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/log2.h> 17 #include <linux/i2c.h> 18 #include <linux/interrupt.h> 19 #include <linux/kernel.h> 20 #include <linux/module.h> 21 #include <linux/rtc.h> 22 23 #define RV8803_I2C_TRY_COUNT 4 24 25 #define RV8803_SEC 0x00 26 #define RV8803_MIN 0x01 27 #define RV8803_HOUR 0x02 28 #define RV8803_WEEK 0x03 29 #define RV8803_DAY 0x04 30 #define RV8803_MONTH 0x05 31 #define RV8803_YEAR 0x06 32 #define RV8803_RAM 0x07 33 #define RV8803_ALARM_MIN 0x08 34 #define RV8803_ALARM_HOUR 0x09 35 #define RV8803_ALARM_WEEK_OR_DAY 0x0A 36 #define RV8803_EXT 0x0D 37 #define RV8803_FLAG 0x0E 38 #define RV8803_CTRL 0x0F 39 40 #define RV8803_EXT_WADA BIT(6) 41 42 #define RV8803_FLAG_V1F BIT(0) 43 #define RV8803_FLAG_V2F BIT(1) 44 #define RV8803_FLAG_AF BIT(3) 45 #define RV8803_FLAG_TF BIT(4) 46 #define RV8803_FLAG_UF BIT(5) 47 48 #define RV8803_CTRL_RESET BIT(0) 49 50 #define RV8803_CTRL_EIE BIT(2) 51 #define RV8803_CTRL_AIE BIT(3) 52 #define RV8803_CTRL_TIE BIT(4) 53 #define RV8803_CTRL_UIE BIT(5) 54 55 #define RX8900_BACKUP_CTRL 0x18 56 #define RX8900_FLAG_SWOFF BIT(2) 57 #define RX8900_FLAG_VDETOFF BIT(3) 58 59 enum rv8803_type { 60 rv_8803, 61 rx_8900 62 }; 63 64 struct rv8803_data { 65 struct i2c_client *client; 66 struct rtc_device *rtc; 67 struct mutex flags_lock; 68 u8 ctrl; 69 enum rv8803_type type; 70 }; 71 72 static int rv8803_read_reg(const struct i2c_client *client, u8 reg) 73 { 74 int try = RV8803_I2C_TRY_COUNT; 75 s32 ret; 76 77 /* 78 * There is a 61µs window during which the RTC does not acknowledge I2C 79 * transfers. In that case, ensure that there are multiple attempts. 80 */ 81 do 82 ret = i2c_smbus_read_byte_data(client, reg); 83 while ((ret == -ENXIO || ret == -EIO) && --try); 84 if (ret < 0) 85 dev_err(&client->dev, "Unable to read register 0x%02x\n", reg); 86 87 return ret; 88 } 89 90 static int rv8803_read_regs(const struct i2c_client *client, 91 u8 reg, u8 count, u8 *values) 92 { 93 int try = RV8803_I2C_TRY_COUNT; 94 s32 ret; 95 96 do 97 ret = i2c_smbus_read_i2c_block_data(client, reg, count, values); 98 while ((ret == -ENXIO || ret == -EIO) && --try); 99 if (ret != count) { 100 dev_err(&client->dev, 101 "Unable to read registers 0x%02x..0x%02x\n", 102 reg, reg + count - 1); 103 return ret < 0 ? ret : -EIO; 104 } 105 106 return 0; 107 } 108 109 static int rv8803_write_reg(const struct i2c_client *client, u8 reg, u8 value) 110 { 111 int try = RV8803_I2C_TRY_COUNT; 112 s32 ret; 113 114 do 115 ret = i2c_smbus_write_byte_data(client, reg, value); 116 while ((ret == -ENXIO || ret == -EIO) && --try); 117 if (ret) 118 dev_err(&client->dev, "Unable to write register 0x%02x\n", reg); 119 120 return ret; 121 } 122 123 static int rv8803_write_regs(const struct i2c_client *client, 124 u8 reg, u8 count, const u8 *values) 125 { 126 int try = RV8803_I2C_TRY_COUNT; 127 s32 ret; 128 129 do 130 ret = i2c_smbus_write_i2c_block_data(client, reg, count, 131 values); 132 while ((ret == -ENXIO || ret == -EIO) && --try); 133 if (ret) 134 dev_err(&client->dev, 135 "Unable to write registers 0x%02x..0x%02x\n", 136 reg, reg + count - 1); 137 138 return ret; 139 } 140 141 static irqreturn_t rv8803_handle_irq(int irq, void *dev_id) 142 { 143 struct i2c_client *client = dev_id; 144 struct rv8803_data *rv8803 = i2c_get_clientdata(client); 145 unsigned long events = 0; 146 int flags; 147 148 mutex_lock(&rv8803->flags_lock); 149 150 flags = rv8803_read_reg(client, RV8803_FLAG); 151 if (flags <= 0) { 152 mutex_unlock(&rv8803->flags_lock); 153 return IRQ_NONE; 154 } 155 156 if (flags & RV8803_FLAG_V1F) 157 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n"); 158 159 if (flags & RV8803_FLAG_V2F) 160 dev_warn(&client->dev, "Voltage low, data loss detected.\n"); 161 162 if (flags & RV8803_FLAG_TF) { 163 flags &= ~RV8803_FLAG_TF; 164 rv8803->ctrl &= ~RV8803_CTRL_TIE; 165 events |= RTC_PF; 166 } 167 168 if (flags & RV8803_FLAG_AF) { 169 flags &= ~RV8803_FLAG_AF; 170 rv8803->ctrl &= ~RV8803_CTRL_AIE; 171 events |= RTC_AF; 172 } 173 174 if (flags & RV8803_FLAG_UF) { 175 flags &= ~RV8803_FLAG_UF; 176 rv8803->ctrl &= ~RV8803_CTRL_UIE; 177 events |= RTC_UF; 178 } 179 180 if (events) { 181 rtc_update_irq(rv8803->rtc, 1, events); 182 rv8803_write_reg(client, RV8803_FLAG, flags); 183 rv8803_write_reg(rv8803->client, RV8803_CTRL, rv8803->ctrl); 184 } 185 186 mutex_unlock(&rv8803->flags_lock); 187 188 return IRQ_HANDLED; 189 } 190 191 static int rv8803_get_time(struct device *dev, struct rtc_time *tm) 192 { 193 struct rv8803_data *rv8803 = dev_get_drvdata(dev); 194 u8 date1[7]; 195 u8 date2[7]; 196 u8 *date = date1; 197 int ret, flags; 198 199 flags = rv8803_read_reg(rv8803->client, RV8803_FLAG); 200 if (flags < 0) 201 return flags; 202 203 if (flags & RV8803_FLAG_V2F) { 204 dev_warn(dev, "Voltage low, data is invalid.\n"); 205 return -EINVAL; 206 } 207 208 ret = rv8803_read_regs(rv8803->client, RV8803_SEC, 7, date); 209 if (ret) 210 return ret; 211 212 if ((date1[RV8803_SEC] & 0x7f) == bin2bcd(59)) { 213 ret = rv8803_read_regs(rv8803->client, RV8803_SEC, 7, date2); 214 if (ret) 215 return ret; 216 217 if ((date2[RV8803_SEC] & 0x7f) != bin2bcd(59)) 218 date = date2; 219 } 220 221 tm->tm_sec = bcd2bin(date[RV8803_SEC] & 0x7f); 222 tm->tm_min = bcd2bin(date[RV8803_MIN] & 0x7f); 223 tm->tm_hour = bcd2bin(date[RV8803_HOUR] & 0x3f); 224 tm->tm_wday = ilog2(date[RV8803_WEEK] & 0x7f); 225 tm->tm_mday = bcd2bin(date[RV8803_DAY] & 0x3f); 226 tm->tm_mon = bcd2bin(date[RV8803_MONTH] & 0x1f) - 1; 227 tm->tm_year = bcd2bin(date[RV8803_YEAR]) + 100; 228 229 return 0; 230 } 231 232 static int rv8803_set_time(struct device *dev, struct rtc_time *tm) 233 { 234 struct rv8803_data *rv8803 = dev_get_drvdata(dev); 235 u8 date[7]; 236 int ctrl, flags, ret; 237 238 if ((tm->tm_year < 100) || (tm->tm_year > 199)) 239 return -EINVAL; 240 241 ctrl = rv8803_read_reg(rv8803->client, RV8803_CTRL); 242 if (ctrl < 0) 243 return ctrl; 244 245 /* Stop the clock */ 246 ret = rv8803_write_reg(rv8803->client, RV8803_CTRL, 247 ctrl | RV8803_CTRL_RESET); 248 if (ret) 249 return ret; 250 251 date[RV8803_SEC] = bin2bcd(tm->tm_sec); 252 date[RV8803_MIN] = bin2bcd(tm->tm_min); 253 date[RV8803_HOUR] = bin2bcd(tm->tm_hour); 254 date[RV8803_WEEK] = 1 << (tm->tm_wday); 255 date[RV8803_DAY] = bin2bcd(tm->tm_mday); 256 date[RV8803_MONTH] = bin2bcd(tm->tm_mon + 1); 257 date[RV8803_YEAR] = bin2bcd(tm->tm_year - 100); 258 259 ret = rv8803_write_regs(rv8803->client, RV8803_SEC, 7, date); 260 if (ret) 261 return ret; 262 263 /* Restart the clock */ 264 ret = rv8803_write_reg(rv8803->client, RV8803_CTRL, 265 ctrl & ~RV8803_CTRL_RESET); 266 if (ret) 267 return ret; 268 269 mutex_lock(&rv8803->flags_lock); 270 271 flags = rv8803_read_reg(rv8803->client, RV8803_FLAG); 272 if (flags < 0) { 273 mutex_unlock(&rv8803->flags_lock); 274 return flags; 275 } 276 277 ret = rv8803_write_reg(rv8803->client, RV8803_FLAG, 278 flags & ~(RV8803_FLAG_V1F | RV8803_FLAG_V2F)); 279 280 mutex_unlock(&rv8803->flags_lock); 281 282 return ret; 283 } 284 285 static int rv8803_get_alarm(struct device *dev, struct rtc_wkalrm *alrm) 286 { 287 struct rv8803_data *rv8803 = dev_get_drvdata(dev); 288 struct i2c_client *client = rv8803->client; 289 u8 alarmvals[3]; 290 int flags, ret; 291 292 ret = rv8803_read_regs(client, RV8803_ALARM_MIN, 3, alarmvals); 293 if (ret) 294 return ret; 295 296 flags = rv8803_read_reg(client, RV8803_FLAG); 297 if (flags < 0) 298 return flags; 299 300 alrm->time.tm_sec = 0; 301 alrm->time.tm_min = bcd2bin(alarmvals[0] & 0x7f); 302 alrm->time.tm_hour = bcd2bin(alarmvals[1] & 0x3f); 303 alrm->time.tm_mday = bcd2bin(alarmvals[2] & 0x3f); 304 305 alrm->enabled = !!(rv8803->ctrl & RV8803_CTRL_AIE); 306 alrm->pending = (flags & RV8803_FLAG_AF) && alrm->enabled; 307 308 return 0; 309 } 310 311 static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 312 { 313 struct i2c_client *client = to_i2c_client(dev); 314 struct rv8803_data *rv8803 = dev_get_drvdata(dev); 315 u8 alarmvals[3]; 316 u8 ctrl[2]; 317 int ret, err; 318 319 /* The alarm has no seconds, round up to nearest minute */ 320 if (alrm->time.tm_sec) { 321 time64_t alarm_time = rtc_tm_to_time64(&alrm->time); 322 323 alarm_time += 60 - alrm->time.tm_sec; 324 rtc_time64_to_tm(alarm_time, &alrm->time); 325 } 326 327 mutex_lock(&rv8803->flags_lock); 328 329 ret = rv8803_read_regs(client, RV8803_FLAG, 2, ctrl); 330 if (ret) { 331 mutex_unlock(&rv8803->flags_lock); 332 return ret; 333 } 334 335 alarmvals[0] = bin2bcd(alrm->time.tm_min); 336 alarmvals[1] = bin2bcd(alrm->time.tm_hour); 337 alarmvals[2] = bin2bcd(alrm->time.tm_mday); 338 339 if (rv8803->ctrl & (RV8803_CTRL_AIE | RV8803_CTRL_UIE)) { 340 rv8803->ctrl &= ~(RV8803_CTRL_AIE | RV8803_CTRL_UIE); 341 err = rv8803_write_reg(rv8803->client, RV8803_CTRL, 342 rv8803->ctrl); 343 if (err) { 344 mutex_unlock(&rv8803->flags_lock); 345 return err; 346 } 347 } 348 349 ctrl[1] &= ~RV8803_FLAG_AF; 350 err = rv8803_write_reg(rv8803->client, RV8803_FLAG, ctrl[1]); 351 mutex_unlock(&rv8803->flags_lock); 352 if (err) 353 return err; 354 355 err = rv8803_write_regs(rv8803->client, RV8803_ALARM_MIN, 3, alarmvals); 356 if (err) 357 return err; 358 359 if (alrm->enabled) { 360 if (rv8803->rtc->uie_rtctimer.enabled) 361 rv8803->ctrl |= RV8803_CTRL_UIE; 362 if (rv8803->rtc->aie_timer.enabled) 363 rv8803->ctrl |= RV8803_CTRL_AIE; 364 365 err = rv8803_write_reg(rv8803->client, RV8803_CTRL, 366 rv8803->ctrl); 367 if (err) 368 return err; 369 } 370 371 return 0; 372 } 373 374 static int rv8803_alarm_irq_enable(struct device *dev, unsigned int enabled) 375 { 376 struct i2c_client *client = to_i2c_client(dev); 377 struct rv8803_data *rv8803 = dev_get_drvdata(dev); 378 int ctrl, flags, err; 379 380 ctrl = rv8803->ctrl; 381 382 if (enabled) { 383 if (rv8803->rtc->uie_rtctimer.enabled) 384 ctrl |= RV8803_CTRL_UIE; 385 if (rv8803->rtc->aie_timer.enabled) 386 ctrl |= RV8803_CTRL_AIE; 387 } else { 388 if (!rv8803->rtc->uie_rtctimer.enabled) 389 ctrl &= ~RV8803_CTRL_UIE; 390 if (!rv8803->rtc->aie_timer.enabled) 391 ctrl &= ~RV8803_CTRL_AIE; 392 } 393 394 mutex_lock(&rv8803->flags_lock); 395 flags = rv8803_read_reg(client, RV8803_FLAG); 396 if (flags < 0) { 397 mutex_unlock(&rv8803->flags_lock); 398 return flags; 399 } 400 flags &= ~(RV8803_FLAG_AF | RV8803_FLAG_UF); 401 err = rv8803_write_reg(client, RV8803_FLAG, flags); 402 mutex_unlock(&rv8803->flags_lock); 403 if (err) 404 return err; 405 406 if (ctrl != rv8803->ctrl) { 407 rv8803->ctrl = ctrl; 408 err = rv8803_write_reg(client, RV8803_CTRL, rv8803->ctrl); 409 if (err) 410 return err; 411 } 412 413 return 0; 414 } 415 416 static int rv8803_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) 417 { 418 struct i2c_client *client = to_i2c_client(dev); 419 struct rv8803_data *rv8803 = dev_get_drvdata(dev); 420 int flags, ret = 0; 421 422 switch (cmd) { 423 case RTC_VL_READ: 424 flags = rv8803_read_reg(client, RV8803_FLAG); 425 if (flags < 0) 426 return flags; 427 428 if (flags & RV8803_FLAG_V1F) 429 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n"); 430 431 if (flags & RV8803_FLAG_V2F) 432 dev_warn(&client->dev, "Voltage low, data loss detected.\n"); 433 434 flags &= RV8803_FLAG_V1F | RV8803_FLAG_V2F; 435 436 if (copy_to_user((void __user *)arg, &flags, sizeof(int))) 437 return -EFAULT; 438 439 return 0; 440 441 case RTC_VL_CLR: 442 mutex_lock(&rv8803->flags_lock); 443 flags = rv8803_read_reg(client, RV8803_FLAG); 444 if (flags < 0) { 445 mutex_unlock(&rv8803->flags_lock); 446 return flags; 447 } 448 449 flags &= ~(RV8803_FLAG_V1F | RV8803_FLAG_V2F); 450 ret = rv8803_write_reg(client, RV8803_FLAG, flags); 451 mutex_unlock(&rv8803->flags_lock); 452 if (ret) 453 return ret; 454 455 return 0; 456 457 default: 458 return -ENOIOCTLCMD; 459 } 460 } 461 462 static ssize_t rv8803_nvram_write(struct file *filp, struct kobject *kobj, 463 struct bin_attribute *attr, 464 char *buf, loff_t off, size_t count) 465 { 466 struct device *dev = kobj_to_dev(kobj); 467 struct i2c_client *client = to_i2c_client(dev); 468 int ret; 469 470 ret = rv8803_write_reg(client, RV8803_RAM, buf[0]); 471 if (ret) 472 return ret; 473 474 return 1; 475 } 476 477 static ssize_t rv8803_nvram_read(struct file *filp, struct kobject *kobj, 478 struct bin_attribute *attr, 479 char *buf, loff_t off, size_t count) 480 { 481 struct device *dev = kobj_to_dev(kobj); 482 struct i2c_client *client = to_i2c_client(dev); 483 int ret; 484 485 ret = rv8803_read_reg(client, RV8803_RAM); 486 if (ret < 0) 487 return ret; 488 489 buf[0] = ret; 490 491 return 1; 492 } 493 494 static struct bin_attribute rv8803_nvram_attr = { 495 .attr = { 496 .name = "nvram", 497 .mode = S_IRUGO | S_IWUSR, 498 }, 499 .size = 1, 500 .read = rv8803_nvram_read, 501 .write = rv8803_nvram_write, 502 }; 503 504 static struct rtc_class_ops rv8803_rtc_ops = { 505 .read_time = rv8803_get_time, 506 .set_time = rv8803_set_time, 507 .ioctl = rv8803_ioctl, 508 }; 509 510 static int rx8900_trickle_charger_init(struct rv8803_data *rv8803) 511 { 512 struct i2c_client *client = rv8803->client; 513 struct device_node *node = client->dev.of_node; 514 int err; 515 u8 flags; 516 517 if (!node) 518 return 0; 519 520 if (rv8803->type != rx_8900) 521 return 0; 522 523 err = i2c_smbus_read_byte_data(rv8803->client, RX8900_BACKUP_CTRL); 524 if (err < 0) 525 return err; 526 527 flags = ~(RX8900_FLAG_VDETOFF | RX8900_FLAG_SWOFF) & (u8)err; 528 529 if (of_property_read_bool(node, "epson,vdet-disable")) 530 flags |= RX8900_FLAG_VDETOFF; 531 532 if (of_property_read_bool(node, "trickle-diode-disable")) 533 flags |= RX8900_FLAG_SWOFF; 534 535 return i2c_smbus_write_byte_data(rv8803->client, RX8900_BACKUP_CTRL, 536 flags); 537 } 538 539 static int rv8803_probe(struct i2c_client *client, 540 const struct i2c_device_id *id) 541 { 542 struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent); 543 struct rv8803_data *rv8803; 544 int err, flags; 545 546 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | 547 I2C_FUNC_SMBUS_I2C_BLOCK)) { 548 dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n"); 549 return -EIO; 550 } 551 552 rv8803 = devm_kzalloc(&client->dev, sizeof(struct rv8803_data), 553 GFP_KERNEL); 554 if (!rv8803) 555 return -ENOMEM; 556 557 mutex_init(&rv8803->flags_lock); 558 rv8803->client = client; 559 rv8803->type = id->driver_data; 560 i2c_set_clientdata(client, rv8803); 561 562 flags = rv8803_read_reg(client, RV8803_FLAG); 563 if (flags < 0) 564 return flags; 565 566 if (flags & RV8803_FLAG_V1F) 567 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n"); 568 569 if (flags & RV8803_FLAG_V2F) 570 dev_warn(&client->dev, "Voltage low, data loss detected.\n"); 571 572 if (flags & RV8803_FLAG_AF) 573 dev_warn(&client->dev, "An alarm maybe have been missed.\n"); 574 575 if (client->irq > 0) { 576 err = devm_request_threaded_irq(&client->dev, client->irq, 577 NULL, rv8803_handle_irq, 578 IRQF_TRIGGER_LOW | IRQF_ONESHOT, 579 "rv8803", client); 580 if (err) { 581 dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n"); 582 client->irq = 0; 583 } else { 584 rv8803_rtc_ops.read_alarm = rv8803_get_alarm; 585 rv8803_rtc_ops.set_alarm = rv8803_set_alarm; 586 rv8803_rtc_ops.alarm_irq_enable = rv8803_alarm_irq_enable; 587 } 588 } 589 590 rv8803->rtc = devm_rtc_device_register(&client->dev, client->name, 591 &rv8803_rtc_ops, THIS_MODULE); 592 if (IS_ERR(rv8803->rtc)) { 593 dev_err(&client->dev, "unable to register the class device\n"); 594 return PTR_ERR(rv8803->rtc); 595 } 596 597 err = rv8803_write_reg(rv8803->client, RV8803_EXT, RV8803_EXT_WADA); 598 if (err) 599 return err; 600 601 err = rx8900_trickle_charger_init(rv8803); 602 if (err) { 603 dev_err(&client->dev, "failed to init charger\n"); 604 return err; 605 } 606 607 err = device_create_bin_file(&client->dev, &rv8803_nvram_attr); 608 if (err) 609 return err; 610 611 rv8803->rtc->max_user_freq = 1; 612 613 return 0; 614 } 615 616 static int rv8803_remove(struct i2c_client *client) 617 { 618 device_remove_bin_file(&client->dev, &rv8803_nvram_attr); 619 620 return 0; 621 } 622 623 static const struct i2c_device_id rv8803_id[] = { 624 { "rv8803", rv_8803 }, 625 { "rx8900", rx_8900 }, 626 { } 627 }; 628 MODULE_DEVICE_TABLE(i2c, rv8803_id); 629 630 static struct i2c_driver rv8803_driver = { 631 .driver = { 632 .name = "rtc-rv8803", 633 }, 634 .probe = rv8803_probe, 635 .remove = rv8803_remove, 636 .id_table = rv8803_id, 637 }; 638 module_i2c_driver(rv8803_driver); 639 640 MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>"); 641 MODULE_DESCRIPTION("Micro Crystal RV8803 RTC driver"); 642 MODULE_LICENSE("GPL v2"); 643