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/of_device.h> 22 #include <linux/rtc.h> 23 24 #define RV8803_I2C_TRY_COUNT 4 25 26 #define RV8803_SEC 0x00 27 #define RV8803_MIN 0x01 28 #define RV8803_HOUR 0x02 29 #define RV8803_WEEK 0x03 30 #define RV8803_DAY 0x04 31 #define RV8803_MONTH 0x05 32 #define RV8803_YEAR 0x06 33 #define RV8803_RAM 0x07 34 #define RV8803_ALARM_MIN 0x08 35 #define RV8803_ALARM_HOUR 0x09 36 #define RV8803_ALARM_WEEK_OR_DAY 0x0A 37 #define RV8803_EXT 0x0D 38 #define RV8803_FLAG 0x0E 39 #define RV8803_CTRL 0x0F 40 41 #define RV8803_EXT_WADA BIT(6) 42 43 #define RV8803_FLAG_V1F BIT(0) 44 #define RV8803_FLAG_V2F BIT(1) 45 #define RV8803_FLAG_AF BIT(3) 46 #define RV8803_FLAG_TF BIT(4) 47 #define RV8803_FLAG_UF BIT(5) 48 49 #define RV8803_CTRL_RESET BIT(0) 50 51 #define RV8803_CTRL_EIE BIT(2) 52 #define RV8803_CTRL_AIE BIT(3) 53 #define RV8803_CTRL_TIE BIT(4) 54 #define RV8803_CTRL_UIE BIT(5) 55 56 #define RX8900_BACKUP_CTRL 0x18 57 #define RX8900_FLAG_SWOFF BIT(2) 58 #define RX8900_FLAG_VDETOFF BIT(3) 59 60 enum rv8803_type { 61 rv_8803, 62 rx_8900 63 }; 64 65 struct rv8803_data { 66 struct i2c_client *client; 67 struct rtc_device *rtc; 68 struct mutex flags_lock; 69 u8 ctrl; 70 enum rv8803_type type; 71 }; 72 73 static int rv8803_read_reg(const struct i2c_client *client, u8 reg) 74 { 75 int try = RV8803_I2C_TRY_COUNT; 76 s32 ret; 77 78 /* 79 * There is a 61µs window during which the RTC does not acknowledge I2C 80 * transfers. In that case, ensure that there are multiple attempts. 81 */ 82 do 83 ret = i2c_smbus_read_byte_data(client, reg); 84 while ((ret == -ENXIO || ret == -EIO) && --try); 85 if (ret < 0) 86 dev_err(&client->dev, "Unable to read register 0x%02x\n", reg); 87 88 return ret; 89 } 90 91 static int rv8803_read_regs(const struct i2c_client *client, 92 u8 reg, u8 count, u8 *values) 93 { 94 int try = RV8803_I2C_TRY_COUNT; 95 s32 ret; 96 97 do 98 ret = i2c_smbus_read_i2c_block_data(client, reg, count, values); 99 while ((ret == -ENXIO || ret == -EIO) && --try); 100 if (ret != count) { 101 dev_err(&client->dev, 102 "Unable to read registers 0x%02x..0x%02x\n", 103 reg, reg + count - 1); 104 return ret < 0 ? ret : -EIO; 105 } 106 107 return 0; 108 } 109 110 static int rv8803_write_reg(const struct i2c_client *client, u8 reg, u8 value) 111 { 112 int try = RV8803_I2C_TRY_COUNT; 113 s32 ret; 114 115 do 116 ret = i2c_smbus_write_byte_data(client, reg, value); 117 while ((ret == -ENXIO || ret == -EIO) && --try); 118 if (ret) 119 dev_err(&client->dev, "Unable to write register 0x%02x\n", reg); 120 121 return ret; 122 } 123 124 static int rv8803_write_regs(const struct i2c_client *client, 125 u8 reg, u8 count, const u8 *values) 126 { 127 int try = RV8803_I2C_TRY_COUNT; 128 s32 ret; 129 130 do 131 ret = i2c_smbus_write_i2c_block_data(client, reg, count, 132 values); 133 while ((ret == -ENXIO || ret == -EIO) && --try); 134 if (ret) 135 dev_err(&client->dev, 136 "Unable to write registers 0x%02x..0x%02x\n", 137 reg, reg + count - 1); 138 139 return ret; 140 } 141 142 static irqreturn_t rv8803_handle_irq(int irq, void *dev_id) 143 { 144 struct i2c_client *client = dev_id; 145 struct rv8803_data *rv8803 = i2c_get_clientdata(client); 146 unsigned long events = 0; 147 int flags; 148 149 mutex_lock(&rv8803->flags_lock); 150 151 flags = rv8803_read_reg(client, RV8803_FLAG); 152 if (flags <= 0) { 153 mutex_unlock(&rv8803->flags_lock); 154 return IRQ_NONE; 155 } 156 157 if (flags & RV8803_FLAG_V1F) 158 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n"); 159 160 if (flags & RV8803_FLAG_V2F) 161 dev_warn(&client->dev, "Voltage low, data loss detected.\n"); 162 163 if (flags & RV8803_FLAG_TF) { 164 flags &= ~RV8803_FLAG_TF; 165 rv8803->ctrl &= ~RV8803_CTRL_TIE; 166 events |= RTC_PF; 167 } 168 169 if (flags & RV8803_FLAG_AF) { 170 flags &= ~RV8803_FLAG_AF; 171 rv8803->ctrl &= ~RV8803_CTRL_AIE; 172 events |= RTC_AF; 173 } 174 175 if (flags & RV8803_FLAG_UF) { 176 flags &= ~RV8803_FLAG_UF; 177 rv8803->ctrl &= ~RV8803_CTRL_UIE; 178 events |= RTC_UF; 179 } 180 181 if (events) { 182 rtc_update_irq(rv8803->rtc, 1, events); 183 rv8803_write_reg(client, RV8803_FLAG, flags); 184 rv8803_write_reg(rv8803->client, RV8803_CTRL, rv8803->ctrl); 185 } 186 187 mutex_unlock(&rv8803->flags_lock); 188 189 return IRQ_HANDLED; 190 } 191 192 static int rv8803_get_time(struct device *dev, struct rtc_time *tm) 193 { 194 struct rv8803_data *rv8803 = dev_get_drvdata(dev); 195 u8 date1[7]; 196 u8 date2[7]; 197 u8 *date = date1; 198 int ret, flags; 199 200 flags = rv8803_read_reg(rv8803->client, RV8803_FLAG); 201 if (flags < 0) 202 return flags; 203 204 if (flags & RV8803_FLAG_V2F) { 205 dev_warn(dev, "Voltage low, data is invalid.\n"); 206 return -EINVAL; 207 } 208 209 ret = rv8803_read_regs(rv8803->client, RV8803_SEC, 7, date); 210 if (ret) 211 return ret; 212 213 if ((date1[RV8803_SEC] & 0x7f) == bin2bcd(59)) { 214 ret = rv8803_read_regs(rv8803->client, RV8803_SEC, 7, date2); 215 if (ret) 216 return ret; 217 218 if ((date2[RV8803_SEC] & 0x7f) != bin2bcd(59)) 219 date = date2; 220 } 221 222 tm->tm_sec = bcd2bin(date[RV8803_SEC] & 0x7f); 223 tm->tm_min = bcd2bin(date[RV8803_MIN] & 0x7f); 224 tm->tm_hour = bcd2bin(date[RV8803_HOUR] & 0x3f); 225 tm->tm_wday = ilog2(date[RV8803_WEEK] & 0x7f); 226 tm->tm_mday = bcd2bin(date[RV8803_DAY] & 0x3f); 227 tm->tm_mon = bcd2bin(date[RV8803_MONTH] & 0x1f) - 1; 228 tm->tm_year = bcd2bin(date[RV8803_YEAR]) + 100; 229 230 return 0; 231 } 232 233 static int rv8803_set_time(struct device *dev, struct rtc_time *tm) 234 { 235 struct rv8803_data *rv8803 = dev_get_drvdata(dev); 236 u8 date[7]; 237 int ctrl, flags, ret; 238 239 if ((tm->tm_year < 100) || (tm->tm_year > 199)) 240 return -EINVAL; 241 242 ctrl = rv8803_read_reg(rv8803->client, RV8803_CTRL); 243 if (ctrl < 0) 244 return ctrl; 245 246 /* Stop the clock */ 247 ret = rv8803_write_reg(rv8803->client, RV8803_CTRL, 248 ctrl | RV8803_CTRL_RESET); 249 if (ret) 250 return ret; 251 252 date[RV8803_SEC] = bin2bcd(tm->tm_sec); 253 date[RV8803_MIN] = bin2bcd(tm->tm_min); 254 date[RV8803_HOUR] = bin2bcd(tm->tm_hour); 255 date[RV8803_WEEK] = 1 << (tm->tm_wday); 256 date[RV8803_DAY] = bin2bcd(tm->tm_mday); 257 date[RV8803_MONTH] = bin2bcd(tm->tm_mon + 1); 258 date[RV8803_YEAR] = bin2bcd(tm->tm_year - 100); 259 260 ret = rv8803_write_regs(rv8803->client, RV8803_SEC, 7, date); 261 if (ret) 262 return ret; 263 264 /* Restart the clock */ 265 ret = rv8803_write_reg(rv8803->client, RV8803_CTRL, 266 ctrl & ~RV8803_CTRL_RESET); 267 if (ret) 268 return ret; 269 270 mutex_lock(&rv8803->flags_lock); 271 272 flags = rv8803_read_reg(rv8803->client, RV8803_FLAG); 273 if (flags < 0) { 274 mutex_unlock(&rv8803->flags_lock); 275 return flags; 276 } 277 278 ret = rv8803_write_reg(rv8803->client, RV8803_FLAG, 279 flags & ~(RV8803_FLAG_V1F | RV8803_FLAG_V2F)); 280 281 mutex_unlock(&rv8803->flags_lock); 282 283 return ret; 284 } 285 286 static int rv8803_get_alarm(struct device *dev, struct rtc_wkalrm *alrm) 287 { 288 struct rv8803_data *rv8803 = dev_get_drvdata(dev); 289 struct i2c_client *client = rv8803->client; 290 u8 alarmvals[3]; 291 int flags, ret; 292 293 ret = rv8803_read_regs(client, RV8803_ALARM_MIN, 3, alarmvals); 294 if (ret) 295 return ret; 296 297 flags = rv8803_read_reg(client, RV8803_FLAG); 298 if (flags < 0) 299 return flags; 300 301 alrm->time.tm_sec = 0; 302 alrm->time.tm_min = bcd2bin(alarmvals[0] & 0x7f); 303 alrm->time.tm_hour = bcd2bin(alarmvals[1] & 0x3f); 304 alrm->time.tm_mday = bcd2bin(alarmvals[2] & 0x3f); 305 306 alrm->enabled = !!(rv8803->ctrl & RV8803_CTRL_AIE); 307 alrm->pending = (flags & RV8803_FLAG_AF) && alrm->enabled; 308 309 return 0; 310 } 311 312 static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 313 { 314 struct i2c_client *client = to_i2c_client(dev); 315 struct rv8803_data *rv8803 = dev_get_drvdata(dev); 316 u8 alarmvals[3]; 317 u8 ctrl[2]; 318 int ret, err; 319 320 /* The alarm has no seconds, round up to nearest minute */ 321 if (alrm->time.tm_sec) { 322 time64_t alarm_time = rtc_tm_to_time64(&alrm->time); 323 324 alarm_time += 60 - alrm->time.tm_sec; 325 rtc_time64_to_tm(alarm_time, &alrm->time); 326 } 327 328 mutex_lock(&rv8803->flags_lock); 329 330 ret = rv8803_read_regs(client, RV8803_FLAG, 2, ctrl); 331 if (ret) { 332 mutex_unlock(&rv8803->flags_lock); 333 return ret; 334 } 335 336 alarmvals[0] = bin2bcd(alrm->time.tm_min); 337 alarmvals[1] = bin2bcd(alrm->time.tm_hour); 338 alarmvals[2] = bin2bcd(alrm->time.tm_mday); 339 340 if (rv8803->ctrl & (RV8803_CTRL_AIE | RV8803_CTRL_UIE)) { 341 rv8803->ctrl &= ~(RV8803_CTRL_AIE | RV8803_CTRL_UIE); 342 err = rv8803_write_reg(rv8803->client, RV8803_CTRL, 343 rv8803->ctrl); 344 if (err) { 345 mutex_unlock(&rv8803->flags_lock); 346 return err; 347 } 348 } 349 350 ctrl[1] &= ~RV8803_FLAG_AF; 351 err = rv8803_write_reg(rv8803->client, RV8803_FLAG, ctrl[1]); 352 mutex_unlock(&rv8803->flags_lock); 353 if (err) 354 return err; 355 356 err = rv8803_write_regs(rv8803->client, RV8803_ALARM_MIN, 3, alarmvals); 357 if (err) 358 return err; 359 360 if (alrm->enabled) { 361 if (rv8803->rtc->uie_rtctimer.enabled) 362 rv8803->ctrl |= RV8803_CTRL_UIE; 363 if (rv8803->rtc->aie_timer.enabled) 364 rv8803->ctrl |= RV8803_CTRL_AIE; 365 366 err = rv8803_write_reg(rv8803->client, RV8803_CTRL, 367 rv8803->ctrl); 368 if (err) 369 return err; 370 } 371 372 return 0; 373 } 374 375 static int rv8803_alarm_irq_enable(struct device *dev, unsigned int enabled) 376 { 377 struct i2c_client *client = to_i2c_client(dev); 378 struct rv8803_data *rv8803 = dev_get_drvdata(dev); 379 int ctrl, flags, err; 380 381 ctrl = rv8803->ctrl; 382 383 if (enabled) { 384 if (rv8803->rtc->uie_rtctimer.enabled) 385 ctrl |= RV8803_CTRL_UIE; 386 if (rv8803->rtc->aie_timer.enabled) 387 ctrl |= RV8803_CTRL_AIE; 388 } else { 389 if (!rv8803->rtc->uie_rtctimer.enabled) 390 ctrl &= ~RV8803_CTRL_UIE; 391 if (!rv8803->rtc->aie_timer.enabled) 392 ctrl &= ~RV8803_CTRL_AIE; 393 } 394 395 mutex_lock(&rv8803->flags_lock); 396 flags = rv8803_read_reg(client, RV8803_FLAG); 397 if (flags < 0) { 398 mutex_unlock(&rv8803->flags_lock); 399 return flags; 400 } 401 flags &= ~(RV8803_FLAG_AF | RV8803_FLAG_UF); 402 err = rv8803_write_reg(client, RV8803_FLAG, flags); 403 mutex_unlock(&rv8803->flags_lock); 404 if (err) 405 return err; 406 407 if (ctrl != rv8803->ctrl) { 408 rv8803->ctrl = ctrl; 409 err = rv8803_write_reg(client, RV8803_CTRL, rv8803->ctrl); 410 if (err) 411 return err; 412 } 413 414 return 0; 415 } 416 417 static int rv8803_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) 418 { 419 struct i2c_client *client = to_i2c_client(dev); 420 struct rv8803_data *rv8803 = dev_get_drvdata(dev); 421 int flags, ret = 0; 422 423 switch (cmd) { 424 case RTC_VL_READ: 425 flags = rv8803_read_reg(client, RV8803_FLAG); 426 if (flags < 0) 427 return flags; 428 429 if (flags & RV8803_FLAG_V1F) 430 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n"); 431 432 if (flags & RV8803_FLAG_V2F) 433 dev_warn(&client->dev, "Voltage low, data loss detected.\n"); 434 435 flags &= RV8803_FLAG_V1F | RV8803_FLAG_V2F; 436 437 if (copy_to_user((void __user *)arg, &flags, sizeof(int))) 438 return -EFAULT; 439 440 return 0; 441 442 case RTC_VL_CLR: 443 mutex_lock(&rv8803->flags_lock); 444 flags = rv8803_read_reg(client, RV8803_FLAG); 445 if (flags < 0) { 446 mutex_unlock(&rv8803->flags_lock); 447 return flags; 448 } 449 450 flags &= ~(RV8803_FLAG_V1F | RV8803_FLAG_V2F); 451 ret = rv8803_write_reg(client, RV8803_FLAG, flags); 452 mutex_unlock(&rv8803->flags_lock); 453 if (ret) 454 return ret; 455 456 return 0; 457 458 default: 459 return -ENOIOCTLCMD; 460 } 461 } 462 463 static ssize_t rv8803_nvram_write(struct file *filp, struct kobject *kobj, 464 struct bin_attribute *attr, 465 char *buf, loff_t off, size_t count) 466 { 467 struct device *dev = kobj_to_dev(kobj); 468 struct i2c_client *client = to_i2c_client(dev); 469 int ret; 470 471 ret = rv8803_write_reg(client, RV8803_RAM, buf[0]); 472 if (ret) 473 return ret; 474 475 return 1; 476 } 477 478 static ssize_t rv8803_nvram_read(struct file *filp, struct kobject *kobj, 479 struct bin_attribute *attr, 480 char *buf, loff_t off, size_t count) 481 { 482 struct device *dev = kobj_to_dev(kobj); 483 struct i2c_client *client = to_i2c_client(dev); 484 int ret; 485 486 ret = rv8803_read_reg(client, RV8803_RAM); 487 if (ret < 0) 488 return ret; 489 490 buf[0] = ret; 491 492 return 1; 493 } 494 495 static struct bin_attribute rv8803_nvram_attr = { 496 .attr = { 497 .name = "nvram", 498 .mode = S_IRUGO | S_IWUSR, 499 }, 500 .size = 1, 501 .read = rv8803_nvram_read, 502 .write = rv8803_nvram_write, 503 }; 504 505 static struct rtc_class_ops rv8803_rtc_ops = { 506 .read_time = rv8803_get_time, 507 .set_time = rv8803_set_time, 508 .ioctl = rv8803_ioctl, 509 }; 510 511 static int rx8900_trickle_charger_init(struct rv8803_data *rv8803) 512 { 513 struct i2c_client *client = rv8803->client; 514 struct device_node *node = client->dev.of_node; 515 int err; 516 u8 flags; 517 518 if (!node) 519 return 0; 520 521 if (rv8803->type != rx_8900) 522 return 0; 523 524 err = i2c_smbus_read_byte_data(rv8803->client, RX8900_BACKUP_CTRL); 525 if (err < 0) 526 return err; 527 528 flags = ~(RX8900_FLAG_VDETOFF | RX8900_FLAG_SWOFF) & (u8)err; 529 530 if (of_property_read_bool(node, "epson,vdet-disable")) 531 flags |= RX8900_FLAG_VDETOFF; 532 533 if (of_property_read_bool(node, "trickle-diode-disable")) 534 flags |= RX8900_FLAG_SWOFF; 535 536 return i2c_smbus_write_byte_data(rv8803->client, RX8900_BACKUP_CTRL, 537 flags); 538 } 539 540 static int rv8803_probe(struct i2c_client *client, 541 const struct i2c_device_id *id) 542 { 543 struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent); 544 struct rv8803_data *rv8803; 545 int err, flags; 546 547 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | 548 I2C_FUNC_SMBUS_I2C_BLOCK)) { 549 dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n"); 550 return -EIO; 551 } 552 553 rv8803 = devm_kzalloc(&client->dev, sizeof(struct rv8803_data), 554 GFP_KERNEL); 555 if (!rv8803) 556 return -ENOMEM; 557 558 mutex_init(&rv8803->flags_lock); 559 rv8803->client = client; 560 if (client->dev.of_node) 561 rv8803->type = (enum rv8803_type) 562 of_device_get_match_data(&client->dev); 563 else 564 rv8803->type = id->driver_data; 565 i2c_set_clientdata(client, rv8803); 566 567 flags = rv8803_read_reg(client, RV8803_FLAG); 568 if (flags < 0) 569 return flags; 570 571 if (flags & RV8803_FLAG_V1F) 572 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n"); 573 574 if (flags & RV8803_FLAG_V2F) 575 dev_warn(&client->dev, "Voltage low, data loss detected.\n"); 576 577 if (flags & RV8803_FLAG_AF) 578 dev_warn(&client->dev, "An alarm maybe have been missed.\n"); 579 580 if (client->irq > 0) { 581 err = devm_request_threaded_irq(&client->dev, client->irq, 582 NULL, rv8803_handle_irq, 583 IRQF_TRIGGER_LOW | IRQF_ONESHOT, 584 "rv8803", client); 585 if (err) { 586 dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n"); 587 client->irq = 0; 588 } else { 589 rv8803_rtc_ops.read_alarm = rv8803_get_alarm; 590 rv8803_rtc_ops.set_alarm = rv8803_set_alarm; 591 rv8803_rtc_ops.alarm_irq_enable = rv8803_alarm_irq_enable; 592 } 593 } 594 595 rv8803->rtc = devm_rtc_device_register(&client->dev, client->name, 596 &rv8803_rtc_ops, THIS_MODULE); 597 if (IS_ERR(rv8803->rtc)) { 598 dev_err(&client->dev, "unable to register the class device\n"); 599 return PTR_ERR(rv8803->rtc); 600 } 601 602 err = rv8803_write_reg(rv8803->client, RV8803_EXT, RV8803_EXT_WADA); 603 if (err) 604 return err; 605 606 err = rx8900_trickle_charger_init(rv8803); 607 if (err) { 608 dev_err(&client->dev, "failed to init charger\n"); 609 return err; 610 } 611 612 err = device_create_bin_file(&client->dev, &rv8803_nvram_attr); 613 if (err) 614 return err; 615 616 rv8803->rtc->max_user_freq = 1; 617 618 return 0; 619 } 620 621 static int rv8803_remove(struct i2c_client *client) 622 { 623 device_remove_bin_file(&client->dev, &rv8803_nvram_attr); 624 625 return 0; 626 } 627 628 static const struct i2c_device_id rv8803_id[] = { 629 { "rv8803", rv_8803 }, 630 { "rx8900", rx_8900 }, 631 { } 632 }; 633 MODULE_DEVICE_TABLE(i2c, rv8803_id); 634 635 static const struct of_device_id rv8803_of_match[] = { 636 { 637 .compatible = "microcrystal,rv8803", 638 .data = (void *)rx_8900 639 }, 640 { 641 .compatible = "epson,rx8900", 642 .data = (void *)rx_8900 643 }, 644 { } 645 }; 646 MODULE_DEVICE_TABLE(of, rv8803_of_match); 647 648 static struct i2c_driver rv8803_driver = { 649 .driver = { 650 .name = "rtc-rv8803", 651 .of_match_table = of_match_ptr(rv8803_of_match), 652 }, 653 .probe = rv8803_probe, 654 .remove = rv8803_remove, 655 .id_table = rv8803_id, 656 }; 657 module_i2c_driver(rv8803_driver); 658 659 MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>"); 660 MODULE_DESCRIPTION("Micro Crystal RV8803 RTC driver"); 661 MODULE_LICENSE("GPL v2"); 662