drivers/rtc/rtc-isl1208.c

   1 /*
   2  * Intersil ISL1208 rtc class driver
   3  *
   4  * Copyright 2005,2006 Hebert Valerio Riedel <hvr@gnu.org>
   5  *
   6  *  This program is free software; you can redistribute  it and/or modify it
   7  *  under  the terms of  the GNU General  Public License as published by the
   8  *  Free Software Foundation;  either version 2 of the  License, or (at your
   9  *  option) any later version.
  10  *
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/i2c.h>
  15 #include <linux/bcd.h>
  16 #include <linux/rtc.h>
  17
  18 #define DRV_NAME "isl1208"
  19 #define DRV_VERSION "0.2"
  20
  21 /* Register map */
  22 /* rtc section */
  23 #define ISL1208_REG_SC  0x00
  24 #define ISL1208_REG_MN  0x01
  25 #define ISL1208_REG_HR  0x02
  26 #define ISL1208_REG_HR_MIL     (1<<7) /* 24h/12h mode */
  27 #define ISL1208_REG_HR_PM      (1<<5) /* PM/AM bit in 12h mode */
  28 #define ISL1208_REG_DT  0x03
  29 #define ISL1208_REG_MO  0x04
  30 #define ISL1208_REG_YR  0x05
  31 #define ISL1208_REG_DW  0x06
  32 #define ISL1208_RTC_SECTION_LEN 7
  33
  34 /* control/status section */
  35 #define ISL1208_REG_SR  0x07
  36 #define ISL1208_REG_SR_ARST    (1<<7) /* auto reset */
  37 #define ISL1208_REG_SR_XTOSCB  (1<<6) /* crystal oscillator */
  38 #define ISL1208_REG_SR_WRTC    (1<<4) /* write rtc */
  39 #define ISL1208_REG_SR_ALM     (1<<2) /* alarm */
  40 #define ISL1208_REG_SR_BAT     (1<<1) /* battery */
  41 #define ISL1208_REG_SR_RTCF    (1<<0) /* rtc fail */
  42 #define ISL1208_REG_INT 0x08
  43 #define ISL1208_REG_09  0x09 /* reserved */
  44 #define ISL1208_REG_ATR 0x0a
  45 #define ISL1208_REG_DTR 0x0b
  46
  47 /* alarm section */
  48 #define ISL1208_REG_SCA 0x0c
  49 #define ISL1208_REG_MNA 0x0d
  50 #define ISL1208_REG_HRA 0x0e
  51 #define ISL1208_REG_DTA 0x0f
  52 #define ISL1208_REG_MOA 0x10
  53 #define ISL1208_REG_DWA 0x11
  54 #define ISL1208_ALARM_SECTION_LEN 6
  55
  56 /* user section */
  57 #define ISL1208_REG_USR1 0x12
  58 #define ISL1208_REG_USR2 0x13
  59 #define ISL1208_USR_SECTION_LEN 2
  60
  61 /* i2c configuration */
  62 #define ISL1208_I2C_ADDR 0xde
  63
  64 static unsigned short normal_i2c[] = {
  65         ISL1208_I2C_ADDR>>1, I2C_CLIENT_END
  66 };
  67 I2C_CLIENT_INSMOD; /* defines addr_data */
  68
  69 static int isl1208_attach_adapter(struct i2c_adapter *adapter);
  70 static int isl1208_detach_client(struct i2c_client *client);
  71
  72 static struct i2c_driver isl1208_driver = {
  73         .driver         = {
  74                 .name   = DRV_NAME,
  75         },
  76         .id             = I2C_DRIVERID_ISL1208,
  77         .attach_adapter = &isl1208_attach_adapter,
  78         .detach_client  = &isl1208_detach_client,
  79 };
  80
  81 /* block read */
  82 static int
  83 isl1208_i2c_read_regs(struct i2c_client *client, u8 reg, u8 buf[],
  84                        unsigned len)
  85 {
  86         u8 reg_addr[1] = { reg };
  87         struct i2c_msg msgs[2] = {
  88                 { client->addr, client->flags, sizeof(reg_addr), reg_addr },
  89                 { client->addr, client->flags | I2C_M_RD, len, buf }
  90         };
  91         int ret;
  92
  93         BUG_ON(len == 0);
  94         BUG_ON(reg > ISL1208_REG_USR2);
  95         BUG_ON(reg + len > ISL1208_REG_USR2 + 1);
  96
  97         ret = i2c_transfer(client->adapter, msgs, 2);
  98         if (ret > 0)
  99                 ret = 0;
 100         return ret;
 101 }
 102
 103 /* block write */
 104 static int
 105 isl1208_i2c_set_regs(struct i2c_client *client, u8 reg, u8 const buf[],
 106                        unsigned len)
 107 {
 108         u8 i2c_buf[ISL1208_REG_USR2 + 2];
 109         struct i2c_msg msgs[1] = {
 110                 { client->addr, client->flags, len + 1, i2c_buf }
 111         };
 112         int ret;
 113
 114         BUG_ON(len == 0);
 115         BUG_ON(reg > ISL1208_REG_USR2);
 116         BUG_ON(reg + len > ISL1208_REG_USR2 + 1);
 117
 118         i2c_buf[0] = reg;
 119         memcpy(&i2c_buf[1], &buf[0], len);
 120
 121         ret = i2c_transfer(client->adapter, msgs, 1);
 122         if (ret > 0)
 123                 ret = 0;
 124         return ret;
 125 }
 126
 127 /* simple check to see wether we have a isl1208 */
 128 static int isl1208_i2c_validate_client(struct i2c_client *client)
 129 {
 130         u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
 131         u8 zero_mask[ISL1208_RTC_SECTION_LEN] = {
 132                 0x80, 0x80, 0x40, 0xc0, 0xe0, 0x00, 0xf8
 133         };
 134         int i;
 135         int ret;
 136
 137         ret = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
 138         if (ret < 0)
 139                 return ret;
 140
 141         for (i = 0; i < ISL1208_RTC_SECTION_LEN; ++i) {
 142                 if (regs[i] & zero_mask[i]) /* check if bits are cleared */
 143                         return -ENODEV;
 144         }
 145
 146         return 0;
 147 }
 148
 149 static int isl1208_i2c_get_sr(struct i2c_client *client)
 150 {
 151         return i2c_smbus_read_byte_data(client, ISL1208_REG_SR) == -1 ? -EIO:0;
 152 }
 153
 154 static int isl1208_i2c_get_atr(struct i2c_client *client)
 155 {
 156         int atr = i2c_smbus_read_byte_data(client, ISL1208_REG_ATR);
 157
 158         if (atr < 0)
 159                 return -EIO;
 160
 161         /* The 6bit value in the ATR register controls the load
 162          * capacitance C_load * in steps of 0.25pF
 163          *
 164          * bit (1<<5) of the ATR register is inverted
 165          *
 166          * C_load(ATR=0x20) =  4.50pF
 167          * C_load(ATR=0x00) = 12.50pF
 168          * C_load(ATR=0x1f) = 20.25pF
 169          *
 170          */
 171
 172         atr &= 0x3f; /* mask out lsb */
 173         atr ^= 1<<5; /* invert 6th bit */
 174         atr += 2*9; /* add offset of 4.5pF; unit[atr] = 0.25pF */
 175
 176         return atr;
 177 }
 178
 179 static int isl1208_i2c_get_dtr(struct i2c_client *client)
 180 {
 181         int dtr = i2c_smbus_read_byte_data(client, ISL1208_REG_DTR);
 182
 183         if (dtr < 0)
 184                 return -EIO;
 185
 186         /* dtr encodes adjustments of {-60,-40,-20,0,20,40,60} ppm */
 187         dtr = ((dtr & 0x3) * 20) * (dtr & (1<<2) ? -1 : 1);
 188
 189         return dtr;
 190 }
 191
 192 static int isl1208_i2c_get_usr(struct i2c_client *client)
 193 {
 194         u8 buf[ISL1208_USR_SECTION_LEN] = { 0, };
 195         int ret;
 196
 197         ret = isl1208_i2c_read_regs (client, ISL1208_REG_USR1, buf,
 198                                    ISL1208_USR_SECTION_LEN);
 199         if (ret < 0)
 200                 return ret;
 201
 202         return (buf[1] << 8) | buf[0];
 203 }
 204
 205 static int isl1208_i2c_set_usr(struct i2c_client *client, u16 usr)
 206 {
 207         u8 buf[ISL1208_USR_SECTION_LEN];
 208
 209         buf[0] = usr & 0xff;
 210         buf[1] = (usr >> 8) & 0xff;
 211
 212         return isl1208_i2c_set_regs (client, ISL1208_REG_USR1, buf,
 213                                      ISL1208_USR_SECTION_LEN);
 214 }
 215
 216 static int isl1208_rtc_proc(struct device *dev, struct seq_file *seq)
 217 {
 218         struct i2c_client *const client = to_i2c_client(dev);
 219         int sr, dtr, atr, usr;
 220
 221         sr = isl1208_i2c_get_sr(client);
 222         if (sr < 0) {
 223                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
 224                 return sr;
 225         }
 226
 227         seq_printf(seq, "status_reg\t:%s%s%s%s%s%s (0x%.2x)\n",
 228                    (sr & ISL1208_REG_SR_RTCF) ? " RTCF" : "",
 229                    (sr & ISL1208_REG_SR_BAT) ? " BAT" : "",
 230                    (sr & ISL1208_REG_SR_ALM) ? " ALM" : "",
 231                    (sr & ISL1208_REG_SR_WRTC) ? " WRTC" : "",
 232                    (sr & ISL1208_REG_SR_XTOSCB) ? " XTOSCB" : "",
 233                    (sr & ISL1208_REG_SR_ARST) ? " ARST" : "",
 234                    sr);
 235
 236         seq_printf(seq, "batt_status\t: %s\n",
 237                    (sr & ISL1208_REG_SR_RTCF) ? "bad" : "okay");
 238
 239         dtr = isl1208_i2c_get_dtr(client);
 240         if (dtr >= 0 -1)
 241                 seq_printf(seq, "digital_trim\t: %d ppm\n", dtr);
 242
 243         atr = isl1208_i2c_get_atr(client);
 244         if (atr >= 0)
 245                 seq_printf(seq, "analog_trim\t: %d.%.2d pF\n",
 246                            atr>>2, (atr&0x3)*25);
 247
 248         usr = isl1208_i2c_get_usr(client);
 249         if (usr >= 0)
 250                 seq_printf(seq, "user_data\t: 0x%.4x\n", usr);
 251
 252         return 0;
 253 }
 254
 255
 256 static int isl1208_i2c_read_time(struct i2c_client *client,
 257                                  struct rtc_time *tm)
 258 {
 259         int sr;
 260         u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
 261
 262         sr = isl1208_i2c_get_sr(client);
 263         if (sr < 0) {
 264                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
 265                 return -EIO;
 266         }
 267
 268         sr = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
 269         if (sr < 0) {
 270                 dev_err(&client->dev, "%s: reading RTC section failed\n",
 271                         __func__);
 272                 return sr;
 273         }
 274
 275         tm->tm_sec = BCD2BIN(regs[ISL1208_REG_SC]);
 276         tm->tm_min = BCD2BIN(regs[ISL1208_REG_MN]);
 277         { /* HR field has a more complex interpretation */
 278                 const u8 _hr = regs[ISL1208_REG_HR];
 279                 if (_hr & ISL1208_REG_HR_MIL) /* 24h format */
 280                         tm->tm_hour = BCD2BIN(_hr & 0x3f);
 281                 else { // 12h format
 282                         tm->tm_hour = BCD2BIN(_hr & 0x1f);
 283                         if (_hr & ISL1208_REG_HR_PM) /* PM flag set */
 284                                 tm->tm_hour += 12;
 285                 }
 286         }
 287
 288         tm->tm_mday = BCD2BIN(regs[ISL1208_REG_DT]);
 289         tm->tm_mon = BCD2BIN(regs[ISL1208_REG_MO]) - 1; /* rtc starts at 1 */
 290         tm->tm_year = BCD2BIN(regs[ISL1208_REG_YR]) + 100;
 291         tm->tm_wday = BCD2BIN(regs[ISL1208_REG_DW]);
 292
 293         return 0;
 294 }
 295
 296 static int isl1208_i2c_read_alarm(struct i2c_client *client,
 297                                   struct rtc_wkalrm *alarm)
 298 {
 299         struct rtc_time *const tm = &alarm->time;
 300         u8 regs[ISL1208_ALARM_SECTION_LEN] = { 0, };
 301         int sr;
 302
 303         sr = isl1208_i2c_get_sr(client);
 304         if (sr < 0) {
 305                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
 306                 return sr;
 307         }
 308
 309         sr = isl1208_i2c_read_regs(client, ISL1208_REG_SCA, regs,
 310                                   ISL1208_ALARM_SECTION_LEN);
 311         if (sr < 0) {
 312                 dev_err(&client->dev, "%s: reading alarm section failed\n",
 313                         __func__);
 314                 return sr;
 315         }
 316
 317         /* MSB of each alarm register is an enable bit */
 318         tm->tm_sec  = BCD2BIN(regs[ISL1208_REG_SCA-ISL1208_REG_SCA] & 0x7f);
 319         tm->tm_min  = BCD2BIN(regs[ISL1208_REG_MNA-ISL1208_REG_SCA] & 0x7f);
 320         tm->tm_hour = BCD2BIN(regs[ISL1208_REG_HRA-ISL1208_REG_SCA] & 0x3f);
 321         tm->tm_mday = BCD2BIN(regs[ISL1208_REG_DTA-ISL1208_REG_SCA] & 0x3f);
 322         tm->tm_mon  = BCD2BIN(regs[ISL1208_REG_MOA-ISL1208_REG_SCA] & 0x1f)-1;
 323         tm->tm_wday = BCD2BIN(regs[ISL1208_REG_DWA-ISL1208_REG_SCA] & 0x03);
 324
 325         return 0;
 326 }
 327
 328 static int isl1208_rtc_read_time(struct device *dev, struct rtc_time *tm)
 329 {
 330         return isl1208_i2c_read_time(to_i2c_client(dev), tm);
 331 }
 332
 333 static int isl1208_i2c_set_time(struct i2c_client *client,
 334                                 struct rtc_time const *tm)
 335 {
 336         int sr;
 337         u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
 338
 339         regs[ISL1208_REG_SC] = BIN2BCD(tm->tm_sec);
 340         regs[ISL1208_REG_MN] = BIN2BCD(tm->tm_min);
 341         regs[ISL1208_REG_HR] = BIN2BCD(tm->tm_hour) | ISL1208_REG_HR_MIL;
 342
 343         regs[ISL1208_REG_DT] = BIN2BCD(tm->tm_mday);
 344         regs[ISL1208_REG_MO] = BIN2BCD(tm->tm_mon + 1);
 345         regs[ISL1208_REG_YR] = BIN2BCD(tm->tm_year - 100);
 346
 347         regs[ISL1208_REG_DW] = BIN2BCD(tm->tm_wday & 7);
 348
 349         sr = isl1208_i2c_get_sr(client);
 350         if (sr < 0) {
 351                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
 352                 return sr;
 353         }
 354
 355         /* set WRTC */
 356         sr = i2c_smbus_write_byte_data (client, ISL1208_REG_SR,
 357                                        sr | ISL1208_REG_SR_WRTC);
 358         if (sr < 0) {
 359                 dev_err(&client->dev, "%s: writing SR failed\n", __func__);
 360                 return sr;
 361         }
 362
 363         /* write RTC registers */
 364         sr = isl1208_i2c_set_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
 365         if (sr < 0) {
 366                 dev_err(&client->dev, "%s: writing RTC section failed\n",
 367                         __func__);
 368                 return sr;
 369         }
 370
 371         /* clear WRTC again */
 372         sr = i2c_smbus_write_byte_data (client, ISL1208_REG_SR,
 373                                        sr & ~ISL1208_REG_SR_WRTC);
 374         if (sr < 0) {
 375                 dev_err(&client->dev, "%s: writing SR failed\n", __func__);
 376                 return sr;
 377         }
 378
 379         return 0;
 380 }
 381
 382
 383 static int isl1208_rtc_set_time(struct device *dev, struct rtc_time *tm)
 384 {
 385         return isl1208_i2c_set_time(to_i2c_client(dev), tm);
 386 }
 387
 388 static int isl1208_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 389 {
 390         return isl1208_i2c_read_alarm(to_i2c_client(dev), alarm);
 391 }
 392
 393 static const struct rtc_class_ops isl1208_rtc_ops = {
 394         .proc           = isl1208_rtc_proc,
 395         .read_time      = isl1208_rtc_read_time,
 396         .set_time       = isl1208_rtc_set_time,
 397         .read_alarm     = isl1208_rtc_read_alarm,
 398         //.set_alarm    = isl1208_rtc_set_alarm,
 399 };
 400
 401 /* sysfs interface */
 402
 403 static ssize_t isl1208_sysfs_show_atrim(struct device *dev,
 404                                         struct device_attribute *attr,
 405                                         char *buf)
 406 {
 407         int atr;
 408
 409         atr = isl1208_i2c_get_atr(to_i2c_client(dev));
 410         if (atr < 0)
 411                 return atr;
 412
 413         return sprintf(buf, "%d.%.2d pF\n", atr>>2, (atr&0x3)*25);
 414 }
 415 static DEVICE_ATTR(atrim, S_IRUGO, isl1208_sysfs_show_atrim, NULL);
 416
 417 static ssize_t isl1208_sysfs_show_dtrim(struct device *dev,
 418                                         struct device_attribute *attr,
 419                                         char *buf)
 420 {
 421         int dtr;
 422
 423         dtr = isl1208_i2c_get_dtr(to_i2c_client(dev));
 424         if (dtr < 0)
 425                 return dtr;
 426
 427         return sprintf(buf, "%d ppm\n", dtr);
 428 }
 429 static DEVICE_ATTR(dtrim, S_IRUGO, isl1208_sysfs_show_dtrim, NULL);
 430
 431 static ssize_t isl1208_sysfs_show_usr(struct device *dev,
 432                                        struct device_attribute *attr,
 433                                        char *buf)
 434 {
 435         int usr;
 436
 437         usr = isl1208_i2c_get_usr(to_i2c_client(dev));
 438         if (usr < 0)
 439                 return usr;
 440
 441         return sprintf(buf, "0x%.4x\n", usr);
 442 }
 443
 444 static ssize_t isl1208_sysfs_store_usr(struct device *dev,
 445                                        struct device_attribute *attr,
 446                                        const char *buf, size_t count)
 447 {
 448         int usr = -1;
 449
 450         if (buf[0] == '0' && (buf[1] == 'x' || buf[1] == 'X')) {
 451                 if (sscanf(buf, "%x", &usr) != 1)
 452                         return -EINVAL;
 453         } else {
 454                 if (sscanf(buf, "%d", &usr) != 1)
 455                         return -EINVAL;
 456         }
 457
 458         if (usr < 0 || usr > 0xffff)
 459                 return -EINVAL;
 460
 461         return isl1208_i2c_set_usr(to_i2c_client(dev), usr) ? -EIO : count;
 462 }
 463 static DEVICE_ATTR(usr, S_IRUGO | S_IWUSR, isl1208_sysfs_show_usr,
 464                    isl1208_sysfs_store_usr);
 465
 466 static int
 467 isl1208_probe(struct i2c_adapter *adapter, int addr, int kind)
 468 {
 469         int rc = 0;
 470         struct i2c_client *new_client = NULL;
 471         struct rtc_device *rtc = NULL;
 472
 473         if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {
 474                 rc = -ENODEV;
 475                 goto failout;
 476         }
 477
 478         new_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
 479         if (new_client == NULL) {
 480                 rc = -ENOMEM;
 481                 goto failout;
 482         }
 483
 484         new_client->addr = addr;
 485         new_client->adapter = adapter;
 486         new_client->driver = &isl1208_driver;
 487         new_client->flags = 0;
 488         strcpy(new_client->name, DRV_NAME);
 489
 490         if (kind < 0) {
 491                 rc = isl1208_i2c_validate_client(new_client);
 492                 if (rc < 0)
 493                         goto failout;
 494         }
 495
 496         rc = i2c_attach_client(new_client);
 497         if (rc < 0)
 498                 goto failout;
 499
 500         dev_info(&new_client->dev,
 501                  "chip found, driver version " DRV_VERSION "\n");
 502
 503         rtc = rtc_device_register(isl1208_driver.driver.name,
 504                                   &new_client->dev,
 505                                   &isl1208_rtc_ops, THIS_MODULE);
 506
 507         if (IS_ERR(rtc)) {
 508                 rc = PTR_ERR(rtc);
 509                 goto failout_detach;
 510         }
 511
 512         i2c_set_clientdata(new_client, rtc);
 513
 514         rc = isl1208_i2c_get_sr(new_client);
 515         if (rc < 0) {
 516                 dev_err(&new_client->dev, "reading status failed\n");
 517                 goto failout_unregister;
 518         }
 519
 520         if (rc & ISL1208_REG_SR_RTCF)
 521                 dev_warn(&new_client->dev, "rtc power failure detected, "
 522                          "please set clock.\n");
 523
 524         rc = device_create_file(&new_client->dev, &dev_attr_atrim);
 525         if (rc < 0)
 526                 goto failout_unregister;
 527         rc = device_create_file(&new_client->dev, &dev_attr_dtrim);
 528         if (rc < 0)
 529                 goto failout_atrim;
 530         rc = device_create_file(&new_client->dev, &dev_attr_usr);
 531         if (rc < 0)
 532                 goto failout_dtrim;
 533
 534         return 0;
 535
 536  failout_dtrim:
 537         device_remove_file(&new_client->dev, &dev_attr_dtrim);
 538  failout_atrim:
 539         device_remove_file(&new_client->dev, &dev_attr_atrim);
 540  failout_unregister:
 541         rtc_device_unregister(rtc);
 542  failout_detach:
 543         i2c_detach_client(new_client);
 544  failout:
 545         kfree(new_client);
 546         return rc;
 547 }
 548
 549 static int
 550 isl1208_attach_adapter (struct i2c_adapter *adapter)
 551 {
 552         return i2c_probe(adapter, &addr_data, isl1208_probe);
 553 }
 554
 555 static int
 556 isl1208_detach_client(struct i2c_client *client)
 557 {
 558         int rc;
 559         struct rtc_device *const rtc = i2c_get_clientdata(client);
 560
 561         if (rtc)
 562                 rtc_device_unregister(rtc); /* do we need to kfree? */
 563
 564         rc = i2c_detach_client(client);
 565         if (rc)
 566                 return rc;
 567
 568         kfree(client);
 569
 570         return 0;
 571 }
 572
 573 /* module management */
 574
 575 static int __init isl1208_init(void)
 576 {
 577         return i2c_add_driver(&isl1208_driver);
 578 }
 579
 580 static void __exit isl1208_exit(void)
 581 {
 582         i2c_del_driver(&isl1208_driver);
 583 }
 584
 585 MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>");
 586 MODULE_DESCRIPTION("Intersil ISL1208 RTC driver");
 587 MODULE_LICENSE("GPL");
 588 MODULE_VERSION(DRV_VERSION);
 589
 590 module_init(isl1208_init);
 591 module_exit(isl1208_exit);