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/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");