data[2], i2c_buf[0x10];
 496         struct i2c_msg msgs0[2] = {
 497                 {
 498                         .addr   = save_client->addr,
 499                         .flags  = 0,
 500                         .len    = 1,
 501                         .buf    = i2c_data,
 502                 },
 503                 {
 504                         .addr   = save_client->addr,
 505                         .flags  = I2C_M_RD,
 506                         .len    = 1,
 507                         .buf    = i2c_buf,
 508                 },
 509         };
 510         struct i2c_msg msgs1[1] = {
 511                 {
 512                         .addr   = save_client->addr,
 513                         .flags  = 0,
 514                         .len    = 2,
 515                         .buf    = i2c_data,
 516                 },
 517         };
 518
 519         i2c_data[0] = 0x09;
 520         i2c_transfer(save_client->adapter, msgs0, 2);
 521
 522         i2c_data[0] = 0x09;
 523         i2c_data[1] = 0x00;
 524         i2c_transfer(save_client->adapter, msgs1, 1);
 525 }
 526
 527 /**
 528  *      wdt_write:
 529  *      @file: file handle to the watchdog
 530  *      @buf: buffer to write (unused as data does not matter here
 531  *      @count: count of bytes
 532  *      @ppos: pointer to the position to write. No seeks allowed
 533  *
 534  *      A write to a watchdog device is defined as a keepalive signal. Any
 535  *      write of data will do, as we we don't define content meaning.
 536  */
 537 static ssize_t wdt_write(struct file *file, const char __user *buf,
 538                          size_t count, loff_t *ppos)
 539 {
 540         if (count) {
 541                 wdt_ping();
 542                 return 1;
 543         }
 544         return 0;
 545 }
 546
 547 static ssize_t wdt_read(struct file *file, char __user *buf,
 548                         size_t count, loff_t *ppos)
 549 {
 550         return 0;
 551 }
 552
 553 /**
 554  *      wdt_ioctl:
 555  *      @inode: inode of the device
 556  *      @file: file handle to the device
 557  *      @cmd: watchdog command
 558  *      @arg: argument pointer
 559  *
 560  *      The watchdog API defines a common set of functions for all watchdogs
 561  *      according to their available features. We only actually usefully support
 562  *      querying capabilities and current status.
 563  */
 564 static int wdt_ioctl(struct file *file, unsigned int cmd,
 565                      unsigned long arg)
 566 {
 567         int new_margin, rv;
 568         static struct watchdog_info ident = {
 569                 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING |
 570                         WDIOF_SETTIMEOUT,
 571                 .firmware_version = 1,
 572                 .identity = "M41T80 WTD"
 573         };
 574
 575         switch (cmd) {
 576         case WDIOC_GETSUPPORT:
 577                 return copy_to_user((struct watchdog_info __user *)arg, &ident,
 578                                     sizeof(ident)) ? -EFAULT : 0;
 579
 580         case WDIOC_GETSTATUS:
 581         case WDIOC_GETBOOTSTATUS:
 582                 return put_user(boot_flag, (int __user *)arg);
 583         case WDIOC_KEEPALIVE:
 584                 wdt_ping();
 585                 return 0;
 586         case WDIOC_SETTIMEOUT:
 587                 if (get_user(new_margin, (int __user *)arg))
 588                         return -EFAULT;
 589                 /* Arbitrary, can't find the card's limits */
 590                 if (new_margin < 1 || new_margin > 124)
 591                         return -EINVAL;
 592                 wdt_margin = new_margin;
 593                 wdt_ping();
 594                 /* Fall */
 595         case WDIOC_GETTIMEOUT:
 596                 return put_user(wdt_margin, (int __user *)arg);
 597
 598         case WDIOC_SETOPTIONS:
 599                 if (copy_from_user(&rv, (int __user *)arg, sizeof(int)))
 600                         return -EFAULT;
 601
 602                 if (rv & WDIOS_DISABLECARD) {
 603                         pr_info("disable watchdog\n");
 604                         wdt_disable();
 605                 }
 606
 607                 if (rv & WDIOS_ENABLECARD) {
 608                         pr_info("enable watchdog\n");
 609                         wdt_ping();
 610                 }
 611
 612                 return -EINVAL;
 613         }
 614         return -ENOTTY;
 615 }
 616
 617 static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd,
 618                                unsigned long arg)
 619 {
 620         int ret;
 621
 622         mutex_lock(&m41t80_rtc_mutex);
 623         ret = wdt_ioctl(file, cmd, arg);
 624         mutex_unlock(&m41t80_rtc_mutex);
 625
 626         return ret;
 627 }
 628
 629 /**
 630  *      wdt_open:
 631  *      @inode: inode of device
 632  *      @file: file handle to device
 633  *
 634  */
 635 static int wdt_open(struct inode *inode, struct file *file)
 636 {
 637         if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
 638                 mutex_lock(&m41t80_rtc_mutex);
 639                 if (test_and_set_bit(0, &wdt_is_open)) {
 640                         mutex_unlock(&m41t80_rtc_mutex);
 641                         return -EBUSY;
 642                 }
 643                 /*
 644                  *      Activate
 645                  */
 646                 wdt_is_open = 1;
 647                 mutex_unlock(&m41t80_rtc_mutex);
 648                 return nonseekable_open(inode, file);
 649         }
 650         return -ENODEV;
 651 }
 652
 653 /**
 654  *      wdt_close:
 655  *      @inode: inode to board
 656  *      @file: file handle to board
 657  *
 658  */
 659 static int wdt_release(struct inode *inode, struct file *file)
 660 {
 661         if (MINOR(inode->i_rdev) == WATCHDOG_MINOR)
 662                 clear_bit(0, &wdt_is_open);
 663         return 0;
 664 }
 665
 666 /**
 667  *      notify_sys:
 668  *      @this: our notifier block
 669  *      @code: the event being reported
 670  *      @unused: unused
 671  *
 672  *      Our notifier is called on system shutdowns. We want to turn the card
 673  *      off at reboot otherwise the machine will reboot again during memory
 674  *      test or worse yet during the following fsck. This would suck, in fact
 675  *      trust me - if it happens it does suck.
 676  */
 677 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
 678                           void *unused)
 679 {
 680         if (code == SYS_DOWN || code == SYS_HALT)
 681                 /* Disable Watchdog */
 682                 wdt_disable();
 683         return NOTIFY_DONE;
 684 }
 685
 686 static const struct file_operations wdt_fops = {
 687         .owner  = THIS_MODULE,
 688         .read   = wdt_read,
 689         .unlocked_ioctl = wdt_unlocked_ioctl,
 690         .write  = wdt_write,
 691         .open   = wdt_open,
 692         .release = wdt_release,
 693         .llseek = no_llseek,
 694 };
 695
 696 static struct miscdevice wdt_dev = {
 697         .minor = WATCHDOG_MINOR,
 698         .name = "watchdog",
 699         .fops = &wdt_fops,
 700 };
 701
 702 /*
 703  *      The WDT card needs to learn about soft shutdowns in order to
 704  *      turn the timebomb registers off.
 705  */
 706 static struct notifier_block wdt_notifier = {
 707         .notifier_call = wdt_notify_sys,
 708 };
 709 #endif /* CONFIG_RTC_DRV_M41T80_WDT */
 710
 711 /*
 712  *****************************************************************************
 713  *
 714  *      Driver Interface
 715  *
 716  *****************************************************************************
 717  */
 718
 719 static void m41t80_remove_sysfs_group(void *_dev)
 720 {
 721         struct device *dev = _dev;
 722
 723         sysfs_remove_group(&dev->kobj, &attr_group);
 724 }
 725
 726 static int m41t80_probe(struct i2c_client *client,
 727                         const struct i2c_device_id *id)
 728 {
 729         struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
 730         int rc = 0;
 731         struct rtc_device *rtc = NULL;
 732         struct rtc_time tm;
 733         struct m41t80_data *m41t80_data = NULL;
 734
 735         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK |
 736                                      I2C_FUNC_SMBUS_BYTE_DATA)) {
 737                 dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n");
 738                 return -ENODEV;
 739         }
 740
 741         m41t80_data = devm_kzalloc(&client->dev, sizeof(*m41t80_data),
 742                                    GFP_KERNEL);
 743         if (!m41t80_data)
 744                 return -ENOMEM;
 745
 746         m41t80_data->features = id->driver_data;
 747         i2c_set_clientdata(client, m41t80_data);
 748
 749         if (client->irq > 0) {
 750                 rc = devm_request_threaded_irq(&client->dev, client->irq,
 751                                                NULL, m41t80_handle_irq,
 752                                                IRQF_TRIGGER_LOW | IRQF_ONESHOT,
 753                                                "m41t80", client);
 754                 if (rc) {
 755                         dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
 756                         client->irq = 0;
 757                 } else {
 758                         m41t80_rtc_ops.read_alarm = m41t80_read_alarm;
 759                         m41t80_rtc_ops.set_alarm = m41t80_set_alarm;
 760                         m41t80_rtc_ops.alarm_irq_enable = m41t80_alarm_irq_enable;
 761                 }
 762         }
 763
 764         rtc = devm_rtc_device_register(&client->dev, client->name,
 765                                        &m41t80_rtc_ops, THIS_MODULE);
 766         if (IS_ERR(rtc))
 767                 return PTR_ERR(rtc);
 768
 769         m41t80_data->rtc = rtc;
 770
 771         /* Make sure HT (Halt Update) bit is cleared */
 772         rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
 773
 774         if (rc >= 0 && rc & M41T80_ALHOUR_HT) {
 775                 if (m41t80_data->features & M41T80_FEATURE_HT) {
 776                         m41t80_get_datetime(client, &tm);
 777                         dev_info(&client->dev, "HT bit was set!\n");
 778                         dev_info(&client->dev,
 779                                  "Power Down at %04i-%02i-%02i %02i:%02i:%02i\n",
 780                                  tm.tm_year + 1900,
 781                                  tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,
 782                                  tm.tm_min, tm.tm_sec);
 783                 }
 784                 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_HOUR,
 785                                                rc & ~M41T80_ALHOUR_HT);
 786         }
 787
 788         if (rc < 0) {
 789                 dev_err(&client->dev, "Can't clear HT bit\n");
 790                 return rc;
 791         }
 792
 793         /* Make sure ST (stop) bit is cleared */
 794         rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
 795
 796         if (rc >= 0 && rc & M41T80_SEC_ST)
 797                 rc = i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
 798                                                rc & ~M41T80_SEC_ST);
 799         if (rc < 0) {
 800                 dev_err(&client->dev, "Can't clear ST bit\n");
 801                 return rc;
 802         }
 803
 804         /* Export sysfs entries */
 805         rc = sysfs_create_group(&(&client->dev)->kobj, &attr_group);
 806         if (rc) {
 807                 dev_err(&client->dev, "Failed to create sysfs group: %d\n", rc);
 808                 return rc;
 809         }
 810
 811         rc = devm_add_action(&client->dev, m41t80_remove_sysfs_group,
 812                              &client->dev);
 813         if (rc) {
 814                 m41t80_remove_sysfs_group(&client->dev);
 815                 dev_err(&client->dev,
 816                         "Failed to add sysfs cleanup action: %d\n", rc);
 817                 return rc;
 818         }
 819
 820 #ifdef CONFIG_RTC_DRV_M41T80_WDT
 821         if (m41t80_data->features & M41T80_FEATURE_HT) {
 822                 save_client = client;
 823                 rc = misc_register(&wdt_dev);
 824                 if (rc)
 825                         return rc;
 826                 rc = register_reboot_notifier(&wdt_notifier);
 827                 if (rc) {
 828                         misc_deregister(&wdt_dev);
 829                         return rc;
 830                 }
 831         }
 832 #endif
 833         return 0;
 834 }
 835
 836 static int m41t80_remove(struct i2c_client *client)
 837 {
 838 #ifdef CONFIG_RTC_DRV_M41T80_WDT
 839         struct m41t80_data *clientdata = i2c_get_clientdata(client);
 840
 841         if (clientdata->features & M41T80_FEATURE_HT) {
 842                 misc_deregister(&wdt_dev);
 843                 unregister_reboot_notifier(&wdt_notifier);
 844         }
 845 #endif
 846
 847         return 0;
 848 }
 849
 850 static struct i2c_driver m41t80_driver = {
 851         .driver = {
 852                 .name = "rtc-m41t80",
 853         },
 854         .probe = m41t80_probe,
 855         .remove = m41t80_remove,
 856         .id_table = m41t80_id,
 857 };
 858
 859 module_i2c_driver(m41t80_driver);
 860
 861 MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
 862 MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
 863 MODULE_LICENSE("GPL");