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_VERSION "0.3"
  19
  20 /* Register map */
  21 /* rtc section */
  22 #define ISL1208_REG_SC  0x00
  23 #define ISL1208_REG_MN  0x01
  24 #define ISL1208_REG_HR  0x02
  25 #define ISL1208_REG_HR_MIL     (1<<7)   /* 24h/12h mode */
  26 #define ISL1208_REG_HR_PM      (1<<5)   /* PM/AM bit in 12h mode */
  27 #define ISL1208_REG_DT  0x03
  28 #define ISL1208_REG_MO  0x04
  29 #define ISL1208_REG_YR  0x05
  30 #define ISL1208_REG_DW  0x06
  31 #define ISL1208_RTC_SECTION_LEN 7
  32
  33 /* control/status section */
  34 #define ISL1208_REG_SR  0x07
  35 #define ISL1208_REG_SR_ARST    (1<<7)   /* auto reset */
  36 #define ISL1208_REG_SR_XTOSCB  (1<<6)   /* crystal oscillator */
  37 #define ISL1208_REG_SR_WRTC    (1<<4)   /* write rtc */
  38 #define ISL1208_REG_SR_ALM     (1<<2)   /* alarm */
  39 #define ISL1208_REG_SR_BAT     (1<<1)   /* battery */
  40 #define ISL1208_REG_SR_RTCF    (1<<0)   /* rtc fail */
  41 #define ISL1208_REG_INT 0x08
  42 #define ISL1208_REG_INT_ALME   (1<<6)   /* alarm enable */
  43 #define ISL1208_REG_INT_IM     (1<<7)   /* interrupt/alarm mode */
  44 #define ISL1208_REG_09  0x09    /* reserved */
  45 #define ISL1208_REG_ATR 0x0a
  46 #define ISL1208_REG_DTR 0x0b
  47
  48 /* alarm section */
  49 #define ISL1208_REG_SCA 0x0c
  50 #define ISL1208_REG_MNA 0x0d
  51 #define ISL1208_REG_HRA 0x0e
  52 #define ISL1208_REG_DTA 0x0f
  53 #define ISL1208_REG_MOA 0x10
  54 #define ISL1208_REG_DWA 0x11
  55 #define ISL1208_ALARM_SECTION_LEN 6
  56
  57 /* user section */
  58 #define ISL1208_REG_USR1 0x12
  59 #define ISL1208_REG_USR2 0x13
  60 #define ISL1208_USR_SECTION_LEN 2
  61
  62 static struct i2c_driver isl1208_driver;
  63
  64 /* block read */
  65 static int
  66 isl1208_i2c_read_regs(struct i2c_client *client, u8 reg, u8 buf[],
  67                       unsigned len)
  68 {
  69         u8 reg_addr[1] = { reg };
  70         struct i2c_msg msgs[2] = {
  71                 {
  72                         .addr = client->addr,
  73                         .len = sizeof(reg_addr),
  74                         .buf = reg_addr
  75                 },
  76                 {
  77                         .addr = client->addr,
  78                         .flags = I2C_M_RD,
  79                         .len = len,
  80                         .buf = buf
  81                 }
  82         };
  83         int ret;
  84
  85         BUG_ON(reg > ISL1208_REG_USR2);
  86         BUG_ON(reg + len > ISL1208_REG_USR2 + 1);
  87
  88         ret = i2c_transfer(client->adapter, msgs, 2);
  89         if (ret > 0)
  90                 ret = 0;
  91         return ret;
  92 }
  93
  94 /* block write */
  95 static int
  96 isl1208_i2c_set_regs(struct i2c_client *client, u8 reg, u8 const buf[],
  97                      unsigned len)
  98 {
  99         u8 i2c_buf[ISL1208_REG_USR2 + 2];
 100         struct i2c_msg msgs[1] = {
 101                 {
 102                         .addr = client->addr,
 103                         .len = len + 1,
 104                         .buf = i2c_buf
 105                 }
 106         };
 107         int ret;
 108
 109         BUG_ON(reg > ISL1208_REG_USR2);
 110         BUG_ON(reg + len > ISL1208_REG_USR2 + 1);
 111
 112         i2c_buf[0] = reg;
 113         memcpy(&i2c_buf[1], &buf[0], len);
 114
 115         ret = i2c_transfer(client->adapter, msgs, 1);
 116         if (ret > 0)
 117                 ret = 0;
 118         return ret;
 119 }
 120
 121 /* simple check to see whether we have a isl1208 */
 122 static int
 123 isl1208_i2c_validate_client(struct i2c_client *client)
 124 {
 125         u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
 126         u8 zero_mask[ISL1208_RTC_SECTION_LEN] = {
 127                 0x80, 0x80, 0x40, 0xc0, 0xe0, 0x00, 0xf8
 128         };
 129         int i;
 130         int ret;
 131
 132         ret = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
 133         if (ret < 0)
 134                 return ret;
 135
 136         for (i = 0; i < ISL1208_RTC_SECTION_LEN; ++i) {
 137                 if (regs[i] & zero_mask[i])     /* check if bits are cleared */
 138                         return -ENODEV;
 139         }
 140
 141         return 0;
 142 }
 143
 144 static int
 145 isl1208_i2c_get_sr(struct i2c_client *client)
 146 {
 147         int sr = i2c_smbus_read_byte_data(client, ISL1208_REG_SR);
 148         if (sr < 0)
 149                 return -EIO;
 150
 151         return sr;
 152 }
 153
 154 static int
 155 isl1208_i2c_get_atr(struct i2c_client *client)
 156 {
 157         int atr = i2c_smbus_read_byte_data(client, ISL1208_REG_ATR);
 158         if (atr < 0)
 159                 return atr;
 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
 180 isl1208_i2c_get_dtr(struct i2c_client *client)
 181 {
 182         int dtr = i2c_smbus_read_byte_data(client, ISL1208_REG_DTR);
 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
 193 isl1208_i2c_get_usr(struct i2c_client *client)
 194 {
 195         u8 buf[ISL1208_USR_SECTION_LEN] = { 0, };
 196         int ret;
 197
 198         ret = isl1208_i2c_read_regs(client, ISL1208_REG_USR1, buf,
 199                                     ISL1208_USR_SECTION_LEN);
 200         if (ret < 0)
 201                 return ret;
 202
 203         return (buf[1] << 8) | buf[0];
 204 }
 205
 206 static int
 207 isl1208_i2c_set_usr(struct i2c_client *client, u16 usr)
 208 {
 209         u8 buf[ISL1208_USR_SECTION_LEN];
 210
 211         buf[0] = usr & 0xff;
 212         buf[1] = (usr >> 8) & 0xff;
 213
 214         return isl1208_i2c_set_regs(client, ISL1208_REG_USR1, buf,
 215                                     ISL1208_USR_SECTION_LEN);
 216 }
 217
 218 static int
 219 isl1208_rtc_toggle_alarm(struct i2c_client *client, int enable)
 220 {
 221         int icr = i2c_smbus_read_byte_data(client, ISL1208_REG_INT);
 222
 223         if (icr < 0) {
 224                 dev_err(&client->dev, "%s: reading INT failed\n", __func__);
 225                 return icr;
 226         }
 227
 228         if (enable)
 229                 icr |= ISL1208_REG_INT_ALME | ISL1208_REG_INT_IM;
 230         else
 231                 icr &= ~(ISL1208_REG_INT_ALME | ISL1208_REG_INT_IM);
 232
 233         icr = i2c_smbus_write_byte_data(client, ISL1208_REG_INT, icr);
 234         if (icr < 0) {
 235                 dev_err(&client->dev, "%s: writing INT failed\n", __func__);
 236                 return icr;
 237         }
 238
 239         return 0;
 240 }
 241
 242 static int
 243 isl1208_rtc_proc(struct device *dev, struct seq_file *seq)
 244 {
 245         struct i2c_client *const client = to_i2c_client(dev);
 246         int sr, dtr, atr, usr;
 247
 248         sr = isl1208_i2c_get_sr(client);
 249         if (sr < 0) {
 250                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
 251                 return sr;
 252         }
 253
 254         seq_printf(seq, "status_reg\t:%s%s%s%s%s%s (0x%.2x)\n",
 255                    (sr & ISL1208_REG_SR_RTCF) ? " RTCF" : "",
 256                    (sr & ISL1208_REG_SR_BAT) ? " BAT" : "",
 257                    (sr & ISL1208_REG_SR_ALM) ? " ALM" : "",
 258                    (sr & ISL1208_REG_SR_WRTC) ? " WRTC" : "",
 259                    (sr & ISL1208_REG_SR_XTOSCB) ? " XTOSCB" : "",
 260                    (sr & ISL1208_REG_SR_ARST) ? " ARST" : "", sr);
 261
 262         seq_printf(seq, "batt_status\t: %s\n",
 263                    (sr & ISL1208_REG_SR_RTCF) ? "bad" : "okay");
 264
 265         dtr = isl1208_i2c_get_dtr(client);
 266         if (dtr >= 0 - 1)
 267                 seq_printf(seq, "digital_trim\t: %d ppm\n", dtr);
 268
 269         atr = isl1208_i2c_get_atr(client);
 270         if (atr >= 0)
 271                 seq_printf(seq, "analog_trim\t: %d.%.2d pF\n",
 272                            atr >> 2, (atr & 0x3) * 25);
 273
 274         usr = isl1208_i2c_get_usr(client);
 275         if (usr >= 0)
 276                 seq_printf(seq, "user_data\t: 0x%.4x\n", usr);
 277
 278         return 0;
 279 }
 280
 281 static int
 282 isl1208_i2c_read_time(struct i2c_client *client, struct rtc_time *tm)
 283 {
 284         int sr;
 285         u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
 286
 287         sr = isl1208_i2c_get_sr(client);
 288         if (sr < 0) {
 289                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
 290                 return -EIO;
 291         }
 292
 293         sr = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
 294         if (sr < 0) {
 295                 dev_err(&client->dev, "%s: reading RTC section failed\n",
 296                         __func__);
 297                 return sr;
 298         }
 299
 300         tm->tm_sec = bcd2bin(regs[ISL1208_REG_SC]);
 301         tm->tm_min = bcd2bin(regs[ISL1208_REG_MN]);
 302
 303         /* HR field has a more complex interpretation */
 304         {
 305                 const u8 _hr = regs[ISL1208_REG_HR];
 306                 if (_hr & ISL1208_REG_HR_MIL)   /* 24h format */
 307                         tm->tm_hour = bcd2bin(_hr & 0x3f);
 308                 else {
 309                         /* 12h format */
 310                         tm->tm_hour = bcd2bin(_hr & 0x1f);
 311                         if (_hr & ISL1208_REG_HR_PM)    /* PM flag set */
 312                                 tm->tm_hour += 12;
 313                 }
 314         }
 315
 316         tm->tm_mday = bcd2bin(regs[ISL1208_REG_DT]);
 317         tm->tm_mon = bcd2bin(regs[ISL1208_REG_MO]) - 1; /* rtc starts at 1 */
 318         tm->tm_year = bcd2bin(regs[ISL1208_REG_YR]) + 100;
 319         tm->tm_wday = bcd2bin(regs[ISL1208_REG_DW]);
 320
 321         return 0;
 322 }
 323
 324 static int
 325 isl1208_i2c_read_alarm(struct i2c_client *client, struct rtc_wkalrm *alarm)
 326 {
 327         struct rtc_time *const tm = &alarm->time;
 328         u8 regs[ISL1208_ALARM_SECTION_LEN] = { 0, };
 329         int icr, yr, sr = isl1208_i2c_get_sr(client);
 330
 331         if (sr < 0) {
 332                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
 333                 return sr;
 334         }
 335
 336         sr = isl1208_i2c_read_regs(client, ISL1208_REG_SCA, regs,
 337                                    ISL1208_ALARM_SECTION_LEN);
 338         if (sr < 0) {
 339                 dev_err(&client->dev, "%s: reading alarm section failed\n",
 340                         __func__);
 341                 return sr;
 342         }
 343
 344         /* MSB of each alarm register is an enable bit */
 345         tm->tm_sec = bcd2bin(regs[ISL1208_REG_SCA - ISL1208_REG_SCA] & 0x7f);
 346         tm->tm_min = bcd2bin(regs[ISL1208_REG_MNA - ISL1208_REG_SCA] & 0x7f);
 347         tm->tm_hour = bcd2bin(regs[ISL1208_REG_HRA - ISL1208_REG_SCA] & 0x3f);
 348         tm->tm_mday = bcd2bin(regs[ISL1208_REG_DTA - ISL1208_REG_SCA] & 0x3f);
 349         tm->tm_mon =
 350                 bcd2bin(regs[ISL1208_REG_MOA - ISL1208_REG_SCA] & 0x1f) - 1;
 351         tm->tm_wday = bcd2bin(regs[ISL1208_REG_DWA - ISL1208_REG_SCA] & 0x03);
 352
 353         /* The alarm doesn't store the year so get it from the rtc section */
 354         yr = i2c_smbus_read_byte_data(client, ISL1208_REG_YR);
 355         if (yr < 0) {
 356                 dev_err(&client->dev, "%s: reading RTC YR failed\n", __func__);
 357                 return yr;
 358         }
 359         tm->tm_year = bcd2bin(yr) + 100;
 360
 361         icr = i2c_smbus_read_byte_data(client, ISL1208_REG_INT);
 362         if (icr < 0) {
 363                 dev_err(&client->dev, "%s: reading INT failed\n", __func__);
 364                 return icr;
 365         }
 366         alarm->enabled = !!(icr & ISL1208_REG_INT_ALME);
 367
 368         return 0;
 369 }
 370
 371 static int
 372 isl1208_i2c_set_alarm(struct i2c_client *client, struct rtc_wkalrm *alarm)
 373 {
 374         struct rtc_time *alarm_tm = &alarm->time;
 375         u8 regs[ISL1208_ALARM_SECTION_LEN] = { 0, };
 376         const int offs = ISL1208_REG_SCA;
 377         unsigned long rtc_secs, alarm_secs;
 378         struct rtc_time rtc_tm;
 379         int err, enable;
 380
 381         err = isl1208_i2c_read_time(client, &rtc_tm);
 382         if (err)
 383                 return err;
 384         err = rtc_tm_to_time(&rtc_tm, &rtc_secs);
 385         if (err)
 386                 return err;
 387         err = rtc_tm_to_time(alarm_tm, &alarm_secs);
 388         if (err)
 389                 return err;
 390
 391         /* If the alarm time is before the current time disable the alarm */
 392         if (!alarm->enabled || alarm_secs <= rtc_secs)
 393                 enable = 0x00;
 394         else
 395                 enable = 0x80;
 396
 397         /* Program the alarm and enable it for each setting */
 398         regs[ISL1208_REG_SCA - offs] = bin2bcd(alarm_tm->tm_sec) | enable;
 399         regs[ISL1208_REG_MNA - offs] = bin2bcd(alarm_tm->tm_min) | enable;
 400         regs[ISL1208_REG_HRA - offs] = bin2bcd(alarm_tm->tm_hour) |
 401                 ISL1208_REG_HR_MIL | enable;
 402
 403         regs[ISL1208_REG_DTA - offs] = bin2bcd(alarm_tm->tm_mday) | enable;
 404         regs[ISL1208_REG_MOA - offs] = bin2bcd(alarm_tm->tm_mon + 1) | enable;
 405         regs[ISL1208_REG_DWA - offs] = bin2bcd(alarm_tm->tm_wday & 7) | enable;
 406
 407         /* write ALARM registers */
 408         err = isl1208_i2c_set_regs(client, offs, regs,
 409                                   ISL1208_ALARM_SECTION_LEN);
 410         if (err < 0) {
 411                 dev_err(&client->dev, "%s: writing ALARM section failed\n",
 412                         __func__);
 413                 return err;
 414         }
 415
 416         err = isl1208_rtc_toggle_alarm(client, enable);
 417         if (err)
 418                 return err;
 419
 420         return 0;
 421 }
 422
 423 static int
 424 isl1208_rtc_read_time(struct device *dev, struct rtc_time *tm)
 425 {
 426         return isl1208_i2c_read_time(to_i2c_client(dev), tm);
 427 }
 428
 429 static int
 430 isl1208_i2c_set_time(struct i2c_client *client, struct rtc_time const *tm)
 431 {
 432         int sr;
 433         u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
 434
 435         /* The clock has an 8 bit wide bcd-coded register (they never learn)
 436          * for the year. tm_year is an offset from 1900 and we are interested
 437          * in the 2000-2099 range, so any value less than 100 is invalid.
 438          */
 439         if (tm->tm_year < 100)
 440                 return -EINVAL;
 441
 442         regs[ISL1208_REG_SC] = bin2bcd(tm->tm_sec);
 443         regs[ISL1208_REG_MN] = bin2bcd(tm->tm_min);
 444         regs[ISL1208_REG_HR] = bin2bcd(tm->tm_hour) | ISL1208_REG_HR_MIL;
 445
 446         regs[ISL1208_REG_DT] = bin2bcd(tm->tm_mday);
 447         regs[ISL1208_REG_MO] = bin2bcd(tm->tm_mon + 1);
 448         regs[ISL1208_REG_YR] = bin2bcd(tm->tm_year - 100);
 449
 450         regs[ISL1208_REG_DW] = bin2bcd(tm->tm_wday & 7);
 451
 452         sr = isl1208_i2c_get_sr(client);
 453         if (sr < 0) {
 454                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
 455                 return sr;
 456         }
 457
 458         /* set WRTC */
 459         sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR,
 460                                        sr | ISL1208_REG_SR_WRTC);
 461         if (sr < 0) {
 462                 dev_err(&client->dev, "%s: writing SR failed\n", __func__);
 463                 return sr;
 464         }
 465
 466         /* write RTC registers */
 467         sr = isl1208_i2c_set_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
 468         if (sr < 0) {
 469                 dev_err(&client->dev, "%s: writing RTC section failed\n",
 470                         __func__);
 471                 return sr;
 472         }
 473
 474         /* clear WRTC again */
 475         sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR,
 476                                        sr & ~ISL1208_REG_SR_WRTC);
 477         if (sr < 0) {
 478                 dev_err(&client->dev, "%s: writing SR failed\n", __func__);
 479                 return sr;
 480         }
 481
 482         return 0;
 483 }
 484
 485
 486 static int
 487 isl1208_rtc_set_time(struct device *dev, struct rtc_time *tm)
 488 {
 489         return isl1208_i2c_set_time(to_i2c_client(dev), tm);
 490 }
 491
 492 static int
 493 isl1208_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 494 {
 495         return isl1208_i2c_read_alarm(to_i2c_client(dev), alarm);
 496 }
 497
 498 static int
 499 isl1208_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 500 {
 501         return isl1208_i2c_set_alarm(to_i2c_client(dev), alarm);
 502 }
 503
 504 static irqreturn_t
 505 isl1208_rtc_interrupt(int irq, void *data)
 506 {
 507         unsigned long timeout = jiffies + msecs_to_jiffies(1000);
 508         struct i2c_client *client = data;
 509         struct rtc_device *rtc = i2c_get_clientdata(client);
 510         int handled = 0, sr, err;
 511
 512         /*
 513          * I2C reads get NAK'ed if we read straight away after an interrupt?
 514          * Using a mdelay/msleep didn't seem to help either, so we work around
 515          * this by continually trying to read the register for a short time.
 516          */
 517         while (1) {
 518                 sr = isl1208_i2c_get_sr(client);
 519                 if (sr >= 0)
 520                         break;
 521
 522                 if (time_after(jiffies, timeout)) {
 523                         dev_err(&client->dev, "%s: reading SR failed\n",
 524                                 __func__);
 525                         return sr;
 526                 }
 527         }
 528
 529         if (sr & ISL1208_REG_SR_ALM) {
 530                 dev_dbg(&client->dev, "alarm!\n");
 531
 532                 rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF);
 533
 534                 /* Clear the alarm */
 535                 sr &= ~ISL1208_REG_SR_ALM;
 536                 sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR, sr);
 537                 if (sr < 0)
 538                         dev_err(&client->dev, "%s: writing SR failed\n",
 539                                 __func__);
 540                 else
 541                         handled = 1;
 542
 543                 /* Disable the alarm */
 544                 err = isl1208_rtc_toggle_alarm(client, 0);
 545                 if (err)
 546                         return err;
 547         }
 548
 549         return handled ? IRQ_HANDLED : IRQ_NONE;
 550 }
 551
 552 static const struct rtc_class_ops isl1208_rtc_ops = {
 553         .proc = isl1208_rtc_proc,
 554         .read_time = isl1208_rtc_read_time,
 555         .set_time = isl1208_rtc_set_time,
 556         .read_alarm = isl1208_rtc_read_alarm,
 557         .set_alarm = isl1208_rtc_set_alarm,
 558 };
 559
 560 /* sysfs interface */
 561
 562 static ssize_t
 563 isl1208_sysfs_show_atrim(struct device *dev,
 564                          struct device_attribute *attr, char *buf)
 565 {
 566         int atr = isl1208_i2c_get_atr(to_i2c_client(dev));
 567         if (atr < 0)
 568                 return atr;
 569
 570         return sprintf(buf, "%d.%.2d pF\n", atr >> 2, (atr & 0x3) * 25);
 571 }
 572
 573 static DEVICE_ATTR(atrim, S_IRUGO, isl1208_sysfs_show_atrim, NULL);
 574
 575 static ssize_t
 576 isl1208_sysfs_show_dtrim(struct device *dev,
 577                          struct device_attribute *attr, char *buf)
 578 {
 579         int dtr = isl1208_i2c_get_dtr(to_i2c_client(dev));
 580         if (dtr < 0)
 581                 return dtr;
 582
 583         return sprintf(buf, "%d ppm\n", dtr);
 584 }
 585
 586 static DEVICE_ATTR(dtrim, S_IRUGO, isl1208_sysfs_show_dtrim, NULL);
 587
 588 static ssize_t
 589 isl1208_sysfs_show_usr(struct device *dev,
 590                        struct device_attribute *attr, char *buf)
 591 {
 592         int usr = isl1208_i2c_get_usr(to_i2c_client(dev));
 593         if (usr < 0)
 594                 return usr;
 595
 596         return sprintf(buf, "0x%.4x\n", usr);
 597 }
 598
 599 static ssize_t
 600 isl1208_sysfs_store_usr(struct device *dev,
 601                         struct device_attribute *attr,
 602                         const char *buf, size_t count)
 603 {
 604         int usr = -1;
 605
 606         if (buf[0] == '0' && (buf[1] == 'x' || buf[1] == 'X')) {
 607                 if (sscanf(buf, "%x", &usr) != 1)
 608                         return -EINVAL;
 609         } else {
 610                 if (sscanf(buf, "%d", &usr) != 1)
 611                         return -EINVAL;
 612         }
 613
 614         if (usr < 0 || usr > 0xffff)
 615                 return -EINVAL;
 616
 617         return isl1208_i2c_set_usr(to_i2c_client(dev), usr) ? -EIO : count;
 618 }
 619
 620 static DEVICE_ATTR(usr, S_IRUGO | S_IWUSR, isl1208_sysfs_show_usr,
 621                    isl1208_sysfs_store_usr);
 622
 623 static struct attribute *isl1208_rtc_attrs[] = {
 624         &dev_attr_atrim.attr,
 625         &dev_attr_dtrim.attr,
 626         &dev_attr_usr.attr,
 627         NULL
 628 };
 629
 630 static const struct attribute_group isl1208_rtc_sysfs_files = {
 631         .attrs  = isl1208_rtc_attrs,
 632 };
 633
 634 static int
 635 isl1208_probe(struct i2c_client *client, const struct i2c_device_id *id)
 636 {
 637         int rc = 0;
 638         struct rtc_device *rtc;
 639
 640         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 641                 return -ENODEV;
 642
 643         if (isl1208_i2c_validate_client(client) < 0)
 644                 return -ENODEV;
 645
 646         dev_info(&client->dev,
 647                  "chip found, driver version " DRV_VERSION "\n");
 648
 649         if (client->irq > 0) {
 650                 rc = request_threaded_irq(client->irq, NULL,
 651                                           isl1208_rtc_interrupt,
 652                                           IRQF_SHARED,
 653                                           isl1208_driver.driver.name, client);
 654                 if (!rc) {
 655                         device_init_wakeup(&client->dev, 1);
 656                         enable_irq_wake(client->irq);
 657                 } else {
 658                         dev_err(&client->dev,
 659                                 "Unable to request irq %d, no alarm support\n",
 660                                 client->irq);
 661                         client->irq = 0;
 662                 }
 663         }
 664
 665         rtc = rtc_device_register(isl1208_driver.driver.name,
 666                                   &client->dev, &isl1208_rtc_ops,
 667                                   THIS_MODULE);
 668         if (IS_ERR(rtc)) {
 669                 rc = PTR_ERR(rtc);
 670                 goto exit_free_irq;
 671         }
 672
 673         i2c_set_clientdata(client, rtc);
 674
 675         rc = isl1208_i2c_get_sr(client);
 676         if (rc < 0) {
 677                 dev_err(&client->dev, "reading status failed\n");
 678                 goto exit_unregister;
 679         }
 680
 681         if (rc & ISL1208_REG_SR_RTCF)
 682                 dev_warn(&client->dev, "rtc power failure detected, "
 683                          "please set clock.\n");
 684
 685         rc = sysfs_create_group(&client->dev.kobj, &isl1208_rtc_sysfs_files);
 686         if (rc)
 687                 goto exit_unregister;
 688
 689         return 0;
 690
 691 exit_unregister:
 692         rtc_device_unregister(rtc);
 693 exit_free_irq:
 694         if (client->irq)
 695                 free_irq(client->irq, client);
 696
 697         return rc;
 698 }
 699
 700 static int
 701 isl1208_remove(struct i2c_client *client)
 702 {
 703         struct rtc_device *rtc = i2c_get_clientdata(client);
 704
 705         sysfs_remove_group(&client->dev.kobj, &isl1208_rtc_sysfs_files);
 706         rtc_device_unregister(rtc);
 707         if (client->irq)
 708                 free_irq(client->irq, client);
 709
 710         return 0;
 711 }
 712
 713 static const struct i2c_device_id isl1208_id[] = {
 714         { "isl1208", 0 },
 715         { "isl1218", 0 },
 716         { }
 717 };
 718 MODULE_DEVICE_TABLE(i2c, isl1208_id);
 719
 720 static struct i2c_driver isl1208_driver = {
 721         .driver = {
 722                    .name = "rtc-isl1208",
 723                    },
 724         .probe = isl1208_probe,
 725         .remove = isl1208_remove,
 726         .id_table = isl1208_id,
 727 };
 728
 729 module_i2c_driver(isl1208_driver);
 730
 731 MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>");
 732 MODULE_DESCRIPTION("Intersil ISL1208 RTC driver");
 733 MODULE_LICENSE("GPL");
 734 MODULE_VERSION(DRV_VERSION);