drivers/rtc/rtc-rv8803.c

   1 /*
   2  * RTC driver for the Micro Crystal RV8803
   3  *
   4  * Copyright (C) 2015 Micro Crystal SA
   5  *
   6  * Alexandre Belloni <alexandre.belloni@free-electrons.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  */
  13
  14 #include <linux/bcd.h>
  15 #include <linux/bitops.h>
  16 #include <linux/i2c.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/kernel.h>
  19 #include <linux/module.h>
  20 #include <linux/rtc.h>
  21
  22 #define RV8803_SEC                      0x00
  23 #define RV8803_MIN                      0x01
  24 #define RV8803_HOUR                     0x02
  25 #define RV8803_WEEK                     0x03
  26 #define RV8803_DAY                      0x04
  27 #define RV8803_MONTH                    0x05
  28 #define RV8803_YEAR                     0x06
  29 #define RV8803_RAM                      0x07
  30 #define RV8803_ALARM_MIN                0x08
  31 #define RV8803_ALARM_HOUR               0x09
  32 #define RV8803_ALARM_WEEK_OR_DAY        0x0A
  33 #define RV8803_EXT                      0x0D
  34 #define RV8803_FLAG                     0x0E
  35 #define RV8803_CTRL                     0x0F
  36
  37 #define RV8803_EXT_WADA                 BIT(6)
  38
  39 #define RV8803_FLAG_V1F                 BIT(0)
  40 #define RV8803_FLAG_V2F                 BIT(1)
  41 #define RV8803_FLAG_AF                  BIT(3)
  42 #define RV8803_FLAG_TF                  BIT(4)
  43 #define RV8803_FLAG_UF                  BIT(5)
  44
  45 #define RV8803_CTRL_RESET               BIT(0)
  46
  47 #define RV8803_CTRL_EIE                 BIT(2)
  48 #define RV8803_CTRL_AIE                 BIT(3)
  49 #define RV8803_CTRL_TIE                 BIT(4)
  50 #define RV8803_CTRL_UIE                 BIT(5)
  51
  52 struct rv8803_data {
  53         struct i2c_client *client;
  54         struct rtc_device *rtc;
  55         struct mutex flags_lock;
  56         u8 ctrl;
  57 };
  58
  59 static irqreturn_t rv8803_handle_irq(int irq, void *dev_id)
  60 {
  61         struct i2c_client *client = dev_id;
  62         struct rv8803_data *rv8803 = i2c_get_clientdata(client);
  63         unsigned long events = 0;
  64         int flags;
  65
  66         mutex_lock(&rv8803->flags_lock);
  67
  68         flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
  69         if (flags <= 0) {
  70                 mutex_unlock(&rv8803->flags_lock);
  71                 return IRQ_NONE;
  72         }
  73
  74         if (flags & RV8803_FLAG_V1F)
  75                 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
  76
  77         if (flags & RV8803_FLAG_V2F)
  78                 dev_warn(&client->dev, "Voltage low, data loss detected.\n");
  79
  80         if (flags & RV8803_FLAG_TF) {
  81                 flags &= ~RV8803_FLAG_TF;
  82                 rv8803->ctrl &= ~RV8803_CTRL_TIE;
  83                 events |= RTC_PF;
  84         }
  85
  86         if (flags & RV8803_FLAG_AF) {
  87                 flags &= ~RV8803_FLAG_AF;
  88                 rv8803->ctrl &= ~RV8803_CTRL_AIE;
  89                 events |= RTC_AF;
  90         }
  91
  92         if (flags & RV8803_FLAG_UF) {
  93                 flags &= ~RV8803_FLAG_UF;
  94                 rv8803->ctrl &= ~RV8803_CTRL_UIE;
  95                 events |= RTC_UF;
  96         }
  97
  98         if (events) {
  99                 rtc_update_irq(rv8803->rtc, 1, events);
 100                 i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
 101                 i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL,
 102                                           rv8803->ctrl);
 103         }
 104
 105         mutex_unlock(&rv8803->flags_lock);
 106
 107         return IRQ_HANDLED;
 108 }
 109
 110 static int rv8803_get_time(struct device *dev, struct rtc_time *tm)
 111 {
 112         struct rv8803_data *rv8803 = dev_get_drvdata(dev);
 113         u8 date1[7];
 114         u8 date2[7];
 115         u8 *date = date1;
 116         int ret, flags;
 117
 118         flags = i2c_smbus_read_byte_data(rv8803->client, RV8803_FLAG);
 119         if (flags < 0)
 120                 return flags;
 121
 122         if (flags & RV8803_FLAG_V2F) {
 123                 dev_warn(dev, "Voltage low, data is invalid.\n");
 124                 return -EINVAL;
 125         }
 126
 127         ret = i2c_smbus_read_i2c_block_data(rv8803->client, RV8803_SEC,
 128                                             7, date);
 129         if (ret != 7)
 130                 return ret < 0 ? ret : -EIO;
 131
 132         if ((date1[RV8803_SEC] & 0x7f) == bin2bcd(59)) {
 133                 ret = i2c_smbus_read_i2c_block_data(rv8803->client, RV8803_SEC,
 134                                                     7, date2);
 135                 if (ret != 7)
 136                         return ret < 0 ? ret : -EIO;
 137
 138                 if ((date2[RV8803_SEC] & 0x7f) != bin2bcd(59))
 139                         date = date2;
 140         }
 141
 142         tm->tm_sec  = bcd2bin(date[RV8803_SEC] & 0x7f);
 143         tm->tm_min  = bcd2bin(date[RV8803_MIN] & 0x7f);
 144         tm->tm_hour = bcd2bin(date[RV8803_HOUR] & 0x3f);
 145         tm->tm_wday = ffs(date[RV8803_WEEK] & 0x7f);
 146         tm->tm_mday = bcd2bin(date[RV8803_DAY] & 0x3f);
 147         tm->tm_mon  = bcd2bin(date[RV8803_MONTH] & 0x1f) - 1;
 148         tm->tm_year = bcd2bin(date[RV8803_YEAR]) + 100;
 149
 150         return rtc_valid_tm(tm);
 151 }
 152
 153 static int rv8803_set_time(struct device *dev, struct rtc_time *tm)
 154 {
 155         struct rv8803_data *rv8803 = dev_get_drvdata(dev);
 156         u8 date[7];
 157         int flags, ret;
 158
 159         if ((tm->tm_year < 100) || (tm->tm_year > 199))
 160                 return -EINVAL;
 161
 162         date[RV8803_SEC]   = bin2bcd(tm->tm_sec);
 163         date[RV8803_MIN]   = bin2bcd(tm->tm_min);
 164         date[RV8803_HOUR]  = bin2bcd(tm->tm_hour);
 165         date[RV8803_WEEK]  = 1 << (tm->tm_wday);
 166         date[RV8803_DAY]   = bin2bcd(tm->tm_mday);
 167         date[RV8803_MONTH] = bin2bcd(tm->tm_mon + 1);
 168         date[RV8803_YEAR]  = bin2bcd(tm->tm_year - 100);
 169
 170         ret = i2c_smbus_write_i2c_block_data(rv8803->client, RV8803_SEC,
 171                                              7, date);
 172         if (ret < 0)
 173                 return ret;
 174
 175         mutex_lock(&rv8803->flags_lock);
 176
 177         flags = i2c_smbus_read_byte_data(rv8803->client, RV8803_FLAG);
 178         if (flags < 0) {
 179                 mutex_unlock(&rv8803->flags_lock);
 180                 return flags;
 181         }
 182
 183         ret = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG,
 184                                         flags & ~RV8803_FLAG_V2F);
 185
 186         mutex_unlock(&rv8803->flags_lock);
 187
 188         return ret;
 189 }
 190
 191 static int rv8803_get_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 192 {
 193         struct rv8803_data *rv8803 = dev_get_drvdata(dev);
 194         struct i2c_client *client = rv8803->client;
 195         u8 alarmvals[3];
 196         int flags, ret;
 197
 198         ret = i2c_smbus_read_i2c_block_data(client, RV8803_ALARM_MIN,
 199                                             3, alarmvals);
 200         if (ret != 3)
 201                 return ret < 0 ? ret : -EIO;
 202
 203         flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
 204         if (flags < 0)
 205                 return flags;
 206
 207         alrm->time.tm_sec  = 0;
 208         alrm->time.tm_min  = bcd2bin(alarmvals[0] & 0x7f);
 209         alrm->time.tm_hour = bcd2bin(alarmvals[1] & 0x3f);
 210         alrm->time.tm_wday = -1;
 211         alrm->time.tm_mday = bcd2bin(alarmvals[2] & 0x3f);
 212         alrm->time.tm_mon  = -1;
 213         alrm->time.tm_year = -1;
 214
 215         alrm->enabled = !!(rv8803->ctrl & RV8803_CTRL_AIE);
 216         alrm->pending = (flags & RV8803_FLAG_AF) && alrm->enabled;
 217
 218         return 0;
 219 }
 220
 221 static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 222 {
 223         struct i2c_client *client = to_i2c_client(dev);
 224         struct rv8803_data *rv8803 = dev_get_drvdata(dev);
 225         u8 alarmvals[3];
 226         u8 ctrl[2];
 227         int ret, err;
 228
 229         /* The alarm has no seconds, round up to nearest minute */
 230         if (alrm->time.tm_sec) {
 231                 time64_t alarm_time = rtc_tm_to_time64(&alrm->time);
 232
 233                 alarm_time += 60 - alrm->time.tm_sec;
 234                 rtc_time64_to_tm(alarm_time, &alrm->time);
 235         }
 236
 237         mutex_lock(&rv8803->flags_lock);
 238
 239         ret = i2c_smbus_read_i2c_block_data(client, RV8803_FLAG, 2, ctrl);
 240         if (ret != 2) {
 241                 mutex_unlock(&rv8803->flags_lock);
 242                 return ret < 0 ? ret : -EIO;
 243         }
 244
 245         alarmvals[0] = bin2bcd(alrm->time.tm_min);
 246         alarmvals[1] = bin2bcd(alrm->time.tm_hour);
 247         alarmvals[2] = bin2bcd(alrm->time.tm_mday);
 248
 249         if (rv8803->ctrl & (RV8803_CTRL_AIE | RV8803_CTRL_UIE)) {
 250                 rv8803->ctrl &= ~(RV8803_CTRL_AIE | RV8803_CTRL_UIE);
 251                 err = i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL,
 252                                                 rv8803->ctrl);
 253                 if (err) {
 254                         mutex_unlock(&rv8803->flags_lock);
 255                         return err;
 256                 }
 257         }
 258
 259         ctrl[1] &= ~RV8803_FLAG_AF;
 260         err = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG, ctrl[1]);
 261         mutex_unlock(&rv8803->flags_lock);
 262         if (err)
 263                 return err;
 264
 265         err = i2c_smbus_write_i2c_block_data(rv8803->client, RV8803_ALARM_MIN,
 266                                              3, alarmvals);
 267         if (err)
 268                 return err;
 269
 270         if (alrm->enabled) {
 271                 if (rv8803->rtc->uie_rtctimer.enabled)
 272                         rv8803->ctrl |= RV8803_CTRL_UIE;
 273                 if (rv8803->rtc->aie_timer.enabled)
 274                         rv8803->ctrl |= RV8803_CTRL_AIE;
 275
 276                 err = i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL,
 277                                                 rv8803->ctrl);
 278                 if (err)
 279                         return err;
 280         }
 281
 282         return 0;
 283 }
 284
 285 static int rv8803_alarm_irq_enable(struct device *dev, unsigned int enabled)
 286 {
 287         struct i2c_client *client = to_i2c_client(dev);
 288         struct rv8803_data *rv8803 = dev_get_drvdata(dev);
 289         int ctrl, flags, err;
 290
 291         ctrl = rv8803->ctrl;
 292
 293         if (enabled) {
 294                 if (rv8803->rtc->uie_rtctimer.enabled)
 295                         ctrl |= RV8803_CTRL_UIE;
 296                 if (rv8803->rtc->aie_timer.enabled)
 297                         ctrl |= RV8803_CTRL_AIE;
 298         } else {
 299                 if (!rv8803->rtc->uie_rtctimer.enabled)
 300                         ctrl &= ~RV8803_CTRL_UIE;
 301                 if (!rv8803->rtc->aie_timer.enabled)
 302                         ctrl &= ~RV8803_CTRL_AIE;
 303         }
 304
 305         mutex_lock(&rv8803->flags_lock);
 306         flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
 307         if (flags < 0) {
 308                 mutex_unlock(&rv8803->flags_lock);
 309                 return flags;
 310         }
 311         flags &= ~(RV8803_FLAG_AF | RV8803_FLAG_UF);
 312         err = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
 313         mutex_unlock(&rv8803->flags_lock);
 314         if (err)
 315                 return err;
 316
 317         if (ctrl != rv8803->ctrl) {
 318                 rv8803->ctrl = ctrl;
 319                 err = i2c_smbus_write_byte_data(client, RV8803_CTRL,
 320                                                 rv8803->ctrl);
 321                 if (err)
 322                         return err;
 323         }
 324
 325         return 0;
 326 }
 327
 328 static int rv8803_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 329 {
 330         struct i2c_client *client = to_i2c_client(dev);
 331         struct rv8803_data *rv8803 = dev_get_drvdata(dev);
 332         int flags, ret = 0;
 333
 334         switch (cmd) {
 335         case RTC_VL_READ:
 336                 flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
 337                 if (flags < 0)
 338                         return flags;
 339
 340                 if (flags & RV8803_FLAG_V1F)
 341                         dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
 342
 343                 if (flags & RV8803_FLAG_V2F)
 344                         dev_warn(&client->dev, "Voltage low, data loss detected.\n");
 345
 346                 flags &= RV8803_FLAG_V1F | RV8803_FLAG_V2F;
 347
 348                 if (copy_to_user((void __user *)arg, &flags, sizeof(int)))
 349                         return -EFAULT;
 350
 351                 return 0;
 352
 353         case RTC_VL_CLR:
 354                 mutex_lock(&rv8803->flags_lock);
 355                 flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
 356                 if (flags < 0) {
 357                         mutex_unlock(&rv8803->flags_lock);
 358                         return flags;
 359                 }
 360
 361                 flags &= ~(RV8803_FLAG_V1F | RV8803_FLAG_V2F);
 362                 ret = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
 363                 mutex_unlock(&rv8803->flags_lock);
 364                 if (ret < 0)
 365                         return ret;
 366
 367                 return 0;
 368
 369         default:
 370                 return -ENOIOCTLCMD;
 371         }
 372 }
 373
 374 static ssize_t rv8803_nvram_write(struct file *filp, struct kobject *kobj,
 375                                   struct bin_attribute *attr,
 376                                   char *buf, loff_t off, size_t count)
 377 {
 378         struct device *dev = kobj_to_dev(kobj);
 379         struct i2c_client *client = to_i2c_client(dev);
 380         int ret;
 381
 382         ret = i2c_smbus_write_byte_data(client, RV8803_RAM, buf[0]);
 383         if (ret < 0)
 384                 return ret;
 385
 386         return 1;
 387 }
 388
 389 static ssize_t rv8803_nvram_read(struct file *filp, struct kobject *kobj,
 390                                  struct bin_attribute *attr,
 391                                  char *buf, loff_t off, size_t count)
 392 {
 393         struct device *dev = kobj_to_dev(kobj);
 394         struct i2c_client *client = to_i2c_client(dev);
 395         int ret;
 396
 397         ret = i2c_smbus_read_byte_data(client, RV8803_RAM);
 398         if (ret < 0)
 399                 return ret;
 400
 401         buf[0] = ret;
 402
 403         return 1;
 404 }
 405
 406 static struct bin_attribute rv8803_nvram_attr = {
 407         .attr = {
 408                 .name = "nvram",
 409                 .mode = S_IRUGO | S_IWUSR,
 410         },
 411         .size = 1,
 412         .read = rv8803_nvram_read,
 413         .write = rv8803_nvram_write,
 414 };
 415
 416 static struct rtc_class_ops rv8803_rtc_ops = {
 417         .read_time = rv8803_get_time,
 418         .set_time = rv8803_set_time,
 419         .ioctl = rv8803_ioctl,
 420 };
 421
 422 static int rv8803_probe(struct i2c_client *client,
 423                         const struct i2c_device_id *id)
 424 {
 425         struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
 426         struct rv8803_data *rv8803;
 427         int err, flags;
 428
 429         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 430                                      I2C_FUNC_SMBUS_I2C_BLOCK)) {
 431                 dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n");
 432                 return -EIO;
 433         }
 434
 435         rv8803 = devm_kzalloc(&client->dev, sizeof(struct rv8803_data),
 436                               GFP_KERNEL);
 437         if (!rv8803)
 438                 return -ENOMEM;
 439
 440         mutex_init(&rv8803->flags_lock);
 441         rv8803->client = client;
 442         i2c_set_clientdata(client, rv8803);
 443
 444         flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
 445         if (flags < 0)
 446                 return flags;
 447
 448         if (flags & RV8803_FLAG_V1F)
 449                 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
 450
 451         if (flags & RV8803_FLAG_V2F)
 452                 dev_warn(&client->dev, "Voltage low, data loss detected.\n");
 453
 454         if (flags & RV8803_FLAG_AF)
 455                 dev_warn(&client->dev, "An alarm maybe have been missed.\n");
 456
 457         if (client->irq > 0) {
 458                 err = devm_request_threaded_irq(&client->dev, client->irq,
 459                                                 NULL, rv8803_handle_irq,
 460                                                 IRQF_TRIGGER_LOW | IRQF_ONESHOT,
 461                                                 "rv8803", client);
 462                 if (err) {
 463                         dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
 464                         client->irq = 0;
 465                 } else {
 466                         rv8803_rtc_ops.read_alarm = rv8803_get_alarm;
 467                         rv8803_rtc_ops.set_alarm = rv8803_set_alarm;
 468                         rv8803_rtc_ops.alarm_irq_enable = rv8803_alarm_irq_enable;
 469                 }
 470         }
 471
 472         rv8803->rtc = devm_rtc_device_register(&client->dev, client->name,
 473                                                &rv8803_rtc_ops, THIS_MODULE);
 474         if (IS_ERR(rv8803->rtc)) {
 475                 dev_err(&client->dev, "unable to register the class device\n");
 476                 return PTR_ERR(rv8803->rtc);
 477         }
 478
 479         err = i2c_smbus_write_byte_data(rv8803->client, RV8803_EXT,
 480                                         RV8803_EXT_WADA);
 481         if (err)
 482                 return err;
 483
 484         err = device_create_bin_file(&client->dev, &rv8803_nvram_attr);
 485         if (err)
 486                 return err;
 487
 488         rv8803->rtc->max_user_freq = 1;
 489
 490         return 0;
 491 }
 492
 493 static int rv8803_remove(struct i2c_client *client)
 494 {
 495         device_remove_bin_file(&client->dev, &rv8803_nvram_attr);
 496
 497         return 0;
 498 }
 499
 500 static const struct i2c_device_id rv8803_id[] = {
 501         { "rv8803", 0 },
 502         { "rx8900", 0 },
 503         { }
 504 };
 505 MODULE_DEVICE_TABLE(i2c, rv8803_id);
 506
 507 static struct i2c_driver rv8803_driver = {
 508         .driver = {
 509                 .name = "rtc-rv8803",
 510         },
 511         .probe          = rv8803_probe,
 512         .remove         = rv8803_remove,
 513         .id_table       = rv8803_id,
 514 };
 515 module_i2c_driver(rv8803_driver);
 516
 517 MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>");
 518 MODULE_DESCRIPTION("Micro Crystal RV8803 RTC driver");
 519 MODULE_LICENSE("GPL v2");