linux/drivers/rtc/rtc-m41t80.c
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   1/*
   2 * I2C client/driver for the ST M41T80 family of i2c rtc chips.
   3 *
   4 * Author: Alexander Bigga <ab@mycable.de>
   5 *
   6 * Based on m41t00.c by Mark A. Greer <mgreer@mvista.com>
   7 *
   8 * 2006 (c) mycable GmbH
   9 *
  10 * This program is free software; you can redistribute it and/or modify
  11 * it under the terms of the GNU General Public License version 2 as
  12 * published by the Free Software Foundation.
  13 *
  14 */
  15
  16#include <linux/bcd.h>
  17#include <linux/i2c.h>
  18#include <linux/init.h>
  19#include <linux/kernel.h>
  20#include <linux/module.h>
  21#include <linux/rtc.h>
  22#include <linux/slab.h>
  23#include <linux/smp_lock.h>
  24#include <linux/string.h>
  25#ifdef CONFIG_RTC_DRV_M41T80_WDT
  26#include <linux/fs.h>
  27#include <linux/ioctl.h>
  28#include <linux/miscdevice.h>
  29#include <linux/reboot.h>
  30#include <linux/watchdog.h>
  31#endif
  32
  33#define M41T80_REG_SSEC 0
  34#define M41T80_REG_SEC  1
  35#define M41T80_REG_MIN  2
  36#define M41T80_REG_HOUR 3
  37#define M41T80_REG_WDAY 4
  38#define M41T80_REG_DAY  5
  39#define M41T80_REG_MON  6
  40#define M41T80_REG_YEAR 7
  41#define M41T80_REG_ALARM_MON    0xa
  42#define M41T80_REG_ALARM_DAY    0xb
  43#define M41T80_REG_ALARM_HOUR   0xc
  44#define M41T80_REG_ALARM_MIN    0xd
  45#define M41T80_REG_ALARM_SEC    0xe
  46#define M41T80_REG_FLAGS        0xf
  47#define M41T80_REG_SQW  0x13
  48
  49#define M41T80_DATETIME_REG_SIZE        (M41T80_REG_YEAR + 1)
  50#define M41T80_ALARM_REG_SIZE   \
  51        (M41T80_REG_ALARM_SEC + 1 - M41T80_REG_ALARM_MON)
  52
  53#define M41T80_SEC_ST           (1 << 7)        /* ST: Stop Bit */
  54#define M41T80_ALMON_AFE        (1 << 7)        /* AFE: AF Enable Bit */
  55#define M41T80_ALMON_SQWE       (1 << 6)        /* SQWE: SQW Enable Bit */
  56#define M41T80_ALHOUR_HT        (1 << 6)        /* HT: Halt Update Bit */
  57#define M41T80_FLAGS_AF         (1 << 6)        /* AF: Alarm Flag Bit */
  58#define M41T80_FLAGS_BATT_LOW   (1 << 4)        /* BL: Battery Low Bit */
  59#define M41T80_WATCHDOG_RB2     (1 << 7)        /* RB: Watchdog resolution */
  60#define M41T80_WATCHDOG_RB1     (1 << 1)        /* RB: Watchdog resolution */
  61#define M41T80_WATCHDOG_RB0     (1 << 0)        /* RB: Watchdog resolution */
  62
  63#define M41T80_FEATURE_HT       (1 << 0)        /* Halt feature */
  64#define M41T80_FEATURE_BL       (1 << 1)        /* Battery low indicator */
  65#define M41T80_FEATURE_SQ       (1 << 2)        /* Squarewave feature */
  66#define M41T80_FEATURE_WD       (1 << 3)        /* Extra watchdog resolution */
  67#define M41T80_FEATURE_SQ_ALT   (1 << 4)        /* RSx bits are in reg 4 */
  68
  69#define DRV_VERSION "0.05"
  70
  71static const struct i2c_device_id m41t80_id[] = {
  72        { "m41t62", M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT },
  73        { "m41t65", M41T80_FEATURE_HT | M41T80_FEATURE_WD },
  74        { "m41t80", M41T80_FEATURE_SQ },
  75        { "m41t81", M41T80_FEATURE_HT | M41T80_FEATURE_SQ},
  76        { "m41t81s", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
  77        { "m41t82", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
  78        { "m41t83", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
  79        { "m41st84", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
  80        { "m41st85", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
  81        { "m41st87", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
  82        { }
  83};
  84MODULE_DEVICE_TABLE(i2c, m41t80_id);
  85
  86struct m41t80_data {
  87        u8 features;
  88        struct rtc_device *rtc;
  89};
  90
  91static int m41t80_get_datetime(struct i2c_client *client,
  92                               struct rtc_time *tm)
  93{
  94        u8 buf[M41T80_DATETIME_REG_SIZE], dt_addr[1] = { M41T80_REG_SEC };
  95        struct i2c_msg msgs[] = {
  96                {
  97                        .addr   = client->addr,
  98                        .flags  = 0,
  99                        .len    = 1,
 100                        .buf    = dt_addr,
 101                },
 102                {
 103                        .addr   = client->addr,
 104                        .flags  = I2C_M_RD,
 105                        .len    = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
 106                        .buf    = buf + M41T80_REG_SEC,
 107                },
 108        };
 109
 110        if (i2c_transfer(client->adapter, msgs, 2) < 0) {
 111                dev_err(&client->dev, "read error\n");
 112                return -EIO;
 113        }
 114
 115        tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f);
 116        tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f);
 117        tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f);
 118        tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f);
 119        tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07;
 120        tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1;
 121
 122        /* assume 20YY not 19YY, and ignore the Century Bit */
 123        tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100;
 124        return 0;
 125}
 126
 127/* Sets the given date and time to the real time clock. */
 128static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm)
 129{
 130        u8 wbuf[1 + M41T80_DATETIME_REG_SIZE];
 131        u8 *buf = &wbuf[1];
 132        u8 dt_addr[1] = { M41T80_REG_SEC };
 133        struct i2c_msg msgs_in[] = {
 134                {
 135                        .addr   = client->addr,
 136                        .flags  = 0,
 137                        .len    = 1,
 138                        .buf    = dt_addr,
 139                },
 140                {
 141                        .addr   = client->addr,
 142                        .flags  = I2C_M_RD,
 143                        .len    = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
 144                        .buf    = buf + M41T80_REG_SEC,
 145                },
 146        };
 147        struct i2c_msg msgs[] = {
 148                {
 149                        .addr   = client->addr,
 150                        .flags  = 0,
 151                        .len    = 1 + M41T80_DATETIME_REG_SIZE,
 152                        .buf    = wbuf,
 153                 },
 154        };
 155
 156        /* Read current reg values into buf[1..7] */
 157        if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {
 158                dev_err(&client->dev, "read error\n");
 159                return -EIO;
 160        }
 161
 162        wbuf[0] = 0; /* offset into rtc's regs */
 163        /* Merge time-data and register flags into buf[0..7] */
 164        buf[M41T80_REG_SSEC] = 0;
 165        buf[M41T80_REG_SEC] =
 166                bin2bcd(tm->tm_sec) | (buf[M41T80_REG_SEC] & ~0x7f);
 167        buf[M41T80_REG_MIN] =
 168                bin2bcd(tm->tm_min) | (buf[M41T80_REG_MIN] & ~0x7f);
 169        buf[M41T80_REG_HOUR] =
 170                bin2bcd(tm->tm_hour) | (buf[M41T80_REG_HOUR] & ~0x3f) ;
 171        buf[M41T80_REG_WDAY] =
 172                (tm->tm_wday & 0x07) | (buf[M41T80_REG_WDAY] & ~0x07);
 173        buf[M41T80_REG_DAY] =
 174                bin2bcd(tm->tm_mday) | (buf[M41T80_REG_DAY] & ~0x3f);
 175        buf[M41T80_REG_MON] =
 176                bin2bcd(tm->tm_mon + 1) | (buf[M41T80_REG_MON] & ~0x1f);
 177        /* assume 20YY not 19YY */
 178        buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year % 100);
 179
 180        if (i2c_transfer(client->adapter, msgs, 1) != 1) {
 181                dev_err(&client->dev, "write error\n");
 182                return -EIO;
 183        }
 184        return 0;
 185}
 186
 187#if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
 188static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq)
 189{
 190        struct i2c_client *client = to_i2c_client(dev);
 191        struct m41t80_data *clientdata = i2c_get_clientdata(client);
 192        u8 reg;
 193
 194        if (clientdata->features & M41T80_FEATURE_BL) {
 195                reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
 196                seq_printf(seq, "battery\t\t: %s\n",
 197                           (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok");
 198        }
 199        return 0;
 200}
 201#else
 202#define m41t80_rtc_proc NULL
 203#endif
 204
 205static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm)
 206{
 207        return m41t80_get_datetime(to_i2c_client(dev), tm);
 208}
 209
 210static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm)
 211{
 212        return m41t80_set_datetime(to_i2c_client(dev), tm);
 213}
 214
 215#if defined(CONFIG_RTC_INTF_DEV) || defined(CONFIG_RTC_INTF_DEV_MODULE)
 216static int
 217m41t80_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 218{
 219        struct i2c_client *client = to_i2c_client(dev);
 220        int rc;
 221
 222        switch (cmd) {
 223        case RTC_AIE_OFF:
 224        case RTC_AIE_ON:
 225                break;
 226        default:
 227                return -ENOIOCTLCMD;
 228        }
 229
 230        rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
 231        if (rc < 0)
 232                goto err;
 233        switch (cmd) {
 234        case RTC_AIE_OFF:
 235                rc &= ~M41T80_ALMON_AFE;
 236                break;
 237        case RTC_AIE_ON:
 238                rc |= M41T80_ALMON_AFE;
 239                break;
 240        }
 241        if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, rc) < 0)
 242                goto err;
 243        return 0;
 244err:
 245        return -EIO;
 246}
 247#else
 248#define m41t80_rtc_ioctl NULL
 249#endif
 250
 251static int m41t80_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 252{
 253        struct i2c_client *client = to_i2c_client(dev);
 254        u8 wbuf[1 + M41T80_ALARM_REG_SIZE];
 255        u8 *buf = &wbuf[1];
 256        u8 *reg = buf - M41T80_REG_ALARM_MON;
 257        u8 dt_addr[1] = { M41T80_REG_ALARM_MON };
 258        struct i2c_msg msgs_in[] = {
 259                {
 260                        .addr   = client->addr,
 261                        .flags  = 0,
 262                        .len    = 1,
 263                        .buf    = dt_addr,
 264                },
 265                {
 266                        .addr   = client->addr,
 267                        .flags  = I2C_M_RD,
 268                        .len    = M41T80_ALARM_REG_SIZE,
 269                        .buf    = buf,
 270                },
 271        };
 272        struct i2c_msg msgs[] = {
 273                {
 274                        .addr   = client->addr,
 275                        .flags  = 0,
 276                        .len    = 1 + M41T80_ALARM_REG_SIZE,
 277                        .buf    = wbuf,
 278                 },
 279        };
 280
 281        if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {
 282                dev_err(&client->dev, "read error\n");
 283                return -EIO;
 284        }
 285        reg[M41T80_REG_ALARM_MON] &= ~(0x1f | M41T80_ALMON_AFE);
 286        reg[M41T80_REG_ALARM_DAY] = 0;
 287        reg[M41T80_REG_ALARM_HOUR] &= ~(0x3f | 0x80);
 288        reg[M41T80_REG_ALARM_MIN] = 0;
 289        reg[M41T80_REG_ALARM_SEC] = 0;
 290
 291        wbuf[0] = M41T80_REG_ALARM_MON; /* offset into rtc's regs */
 292        reg[M41T80_REG_ALARM_SEC] |= t->time.tm_sec >= 0 ?
 293                bin2bcd(t->time.tm_sec) : 0x80;
 294        reg[M41T80_REG_ALARM_MIN] |= t->time.tm_min >= 0 ?
 295                bin2bcd(t->time.tm_min) : 0x80;
 296        reg[M41T80_REG_ALARM_HOUR] |= t->time.tm_hour >= 0 ?
 297                bin2bcd(t->time.tm_hour) : 0x80;
 298        reg[M41T80_REG_ALARM_DAY] |= t->time.tm_mday >= 0 ?
 299                bin2bcd(t->time.tm_mday) : 0x80;
 300        if (t->time.tm_mon >= 0)
 301                reg[M41T80_REG_ALARM_MON] |= bin2bcd(t->time.tm_mon + 1);
 302        else
 303                reg[M41T80_REG_ALARM_DAY] |= 0x40;
 304
 305        if (i2c_transfer(client->adapter, msgs, 1) != 1) {
 306                dev_err(&client->dev, "write error\n");
 307                return -EIO;
 308        }
 309
 310        if (t->enabled) {
 311                reg[M41T80_REG_ALARM_MON] |= M41T80_ALMON_AFE;
 312                if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
 313                                              reg[M41T80_REG_ALARM_MON]) < 0) {
 314                        dev_err(&client->dev, "write error\n");
 315                        return -EIO;
 316                }
 317        }
 318        return 0;
 319}
 320
 321static int m41t80_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 322{
 323        struct i2c_client *client = to_i2c_client(dev);
 324        u8 buf[M41T80_ALARM_REG_SIZE + 1]; /* all alarm regs and flags */
 325        u8 dt_addr[1] = { M41T80_REG_ALARM_MON };
 326        u8 *reg = buf - M41T80_REG_ALARM_MON;
 327        struct i2c_msg msgs[] = {
 328                {
 329                        .addr   = client->addr,
 330                        .flags  = 0,
 331                        .len    = 1,
 332                        .buf    = dt_addr,
 333                },
 334                {
 335                        .addr   = client->addr,
 336                        .flags  = I2C_M_RD,
 337                        .len    = M41T80_ALARM_REG_SIZE + 1,
 338                        .buf    = buf,
 339                },
 340        };
 341
 342        if (i2c_transfer(client->adapter, msgs, 2) < 0) {
 343                dev_err(&client->dev, "read error\n");
 344                return -EIO;
 345        }
 346        t->time.tm_sec = -1;
 347        t->time.tm_min = -1;
 348        t->time.tm_hour = -1;
 349        t->time.tm_mday = -1;
 350        t->time.tm_mon = -1;
 351        if (!(reg[M41T80_REG_ALARM_SEC] & 0x80))
 352                t->time.tm_sec = bcd2bin(reg[M41T80_REG_ALARM_SEC] & 0x7f);
 353        if (!(reg[M41T80_REG_ALARM_MIN] & 0x80))
 354                t->time.tm_min = bcd2bin(reg[M41T80_REG_ALARM_MIN] & 0x7f);
 355        if (!(reg[M41T80_REG_ALARM_HOUR] & 0x80))
 356                t->time.tm_hour = bcd2bin(reg[M41T80_REG_ALARM_HOUR] & 0x3f);
 357        if (!(reg[M41T80_REG_ALARM_DAY] & 0x80))
 358                t->time.tm_mday = bcd2bin(reg[M41T80_REG_ALARM_DAY] & 0x3f);
 359        if (!(reg[M41T80_REG_ALARM_DAY] & 0x40))
 360                t->time.tm_mon = bcd2bin(reg[M41T80_REG_ALARM_MON] & 0x1f) - 1;
 361        t->time.tm_year = -1;
 362        t->time.tm_wday = -1;
 363        t->time.tm_yday = -1;
 364        t->time.tm_isdst = -1;
 365        t->enabled = !!(reg[M41T80_REG_ALARM_MON] & M41T80_ALMON_AFE);
 366        t->pending = !!(reg[M41T80_REG_FLAGS] & M41T80_FLAGS_AF);
 367        return 0;
 368}
 369
 370static struct rtc_class_ops m41t80_rtc_ops = {
 371        .read_time = m41t80_rtc_read_time,
 372        .set_time = m41t80_rtc_set_time,
 373        .read_alarm = m41t80_rtc_read_alarm,
 374        .set_alarm = m41t80_rtc_set_alarm,
 375        .proc = m41t80_rtc_proc,
 376        .ioctl = m41t80_rtc_ioctl,
 377};
 378
 379#if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
 380static ssize_t m41t80_sysfs_show_flags(struct device *dev,
 381                                struct device_attribute *attr, char *buf)
 382{
 383        struct i2c_client *client = to_i2c_client(dev);
 384        int val;
 385
 386        val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
 387        if (val < 0)
 388                return -EIO;
 389        return sprintf(buf, "%#x\n", val);
 390}
 391static DEVICE_ATTR(flags, S_IRUGO, m41t80_sysfs_show_flags, NULL);
 392
 393static ssize_t m41t80_sysfs_show_sqwfreq(struct device *dev,
 394                                struct device_attribute *attr, char *buf)
 395{
 396        struct i2c_client *client = to_i2c_client(dev);
 397        struct m41t80_data *clientdata = i2c_get_clientdata(client);
 398        int val, reg_sqw;
 399
 400        if (!(clientdata->features & M41T80_FEATURE_SQ))
 401                return -EINVAL;
 402
 403        reg_sqw = M41T80_REG_SQW;
 404        if (clientdata->features & M41T80_FEATURE_SQ_ALT)
 405                reg_sqw = M41T80_REG_WDAY;
 406        val = i2c_smbus_read_byte_data(client, reg_sqw);
 407        if (val < 0)
 408                return -EIO;
 409        val = (val >> 4) & 0xf;
 410        switch (val) {
 411        case 0:
 412                break;
 413        case 1:
 414                val = 32768;
 415                break;
 416        default:
 417                val = 32768 >> val;
 418        }
 419        return sprintf(buf, "%d\n", val);
 420}
 421static ssize_t m41t80_sysfs_set_sqwfreq(struct device *dev,
 422                                struct device_attribute *attr,
 423                                const char *buf, size_t count)
 424{
 425        struct i2c_client *client = to_i2c_client(dev);
 426        struct m41t80_data *clientdata = i2c_get_clientdata(client);
 427        int almon, sqw, reg_sqw;
 428        int val = simple_strtoul(buf, NULL, 0);
 429
 430        if (!(clientdata->features & M41T80_FEATURE_SQ))
 431                return -EINVAL;
 432
 433        if (val) {
 434                if (!is_power_of_2(val))
 435                        return -EINVAL;
 436                val = ilog2(val);
 437                if (val == 15)
 438                        val = 1;
 439                else if (val < 14)
 440                        val = 15 - val;
 441                else
 442                        return -EINVAL;
 443        }
 444        /* disable SQW, set SQW frequency & re-enable */
 445        almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
 446        if (almon < 0)
 447                return -EIO;
 448        reg_sqw = M41T80_REG_SQW;
 449        if (clientdata->features & M41T80_FEATURE_SQ_ALT)
 450                reg_sqw = M41T80_REG_WDAY;
 451        sqw = i2c_smbus_read_byte_data(client, reg_sqw);
 452        if (sqw < 0)
 453                return -EIO;
 454        sqw = (sqw & 0x0f) | (val << 4);
 455        if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
 456                                      almon & ~M41T80_ALMON_SQWE) < 0 ||
 457            i2c_smbus_write_byte_data(client, reg_sqw, sqw) < 0)
 458                return -EIO;
 459        if (val && i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
 460                                             almon | M41T80_ALMON_SQWE) < 0)
 461                return -EIO;
 462        return count;
 463}
 464static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR,
 465                   m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq);
 466
 467static struct attribute *attrs[] = {
 468        &dev_attr_flags.attr,
 469        &dev_attr_sqwfreq.attr,
 470        NULL,
 471};
 472static struct attribute_group attr_group = {
 473        .attrs = attrs,
 474};
 475
 476static int m41t80_sysfs_register(struct device *dev)
 477{
 478        return sysfs_create_group(&dev->kobj, &attr_group);
 479}
 480#else
 481static int m41t80_sysfs_register(struct device *dev)
 482{
 483        return 0;
 484}
 485#endif
 486
 487#ifdef CONFIG_RTC_DRV_M41T80_WDT
 488/*
 489 *****************************************************************************
 490 *
 491 * Watchdog Driver
 492 *
 493 *****************************************************************************
 494 */
 495static struct i2c_client *save_client;
 496
 497/* Default margin */
 498#define WD_TIMO 60              /* 1..31 seconds */
 499
 500static int wdt_margin = WD_TIMO;
 501module_param(wdt_margin, int, 0);
 502MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)");
 503
 504static unsigned long wdt_is_open;
 505static int boot_flag;
 506
 507/**
 508 *      wdt_ping:
 509 *
 510 *      Reload counter one with the watchdog timeout. We don't bother reloading
 511 *      the cascade counter.
 512 */
 513static void wdt_ping(void)
 514{
 515        unsigned char i2c_data[2];
 516        struct i2c_msg msgs1[1] = {
 517                {
 518                        .addr   = save_client->addr,
 519                        .flags  = 0,
 520                        .len    = 2,
 521                        .buf    = i2c_data,
 522                },
 523        };
 524        struct m41t80_data *clientdata = i2c_get_clientdata(save_client);
 525
 526        i2c_data[0] = 0x09;             /* watchdog register */
 527
 528        if (wdt_margin > 31)
 529                i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */
 530        else
 531                /*
 532                 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02)
 533                 */
 534                i2c_data[1] = wdt_margin<<2 | 0x82;
 535
 536        /*
 537         * M41T65 has three bits for watchdog resolution.  Don't set bit 7, as
 538         * that would be an invalid resolution.
 539         */
 540        if (clientdata->features & M41T80_FEATURE_WD)
 541                i2c_data[1] &= ~M41T80_WATCHDOG_RB2;
 542
 543        i2c_transfer(save_client->adapter, msgs1, 1);
 544}
 545
 546/**
 547 *      wdt_disable:
 548 *
 549 *      disables watchdog.
 550 */
 551static void wdt_disable(void)
 552{
 553        unsigned char i2c_data[2], i2c_buf[0x10];
 554        struct i2c_msg msgs0[2] = {
 555                {
 556                        .addr   = save_client->addr,
 557                        .flags  = 0,
 558                        .len    = 1,
 559                        .buf    = i2c_data,
 560                },
 561                {
 562                        .addr   = save_client->addr,
 563                        .flags  = I2C_M_RD,
 564                        .len    = 1,
 565                        .buf    = i2c_buf,
 566                },
 567        };
 568        struct i2c_msg msgs1[1] = {
 569                {
 570                        .addr   = save_client->addr,
 571                        .flags  = 0,
 572                        .len    = 2,
 573                        .buf    = i2c_data,
 574                },
 575        };
 576
 577        i2c_data[0] = 0x09;
 578        i2c_transfer(save_client->adapter, msgs0, 2);
 579
 580        i2c_data[0] = 0x09;
 581        i2c_data[1] = 0x00;
 582        i2c_transfer(save_client->adapter, msgs1, 1);
 583}
 584
 585/**
 586 *      wdt_write:
 587 *      @file: file handle to the watchdog
 588 *      @buf: buffer to write (unused as data does not matter here
 589 *      @count: count of bytes
 590 *      @ppos: pointer to the position to write. No seeks allowed
 591 *
 592 *      A write to a watchdog device is defined as a keepalive signal. Any
 593 *      write of data will do, as we we don't define content meaning.
 594 */
 595static ssize_t wdt_write(struct file *file, const char __user *buf,
 596                         size_t count, loff_t *ppos)
 597{
 598        /*  Can't seek (pwrite) on this device
 599        if (ppos != &file->f_pos)
 600        return -ESPIPE;
 601        */
 602        if (count) {
 603                wdt_ping();
 604                return 1;
 605        }
 606        return 0;
 607}
 608
 609static ssize_t wdt_read(struct file *file, char __user *buf,
 610                        size_t count, loff_t *ppos)
 611{
 612        return 0;
 613}
 614
 615/**
 616 *      wdt_ioctl:
 617 *      @inode: inode of the device
 618 *      @file: file handle to the device
 619 *      @cmd: watchdog command
 620 *      @arg: argument pointer
 621 *
 622 *      The watchdog API defines a common set of functions for all watchdogs
 623 *      according to their available features. We only actually usefully support
 624 *      querying capabilities and current status.
 625 */
 626static int wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 627                     unsigned long arg)
 628{
 629        int new_margin, rv;
 630        static struct watchdog_info ident = {
 631                .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING |
 632                        WDIOF_SETTIMEOUT,
 633                .firmware_version = 1,
 634                .identity = "M41T80 WTD"
 635        };
 636
 637        switch (cmd) {
 638        case WDIOC_GETSUPPORT:
 639                return copy_to_user((struct watchdog_info __user *)arg, &ident,
 640                                    sizeof(ident)) ? -EFAULT : 0;
 641
 642        case WDIOC_GETSTATUS:
 643        case WDIOC_GETBOOTSTATUS:
 644                return put_user(boot_flag, (int __user *)arg);
 645        case WDIOC_KEEPALIVE:
 646                wdt_ping();
 647                return 0;
 648        case WDIOC_SETTIMEOUT:
 649                if (get_user(new_margin, (int __user *)arg))
 650                        return -EFAULT;
 651                /* Arbitrary, can't find the card's limits */
 652                if (new_margin < 1 || new_margin > 124)
 653                        return -EINVAL;
 654                wdt_margin = new_margin;
 655                wdt_ping();
 656                /* Fall */
 657        case WDIOC_GETTIMEOUT:
 658                return put_user(wdt_margin, (int __user *)arg);
 659
 660        case WDIOC_SETOPTIONS:
 661                if (copy_from_user(&rv, (int __user *)arg, sizeof(int)))
 662                        return -EFAULT;
 663
 664                if (rv & WDIOS_DISABLECARD) {
 665                        pr_info("rtc-m41t80: disable watchdog\n");
 666                        wdt_disable();
 667                }
 668
 669                if (rv & WDIOS_ENABLECARD) {
 670                        pr_info("rtc-m41t80: enable watchdog\n");
 671                        wdt_ping();
 672                }
 673
 674                return -EINVAL;
 675        }
 676        return -ENOTTY;
 677}
 678
 679/**
 680 *      wdt_open:
 681 *      @inode: inode of device
 682 *      @file: file handle to device
 683 *
 684 */
 685static int wdt_open(struct inode *inode, struct file *file)
 686{
 687        if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
 688                lock_kernel();
 689                if (test_and_set_bit(0, &wdt_is_open)) {
 690                        unlock_kernel();
 691                        return -EBUSY;
 692                }
 693                /*
 694                 *      Activate
 695                 */
 696                wdt_is_open = 1;
 697                unlock_kernel();
 698                return 0;
 699        }
 700        return -ENODEV;
 701}
 702
 703/**
 704 *      wdt_close:
 705 *      @inode: inode to board
 706 *      @file: file handle to board
 707 *
 708 */
 709static int wdt_release(struct inode *inode, struct file *file)
 710{
 711        if (MINOR(inode->i_rdev) == WATCHDOG_MINOR)
 712                clear_bit(0, &wdt_is_open);
 713        return 0;
 714}
 715
 716/**
 717 *      notify_sys:
 718 *      @this: our notifier block
 719 *      @code: the event being reported
 720 *      @unused: unused
 721 *
 722 *      Our notifier is called on system shutdowns. We want to turn the card
 723 *      off at reboot otherwise the machine will reboot again during memory
 724 *      test or worse yet during the following fsck. This would suck, in fact
 725 *      trust me - if it happens it does suck.
 726 */
 727static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
 728                          void *unused)
 729{
 730        if (code == SYS_DOWN || code == SYS_HALT)
 731                /* Disable Watchdog */
 732                wdt_disable();
 733        return NOTIFY_DONE;
 734}
 735
 736static const struct file_operations wdt_fops = {
 737        .owner  = THIS_MODULE,
 738        .read   = wdt_read,
 739        .ioctl  = wdt_ioctl,
 740        .write  = wdt_write,
 741        .open   = wdt_open,
 742        .release = wdt_release,
 743};
 744
 745static struct miscdevice wdt_dev = {
 746        .minor = WATCHDOG_MINOR,
 747        .name = "watchdog",
 748        .fops = &wdt_fops,
 749};
 750
 751/*
 752 *      The WDT card needs to learn about soft shutdowns in order to
 753 *      turn the timebomb registers off.
 754 */
 755static struct notifier_block wdt_notifier = {
 756        .notifier_call = wdt_notify_sys,
 757};
 758#endif /* CONFIG_RTC_DRV_M41T80_WDT */
 759
 760/*
 761 *****************************************************************************
 762 *
 763 *      Driver Interface
 764 *
 765 *****************************************************************************
 766 */
 767static int m41t80_probe(struct i2c_client *client,
 768                        const struct i2c_device_id *id)
 769{
 770        int rc = 0;
 771        struct rtc_device *rtc = NULL;
 772        struct rtc_time tm;
 773        struct m41t80_data *clientdata = NULL;
 774
 775        if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C
 776                                     | I2C_FUNC_SMBUS_BYTE_DATA)) {
 777                rc = -ENODEV;
 778                goto exit;
 779        }
 780
 781        dev_info(&client->dev,
 782                 "chip found, driver version " DRV_VERSION "\n");
 783
 784        clientdata = kzalloc(sizeof(*clientdata), GFP_KERNEL);
 785        if (!clientdata) {
 786                rc = -ENOMEM;
 787                goto exit;
 788        }
 789
 790        rtc = rtc_device_register(client->name, &client->dev,
 791                                  &m41t80_rtc_ops, THIS_MODULE);
 792        if (IS_ERR(rtc)) {
 793                rc = PTR_ERR(rtc);
 794                rtc = NULL;
 795                goto exit;
 796        }
 797
 798        clientdata->rtc = rtc;
 799        clientdata->features = id->driver_data;
 800        i2c_set_clientdata(client, clientdata);
 801
 802        /* Make sure HT (Halt Update) bit is cleared */
 803        rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
 804        if (rc < 0)
 805                goto ht_err;
 806
 807        if (rc & M41T80_ALHOUR_HT) {
 808                if (clientdata->features & M41T80_FEATURE_HT) {
 809                        m41t80_get_datetime(client, &tm);
 810                        dev_info(&client->dev, "HT bit was set!\n");
 811                        dev_info(&client->dev,
 812                                 "Power Down at "
 813                                 "%04i-%02i-%02i %02i:%02i:%02i\n",
 814                                 tm.tm_year + 1900,
 815                                 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,
 816                                 tm.tm_min, tm.tm_sec);
 817                }
 818                if (i2c_smbus_write_byte_data(client,
 819                                              M41T80_REG_ALARM_HOUR,
 820                                              rc & ~M41T80_ALHOUR_HT) < 0)
 821                        goto ht_err;
 822        }
 823
 824        /* Make sure ST (stop) bit is cleared */
 825        rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
 826        if (rc < 0)
 827                goto st_err;
 828
 829        if (rc & M41T80_SEC_ST) {
 830                if (i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
 831                                              rc & ~M41T80_SEC_ST) < 0)
 832                        goto st_err;
 833        }
 834
 835        rc = m41t80_sysfs_register(&client->dev);
 836        if (rc)
 837                goto exit;
 838
 839#ifdef CONFIG_RTC_DRV_M41T80_WDT
 840        if (clientdata->features & M41T80_FEATURE_HT) {
 841                save_client = client;
 842                rc = misc_register(&wdt_dev);
 843                if (rc)
 844                        goto exit;
 845                rc = register_reboot_notifier(&wdt_notifier);
 846                if (rc) {
 847                        misc_deregister(&wdt_dev);
 848                        goto exit;
 849                }
 850        }
 851#endif
 852        return 0;
 853
 854st_err:
 855        rc = -EIO;
 856        dev_err(&client->dev, "Can't clear ST bit\n");
 857        goto exit;
 858ht_err:
 859        rc = -EIO;
 860        dev_err(&client->dev, "Can't clear HT bit\n");
 861        goto exit;
 862
 863exit:
 864        if (rtc)
 865                rtc_device_unregister(rtc);
 866        kfree(clientdata);
 867        return rc;
 868}
 869
 870static int m41t80_remove(struct i2c_client *client)
 871{
 872        struct m41t80_data *clientdata = i2c_get_clientdata(client);
 873        struct rtc_device *rtc = clientdata->rtc;
 874
 875#ifdef CONFIG_RTC_DRV_M41T80_WDT
 876        if (clientdata->features & M41T80_FEATURE_HT) {
 877                misc_deregister(&wdt_dev);
 878                unregister_reboot_notifier(&wdt_notifier);
 879        }
 880#endif
 881        if (rtc)
 882                rtc_device_unregister(rtc);
 883        kfree(clientdata);
 884
 885        return 0;
 886}
 887
 888static struct i2c_driver m41t80_driver = {
 889        .driver = {
 890                .name = "rtc-m41t80",
 891        },
 892        .probe = m41t80_probe,
 893        .remove = m41t80_remove,
 894        .id_table = m41t80_id,
 895};
 896
 897static int __init m41t80_rtc_init(void)
 898{
 899        return i2c_add_driver(&m41t80_driver);
 900}
 901
 902static void __exit m41t80_rtc_exit(void)
 903{
 904        i2c_del_driver(&m41t80_driver);
 905}
 906
 907MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
 908MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
 909MODULE_LICENSE("GPL");
 910MODULE_VERSION(DRV_VERSION);
 911
 912module_init(m41t80_rtc_init);
 913module_exit(m41t80_rtc_exit);
 914