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/bcd.h>
  14 #include <linux/i2c.h>
  15 #include <linux/module.h>
  16 #include <linux/of_device.h>
  17 #include <linux/of_irq.h>
  18 #include <linux/rtc.h>
  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_EVT     (1<<3)   /* event */
  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_INT_ALME   (1<<6)   /* alarm enable */
  44 #define ISL1208_REG_INT_IM     (1<<7)   /* interrupt/alarm mode */
  45 #define ISL1219_REG_EV  0x09
  46 #define ISL1219_REG_EV_EVEN    (1<<4)   /* event detection enable */
  47 #define ISL1219_REG_EV_EVIENB  (1<<7)   /* event in pull-up disable */
  48 #define ISL1208_REG_ATR 0x0a
  49 #define ISL1208_REG_DTR 0x0b
  50
  51 /* alarm section */
  52 #define ISL1208_REG_SCA 0x0c
  53 #define ISL1208_REG_MNA 0x0d
  54 #define ISL1208_REG_HRA 0x0e
  55 #define ISL1208_REG_DTA 0x0f
  56 #define ISL1208_REG_MOA 0x10
  57 #define ISL1208_REG_DWA 0x11
  58 #define ISL1208_ALARM_SECTION_LEN 6
  59
  60 /* user section */
  61 #define ISL1208_REG_USR1 0x12
  62 #define ISL1208_REG_USR2 0x13
  63 #define ISL1208_USR_SECTION_LEN 2
  64
  65 /* event section */
  66 #define ISL1219_REG_SCT 0x14
  67 #define ISL1219_REG_MNT 0x15
  68 #define ISL1219_REG_HRT 0x16
  69 #define ISL1219_REG_DTT 0x17
  70 #define ISL1219_REG_MOT 0x18
  71 #define ISL1219_REG_YRT 0x19
  72 #define ISL1219_EVT_SECTION_LEN 6
  73
  74 static struct i2c_driver isl1208_driver;
  75
  76 /* ISL1208 various variants */
  77 enum isl1208_id {
  78         TYPE_ISL1208 = 0,
  79         TYPE_ISL1209,
  80         TYPE_ISL1218,
  81         TYPE_ISL1219,
  82         ISL_LAST_ID
  83 };
  84
  85 /* Chip capabilities table */
  86 static const struct isl1208_config {
  87         const char      name[8];
  88         unsigned int    nvmem_length;
  89         unsigned        has_tamper:1;
  90         unsigned        has_timestamp:1;
  91 } isl1208_configs[] = {
  92         [TYPE_ISL1208] = { "isl1208", 2, false, false },
  93         [TYPE_ISL1209] = { "isl1209", 2, true,  false },
  94         [TYPE_ISL1218] = { "isl1218", 8, false, false },
  95         [TYPE_ISL1219] = { "isl1219", 2, true,  true },
  96 };
  97
  98 static const struct i2c_device_id isl1208_id[] = {
  99         { "isl1208", TYPE_ISL1208 },
 100         { "isl1209", TYPE_ISL1209 },
 101         { "isl1218", TYPE_ISL1218 },
 102         { "isl1219", TYPE_ISL1219 },
 103         { }
 104 };
 105 MODULE_DEVICE_TABLE(i2c, isl1208_id);
 106
 107 static const struct of_device_id isl1208_of_match[] = {
 108         { .compatible = "isil,isl1208", .data = &isl1208_configs[TYPE_ISL1208] },
 109         { .compatible = "isil,isl1209", .data = &isl1208_configs[TYPE_ISL1209] },
 110         { .compatible = "isil,isl1218", .data = &isl1208_configs[TYPE_ISL1218] },
 111         { .compatible = "isil,isl1219", .data = &isl1208_configs[TYPE_ISL1219] },
 112         { }
 113 };
 114 MODULE_DEVICE_TABLE(of, isl1208_of_match);
 115
 116 /* Device state */
 117 struct isl1208_state {
 118         struct nvmem_config nvmem_config;
 119         struct rtc_device *rtc;
 120         const struct isl1208_config *config;
 121 };
 122
 123 /* block read */
 124 static int
 125 isl1208_i2c_read_regs(struct i2c_client *client, u8 reg, u8 buf[],
 126                       unsigned len)
 127 {
 128         int ret;
 129
 130         WARN_ON(reg > ISL1219_REG_YRT);
 131         WARN_ON(reg + len > ISL1219_REG_YRT + 1);
 132
 133         ret = i2c_smbus_read_i2c_block_data(client, reg, len, buf);
 134         return (ret < 0) ? ret : 0;
 135 }
 136
 137 /* block write */
 138 static int
 139 isl1208_i2c_set_regs(struct i2c_client *client, u8 reg, u8 const buf[],
 140                      unsigned len)
 141 {
 142         int ret;
 143
 144         WARN_ON(reg > ISL1219_REG_YRT);
 145         WARN_ON(reg + len > ISL1219_REG_YRT + 1);
 146
 147         ret = i2c_smbus_write_i2c_block_data(client, reg, len, buf);
 148         return (ret < 0) ? ret : 0;
 149 }
 150
 151 /* simple check to see whether we have a isl1208 */
 152 static int
 153 isl1208_i2c_validate_client(struct i2c_client *client)
 154 {
 155         u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
 156         u8 zero_mask[ISL1208_RTC_SECTION_LEN] = {
 157                 0x80, 0x80, 0x40, 0xc0, 0xe0, 0x00, 0xf8
 158         };
 159         int i;
 160         int ret;
 161
 162         ret = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
 163         if (ret < 0)
 164                 return ret;
 165
 166         for (i = 0; i < ISL1208_RTC_SECTION_LEN; ++i) {
 167                 if (regs[i] & zero_mask[i])     /* check if bits are cleared */
 168                         return -ENODEV;
 169         }
 170
 171         return 0;
 172 }
 173
 174 static int
 175 isl1208_i2c_get_sr(struct i2c_client *client)
 176 {
 177         return i2c_smbus_read_byte_data(client, ISL1208_REG_SR);
 178 }
 179
 180 static int
 181 isl1208_i2c_get_atr(struct i2c_client *client)
 182 {
 183         int atr = i2c_smbus_read_byte_data(client, ISL1208_REG_ATR);
 184         if (atr < 0)
 185                 return atr;
 186
 187         /* The 6bit value in the ATR register controls the load
 188          * capacitance C_load * in steps of 0.25pF
 189          *
 190          * bit (1<<5) of the ATR register is inverted
 191          *
 192          * C_load(ATR=0x20) =  4.50pF
 193          * C_load(ATR=0x00) = 12.50pF
 194          * C_load(ATR=0x1f) = 20.25pF
 195          *
 196          */
 197
 198         atr &= 0x3f;            /* mask out lsb */
 199         atr ^= 1 << 5;          /* invert 6th bit */
 200         atr += 2 * 9;           /* add offset of 4.5pF; unit[atr] = 0.25pF */
 201
 202         return atr;
 203 }
 204
 205 /* returns adjustment value + 100 */
 206 static int
 207 isl1208_i2c_get_dtr(struct i2c_client *client)
 208 {
 209         int dtr = i2c_smbus_read_byte_data(client, ISL1208_REG_DTR);
 210         if (dtr < 0)
 211                 return -EIO;
 212
 213         /* dtr encodes adjustments of {-60,-40,-20,0,20,40,60} ppm */
 214         dtr = ((dtr & 0x3) * 20) * (dtr & (1 << 2) ? -1 : 1);
 215
 216         return dtr + 100;
 217 }
 218
 219 static int
 220 isl1208_i2c_get_usr(struct i2c_client *client)
 221 {
 222         u8 buf[ISL1208_USR_SECTION_LEN] = { 0, };
 223         int ret;
 224
 225         ret = isl1208_i2c_read_regs(client, ISL1208_REG_USR1, buf,
 226                                     ISL1208_USR_SECTION_LEN);
 227         if (ret < 0)
 228                 return ret;
 229
 230         return (buf[1] << 8) | buf[0];
 231 }
 232
 233 static int
 234 isl1208_i2c_set_usr(struct i2c_client *client, u16 usr)
 235 {
 236         u8 buf[ISL1208_USR_SECTION_LEN];
 237
 238         buf[0] = usr & 0xff;
 239         buf[1] = (usr >> 8) & 0xff;
 240
 241         return isl1208_i2c_set_regs(client, ISL1208_REG_USR1, buf,
 242                                     ISL1208_USR_SECTION_LEN);
 243 }
 244
 245 static int
 246 isl1208_rtc_toggle_alarm(struct i2c_client *client, int enable)
 247 {
 248         int icr = i2c_smbus_read_byte_data(client, ISL1208_REG_INT);
 249
 250         if (icr < 0) {
 251                 dev_err(&client->dev, "%s: reading INT failed\n", __func__);
 252                 return icr;
 253         }
 254
 255         if (enable)
 256                 icr |= ISL1208_REG_INT_ALME | ISL1208_REG_INT_IM;
 257         else
 258                 icr &= ~(ISL1208_REG_INT_ALME | ISL1208_REG_INT_IM);
 259
 260         icr = i2c_smbus_write_byte_data(client, ISL1208_REG_INT, icr);
 261         if (icr < 0) {
 262                 dev_err(&client->dev, "%s: writing INT failed\n", __func__);
 263                 return icr;
 264         }
 265
 266         return 0;
 267 }
 268
 269 static int
 270 isl1208_rtc_proc(struct device *dev, struct seq_file *seq)
 271 {
 272         struct i2c_client *const client = to_i2c_client(dev);
 273         int sr, dtr, atr, usr;
 274
 275         sr = isl1208_i2c_get_sr(client);
 276         if (sr < 0) {
 277                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
 278                 return sr;
 279         }
 280
 281         seq_printf(seq, "status_reg\t:%s%s%s%s%s%s (0x%.2x)\n",
 282                    (sr & ISL1208_REG_SR_RTCF) ? " RTCF" : "",
 283                    (sr & ISL1208_REG_SR_BAT) ? " BAT" : "",
 284                    (sr & ISL1208_REG_SR_ALM) ? " ALM" : "",
 285                    (sr & ISL1208_REG_SR_WRTC) ? " WRTC" : "",
 286                    (sr & ISL1208_REG_SR_XTOSCB) ? " XTOSCB" : "",
 287                    (sr & ISL1208_REG_SR_ARST) ? " ARST" : "", sr);
 288
 289         seq_printf(seq, "batt_status\t: %s\n",
 290                    (sr & ISL1208_REG_SR_RTCF) ? "bad" : "okay");
 291
 292         dtr = isl1208_i2c_get_dtr(client);
 293         if (dtr >= 0)
 294                 seq_printf(seq, "digital_trim\t: %d ppm\n", dtr - 100);
 295
 296         atr = isl1208_i2c_get_atr(client);
 297         if (atr >= 0)
 298                 seq_printf(seq, "analog_trim\t: %d.%.2d pF\n",
 299                            atr >> 2, (atr & 0x3) * 25);
 300
 301         usr = isl1208_i2c_get_usr(client);
 302         if (usr >= 0)
 303                 seq_printf(seq, "user_data\t: 0x%.4x\n", usr);
 304
 305         return 0;
 306 }
 307
 308 static int
 309 isl1208_i2c_read_time(struct i2c_client *client, struct rtc_time *tm)
 310 {
 311         int sr;
 312         u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
 313
 314         sr = isl1208_i2c_get_sr(client);
 315         if (sr < 0) {
 316                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
 317                 return -EIO;
 318         }
 319
 320         sr = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
 321         if (sr < 0) {
 322                 dev_err(&client->dev, "%s: reading RTC section failed\n",
 323                         __func__);
 324                 return sr;
 325         }
 326
 327         tm->tm_sec = bcd2bin(regs[ISL1208_REG_SC]);
 328         tm->tm_min = bcd2bin(regs[ISL1208_REG_MN]);
 329
 330         /* HR field has a more complex interpretation */
 331         {
 332                 const u8 _hr = regs[ISL1208_REG_HR];
 333                 if (_hr & ISL1208_REG_HR_MIL)   /* 24h format */
 334                         tm->tm_hour = bcd2bin(_hr & 0x3f);
 335                 else {
 336                         /* 12h format */
 337                         tm->tm_hour = bcd2bin(_hr & 0x1f);
 338                         if (_hr & ISL1208_REG_HR_PM)    /* PM flag set */
 339                                 tm->tm_hour += 12;
 340                 }
 341         }
 342
 343         tm->tm_mday = bcd2bin(regs[ISL1208_REG_DT]);
 344         tm->tm_mon = bcd2bin(regs[ISL1208_REG_MO]) - 1; /* rtc starts at 1 */
 345         tm->tm_year = bcd2bin(regs[ISL1208_REG_YR]) + 100;
 346         tm->tm_wday = bcd2bin(regs[ISL1208_REG_DW]);
 347
 348         return 0;
 349 }
 350
 351 static int
 352 isl1208_i2c_read_alarm(struct i2c_client *client, struct rtc_wkalrm *alarm)
 353 {
 354         struct rtc_time *const tm = &alarm->time;
 355         u8 regs[ISL1208_ALARM_SECTION_LEN] = { 0, };
 356         int icr, yr, sr = isl1208_i2c_get_sr(client);
 357
 358         if (sr < 0) {
 359                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
 360                 return sr;
 361         }
 362
 363         sr = isl1208_i2c_read_regs(client, ISL1208_REG_SCA, regs,
 364                                    ISL1208_ALARM_SECTION_LEN);
 365         if (sr < 0) {
 366                 dev_err(&client->dev, "%s: reading alarm section failed\n",
 367                         __func__);
 368                 return sr;
 369         }
 370
 371         /* MSB of each alarm register is an enable bit */
 372         tm->tm_sec = bcd2bin(regs[ISL1208_REG_SCA - ISL1208_REG_SCA] & 0x7f);
 373         tm->tm_min = bcd2bin(regs[ISL1208_REG_MNA - ISL1208_REG_SCA] & 0x7f);
 374         tm->tm_hour = bcd2bin(regs[ISL1208_REG_HRA - ISL1208_REG_SCA] & 0x3f);
 375         tm->tm_mday = bcd2bin(regs[ISL1208_REG_DTA - ISL1208_REG_SCA] & 0x3f);
 376         tm->tm_mon =
 377                 bcd2bin(regs[ISL1208_REG_MOA - ISL1208_REG_SCA] & 0x1f) - 1;
 378         tm->tm_wday = bcd2bin(regs[ISL1208_REG_DWA - ISL1208_REG_SCA] & 0x03);
 379
 380         /* The alarm doesn't store the year so get it from the rtc section */
 381         yr = i2c_smbus_read_byte_data(client, ISL1208_REG_YR);
 382         if (yr < 0) {
 383                 dev_err(&client->dev, "%s: reading RTC YR failed\n", __func__);
 384                 return yr;
 385         }
 386         tm->tm_year = bcd2bin(yr) + 100;
 387
 388         icr = i2c_smbus_read_byte_data(client, ISL1208_REG_INT);
 389         if (icr < 0) {
 390                 dev_err(&client->dev, "%s: reading INT failed\n", __func__);
 391                 return icr;
 392         }
 393         alarm->enabled = !!(icr & ISL1208_REG_INT_ALME);
 394
 395         return 0;
 396 }
 397
 398 static int
 399 isl1208_i2c_set_alarm(struct i2c_client *client, struct rtc_wkalrm *alarm)
 400 {
 401         struct rtc_time *alarm_tm = &alarm->time;
 402         u8 regs[ISL1208_ALARM_SECTION_LEN] = { 0, };
 403         const int offs = ISL1208_REG_SCA;
 404         struct rtc_time rtc_tm;
 405         int err, enable;
 406
 407         err = isl1208_i2c_read_time(client, &rtc_tm);
 408         if (err)
 409                 return err;
 410
 411         /* If the alarm time is before the current time disable the alarm */
 412         if (!alarm->enabled || rtc_tm_sub(alarm_tm, &rtc_tm) <= 0)
 413                 enable = 0x00;
 414         else
 415                 enable = 0x80;
 416
 417         /* Program the alarm and enable it for each setting */
 418         regs[ISL1208_REG_SCA - offs] = bin2bcd(alarm_tm->tm_sec) | enable;
 419         regs[ISL1208_REG_MNA - offs] = bin2bcd(alarm_tm->tm_min) | enable;
 420         regs[ISL1208_REG_HRA - offs] = bin2bcd(alarm_tm->tm_hour) |
 421                 ISL1208_REG_HR_MIL | enable;
 422
 423         regs[ISL1208_REG_DTA - offs] = bin2bcd(alarm_tm->tm_mday) | enable;
 424         regs[ISL1208_REG_MOA - offs] = bin2bcd(alarm_tm->tm_mon + 1) | enable;
 425         regs[ISL1208_REG_DWA - offs] = bin2bcd(alarm_tm->tm_wday & 7) | enable;
 426
 427         /* write ALARM registers */
 428         err = isl1208_i2c_set_regs(client, offs, regs,
 429                                   ISL1208_ALARM_SECTION_LEN);
 430         if (err < 0) {
 431                 dev_err(&client->dev, "%s: writing ALARM section failed\n",
 432                         __func__);
 433                 return err;
 434         }
 435
 436         err = isl1208_rtc_toggle_alarm(client, enable);
 437         if (err)
 438                 return err;
 439
 440         return 0;
 441 }
 442
 443 static int
 444 isl1208_rtc_read_time(struct device *dev, struct rtc_time *tm)
 445 {
 446         return isl1208_i2c_read_time(to_i2c_client(dev), tm);
 447 }
 448
 449 static int
 450 isl1208_i2c_set_time(struct i2c_client *client, struct rtc_time const *tm)
 451 {
 452         int sr;
 453         u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
 454
 455         /* The clock has an 8 bit wide bcd-coded register (they never learn)
 456          * for the year. tm_year is an offset from 1900 and we are interested
 457          * in the 2000-2099 range, so any value less than 100 is invalid.
 458          */
 459         if (tm->tm_year < 100)
 460                 return -EINVAL;
 461
 462         regs[ISL1208_REG_SC] = bin2bcd(tm->tm_sec);
 463         regs[ISL1208_REG_MN] = bin2bcd(tm->tm_min);
 464         regs[ISL1208_REG_HR] = bin2bcd(tm->tm_hour) | ISL1208_REG_HR_MIL;
 465
 466         regs[ISL1208_REG_DT] = bin2bcd(tm->tm_mday);
 467         regs[ISL1208_REG_MO] = bin2bcd(tm->tm_mon + 1);
 468         regs[ISL1208_REG_YR] = bin2bcd(tm->tm_year - 100);
 469
 470         regs[ISL1208_REG_DW] = bin2bcd(tm->tm_wday & 7);
 471
 472         sr = isl1208_i2c_get_sr(client);
 473         if (sr < 0) {
 474                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
 475                 return sr;
 476         }
 477
 478         /* set WRTC */
 479         sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR,
 480                                        sr | ISL1208_REG_SR_WRTC);
 481         if (sr < 0) {
 482                 dev_err(&client->dev, "%s: writing SR failed\n", __func__);
 483                 return sr;
 484         }
 485
 486         /* write RTC registers */
 487         sr = isl1208_i2c_set_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
 488         if (sr < 0) {
 489                 dev_err(&client->dev, "%s: writing RTC section failed\n",
 490                         __func__);
 491                 return sr;
 492         }
 493
 494         /* clear WRTC again */
 495         sr = isl1208_i2c_get_sr(client);
 496         if (sr < 0) {
 497                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
 498                 return sr;
 499         }
 500         sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR,
 501                                        sr & ~ISL1208_REG_SR_WRTC);
 502         if (sr < 0) {
 503                 dev_err(&client->dev, "%s: writing SR failed\n", __func__);
 504                 return sr;
 505         }
 506
 507         return 0;
 508 }
 509
 510
 511 static int
 512 isl1208_rtc_set_time(struct device *dev, struct rtc_time *tm)
 513 {
 514         return isl1208_i2c_set_time(to_i2c_client(dev), tm);
 515 }
 516
 517 static int
 518 isl1208_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 519 {
 520         return isl1208_i2c_read_alarm(to_i2c_client(dev), alarm);
 521 }
 522
 523 static int
 524 isl1208_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 525 {
 526         return isl1208_i2c_set_alarm(to_i2c_client(dev), alarm);
 527 }
 528
 529 static ssize_t timestamp0_store(struct device *dev,
 530                                 struct device_attribute *attr,
 531                                 const char *buf, size_t count)
 532 {
 533         struct i2c_client *client = to_i2c_client(dev->parent);
 534         int sr;
 535
 536         sr = isl1208_i2c_get_sr(client);
 537         if (sr < 0) {
 538                 dev_err(dev, "%s: reading SR failed\n", __func__);
 539                 return sr;
 540         }
 541
 542         sr &= ~ISL1208_REG_SR_EVT;
 543
 544         sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR, sr);
 545         if (sr < 0)
 546                 dev_err(dev, "%s: writing SR failed\n",
 547                         __func__);
 548
 549         return count;
 550 };
 551
 552 static ssize_t timestamp0_show(struct device *dev,
 553                                struct device_attribute *attr, char *buf)
 554 {
 555         struct i2c_client *client = to_i2c_client(dev->parent);
 556         u8 regs[ISL1219_EVT_SECTION_LEN] = { 0, };
 557         struct rtc_time tm;
 558         int sr;
 559
 560         sr = isl1208_i2c_get_sr(client);
 561         if (sr < 0) {
 562                 dev_err(dev, "%s: reading SR failed\n", __func__);
 563                 return sr;
 564         }
 565
 566         if (!(sr & ISL1208_REG_SR_EVT))
 567                 return 0;
 568
 569         sr = isl1208_i2c_read_regs(client, ISL1219_REG_SCT, regs,
 570                                    ISL1219_EVT_SECTION_LEN);
 571         if (sr < 0) {
 572                 dev_err(dev, "%s: reading event section failed\n",
 573                         __func__);
 574                 return 0;
 575         }
 576
 577         /* MSB of each alarm register is an enable bit */
 578         tm.tm_sec = bcd2bin(regs[ISL1219_REG_SCT - ISL1219_REG_SCT] & 0x7f);
 579         tm.tm_min = bcd2bin(regs[ISL1219_REG_MNT - ISL1219_REG_SCT] & 0x7f);
 580         tm.tm_hour = bcd2bin(regs[ISL1219_REG_HRT - ISL1219_REG_SCT] & 0x3f);
 581         tm.tm_mday = bcd2bin(regs[ISL1219_REG_DTT - ISL1219_REG_SCT] & 0x3f);
 582         tm.tm_mon =
 583                 bcd2bin(regs[ISL1219_REG_MOT - ISL1219_REG_SCT] & 0x1f) - 1;
 584         tm.tm_year = bcd2bin(regs[ISL1219_REG_YRT - ISL1219_REG_SCT]) + 100;
 585
 586         sr = rtc_valid_tm(&tm);
 587         if (sr)
 588                 return sr;
 589
 590         return sprintf(buf, "%llu\n",
 591                                 (unsigned long long)rtc_tm_to_time64(&tm));
 592 };
 593
 594 static DEVICE_ATTR_RW(timestamp0);
 595
 596 static irqreturn_t
 597 isl1208_rtc_interrupt(int irq, void *data)
 598 {
 599         unsigned long timeout = jiffies + msecs_to_jiffies(1000);
 600         struct i2c_client *client = data;
 601         struct isl1208_state *isl1208 = i2c_get_clientdata(client);
 602         int handled = 0, sr, err;
 603
 604         /*
 605          * I2C reads get NAK'ed if we read straight away after an interrupt?
 606          * Using a mdelay/msleep didn't seem to help either, so we work around
 607          * this by continually trying to read the register for a short time.
 608          */
 609         while (1) {
 610                 sr = isl1208_i2c_get_sr(client);
 611                 if (sr >= 0)
 612                         break;
 613
 614                 if (time_after(jiffies, timeout)) {
 615                         dev_err(&client->dev, "%s: reading SR failed\n",
 616                                 __func__);
 617                         return sr;
 618                 }
 619         }
 620
 621         if (sr & ISL1208_REG_SR_ALM) {
 622                 dev_dbg(&client->dev, "alarm!\n");
 623
 624                 rtc_update_irq(isl1208->rtc, 1, RTC_IRQF | RTC_AF);
 625
 626                 /* Clear the alarm */
 627                 sr &= ~ISL1208_REG_SR_ALM;
 628                 sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR, sr);
 629                 if (sr < 0)
 630                         dev_err(&client->dev, "%s: writing SR failed\n",
 631                                 __func__);
 632                 else
 633                         handled = 1;
 634
 635                 /* Disable the alarm */
 636                 err = isl1208_rtc_toggle_alarm(client, 0);
 637                 if (err)
 638                         return err;
 639         }
 640
 641         if (isl1208->config->has_tamper && (sr & ISL1208_REG_SR_EVT)) {
 642                 dev_warn(&client->dev, "event detected");
 643                 handled = 1;
 644                 if (isl1208->config->has_timestamp)
 645                         sysfs_notify(&isl1208->rtc->dev.kobj, NULL,
 646                                      dev_attr_timestamp0.attr.name);
 647         }
 648
 649         return handled ? IRQ_HANDLED : IRQ_NONE;
 650 }
 651
 652 static const struct rtc_class_ops isl1208_rtc_ops = {
 653         .proc = isl1208_rtc_proc,
 654         .read_time = isl1208_rtc_read_time,
 655         .set_time = isl1208_rtc_set_time,
 656         .read_alarm = isl1208_rtc_read_alarm,
 657         .set_alarm = isl1208_rtc_set_alarm,
 658 };
 659
 660 /* sysfs interface */
 661
 662 static ssize_t
 663 isl1208_sysfs_show_atrim(struct device *dev,
 664                          struct device_attribute *attr, char *buf)
 665 {
 666         int atr = isl1208_i2c_get_atr(to_i2c_client(dev->parent));
 667         if (atr < 0)
 668                 return atr;
 669
 670         return sprintf(buf, "%d.%.2d pF\n", atr >> 2, (atr & 0x3) * 25);
 671 }
 672
 673 static DEVICE_ATTR(atrim, S_IRUGO, isl1208_sysfs_show_atrim, NULL);
 674
 675 static ssize_t
 676 isl1208_sysfs_show_dtrim(struct device *dev,
 677                          struct device_attribute *attr, char *buf)
 678 {
 679         int dtr = isl1208_i2c_get_dtr(to_i2c_client(dev->parent));
 680         if (dtr < 0)
 681                 return dtr;
 682
 683         return sprintf(buf, "%d ppm\n", dtr - 100);
 684 }
 685
 686 static DEVICE_ATTR(dtrim, S_IRUGO, isl1208_sysfs_show_dtrim, NULL);
 687
 688 static ssize_t
 689 isl1208_sysfs_show_usr(struct device *dev,
 690                        struct device_attribute *attr, char *buf)
 691 {
 692         int usr = isl1208_i2c_get_usr(to_i2c_client(dev->parent));
 693         if (usr < 0)
 694                 return usr;
 695
 696         return sprintf(buf, "0x%.4x\n", usr);
 697 }
 698
 699 static ssize_t
 700 isl1208_sysfs_store_usr(struct device *dev,
 701                         struct device_attribute *attr,
 702                         const char *buf, size_t count)
 703 {
 704         int usr = -1;
 705
 706         if (buf[0] == '0' && (buf[1] == 'x' || buf[1] == 'X')) {
 707                 if (sscanf(buf, "%x", &usr) != 1)
 708                         return -EINVAL;
 709         } else {
 710                 if (sscanf(buf, "%d", &usr) != 1)
 711                         return -EINVAL;
 712         }
 713
 714         if (usr < 0 || usr > 0xffff)
 715                 return -EINVAL;
 716
 717         if (isl1208_i2c_set_usr(to_i2c_client(dev->parent), usr))
 718                 return -EIO;
 719
 720         return count;
 721 }
 722
 723 static DEVICE_ATTR(usr, S_IRUGO | S_IWUSR, isl1208_sysfs_show_usr,
 724                    isl1208_sysfs_store_usr);
 725
 726 static struct attribute *isl1208_rtc_attrs[] = {
 727         &dev_attr_atrim.attr,
 728         &dev_attr_dtrim.attr,
 729         &dev_attr_usr.attr,
 730         NULL
 731 };
 732
 733 static const struct attribute_group isl1208_rtc_sysfs_files = {
 734         .attrs  = isl1208_rtc_attrs,
 735 };
 736
 737 static struct attribute *isl1219_rtc_attrs[] = {
 738         &dev_attr_timestamp0.attr,
 739         NULL
 740 };
 741
 742 static const struct attribute_group isl1219_rtc_sysfs_files = {
 743         .attrs  = isl1219_rtc_attrs,
 744 };
 745
 746 static int isl1208_nvmem_read(void *priv, unsigned int off, void *buf,
 747                               size_t count)
 748 {
 749         struct isl1208_state *isl1208 = priv;
 750         struct i2c_client *client = to_i2c_client(isl1208->rtc->dev.parent);
 751         int ret;
 752
 753         /* nvmem sanitizes offset/count for us, but count==0 is possible */
 754         if (!count)
 755                 return count;
 756         ret = isl1208_i2c_read_regs(client, ISL1208_REG_USR1 + off, buf,
 757                                     count);
 758         return ret == 0 ? count : ret;
 759 }
 760
 761 static int isl1208_nvmem_write(void *priv, unsigned int off, void *buf,
 762                                size_t count)
 763 {
 764         struct isl1208_state *isl1208 = priv;
 765         struct i2c_client *client = to_i2c_client(isl1208->rtc->dev.parent);
 766         int ret;
 767
 768         /* nvmem sanitizes off/count for us, but count==0 is possible */
 769         if (!count)
 770                 return count;
 771         ret = isl1208_i2c_set_regs(client, ISL1208_REG_USR1 + off, buf,
 772                                    count);
 773
 774         return ret == 0 ? count : ret;
 775 }
 776
 777 static const struct nvmem_config isl1208_nvmem_config = {
 778         .name = "isl1208_nvram",
 779         .word_size = 1,
 780         .stride = 1,
 781         /* .size from chip specific config */
 782         .reg_read = isl1208_nvmem_read,
 783         .reg_write = isl1208_nvmem_write,
 784 };
 785
 786 static int isl1208_setup_irq(struct i2c_client *client, int irq)
 787 {
 788         int rc = devm_request_threaded_irq(&client->dev, irq, NULL,
 789                                         isl1208_rtc_interrupt,
 790                                         IRQF_SHARED | IRQF_ONESHOT,
 791                                         isl1208_driver.driver.name,
 792                                         client);
 793         if (!rc) {
 794                 device_init_wakeup(&client->dev, 1);
 795                 enable_irq_wake(irq);
 796         } else {
 797                 dev_err(&client->dev,
 798                         "Unable to request irq %d, no alarm support\n",
 799                         irq);
 800         }
 801         return rc;
 802 }
 803
 804 static int
 805 isl1208_probe(struct i2c_client *client, const struct i2c_device_id *id)
 806 {
 807         int rc = 0;
 808         struct isl1208_state *isl1208;
 809         int evdet_irq = -1;
 810
 811         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 812                 return -ENODEV;
 813
 814         if (isl1208_i2c_validate_client(client) < 0)
 815                 return -ENODEV;
 816
 817         /* Allocate driver state, point i2c client data to it */
 818         isl1208 = devm_kzalloc(&client->dev, sizeof(*isl1208), GFP_KERNEL);
 819         if (!isl1208)
 820                 return -ENOMEM;
 821         i2c_set_clientdata(client, isl1208);
 822
 823         /* Determine which chip we have */
 824         if (client->dev.of_node) {
 825                 isl1208->config = of_device_get_match_data(&client->dev);
 826                 if (!isl1208->config)
 827                         return -ENODEV;
 828         } else {
 829                 if (id->driver_data >= ISL_LAST_ID)
 830                         return -ENODEV;
 831                 isl1208->config = &isl1208_configs[id->driver_data];
 832         }
 833
 834         isl1208->rtc = devm_rtc_allocate_device(&client->dev);
 835         if (IS_ERR(isl1208->rtc))
 836                 return PTR_ERR(isl1208->rtc);
 837
 838         isl1208->rtc->ops = &isl1208_rtc_ops;
 839
 840         /* Setup nvmem configuration in driver state struct */
 841         isl1208->nvmem_config = isl1208_nvmem_config;
 842         isl1208->nvmem_config.size = isl1208->config->nvmem_length;
 843         isl1208->nvmem_config.priv = isl1208;
 844
 845         rc = isl1208_i2c_get_sr(client);
 846         if (rc < 0) {
 847                 dev_err(&client->dev, "reading status failed\n");
 848                 return rc;
 849         }
 850
 851         if (rc & ISL1208_REG_SR_RTCF)
 852                 dev_warn(&client->dev, "rtc power failure detected, "
 853                          "please set clock.\n");
 854
 855         if (isl1208->config->has_tamper) {
 856                 struct device_node *np = client->dev.of_node;
 857                 u32 evienb;
 858
 859                 rc = i2c_smbus_read_byte_data(client, ISL1219_REG_EV);
 860                 if (rc < 0) {
 861                         dev_err(&client->dev, "failed to read EV reg\n");
 862                         return rc;
 863                 }
 864                 rc |= ISL1219_REG_EV_EVEN;
 865                 if (!of_property_read_u32(np, "isil,ev-evienb", &evienb)) {
 866                         if (evienb)
 867                                 rc |= ISL1219_REG_EV_EVIENB;
 868                         else
 869                                 rc &= ~ISL1219_REG_EV_EVIENB;
 870                 }
 871                 rc = i2c_smbus_write_byte_data(client, ISL1219_REG_EV, rc);
 872                 if (rc < 0) {
 873                         dev_err(&client->dev, "could not enable tamper detection\n");
 874                         return rc;
 875                 }
 876                 evdet_irq = of_irq_get_byname(np, "evdet");
 877         }
 878         if (isl1208->config->has_timestamp) {
 879                 rc = rtc_add_group(isl1208->rtc, &isl1219_rtc_sysfs_files);
 880                 if (rc)
 881                         return rc;
 882         }
 883
 884         rc = rtc_add_group(isl1208->rtc, &isl1208_rtc_sysfs_files);
 885         if (rc)
 886                 return rc;
 887
 888         if (client->irq > 0)
 889                 rc = isl1208_setup_irq(client, client->irq);
 890         if (rc)
 891                 return rc;
 892
 893         if (evdet_irq > 0 && evdet_irq != client->irq)
 894                 rc = isl1208_setup_irq(client, evdet_irq);
 895         if (rc)
 896                 return rc;
 897
 898         rc = rtc_nvmem_register(isl1208->rtc, &isl1208->nvmem_config);
 899         if (rc)
 900                 return rc;
 901
 902         return rtc_register_device(isl1208->rtc);
 903 }
 904
 905 static struct i2c_driver isl1208_driver = {
 906         .driver = {
 907                 .name = "rtc-isl1208",
 908                 .of_match_table = of_match_ptr(isl1208_of_match),
 909         },
 910         .probe = isl1208_probe,
 911         .id_table = isl1208_id,
 912 };
 913
 914 module_i2c_driver(isl1208_driver);
 915
 916 MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>");
 917 MODULE_DESCRIPTION("Intersil ISL1208 RTC driver");
 918 MODULE_LICENSE("GPL");