kernel/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         spinlock_t 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         u8 flags;
  65
  66         spin_lock(&rv8803->flags_lock);
  67
  68         flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
  69         if (flags <= 0) {
  70                 spin_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         spin_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         unsigned long irqflags;
 159
 160         if ((tm->tm_year < 100) || (tm->tm_year > 199))
 161                 return -EINVAL;
 162
 163         date[RV8803_SEC]   = bin2bcd(tm->tm_sec);
 164         date[RV8803_MIN]   = bin2bcd(tm->tm_min);
 165         date[RV8803_HOUR]  = bin2bcd(tm->tm_hour);
 166         date[RV8803_WEEK]  = 1 << (tm->tm_wday);
 167         date[RV8803_DAY]   = bin2bcd(tm->tm_mday);
 168         date[RV8803_MONTH] = bin2bcd(tm->tm_mon + 1);
 169         date[RV8803_YEAR]  = bin2bcd(tm->tm_year - 100);
 170
 171         ret = i2c_smbus_write_i2c_block_data(rv8803->client, RV8803_SEC,
 172                                              7, date);
 173         if (ret < 0)
 174                 return ret;
 175
 176         spin_lock_irqsave(&rv8803->flags_lock, irqflags);
 177
 178         flags = i2c_smbus_read_byte_data(rv8803->client, RV8803_FLAG);
 179         if (flags < 0) {
 180                 spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
 181                 return flags;
 182         }
 183
 184         ret = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG,
 185                                         flags & ~RV8803_FLAG_V2F);
 186
 187         spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
 188
 189         return ret;
 190 }
 191
 192 static int rv8803_get_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 193 {
 194         struct rv8803_data *rv8803 = dev_get_drvdata(dev);
 195         struct i2c_client *client = rv8803->client;
 196         u8 alarmvals[3];
 197         int flags, ret;
 198
 199         ret = i2c_smbus_read_i2c_block_data(client, RV8803_ALARM_MIN,
 200                                             3, alarmvals);
 201         if (ret != 3)
 202                 return ret < 0 ? ret : -EIO;
 203
 204         flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
 205         if (flags < 0)
 206                 return flags;
 207
 208         alrm->time.tm_sec  = 0;
 209         alrm->time.tm_min  = bcd2bin(alarmvals[0] & 0x7f);
 210         alrm->time.tm_hour = bcd2bin(alarmvals[1] & 0x3f);
 211         alrm->time.tm_wday = -1;
 212         alrm->time.tm_mday = bcd2bin(alarmvals[2] & 0x3f);
 213         alrm->time.tm_mon  = -1;
 214         alrm->time.tm_year = -1;
 215
 216         alrm->enabled = !!(rv8803->ctrl & RV8803_CTRL_AIE);
 217         alrm->pending = (flags & RV8803_FLAG_AF) && alrm->enabled;
 218
 219         return 0;
 220 }
 221
 222 static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 223 {
 224         struct i2c_client *client = to_i2c_client(dev);
 225         struct rv8803_data *rv8803 = dev_get_drvdata(dev);
 226         u8 alarmvals[3];
 227         u8 ctrl[2];
 228         int ret, err;
 229         unsigned long irqflags;
 230
 231         /* The alarm has no seconds, round up to nearest minute */
 232         if (alrm->time.tm_sec) {
 233                 time64_t alarm_time = rtc_tm_to_time64(&alrm->time);
 234
 235                 alarm_time += 60 - alrm->time.tm_sec;
 236                 rtc_time64_to_tm(alarm_time, &alrm->time);
 237         }
 238
 239         spin_lock_irqsave(&rv8803->flags_lock, irqflags);
 240
 241         ret = i2c_smbus_read_i2c_block_data(client, RV8803_FLAG, 2, ctrl);
 242         if (ret != 2) {
 243                 spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
 244                 return ret < 0 ? ret : -EIO;
 245         }
 246
 247         alarmvals[0] = bin2bcd(alrm->time.tm_min);
 248         alarmvals[1] = bin2bcd(alrm->time.tm_hour);
 249         alarmvals[2] = bin2bcd(alrm->time.tm_mday);
 250
 251         if (rv8803->ctrl & (RV8803_CTRL_AIE | RV8803_CTRL_UIE)) {
 252                 rv8803->ctrl &= ~(RV8803_CTRL_AIE | RV8803_CTRL_UIE);
 253                 err = i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL,
 254                                                 rv8803->ctrl);
 255                 if (err) {
 256                         spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
 257                         return err;
 258                 }
 259         }
 260
 261         ctrl[1] &= ~RV8803_FLAG_AF;
 262         err = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG, ctrl[1]);
 263         spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
 264         if (err)
 265                 return err;
 266
 267         err = i2c_smbus_write_i2c_block_data(rv8803->client, RV8803_ALARM_MIN,
 268                                              3, alarmvals);
 269         if (err)
 270                 return err;
 271
 272         if (alrm->enabled) {
 273                 if (rv8803->rtc->uie_rtctimer.enabled)
 274                         rv8803->ctrl |= RV8803_CTRL_UIE;
 275                 if (rv8803->rtc->aie_timer.enabled)
 276                         rv8803->ctrl |= RV8803_CTRL_AIE;
 277
 278                 err = i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL,
 279                                                 rv8803->ctrl);
 280                 if (err)
 281                         return err;
 282         }
 283
 284         return 0;
 285 }
 286
 287 static int rv8803_alarm_irq_enable(struct device *dev, unsigned int enabled)
 288 {
 289         struct i2c_client *client = to_i2c_client(dev);
 290         struct rv8803_data *rv8803 = dev_get_drvdata(dev);
 291         int ctrl, flags, err;
 292         unsigned long irqflags;
 293
 294         ctrl = rv8803->ctrl;
 295
 296         if (enabled) {
 297                 if (rv8803->rtc->uie_rtctimer.enabled)
 298                         ctrl |= RV8803_CTRL_UIE;
 299                 if (rv8803->rtc->aie_timer.enabled)
 300                         ctrl |= RV8803_CTRL_AIE;
 301         } else {
 302                 if (!rv8803->rtc->uie_rtctimer.enabled)
 303                         ctrl &= ~RV8803_CTRL_UIE;
 304                 if (!rv8803->rtc->aie_timer.enabled)
 305                         ctrl &= ~RV8803_CTRL_AIE;
 306         }
 307
 308         spin_lock_irqsave(&rv8803->flags_lock, irqflags);
 309         flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
 310         if (flags < 0) {
 311                 spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
 312                 return flags;
 313         }
 314         flags &= ~(RV8803_FLAG_AF | RV8803_FLAG_UF);
 315         err = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
 316         spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
 317         if (err)
 318                 return err;
 319
 320         if (ctrl != rv8803->ctrl) {
 321                 rv8803->ctrl = ctrl;
 322                 err = i2c_smbus_write_byte_data(client, RV8803_CTRL,
 323                                                 rv8803->ctrl);
 324                 if (err)
 325                         return err;
 326         }
 327
 328         return 0;
 329 }
 330
 331 static int rv8803_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 332 {
 333         struct i2c_client *client = to_i2c_client(dev);
 334         struct rv8803_data *rv8803 = dev_get_drvdata(dev);
 335         int flags, ret = 0;
 336         unsigned long irqflags;
 337
 338         switch (cmd) {
 339         case RTC_VL_READ:
 340                 flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
 341                 if (flags < 0)
 342                         return flags;
 343
 344                 if (flags & RV8803_FLAG_V1F)
 345                         dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
 346
 347                 if (flags & RV8803_FLAG_V2F)
 348                         dev_warn(&client->dev, "Voltage low, data loss detected.\n");
 349
 350                 flags &= RV8803_FLAG_V1F | RV8803_FLAG_V2F;
 351
 352                 if (copy_to_user((void __user *)arg, &flags, sizeof(int)))
 353                         return -EFAULT;
 354
 355                 return 0;
 356
 357         case RTC_VL_CLR:
 358                 spin_lock_irqsave(&rv8803->flags_lock, irqflags);
 359                 flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
 360                 if (flags < 0) {
 361                         spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
 362                         return flags;
 363                 }
 364
 365                 flags &= ~(RV8803_FLAG_V1F | RV8803_FLAG_V2F);
 366                 ret = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
 367                 spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
 368                 if (ret < 0)
 369                         return ret;
 370
 371                 return 0;
 372
 373         default:
 374                 return -ENOIOCTLCMD;
 375         }
 376 }
 377
 378 static ssize_t rv8803_nvram_write(struct file *filp, struct kobject *kobj,
 379                                   struct bin_attribute *attr,
 380                                   char *buf, loff_t off, size_t count)
 381 {
 382         struct device *dev = kobj_to_dev(kobj);
 383         struct i2c_client *client = to_i2c_client(dev);
 384         int ret;
 385
 386         ret = i2c_smbus_write_byte_data(client, RV8803_RAM, buf[0]);
 387         if (ret < 0)
 388                 return ret;
 389
 390         return 1;
 391 }
 392
 393 static ssize_t rv8803_nvram_read(struct file *filp, struct kobject *kobj,
 394                                  struct bin_attribute *attr,
 395                                  char *buf, loff_t off, size_t count)
 396 {
 397         struct device *dev = kobj_to_dev(kobj);
 398         struct i2c_client *client = to_i2c_client(dev);
 399         int ret;
 400
 401         ret = i2c_smbus_read_byte_data(client, RV8803_RAM);
 402         if (ret < 0)
 403                 return ret;
 404
 405         buf[0] = ret;
 406
 407         return 1;
 408 }
 409
 410 static struct bin_attribute rv8803_nvram_attr = {
 411         .attr = {
 412                 .name = "nvram",
 413                 .mode = S_IRUGO | S_IWUSR,
 414         },
 415         .size = 1,
 416         .read = rv8803_nvram_read,
 417         .write = rv8803_nvram_write,
 418 };
 419
 420 static struct rtc_class_ops rv8803_rtc_ops = {
 421         .read_time = rv8803_get_time,
 422         .set_time = rv8803_set_time,
 423         .ioctl = rv8803_ioctl,
 424 };
 425
 426 static int rv8803_probe(struct i2c_client *client,
 427                         const struct i2c_device_id *id)
 428 {
 429         struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
 430         struct rv8803_data *rv8803;
 431         int err, flags;
 432
 433         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 434                                      I2C_FUNC_SMBUS_I2C_BLOCK)) {
 435                 dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n");
 436                 return -EIO;
 437         }
 438
 439         rv8803 = devm_kzalloc(&client->dev, sizeof(struct rv8803_data),
 440                               GFP_KERNEL);
 441         if (!rv8803)
 442                 return -ENOMEM;
 443
 444         rv8803->client = client;
 445         i2c_set_clientdata(client, rv8803);
 446
 447         flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
 448         if (flags < 0)
 449                 return flags;
 450
 451         if (flags & RV8803_FLAG_V1F)
 452                 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
 453
 454         if (flags & RV8803_FLAG_V2F)
 455                 dev_warn(&client->dev, "Voltage low, data loss detected.\n");
 456
 457         if (flags & RV8803_FLAG_AF)
 458                 dev_warn(&client->dev, "An alarm maybe have been missed.\n");
 459
 460         if (client->irq > 0) {
 461                 err = devm_request_threaded_irq(&client->dev, client->irq,
 462                                                 NULL, rv8803_handle_irq,
 463                                                 IRQF_TRIGGER_LOW | IRQF_ONESHOT,
 464                                                 "rv8803", client);
 465                 if (err) {
 466                         dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
 467                         client->irq = 0;
 468                 } else {
 469                         rv8803_rtc_ops.read_alarm = rv8803_get_alarm;
 470                         rv8803_rtc_ops.set_alarm = rv8803_set_alarm;
 471                         rv8803_rtc_ops.alarm_irq_enable = rv8803_alarm_irq_enable;
 472                 }
 473         }
 474
 475         rv8803->rtc = devm_rtc_device_register(&client->dev, client->name,
 476                                                &rv8803_rtc_ops, THIS_MODULE);
 477         if (IS_ERR(rv8803->rtc)) {
 478                 dev_err(&client->dev, "unable to register the class device\n");
 479                 return PTR_ERR(rv8803->rtc);
 480         }
 481
 482         err = i2c_smbus_write_byte_data(rv8803->client, RV8803_EXT,
 483                                         RV8803_EXT_WADA);
 484         if (err)
 485                 return err;
 486
 487         err = device_create_bin_file(&client->dev, &rv8803_nvram_attr);
 488         if (err)
 489                 return err;
 490
 491         rv8803->rtc->max_user_freq = 1;
 492
 493         return 0;
 494 }
 495
 496 static int rv8803_remove(struct i2c_client *client)
 497 {
 498         device_remove_bin_file(&client->dev, &rv8803_nvram_attr);
 499
 500         return 0;
 501 }
 502
 503 static const struct i2c_device_id rv8803_id[] = {
 504         { "rv8803", 0 },
 505         { }
 506 };
 507 MODULE_DEVICE_TABLE(i2c, rv8803_id);
 508
 509 static struct i2c_driver rv8803_driver = {
 510         .driver = {
 511                 .name = "rtc-rv8803",
 512         },
 513         .probe          = rv8803_probe,
 514         .remove         = rv8803_remove,
 515         .id_table       = rv8803_id,
 516 };
 517 module_i2c_driver(rv8803_driver);
 518
 519 MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>");
 520 MODULE_DESCRIPTION("Micro Crystal RV8803 RTC driver");
 521 MODULE_LICENSE("GPL v2");