drivers/rtc/rtc-s35390a.c

   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
  50 static const struct i2c_device_id s35390a_id[] = {
  51         { "s35390a", 0 },
  52         { }
  53 };
  54 MODULE_DEVICE_TABLE(i2c, s35390a_id);
  55
  56 struct s35390a {
  57         struct i2c_client *client[8];
  58         struct rtc_device *rtc;
  59         int twentyfourhour;
  60 };
  61
  62 static 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
  79 static 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
  97 static 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
 112 static 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
 126 static 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
 137 static 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
 151 static 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
 179 static 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
 209 static 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
 262 static 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
 297 static 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
 302 static 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
 307 static 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
 312 static 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
 317 static 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
 325 static struct i2c_driver s35390a_driver;
 326
 327 static 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 = devm_kzalloc(&client->dev, sizeof(struct s35390a),
 342                                 GFP_KERNEL);
 343         if (!s35390a) {
 344                 err = -ENOMEM;
 345                 goto exit;
 346         }
 347
 348         s35390a->client[0] = client;
 349         i2c_set_clientdata(client, s35390a);
 350
 351         /* This chip uses multiple addresses, use dummy devices for them */
 352         for (i = 1; i < 8; ++i) {
 353                 s35390a->client[i] = i2c_new_dummy(client->adapter,
 354                                         client->addr + i);
 355                 if (!s35390a->client[i]) {
 356                         dev_err(&client->dev, "Address %02x unavailable\n",
 357                                                 client->addr + i);
 358                         err = -EBUSY;
 359                         goto exit_dummy;
 360                 }
 361         }
 362
 363         err = s35390a_reset(s35390a);
 364         if (err < 0) {
 365                 dev_err(&client->dev, "error resetting chip\n");
 366                 goto exit_dummy;
 367         }
 368
 369         err = s35390a_disable_test_mode(s35390a);
 370         if (err < 0) {
 371                 dev_err(&client->dev, "error disabling test mode\n");
 372                 goto exit_dummy;
 373         }
 374
 375         err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf));
 376         if (err < 0) {
 377                 dev_err(&client->dev, "error checking 12/24 hour mode\n");
 378                 goto exit_dummy;
 379         }
 380         if (buf[0] & S35390A_FLAG_24H)
 381                 s35390a->twentyfourhour = 1;
 382         else
 383                 s35390a->twentyfourhour = 0;
 384
 385         if (s35390a_get_datetime(client, &tm) < 0)
 386                 dev_warn(&client->dev, "clock needs to be set\n");
 387
 388         device_set_wakeup_capable(&client->dev, 1);
 389
 390         s35390a->rtc = devm_rtc_device_register(&client->dev,
 391                                         s35390a_driver.driver.name,
 392                                         &s35390a_rtc_ops, THIS_MODULE);
 393
 394         if (IS_ERR(s35390a->rtc)) {
 395                 err = PTR_ERR(s35390a->rtc);
 396                 goto exit_dummy;
 397         }
 398         return 0;
 399
 400 exit_dummy:
 401         for (i = 1; i < 8; ++i)
 402                 if (s35390a->client[i])
 403                         i2c_unregister_device(s35390a->client[i]);
 404
 405 exit:
 406         return err;
 407 }
 408
 409 static int s35390a_remove(struct i2c_client *client)
 410 {
 411         unsigned int i;
 412         struct s35390a *s35390a = i2c_get_clientdata(client);
 413
 414         for (i = 1; i < 8; ++i)
 415                 if (s35390a->client[i])
 416                         i2c_unregister_device(s35390a->client[i]);
 417
 418         return 0;
 419 }
 420
 421 static struct i2c_driver s35390a_driver = {
 422         .driver         = {
 423                 .name   = "rtc-s35390a",
 424         },
 425         .probe          = s35390a_probe,
 426         .remove         = s35390a_remove,
 427         .id_table       = s35390a_id,
 428 };
 429
 430 module_i2c_driver(s35390a_driver);
 431
 432 MODULE_AUTHOR("Byron Bradley <byron.bbradley@gmail.com>");
 433 MODULE_DESCRIPTION("S35390A RTC driver");
 434 MODULE_LICENSE("GPL");