drivers/rtc/rtc-isl1208.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Intersil ISL1208 rtc class driver
   4  *
   5  * Copyright 2005,2006 Hebert Valerio Riedel <[email protected]>
   6  */
   7
   8 #include <linux/bcd.h>
   9 #include <linux/clk.h>
  10 #include <linux/delay.h>
  11 #include <linux/i2c.h>
  12 #include <linux/module.h>
  13 #include <linux/of.h>
  14 #include <linux/of_irq.h>
  15 #include <linux/rtc.h>
  16
  17 /* Register map */
  18 /* rtc section */
  19 #define ISL1208_REG_SC  0x00
  20 #define ISL1208_REG_MN  0x01
  21 #define ISL1208_REG_HR  0x02
  22 #define ISL1208_REG_HR_MIL     (1<<7)   /* 24h/12h mode */
  23 #define ISL1208_REG_HR_PM      (1<<5)   /* PM/AM bit in 12h mode */
  24 #define ISL1208_REG_DT  0x03
  25 #define ISL1208_REG_MO  0x04
  26 #define ISL1208_REG_YR  0x05
  27 #define ISL1208_REG_DW  0x06
  28 #define ISL1208_RTC_SECTION_LEN 7
  29
  30 /* control/status section */
  31 #define ISL1208_REG_SR  0x07
  32 #define ISL1208_REG_SR_ARST    (1<<7)   /* auto reset */
  33 #define ISL1208_REG_SR_XTOSCB  (1<<6)   /* crystal oscillator */
  34 #define ISL1208_REG_SR_WRTC    (1<<4)   /* write rtc */
  35 #define ISL1208_REG_SR_EVT     (1<<3)   /* event */
  36 #define ISL1208_REG_SR_ALM     (1<<2)   /* alarm */
  37 #define ISL1208_REG_SR_BAT     (1<<1)   /* battery */
  38 #define ISL1208_REG_SR_RTCF    (1<<0)   /* rtc fail */
  39 #define ISL1208_REG_INT 0x08
  40 #define ISL1208_REG_INT_ALME   (1<<6)   /* alarm enable */
  41 #define ISL1208_REG_INT_IM     (1<<7)   /* interrupt/alarm mode */
  42 #define ISL1219_REG_EV  0x09
  43 #define ISL1219_REG_EV_EVEN    (1<<4)   /* event detection enable */
  44 #define ISL1219_REG_EV_EVIENB  (1<<7)   /* event in pull-up disable */
  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 /* event section */
  63 #define ISL1219_REG_SCT 0x14
  64 #define ISL1219_REG_MNT 0x15
  65 #define ISL1219_REG_HRT 0x16
  66 #define ISL1219_REG_DTT 0x17
  67 #define ISL1219_REG_MOT 0x18
  68 #define ISL1219_REG_YRT 0x19
  69 #define ISL1219_EVT_SECTION_LEN 6
  70
  71 static struct i2c_driver isl1208_driver;
  72
  73 /* Chip capabilities table */
  74 struct isl1208_config {
  75         unsigned int    nvmem_length;
  76         unsigned        has_tamper:1;
  77         unsigned        has_timestamp:1;
  78         unsigned        has_inverted_osc_bit:1;
  79 };
  80
  81 static const struct isl1208_config config_isl1208 = {
  82         .nvmem_length = 2,
  83         .has_tamper = false,
  84         .has_timestamp = false
  85 };
  86
  87 static const struct isl1208_config config_isl1209 = {
  88         .nvmem_length = 2,
  89         .has_tamper = true,
  90         .has_timestamp = false
  91 };
  92
  93 static const struct isl1208_config config_isl1218 = {
  94         .nvmem_length = 8,
  95         .has_tamper = false,
  96         .has_timestamp = false
  97 };
  98
  99 static const struct isl1208_config config_isl1219 = {
 100         .nvmem_length = 2,
 101         .has_tamper = true,
 102         .has_timestamp = true
 103 };
 104
 105 static const struct isl1208_config config_raa215300_a0 = {
 106         .nvmem_length = 2,
 107         .has_tamper = false,
 108         .has_timestamp = false,
 109         .has_inverted_osc_bit = true
 110 };
 111
 112 static const struct i2c_device_id isl1208_id[] = {
 113         { "isl1208", .driver_data = (kernel_ulong_t)&config_isl1208 },
 114         { "isl1209", .driver_data = (kernel_ulong_t)&config_isl1209 },
 115         { "isl1218", .driver_data = (kernel_ulong_t)&config_isl1218 },
 116         { "isl1219", .driver_data = (kernel_ulong_t)&config_isl1219 },
 117         { "raa215300_a0", .driver_data = (kernel_ulong_t)&config_raa215300_a0 },
 118         { }
 119 };
 120 MODULE_DEVICE_TABLE(i2c, isl1208_id);
 121
 122 static const __maybe_unused struct of_device_id isl1208_of_match[] = {
 123         { .compatible = "isil,isl1208", .data = &config_isl1208 },
 124         { .compatible = "isil,isl1209", .data = &config_isl1209 },
 125         { .compatible = "isil,isl1218", .data = &config_isl1218 },
 126         { .compatible = "isil,isl1219", .data = &config_isl1219 },
 127         { }
 128 };
 129 MODULE_DEVICE_TABLE(of, isl1208_of_match);
 130
 131 /* Device state */
 132 struct isl1208_state {
 133         struct nvmem_config nvmem_config;
 134         struct rtc_device *rtc;
 135         const struct isl1208_config *config;
 136 };
 137
 138 /* block read */
 139 static int
 140 isl1208_i2c_read_regs(struct i2c_client *client, u8 reg, u8 buf[],
 141                       unsigned len)
 142 {
 143         int ret;
 144
 145         WARN_ON(reg > ISL1219_REG_YRT);
 146         WARN_ON(reg + len > ISL1219_REG_YRT + 1);
 147
 148         ret = i2c_smbus_read_i2c_block_data(client, reg, len, buf);
 149         return (ret < 0) ? ret : 0;
 150 }
 151
 152 /* block write */
 153 static int
 154 isl1208_i2c_set_regs(struct i2c_client *client, u8 reg, u8 const buf[],
 155                      unsigned len)
 156 {
 157         int ret;
 158
 159         WARN_ON(reg > ISL1219_REG_YRT);
 160         WARN_ON(reg + len > ISL1219_REG_YRT + 1);
 161
 162         ret = i2c_smbus_write_i2c_block_data(client, reg, len, buf);
 163         return (ret < 0) ? ret : 0;
 164 }
 165
 166 /* simple check to see whether we have a isl1208 */
 167 static int
 168 isl1208_i2c_validate_client(struct i2c_client *client)
 169 {
 170         u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
 171         u8 zero_mask[ISL1208_RTC_SECTION_LEN] = {
 172                 0x80, 0x80, 0x40, 0xc0, 0xe0, 0x00, 0xf8
 173         };
 174         int i;
 175         int ret;
 176
 177         ret = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
 178         if (ret < 0)
 179                 return ret;
 180
 181         for (i = 0; i < ISL1208_RTC_SECTION_LEN; ++i) {
 182                 if (regs[i] & zero_mask[i])     /* check if bits are cleared */
 183                         return -ENODEV;
 184         }
 185
 186         return 0;
 187 }
 188
 189 static int isl1208_set_xtoscb(struct i2c_client *client, int sr, int xtosb_val)
 190 {
 191         /* Do nothing if bit is already set to desired value */
 192         if (!!(sr & ISL1208_REG_SR_XTOSCB) == xtosb_val)
 193                 return 0;
 194
 195         if (xtosb_val)
 196                 sr |= ISL1208_REG_SR_XTOSCB;
 197         else
 198                 sr &= ~ISL1208_REG_SR_XTOSCB;
 199
 200         return i2c_smbus_write_byte_data(client, ISL1208_REG_SR, sr);
 201 }
 202
 203 static int
 204 isl1208_i2c_get_sr(struct i2c_client *client)
 205 {
 206         return i2c_smbus_read_byte_data(client, ISL1208_REG_SR);
 207 }
 208
 209 static int
 210 isl1208_i2c_get_atr(struct i2c_client *client)
 211 {
 212         int atr = i2c_smbus_read_byte_data(client, ISL1208_REG_ATR);
 213         if (atr < 0)
 214                 return atr;
 215
 216         /* The 6bit value in the ATR register controls the load
 217          * capacitance C_load * in steps of 0.25pF
 218          *
 219          * bit (1<<5) of the ATR register is inverted
 220          *
 221          * C_load(ATR=0x20) =  4.50pF
 222          * C_load(ATR=0x00) = 12.50pF
 223          * C_load(ATR=0x1f) = 20.25pF
 224          *
 225          */
 226
 227         atr &= 0x3f;            /* mask out lsb */
 228         atr ^= 1 << 5;          /* invert 6th bit */
 229         atr += 2 * 9;           /* add offset of 4.5pF; unit[atr] = 0.25pF */
 230
 231         return atr;
 232 }
 233
 234 /* returns adjustment value + 100 */
 235 static int
 236 isl1208_i2c_get_dtr(struct i2c_client *client)
 237 {
 238         int dtr = i2c_smbus_read_byte_data(client, ISL1208_REG_DTR);
 239         if (dtr < 0)
 240                 return -EIO;
 241
 242         /* dtr encodes adjustments of {-60,-40,-20,0,20,40,60} ppm */
 243         dtr = ((dtr & 0x3) * 20) * (dtr & (1 << 2) ? -1 : 1);
 244
 245         return dtr + 100;
 246 }
 247
 248 static int
 249 isl1208_i2c_get_usr(struct i2c_client *client)
 250 {
 251         u8 buf[ISL1208_USR_SECTION_LEN] = { 0, };
 252         int ret;
 253
 254         ret = isl1208_i2c_read_regs(client, ISL1208_REG_USR1, buf,
 255                                     ISL1208_USR_SECTION_LEN);
 256         if (ret < 0)
 257                 return ret;
 258
 259         return (buf[1] << 8) | buf[0];
 260 }
 261
 262 static int
 263 isl1208_i2c_set_usr(struct i2c_client *client, u16 usr)
 264 {
 265         u8 buf[ISL1208_USR_SECTION_LEN];
 266
 267         buf[0] = usr & 0xff;
 268         buf[1] = (usr >> 8) & 0xff;
 269
 270         return isl1208_i2c_set_regs(client, ISL1208_REG_USR1, buf,
 271                                     ISL1208_USR_SECTION_LEN);
 272 }
 273
 274 static int
 275 isl1208_rtc_toggle_alarm(struct i2c_client *client, int enable)
 276 {
 277         int icr = i2c_smbus_read_byte_data(client, ISL1208_REG_INT);
 278
 279         if (icr < 0) {
 280                 dev_err(&client->dev, "%s: reading INT failed\n", __func__);
 281                 return icr;
 282         }
 283
 284         if (enable)
 285                 icr |= ISL1208_REG_INT_ALME | ISL1208_REG_INT_IM;
 286         else
 287                 icr &= ~(ISL1208_REG_INT_ALME | ISL1208_REG_INT_IM);
 288
 289         icr = i2c_smbus_write_byte_data(client, ISL1208_REG_INT, icr);
 290         if (icr < 0) {
 291                 dev_err(&client->dev, "%s: writing INT failed\n", __func__);
 292                 return icr;
 293         }
 294
 295         return 0;
 296 }
 297
 298 static int
 299 isl1208_rtc_proc(struct device *dev, struct seq_file *seq)
 300 {
 301         struct i2c_client *const client = to_i2c_client(dev);
 302         int sr, dtr, atr, usr;
 303
 304         sr = isl1208_i2c_get_sr(client);
 305         if (sr < 0) {
 306                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
 307                 return sr;
 308         }
 309
 310         seq_printf(seq, "status_reg\t:%s%s%s%s%s%s (0x%.2x)\n",
 311                    (sr & ISL1208_REG_SR_RTCF) ? " RTCF" : "",
 312                    (sr & ISL1208_REG_SR_BAT) ? " BAT" : "",
 313                    (sr & ISL1208_REG_SR_ALM) ? " ALM" : "",
 314                    (sr & ISL1208_REG_SR_WRTC) ? " WRTC" : "",
 315                    (sr & ISL1208_REG_SR_XTOSCB) ? " XTOSCB" : "",
 316                    (sr & ISL1208_REG_SR_ARST) ? " ARST" : "", sr);
 317
 318         seq_printf(seq, "batt_status\t: %s\n",
 319                    (sr & ISL1208_REG_SR_RTCF) ? "bad" : "okay");
 320
 321         dtr = isl1208_i2c_get_dtr(client);
 322         if (dtr >= 0)
 323                 seq_printf(seq, "digital_trim\t: %d ppm\n", dtr - 100);
 324
 325         atr = isl1208_i2c_get_atr(client);
 326         if (atr >= 0)
 327                 seq_printf(seq, "analog_trim\t: %d.%.2d pF\n",
 328                            atr >> 2, (atr & 0x3) * 25);
 329
 330         usr = isl1208_i2c_get_usr(client);
 331         if (usr >= 0)
 332                 seq_printf(seq, "user_data\t: 0x%.4x\n", usr);
 333
 334         return 0;
 335 }
 336
 337 static int
 338 isl1208_i2c_read_time(struct i2c_client *client, struct rtc_time *tm)
 339 {
 340         int sr;
 341         u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
 342
 343         sr = isl1208_i2c_get_sr(client);
 344         if (sr < 0) {
 345                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
 346                 return -EIO;
 347         }
 348
 349         sr = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
 350         if (sr < 0) {
 351                 dev_err(&client->dev, "%s: reading RTC section failed\n",
 352                         __func__);
 353                 return sr;
 354         }
 355
 356         tm->tm_sec = bcd2bin(regs[ISL1208_REG_SC]);
 357         tm->tm_min = bcd2bin(regs[ISL1208_REG_MN]);
 358
 359         /* HR field has a more complex interpretation */
 360         {
 361                 const u8 _hr = regs[ISL1208_REG_HR];
 362                 if (_hr & ISL1208_REG_HR_MIL)   /* 24h format */
 363                         tm->tm_hour = bcd2bin(_hr & 0x3f);
 364                 else {
 365                         /* 12h format */
 366                         tm->tm_hour = bcd2bin(_hr & 0x1f);
 367                         if (_hr & ISL1208_REG_HR_PM)    /* PM flag set */
 368                                 tm->tm_hour += 12;
 369                 }
 370         }
 371
 372         tm->tm_mday = bcd2bin(regs[ISL1208_REG_DT]);
 373         tm->tm_mon = bcd2bin(regs[ISL1208_REG_MO]) - 1; /* rtc starts at 1 */
 374         tm->tm_year = bcd2bin(regs[ISL1208_REG_YR]) + 100;
 375         tm->tm_wday = bcd2bin(regs[ISL1208_REG_DW]);
 376
 377         return 0;
 378 }
 379
 380 static int
 381 isl1208_i2c_read_alarm(struct i2c_client *client, struct rtc_wkalrm *alarm)
 382 {
 383         struct rtc_time *const tm = &alarm->time;
 384         u8 regs[ISL1208_ALARM_SECTION_LEN] = { 0, };
 385         int icr, yr, sr = isl1208_i2c_get_sr(client);
 386
 387         if (sr < 0) {
 388                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
 389                 return sr;
 390         }
 391
 392         sr = isl1208_i2c_read_regs(client, ISL1208_REG_SCA, regs,
 393                                    ISL1208_ALARM_SECTION_LEN);
 394         if (sr < 0) {
 395                 dev_err(&client->dev, "%s: reading alarm section failed\n",
 396                         __func__);
 397                 return sr;
 398         }
 399
 400         /* MSB of each alarm register is an enable bit */
 401         tm->tm_sec = bcd2bin(regs[ISL1208_REG_SCA - ISL1208_REG_SCA] & 0x7f);
 402         tm->tm_min = bcd2bin(regs[ISL1208_REG_MNA - ISL1208_REG_SCA] & 0x7f);
 403         tm->tm_hour = bcd2bin(regs[ISL1208_REG_HRA - ISL1208_REG_SCA] & 0x3f);
 404         tm->tm_mday = bcd2bin(regs[ISL1208_REG_DTA - ISL1208_REG_SCA] & 0x3f);
 405         tm->tm_mon =
 406                 bcd2bin(regs[ISL1208_REG_MOA - ISL1208_REG_SCA] & 0x1f) - 1;
 407         tm->tm_wday = bcd2bin(regs[ISL1208_REG_DWA - ISL1208_REG_SCA] & 0x03);
 408
 409         /* The alarm doesn't store the year so get it from the rtc section */
 410         yr = i2c_smbus_read_byte_data(client, ISL1208_REG_YR);
 411         if (yr < 0) {
 412                 dev_err(&client->dev, "%s: reading RTC YR failed\n", __func__);
 413                 return yr;
 414         }
 415         tm->tm_year = bcd2bin(yr) + 100;
 416
 417         icr = i2c_smbus_read_byte_data(client, ISL1208_REG_INT);
 418         if (icr < 0) {
 419                 dev_err(&client->dev, "%s: reading INT failed\n", __func__);
 420                 return icr;
 421         }
 422         alarm->enabled = !!(icr & ISL1208_REG_INT_ALME);
 423
 424         return 0;
 425 }
 426
 427 static int
 428 isl1208_i2c_set_alarm(struct i2c_client *client, struct rtc_wkalrm *alarm)
 429 {
 430         struct rtc_time *alarm_tm = &alarm->time;
 431         u8 regs[ISL1208_ALARM_SECTION_LEN] = { 0, };
 432         const int offs = ISL1208_REG_SCA;
 433         struct rtc_time rtc_tm;
 434         int err, enable;
 435
 436         err = isl1208_i2c_read_time(client, &rtc_tm);
 437         if (err)
 438                 return err;
 439
 440         /* If the alarm time is before the current time disable the alarm */
 441         if (!alarm->enabled || rtc_tm_sub(alarm_tm, &rtc_tm) <= 0)
 442                 enable = 0x00;
 443         else
 444                 enable = 0x80;
 445
 446         /* Program the alarm and enable it for each setting */
 447         regs[ISL1208_REG_SCA - offs] = bin2bcd(alarm_tm->tm_sec) | enable;
 448         regs[ISL1208_REG_MNA - offs] = bin2bcd(alarm_tm->tm_min) | enable;
 449         regs[ISL1208_REG_HRA - offs] = bin2bcd(alarm_tm->tm_hour) |
 450                 ISL1208_REG_HR_MIL | enable;
 451
 452         regs[ISL1208_REG_DTA - offs] = bin2bcd(alarm_tm->tm_mday) | enable;
 453         regs[ISL1208_REG_MOA - offs] = bin2bcd(alarm_tm->tm_mon + 1) | enable;
 454         regs[ISL1208_REG_DWA - offs] = bin2bcd(alarm_tm->tm_wday & 7) | enable;
 455
 456         /* write ALARM registers */
 457         err = isl1208_i2c_set_regs(client, offs, regs,
 458                                   ISL1208_ALARM_SECTION_LEN);
 459         if (err < 0) {
 460                 dev_err(&client->dev, "%s: writing ALARM section failed\n",
 461                         __func__);
 462                 return err;
 463         }
 464
 465         err = isl1208_rtc_toggle_alarm(client, enable);
 466         if (err)
 467                 return err;
 468
 469         return 0;
 470 }
 471
 472 static int
 473 isl1208_rtc_read_time(struct device *dev, struct rtc_time *tm)
 474 {
 475         return isl1208_i2c_read_time(to_i2c_client(dev), tm);
 476 }
 477
 478 static int
 479 isl1208_i2c_set_time(struct i2c_client *client, struct rtc_time const *tm)
 480 {
 481         int sr;
 482         u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
 483
 484         /* The clock has an 8 bit wide bcd-coded register (they never learn)
 485          * for the year. tm_year is an offset from 1900 and we are interested
 486          * in the 2000-2099 range, so any value less than 100 is invalid.
 487          */
 488         if (tm->tm_year < 100)
 489                 return -EINVAL;
 490
 491         regs[ISL1208_REG_SC] = bin2bcd(tm->tm_sec);
 492         regs[ISL1208_REG_MN] = bin2bcd(tm->tm_min);
 493         regs[ISL1208_REG_HR] = bin2bcd(tm->tm_hour) | ISL1208_REG_HR_MIL;
 494
 495         regs[ISL1208_REG_DT] = bin2bcd(tm->tm_mday);
 496         regs[ISL1208_REG_MO] = bin2bcd(tm->tm_mon + 1);
 497         regs[ISL1208_REG_YR] = bin2bcd(tm->tm_year - 100);
 498
 499         regs[ISL1208_REG_DW] = bin2bcd(tm->tm_wday & 7);
 500
 501         sr = isl1208_i2c_get_sr(client);
 502         if (sr < 0) {
 503                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
 504                 return sr;
 505         }
 506
 507         /* set WRTC */
 508         sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR,
 509                                        sr | ISL1208_REG_SR_WRTC);
 510         if (sr < 0) {
 511                 dev_err(&client->dev, "%s: writing SR failed\n", __func__);
 512                 return sr;
 513         }
 514
 515         /* write RTC registers */
 516         sr = isl1208_i2c_set_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
 517         if (sr < 0) {
 518                 dev_err(&client->dev, "%s: writing RTC section failed\n",
 519                         __func__);
 520                 return sr;
 521         }
 522
 523         /* clear WRTC again */
 524         sr = isl1208_i2c_get_sr(client);
 525         if (sr < 0) {
 526                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
 527                 return sr;
 528         }
 529         sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR,
 530                                        sr & ~ISL1208_REG_SR_WRTC);
 531         if (sr < 0) {
 532                 dev_err(&client->dev, "%s: writing SR failed\n", __func__);
 533                 return sr;
 534         }
 535
 536         return 0;
 537 }
 538
 539 static int
 540 isl1208_rtc_set_time(struct device *dev, struct rtc_time *tm)
 541 {
 542         return isl1208_i2c_set_time(to_i2c_client(dev), tm);
 543 }
 544
 545 static int
 546 isl1208_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 547 {
 548         return isl1208_i2c_read_alarm(to_i2c_client(dev), alarm);
 549 }
 550
 551 static int
 552 isl1208_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 553 {
 554         return isl1208_i2c_set_alarm(to_i2c_client(dev), alarm);
 555 }
 556
 557 static ssize_t timestamp0_store(struct device *dev,
 558                                 struct device_attribute *attr,
 559                                 const char *buf, size_t count)
 560 {
 561         struct i2c_client *client = to_i2c_client(dev->parent);
 562         int sr;
 563
 564         sr = isl1208_i2c_get_sr(client);
 565         if (sr < 0) {
 566                 dev_err(dev, "%s: reading SR failed\n", __func__);
 567                 return sr;
 568         }
 569
 570         sr &= ~ISL1208_REG_SR_EVT;
 571
 572         sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR, sr);
 573         if (sr < 0)
 574                 dev_err(dev, "%s: writing SR failed\n",
 575                         __func__);
 576
 577         return count;
 578 };
 579
 580 static ssize_t timestamp0_show(struct device *dev,
 581                                struct device_attribute *attr, char *buf)
 582 {
 583         struct i2c_client *client = to_i2c_client(dev->parent);
 584         u8 regs[ISL1219_EVT_SECTION_LEN] = { 0, };
 585         struct rtc_time tm;
 586         int sr;
 587
 588         sr = isl1208_i2c_get_sr(client);
 589         if (sr < 0) {
 590                 dev_err(dev, "%s: reading SR failed\n", __func__);
 591                 return sr;
 592         }
 593
 594         if (!(sr & ISL1208_REG_SR_EVT))
 595                 return 0;
 596
 597         sr = isl1208_i2c_read_regs(client, ISL1219_REG_SCT, regs,
 598                                    ISL1219_EVT_SECTION_LEN);
 599         if (sr < 0) {
 600                 dev_err(dev, "%s: reading event section failed\n",
 601                         __func__);
 602                 return 0;
 603         }
 604
 605         /* MSB of each alarm register is an enable bit */
 606         tm.tm_sec = bcd2bin(regs[ISL1219_REG_SCT - ISL1219_REG_SCT] & 0x7f);
 607         tm.tm_min = bcd2bin(regs[ISL1219_REG_MNT - ISL1219_REG_SCT] & 0x7f);
 608         tm.tm_hour = bcd2bin(regs[ISL1219_REG_HRT - ISL1219_REG_SCT] & 0x3f);
 609         tm.tm_mday = bcd2bin(regs[ISL1219_REG_DTT - ISL1219_REG_SCT] & 0x3f);
 610         tm.tm_mon =
 611                 bcd2bin(regs[ISL1219_REG_MOT - ISL1219_REG_SCT] & 0x1f) - 1;
 612         tm.tm_year = bcd2bin(regs[ISL1219_REG_YRT - ISL1219_REG_SCT]) + 100;
 613
 614         sr = rtc_valid_tm(&tm);
 615         if (sr)
 616                 return sr;
 617
 618         return sprintf(buf, "%llu\n",
 619                                 (unsigned long long)rtc_tm_to_time64(&tm));
 620 };
 621
 622 static DEVICE_ATTR_RW(timestamp0);
 623
 624 static irqreturn_t
 625 isl1208_rtc_interrupt(int irq, void *data)
 626 {
 627         unsigned long timeout = jiffies + msecs_to_jiffies(1000);
 628         struct i2c_client *client = data;
 629         struct isl1208_state *isl1208 = i2c_get_clientdata(client);
 630         int handled = 0, sr, err;
 631
 632         if (!isl1208->config->has_tamper) {
 633                 /*
 634                  * The INT# output is pulled low 250ms after the alarm is
 635                  * triggered. After the INT# output is pulled low, it is low for
 636                  * at least 250ms, even if the correct action is taken to clear
 637                  * it. It is impossible to clear ALM if it is still active. The
 638                  * host must wait for the RTC to progress past the alarm time
 639                  * plus the 250ms delay before clearing ALM.
 640                  */
 641                 msleep(250);
 642         }
 643
 644         /*
 645          * I2C reads get NAK'ed if we read straight away after an interrupt?
 646          * Using a mdelay/msleep didn't seem to help either, so we work around
 647          * this by continually trying to read the register for a short time.
 648          */
 649         while (1) {
 650                 sr = isl1208_i2c_get_sr(client);
 651                 if (sr >= 0)
 652                         break;
 653
 654                 if (time_after(jiffies, timeout)) {
 655                         dev_err(&client->dev, "%s: reading SR failed\n",
 656                                 __func__);
 657                         return sr;
 658                 }
 659         }
 660
 661         if (sr & ISL1208_REG_SR_ALM) {
 662                 dev_dbg(&client->dev, "alarm!\n");
 663
 664                 rtc_update_irq(isl1208->rtc, 1, RTC_IRQF | RTC_AF);
 665
 666                 /* Disable the alarm */
 667                 err = isl1208_rtc_toggle_alarm(client, 0);
 668                 if (err)
 669                         return err;
 670
 671                 fsleep(275);
 672
 673                 /* Clear the alarm */
 674                 sr &= ~ISL1208_REG_SR_ALM;
 675                 sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR, sr);
 676                 if (sr < 0)
 677                         dev_err(&client->dev, "%s: writing SR failed\n",
 678                                 __func__);
 679                 else
 680                         handled = 1;
 681         }
 682
 683         if (isl1208->config->has_tamper && (sr & ISL1208_REG_SR_EVT)) {
 684                 dev_warn(&client->dev, "event detected");
 685                 handled = 1;
 686                 if (isl1208->config->has_timestamp)
 687                         sysfs_notify(&isl1208->rtc->dev.kobj, NULL,
 688                                      dev_attr_timestamp0.attr.name);
 689         }
 690
 691         return handled ? IRQ_HANDLED : IRQ_NONE;
 692 }
 693
 694 static const struct rtc_class_ops isl1208_rtc_ops = {
 695         .proc = isl1208_rtc_proc,
 696         .read_time = isl1208_rtc_read_time,
 697         .set_time = isl1208_rtc_set_time,
 698         .read_alarm = isl1208_rtc_read_alarm,
 699         .set_alarm = isl1208_rtc_set_alarm,
 700 };
 701
 702 /* sysfs interface */
 703
 704 static ssize_t
 705 isl1208_sysfs_show_atrim(struct device *dev,
 706                          struct device_attribute *attr, char *buf)
 707 {
 708         int atr = isl1208_i2c_get_atr(to_i2c_client(dev->parent));
 709         if (atr < 0)
 710                 return atr;
 711
 712         return sprintf(buf, "%d.%.2d pF\n", atr >> 2, (atr & 0x3) * 25);
 713 }
 714
 715 static DEVICE_ATTR(atrim, S_IRUGO, isl1208_sysfs_show_atrim, NULL);
 716
 717 static ssize_t
 718 isl1208_sysfs_show_dtrim(struct device *dev,
 719                          struct device_attribute *attr, char *buf)
 720 {
 721         int dtr = isl1208_i2c_get_dtr(to_i2c_client(dev->parent));
 722         if (dtr < 0)
 723                 return dtr;
 724
 725         return sprintf(buf, "%d ppm\n", dtr - 100);
 726 }
 727
 728 static DEVICE_ATTR(dtrim, S_IRUGO, isl1208_sysfs_show_dtrim, NULL);
 729
 730 static ssize_t
 731 isl1208_sysfs_show_usr(struct device *dev,
 732                        struct device_attribute *attr, char *buf)
 733 {
 734         int usr = isl1208_i2c_get_usr(to_i2c_client(dev->parent));
 735         if (usr < 0)
 736                 return usr;
 737
 738         return sprintf(buf, "0x%.4x\n", usr);
 739 }
 740
 741 static ssize_t
 742 isl1208_sysfs_store_usr(struct device *dev,
 743                         struct device_attribute *attr,
 744                         const char *buf, size_t count)
 745 {
 746         int usr = -1;
 747
 748         if (buf[0] == '0' && (buf[1] == 'x' || buf[1] == 'X')) {
 749                 if (sscanf(buf, "%x", &usr) != 1)
 750                         return -EINVAL;
 751         } else {
 752                 if (sscanf(buf, "%d", &usr) != 1)
 753                         return -EINVAL;
 754         }
 755
 756         if (usr < 0 || usr > 0xffff)
 757                 return -EINVAL;
 758
 759         if (isl1208_i2c_set_usr(to_i2c_client(dev->parent), usr))
 760                 return -EIO;
 761
 762         return count;
 763 }
 764
 765 static DEVICE_ATTR(usr, S_IRUGO | S_IWUSR, isl1208_sysfs_show_usr,
 766                    isl1208_sysfs_store_usr);
 767
 768 static struct attribute *isl1208_rtc_attrs[] = {
 769         &dev_attr_atrim.attr,
 770         &dev_attr_dtrim.attr,
 771         &dev_attr_usr.attr,
 772         NULL
 773 };
 774
 775 static const struct attribute_group isl1208_rtc_sysfs_files = {
 776         .attrs  = isl1208_rtc_attrs,
 777 };
 778
 779 static struct attribute *isl1219_rtc_attrs[] = {
 780         &dev_attr_timestamp0.attr,
 781         NULL
 782 };
 783
 784 static const struct attribute_group isl1219_rtc_sysfs_files = {
 785         .attrs  = isl1219_rtc_attrs,
 786 };
 787
 788 static int isl1208_nvmem_read(void *priv, unsigned int off, void *buf,
 789                               size_t count)
 790 {
 791         struct isl1208_state *isl1208 = priv;
 792         struct i2c_client *client = to_i2c_client(isl1208->rtc->dev.parent);
 793
 794         /* nvmem sanitizes offset/count for us, but count==0 is possible */
 795         if (!count)
 796                 return count;
 797
 798         return isl1208_i2c_read_regs(client, ISL1208_REG_USR1 + off, buf,
 799                                     count);
 800 }
 801
 802 static int isl1208_nvmem_write(void *priv, unsigned int off, void *buf,
 803                                size_t count)
 804 {
 805         struct isl1208_state *isl1208 = priv;
 806         struct i2c_client *client = to_i2c_client(isl1208->rtc->dev.parent);
 807
 808         /* nvmem sanitizes off/count for us, but count==0 is possible */
 809         if (!count)
 810                 return count;
 811
 812         return isl1208_i2c_set_regs(client, ISL1208_REG_USR1 + off, buf,
 813                                    count);
 814 }
 815
 816 static const struct nvmem_config isl1208_nvmem_config = {
 817         .name = "isl1208_nvram",
 818         .word_size = 1,
 819         .stride = 1,
 820         /* .size from chip specific config */
 821         .reg_read = isl1208_nvmem_read,
 822         .reg_write = isl1208_nvmem_write,
 823 };
 824
 825 static int isl1208_setup_irq(struct i2c_client *client, int irq)
 826 {
 827         int rc = devm_request_threaded_irq(&client->dev, irq, NULL,
 828                                         isl1208_rtc_interrupt,
 829                                         IRQF_SHARED | IRQF_ONESHOT,
 830                                         isl1208_driver.driver.name,
 831                                         client);
 832         if (!rc) {
 833                 device_init_wakeup(&client->dev, 1);
 834                 enable_irq_wake(irq);
 835         } else {
 836                 dev_err(&client->dev,
 837                         "Unable to request irq %d, no alarm support\n",
 838                         irq);
 839         }
 840         return rc;
 841 }
 842
 843 static int
 844 isl1208_clk_present(struct i2c_client *client, const char *name)
 845 {
 846         struct clk *clk;
 847
 848         clk = devm_clk_get_optional(&client->dev, name);
 849         if (IS_ERR(clk))
 850                 return PTR_ERR(clk);
 851
 852         return !!clk;
 853 }
 854
 855 static int
 856 isl1208_probe(struct i2c_client *client)
 857 {
 858         struct isl1208_state *isl1208;
 859         int evdet_irq = -1;
 860         int xtosb_val = 0;
 861         int rc = 0;
 862         int sr;
 863
 864         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 865                 return -ENODEV;
 866
 867         if (isl1208_i2c_validate_client(client) < 0)
 868                 return -ENODEV;
 869
 870         /* Allocate driver state, point i2c client data to it */
 871         isl1208 = devm_kzalloc(&client->dev, sizeof(*isl1208), GFP_KERNEL);
 872         if (!isl1208)
 873                 return -ENOMEM;
 874         i2c_set_clientdata(client, isl1208);
 875
 876         /* Determine which chip we have */
 877         isl1208->config = i2c_get_match_data(client);
 878         if (!isl1208->config)
 879                 return -ENODEV;
 880
 881         rc = isl1208_clk_present(client, "xin");
 882         if (rc < 0)
 883                 return rc;
 884
 885         if (!rc) {
 886                 rc = isl1208_clk_present(client, "clkin");
 887                 if (rc < 0)
 888                         return rc;
 889
 890                 if (rc)
 891                         xtosb_val = 1;
 892         }
 893
 894         isl1208->rtc = devm_rtc_allocate_device(&client->dev);
 895         if (IS_ERR(isl1208->rtc))
 896                 return PTR_ERR(isl1208->rtc);
 897
 898         isl1208->rtc->ops = &isl1208_rtc_ops;
 899
 900         /* Setup nvmem configuration in driver state struct */
 901         isl1208->nvmem_config = isl1208_nvmem_config;
 902         isl1208->nvmem_config.size = isl1208->config->nvmem_length;
 903         isl1208->nvmem_config.priv = isl1208;
 904
 905         sr = isl1208_i2c_get_sr(client);
 906         if (sr < 0) {
 907                 dev_err(&client->dev, "reading status failed\n");
 908                 return sr;
 909         }
 910
 911         if (isl1208->config->has_inverted_osc_bit)
 912                 xtosb_val = !xtosb_val;
 913
 914         rc = isl1208_set_xtoscb(client, sr, xtosb_val);
 915         if (rc)
 916                 return rc;
 917
 918         if (sr & ISL1208_REG_SR_RTCF)
 919                 dev_warn(&client->dev, "rtc power failure detected, "
 920                          "please set clock.\n");
 921
 922         if (isl1208->config->has_tamper) {
 923                 struct device_node *np = client->dev.of_node;
 924                 u32 evienb;
 925
 926                 rc = i2c_smbus_read_byte_data(client, ISL1219_REG_EV);
 927                 if (rc < 0) {
 928                         dev_err(&client->dev, "failed to read EV reg\n");
 929                         return rc;
 930                 }
 931                 rc |= ISL1219_REG_EV_EVEN;
 932                 if (!of_property_read_u32(np, "isil,ev-evienb", &evienb)) {
 933                         if (evienb)
 934                                 rc |= ISL1219_REG_EV_EVIENB;
 935                         else
 936                                 rc &= ~ISL1219_REG_EV_EVIENB;
 937                 }
 938                 rc = i2c_smbus_write_byte_data(client, ISL1219_REG_EV, rc);
 939                 if (rc < 0) {
 940                         dev_err(&client->dev, "could not enable tamper detection\n");
 941                         return rc;
 942                 }
 943                 evdet_irq = of_irq_get_byname(np, "evdet");
 944         }
 945         if (isl1208->config->has_timestamp) {
 946                 rc = rtc_add_group(isl1208->rtc, &isl1219_rtc_sysfs_files);
 947                 if (rc)
 948                         return rc;
 949         }
 950
 951         rc = rtc_add_group(isl1208->rtc, &isl1208_rtc_sysfs_files);
 952         if (rc)
 953                 return rc;
 954
 955         if (client->irq > 0) {
 956                 rc = isl1208_setup_irq(client, client->irq);
 957                 if (rc)
 958                         return rc;
 959         } else {
 960                 clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, isl1208->rtc->features);
 961         }
 962
 963         if (evdet_irq > 0 && evdet_irq != client->irq)
 964                 rc = isl1208_setup_irq(client, evdet_irq);
 965         if (rc)
 966                 return rc;
 967
 968         rc = devm_rtc_nvmem_register(isl1208->rtc, &isl1208->nvmem_config);
 969         if (rc)
 970                 return rc;
 971
 972         return devm_rtc_register_device(isl1208->rtc);
 973 }
 974
 975 static struct i2c_driver isl1208_driver = {
 976         .driver = {
 977                 .name = "rtc-isl1208",
 978                 .of_match_table = of_match_ptr(isl1208_of_match),
 979         },
 980         .probe = isl1208_probe,
 981         .id_table = isl1208_id,
 982 };
 983
 984 module_i2c_driver(isl1208_driver);
 985
 986 MODULE_AUTHOR("Herbert Valerio Riedel <[email protected]>");
 987 MODULE_DESCRIPTION("Intersil ISL1208 RTC driver");
 988 MODULE_LICENSE("GPL");