linux/drivers/rtc/rtc-s35390a.c
<<
>>
Prefs
   1/*
   2 * Seiko Instruments S-35390A RTC Driver
   3 *
   4 * Copyright (c) 2007 Byron Bradley
   5 *
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public License
   8 * as published by the Free Software Foundation; either version
   9 * 2 of the License, or (at your option) any later version.
  10 */
  11
  12#include <linux/module.h>
  13#include <linux/rtc.h>
  14#include <linux/i2c.h>
  15#include <linux/bitrev.h>
  16#include <linux/bcd.h>
  17#include <linux/slab.h>
  18
  19#define S35390A_CMD_STATUS1     0
  20#define S35390A_CMD_STATUS2     1
  21#define S35390A_CMD_TIME1       2
  22#define S35390A_CMD_TIME2       3
  23#define S35390A_CMD_INT2_REG1   5
  24
  25#define S35390A_BYTE_YEAR       0
  26#define S35390A_BYTE_MONTH      1
  27#define S35390A_BYTE_DAY        2
  28#define S35390A_BYTE_WDAY       3
  29#define S35390A_BYTE_HOURS      4
  30#define S35390A_BYTE_MINS       5
  31#define S35390A_BYTE_SECS       6
  32
  33#define S35390A_ALRM_BYTE_WDAY  0
  34#define S35390A_ALRM_BYTE_HOURS 1
  35#define S35390A_ALRM_BYTE_MINS  2
  36
  37#define S35390A_FLAG_POC        0x01
  38#define S35390A_FLAG_BLD        0x02
  39#define S35390A_FLAG_24H        0x40
  40#define S35390A_FLAG_RESET      0x80
  41#define S35390A_FLAG_TEST       0x01
  42
  43#define S35390A_INT2_MODE_MASK          0xF0
  44
  45#define S35390A_INT2_MODE_NOINTR        0x00
  46#define S35390A_INT2_MODE_FREQ          0x10
  47#define S35390A_INT2_MODE_ALARM         0x40
  48#define S35390A_INT2_MODE_PMIN_EDG      0x20
  49
  50static const struct i2c_device_id s35390a_id[] = {
  51        { "s35390a", 0 },
  52        { }
  53};
  54MODULE_DEVICE_TABLE(i2c, s35390a_id);
  55
  56struct s35390a {
  57        struct i2c_client *client[8];
  58        struct rtc_device *rtc;
  59        int twentyfourhour;
  60};
  61
  62static int s35390a_set_reg(struct s35390a *s35390a, int reg, char *buf, int len)
  63{
  64        struct i2c_client *client = s35390a->client[reg];
  65        struct i2c_msg msg[] = {
  66                {
  67                        .addr = client->addr,
  68                        .len = len,
  69                        .buf = buf
  70                },
  71        };
  72
  73        if ((i2c_transfer(client->adapter, msg, 1)) != 1)
  74                return -EIO;
  75
  76        return 0;
  77}
  78
  79static int s35390a_get_reg(struct s35390a *s35390a, int reg, char *buf, int len)
  80{
  81        struct i2c_client *client = s35390a->client[reg];
  82        struct i2c_msg msg[] = {
  83                {
  84                        .addr = client->addr,
  85                        .flags = I2C_M_RD,
  86                        .len = len,
  87                        .buf = buf
  88                },
  89        };
  90
  91        if ((i2c_transfer(client->adapter, msg, 1)) != 1)
  92                return -EIO;
  93
  94        return 0;
  95}
  96
  97static int s35390a_reset(struct s35390a *s35390a)
  98{
  99        char buf[1];
 100
 101        if (s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf)) < 0)
 102                return -EIO;
 103
 104        if (!(buf[0] & (S35390A_FLAG_POC | S35390A_FLAG_BLD)))
 105                return 0;
 106
 107        buf[0] |= (S35390A_FLAG_RESET | S35390A_FLAG_24H);
 108        buf[0] &= 0xf0;
 109        return s35390a_set_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf));
 110}
 111
 112static int s35390a_disable_test_mode(struct s35390a *s35390a)
 113{
 114        char buf[1];
 115
 116        if (s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf)) < 0)
 117                return -EIO;
 118
 119        if (!(buf[0] & S35390A_FLAG_TEST))
 120                return 0;
 121
 122        buf[0] &= ~S35390A_FLAG_TEST;
 123        return s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf));
 124}
 125
 126static char s35390a_hr2reg(struct s35390a *s35390a, int hour)
 127{
 128        if (s35390a->twentyfourhour)
 129                return bin2bcd(hour);
 130
 131        if (hour < 12)
 132                return bin2bcd(hour);
 133
 134        return 0x40 | bin2bcd(hour - 12);
 135}
 136
 137static int s35390a_reg2hr(struct s35390a *s35390a, char reg)
 138{
 139        unsigned hour;
 140
 141        if (s35390a->twentyfourhour)
 142                return bcd2bin(reg & 0x3f);
 143
 144        hour = bcd2bin(reg & 0x3f);
 145        if (reg & 0x40)
 146                hour += 12;
 147
 148        return hour;
 149}
 150
 151static int s35390a_set_datetime(struct i2c_client *client, struct rtc_time *tm)
 152{
 153        struct s35390a  *s35390a = i2c_get_clientdata(client);
 154        int i, err;
 155        char buf[7];
 156
 157        dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d mday=%d, "
 158                "mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec,
 159                tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year,
 160                tm->tm_wday);
 161
 162        buf[S35390A_BYTE_YEAR] = bin2bcd(tm->tm_year - 100);
 163        buf[S35390A_BYTE_MONTH] = bin2bcd(tm->tm_mon + 1);
 164        buf[S35390A_BYTE_DAY] = bin2bcd(tm->tm_mday);
 165        buf[S35390A_BYTE_WDAY] = bin2bcd(tm->tm_wday);
 166        buf[S35390A_BYTE_HOURS] = s35390a_hr2reg(s35390a, tm->tm_hour);
 167        buf[S35390A_BYTE_MINS] = bin2bcd(tm->tm_min);
 168        buf[S35390A_BYTE_SECS] = bin2bcd(tm->tm_sec);
 169
 170        /* This chip expects the bits of each byte to be in reverse order */
 171        for (i = 0; i < 7; ++i)
 172                buf[i] = bitrev8(buf[i]);
 173
 174        err = s35390a_set_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf));
 175
 176        return err;
 177}
 178
 179static int s35390a_get_datetime(struct i2c_client *client, struct rtc_time *tm)
 180{
 181        struct s35390a *s35390a = i2c_get_clientdata(client);
 182        char buf[7];
 183        int i, err;
 184
 185        err = s35390a_get_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf));
 186        if (err < 0)
 187                return err;
 188
 189        /* This chip returns the bits of each byte in reverse order */
 190        for (i = 0; i < 7; ++i)
 191                buf[i] = bitrev8(buf[i]);
 192
 193        tm->tm_sec = bcd2bin(buf[S35390A_BYTE_SECS]);
 194        tm->tm_min = bcd2bin(buf[S35390A_BYTE_MINS]);
 195        tm->tm_hour = s35390a_reg2hr(s35390a, buf[S35390A_BYTE_HOURS]);
 196        tm->tm_wday = bcd2bin(buf[S35390A_BYTE_WDAY]);
 197        tm->tm_mday = bcd2bin(buf[S35390A_BYTE_DAY]);
 198        tm->tm_mon = bcd2bin(buf[S35390A_BYTE_MONTH]) - 1;
 199        tm->tm_year = bcd2bin(buf[S35390A_BYTE_YEAR]) + 100;
 200
 201        dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, mday=%d, "
 202                "mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec,
 203                tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year,
 204                tm->tm_wday);
 205
 206        return rtc_valid_tm(tm);
 207}
 208
 209static int s35390a_set_alarm(struct i2c_client *client, struct rtc_wkalrm *alm)
 210{
 211        struct s35390a *s35390a = i2c_get_clientdata(client);
 212        char buf[3], sts = 0;
 213        int err, i;
 214
 215        dev_dbg(&client->dev, "%s: alm is secs=%d, mins=%d, hours=%d mday=%d, "\
 216                "mon=%d, year=%d, wday=%d\n", __func__, alm->time.tm_sec,
 217                alm->time.tm_min, alm->time.tm_hour, alm->time.tm_mday,
 218                alm->time.tm_mon, alm->time.tm_year, alm->time.tm_wday);
 219
 220        /* disable interrupt */
 221        err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
 222        if (err < 0)
 223                return err;
 224
 225        /* clear pending interrupt, if any */
 226        err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, &sts, sizeof(sts));
 227        if (err < 0)
 228                return err;
 229
 230        if (alm->enabled)
 231                sts = S35390A_INT2_MODE_ALARM;
 232        else
 233                sts = S35390A_INT2_MODE_NOINTR;
 234
 235        /* This chip expects the bits of each byte to be in reverse order */
 236        sts = bitrev8(sts);
 237
 238        /* set interupt mode*/
 239        err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
 240        if (err < 0)
 241                return err;
 242
 243        if (alm->time.tm_wday != -1)
 244                buf[S35390A_ALRM_BYTE_WDAY] = bin2bcd(alm->time.tm_wday) | 0x80;
 245
 246        buf[S35390A_ALRM_BYTE_HOURS] = s35390a_hr2reg(s35390a,
 247                        alm->time.tm_hour) | 0x80;
 248        buf[S35390A_ALRM_BYTE_MINS] = bin2bcd(alm->time.tm_min) | 0x80;
 249
 250        if (alm->time.tm_hour >= 12)
 251                buf[S35390A_ALRM_BYTE_HOURS] |= 0x40;
 252
 253        for (i = 0; i < 3; ++i)
 254                buf[i] = bitrev8(buf[i]);
 255
 256        err = s35390a_set_reg(s35390a, S35390A_CMD_INT2_REG1, buf,
 257                                                                sizeof(buf));
 258
 259        return err;
 260}
 261
 262static int s35390a_read_alarm(struct i2c_client *client, struct rtc_wkalrm *alm)
 263{
 264        struct s35390a *s35390a = i2c_get_clientdata(client);
 265        char buf[3], sts;
 266        int i, err;
 267
 268        err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
 269        if (err < 0)
 270                return err;
 271
 272        if (bitrev8(sts) != S35390A_INT2_MODE_ALARM)
 273                return -EINVAL;
 274
 275        err = s35390a_get_reg(s35390a, S35390A_CMD_INT2_REG1, buf, sizeof(buf));
 276        if (err < 0)
 277                return err;
 278
 279        /* This chip returns the bits of each byte in reverse order */
 280        for (i = 0; i < 3; ++i) {
 281                buf[i] = bitrev8(buf[i]);
 282                buf[i] &= ~0x80;
 283        }
 284
 285        alm->time.tm_wday = bcd2bin(buf[S35390A_ALRM_BYTE_WDAY]);
 286        alm->time.tm_hour = s35390a_reg2hr(s35390a,
 287                                                buf[S35390A_ALRM_BYTE_HOURS]);
 288        alm->time.tm_min = bcd2bin(buf[S35390A_ALRM_BYTE_MINS]);
 289
 290        dev_dbg(&client->dev, "%s: alm is mins=%d, hours=%d, wday=%d\n",
 291                        __func__, alm->time.tm_min, alm->time.tm_hour,
 292                        alm->time.tm_wday);
 293
 294        return 0;
 295}
 296
 297static int s35390a_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 298{
 299        return s35390a_read_alarm(to_i2c_client(dev), alm);
 300}
 301
 302static int s35390a_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 303{
 304        return s35390a_set_alarm(to_i2c_client(dev), alm);
 305}
 306
 307static int s35390a_rtc_read_time(struct device *dev, struct rtc_time *tm)
 308{
 309        return s35390a_get_datetime(to_i2c_client(dev), tm);
 310}
 311
 312static int s35390a_rtc_set_time(struct device *dev, struct rtc_time *tm)
 313{
 314        return s35390a_set_datetime(to_i2c_client(dev), tm);
 315}
 316
 317static const struct rtc_class_ops s35390a_rtc_ops = {
 318        .read_time      = s35390a_rtc_read_time,
 319        .set_time       = s35390a_rtc_set_time,
 320        .set_alarm      = s35390a_rtc_set_alarm,
 321        .read_alarm     = s35390a_rtc_read_alarm,
 322
 323};
 324
 325static struct i2c_driver s35390a_driver;
 326
 327static int s35390a_probe(struct i2c_client *client,
 328                         const struct i2c_device_id *id)
 329{
 330        int err;
 331        unsigned int i;
 332        struct s35390a *s35390a;
 333        struct rtc_time tm;
 334        char buf[1];
 335
 336        if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 337                err = -ENODEV;
 338                goto exit;
 339        }
 340
 341        s35390a = kzalloc(sizeof(struct s35390a), GFP_KERNEL);
 342        if (!s35390a) {
 343                err = -ENOMEM;
 344                goto exit;
 345        }
 346
 347        s35390a->client[0] = client;
 348        i2c_set_clientdata(client, s35390a);
 349
 350        /* This chip uses multiple addresses, use dummy devices for them */
 351        for (i = 1; i < 8; ++i) {
 352                s35390a->client[i] = i2c_new_dummy(client->adapter,
 353                                        client->addr + i);
 354                if (!s35390a->client[i]) {
 355                        dev_err(&client->dev, "Address %02x unavailable\n",
 356                                                client->addr + i);
 357                        err = -EBUSY;
 358                        goto exit_dummy;
 359                }
 360        }
 361
 362        err = s35390a_reset(s35390a);
 363        if (err < 0) {
 364                dev_err(&client->dev, "error resetting chip\n");
 365                goto exit_dummy;
 366        }
 367
 368        err = s35390a_disable_test_mode(s35390a);
 369        if (err < 0) {
 370                dev_err(&client->dev, "error disabling test mode\n");
 371                goto exit_dummy;
 372        }
 373
 374        err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf));
 375        if (err < 0) {
 376                dev_err(&client->dev, "error checking 12/24 hour mode\n");
 377                goto exit_dummy;
 378        }
 379        if (buf[0] & S35390A_FLAG_24H)
 380                s35390a->twentyfourhour = 1;
 381        else
 382                s35390a->twentyfourhour = 0;
 383
 384        if (s35390a_get_datetime(client, &tm) < 0)
 385                dev_warn(&client->dev, "clock needs to be set\n");
 386
 387        device_set_wakeup_capable(&client->dev, 1);
 388
 389        s35390a->rtc = rtc_device_register(s35390a_driver.driver.name,
 390                                &client->dev, &s35390a_rtc_ops, THIS_MODULE);
 391
 392        if (IS_ERR(s35390a->rtc)) {
 393                err = PTR_ERR(s35390a->rtc);
 394                goto exit_dummy;
 395        }
 396        return 0;
 397
 398exit_dummy:
 399        for (i = 1; i < 8; ++i)
 400                if (s35390a->client[i])
 401                        i2c_unregister_device(s35390a->client[i]);
 402        kfree(s35390a);
 403
 404exit:
 405        return err;
 406}
 407
 408static int s35390a_remove(struct i2c_client *client)
 409{
 410        unsigned int i;
 411
 412        struct s35390a *s35390a = i2c_get_clientdata(client);
 413        for (i = 1; i < 8; ++i)
 414                if (s35390a->client[i])
 415                        i2c_unregister_device(s35390a->client[i]);
 416
 417        rtc_device_unregister(s35390a->rtc);
 418        kfree(s35390a);
 419
 420        return 0;
 421}
 422
 423static struct i2c_driver s35390a_driver = {
 424        .driver         = {
 425                .name   = "rtc-s35390a",
 426        },
 427        .probe          = s35390a_probe,
 428        .remove         = s35390a_remove,
 429        .id_table       = s35390a_id,
 430};
 431
 432module_i2c_driver(s35390a_driver);
 433
 434MODULE_AUTHOR("Byron Bradley <byron.bbradley@gmail.com>");
 435MODULE_DESCRIPTION("S35390A RTC driver");
 436MODULE_LICENSE("GPL");
 437
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.