1 /* 2 * RTC client/driver for the Maxim/Dallas DS3232/DS3234 Real-Time Clock 3 * 4 * Copyright (C) 2009-2011 Freescale Semiconductor. 5 * Author: Jack Lan <jack.lan@freescale.com> 6 * Copyright (C) 2008 MIMOMax Wireless Ltd. 7 * 8 * This program is free software; you can redistribute it and/or modify it 9 * under the terms of the GNU General Public License as published by the 10 * Free Software Foundation; either version 2 of the License, or (at your 11 * option) any later version. 12 */ 13 14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 15 16 #include <linux/kernel.h> 17 #include <linux/module.h> 18 #include <linux/interrupt.h> 19 #include <linux/i2c.h> 20 #include <linux/spi/spi.h> 21 #include <linux/rtc.h> 22 #include <linux/bcd.h> 23 #include <linux/slab.h> 24 #include <linux/regmap.h> 25 #include <linux/hwmon.h> 26 27 #define DS3232_REG_SECONDS 0x00 28 #define DS3232_REG_MINUTES 0x01 29 #define DS3232_REG_HOURS 0x02 30 #define DS3232_REG_AMPM 0x02 31 #define DS3232_REG_DAY 0x03 32 #define DS3232_REG_DATE 0x04 33 #define DS3232_REG_MONTH 0x05 34 #define DS3232_REG_CENTURY 0x05 35 #define DS3232_REG_YEAR 0x06 36 #define DS3232_REG_ALARM1 0x07 /* Alarm 1 BASE */ 37 #define DS3232_REG_ALARM2 0x0B /* Alarm 2 BASE */ 38 #define DS3232_REG_CR 0x0E /* Control register */ 39 # define DS3232_REG_CR_nEOSC 0x80 40 # define DS3232_REG_CR_INTCN 0x04 41 # define DS3232_REG_CR_A2IE 0x02 42 # define DS3232_REG_CR_A1IE 0x01 43 44 #define DS3232_REG_SR 0x0F /* control/status register */ 45 # define DS3232_REG_SR_OSF 0x80 46 # define DS3232_REG_SR_BSY 0x04 47 # define DS3232_REG_SR_A2F 0x02 48 # define DS3232_REG_SR_A1F 0x01 49 50 #define DS3232_REG_TEMPERATURE 0x11 51 52 struct ds3232 { 53 struct device *dev; 54 struct regmap *regmap; 55 int irq; 56 struct rtc_device *rtc; 57 58 bool suspended; 59 }; 60 61 static int ds3232_check_rtc_status(struct device *dev) 62 { 63 struct ds3232 *ds3232 = dev_get_drvdata(dev); 64 int ret = 0; 65 int control, stat; 66 67 ret = regmap_read(ds3232->regmap, DS3232_REG_SR, &stat); 68 if (ret) 69 return ret; 70 71 if (stat & DS3232_REG_SR_OSF) 72 dev_warn(dev, 73 "oscillator discontinuity flagged, " 74 "time unreliable\n"); 75 76 stat &= ~(DS3232_REG_SR_OSF | DS3232_REG_SR_A1F | DS3232_REG_SR_A2F); 77 78 ret = regmap_write(ds3232->regmap, DS3232_REG_SR, stat); 79 if (ret) 80 return ret; 81 82 /* If the alarm is pending, clear it before requesting 83 * the interrupt, so an interrupt event isn't reported 84 * before everything is initialized. 85 */ 86 87 ret = regmap_read(ds3232->regmap, DS3232_REG_CR, &control); 88 if (ret) 89 return ret; 90 91 control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE); 92 control |= DS3232_REG_CR_INTCN; 93 94 return regmap_write(ds3232->regmap, DS3232_REG_CR, control); 95 } 96 97 static int ds3232_read_time(struct device *dev, struct rtc_time *time) 98 { 99 struct ds3232 *ds3232 = dev_get_drvdata(dev); 100 int ret; 101 u8 buf[7]; 102 unsigned int year, month, day, hour, minute, second; 103 unsigned int week, twelve_hr, am_pm; 104 unsigned int century, add_century = 0; 105 106 ret = regmap_bulk_read(ds3232->regmap, DS3232_REG_SECONDS, buf, 7); 107 if (ret) 108 return ret; 109 110 second = buf[0]; 111 minute = buf[1]; 112 hour = buf[2]; 113 week = buf[3]; 114 day = buf[4]; 115 month = buf[5]; 116 year = buf[6]; 117 118 /* Extract additional information for AM/PM and century */ 119 120 twelve_hr = hour & 0x40; 121 am_pm = hour & 0x20; 122 century = month & 0x80; 123 124 /* Write to rtc_time structure */ 125 126 time->tm_sec = bcd2bin(second); 127 time->tm_min = bcd2bin(minute); 128 if (twelve_hr) { 129 /* Convert to 24 hr */ 130 if (am_pm) 131 time->tm_hour = bcd2bin(hour & 0x1F) + 12; 132 else 133 time->tm_hour = bcd2bin(hour & 0x1F); 134 } else { 135 time->tm_hour = bcd2bin(hour); 136 } 137 138 /* Day of the week in linux range is 0~6 while 1~7 in RTC chip */ 139 time->tm_wday = bcd2bin(week) - 1; 140 time->tm_mday = bcd2bin(day); 141 /* linux tm_mon range:0~11, while month range is 1~12 in RTC chip */ 142 time->tm_mon = bcd2bin(month & 0x7F) - 1; 143 if (century) 144 add_century = 100; 145 146 time->tm_year = bcd2bin(year) + add_century; 147 148 return 0; 149 } 150 151 static int ds3232_set_time(struct device *dev, struct rtc_time *time) 152 { 153 struct ds3232 *ds3232 = dev_get_drvdata(dev); 154 u8 buf[7]; 155 156 /* Extract time from rtc_time and load into ds3232*/ 157 158 buf[0] = bin2bcd(time->tm_sec); 159 buf[1] = bin2bcd(time->tm_min); 160 buf[2] = bin2bcd(time->tm_hour); 161 /* Day of the week in linux range is 0~6 while 1~7 in RTC chip */ 162 buf[3] = bin2bcd(time->tm_wday + 1); 163 buf[4] = bin2bcd(time->tm_mday); /* Date */ 164 /* linux tm_mon range:0~11, while month range is 1~12 in RTC chip */ 165 buf[5] = bin2bcd(time->tm_mon + 1); 166 if (time->tm_year >= 100) { 167 buf[5] |= 0x80; 168 buf[6] = bin2bcd(time->tm_year - 100); 169 } else { 170 buf[6] = bin2bcd(time->tm_year); 171 } 172 173 return regmap_bulk_write(ds3232->regmap, DS3232_REG_SECONDS, buf, 7); 174 } 175 176 /* 177 * DS3232 has two alarm, we only use alarm1 178 * According to linux specification, only support one-shot alarm 179 * no periodic alarm mode 180 */ 181 static int ds3232_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) 182 { 183 struct ds3232 *ds3232 = dev_get_drvdata(dev); 184 int control, stat; 185 int ret; 186 u8 buf[4]; 187 188 ret = regmap_read(ds3232->regmap, DS3232_REG_SR, &stat); 189 if (ret) 190 goto out; 191 ret = regmap_read(ds3232->regmap, DS3232_REG_CR, &control); 192 if (ret) 193 goto out; 194 ret = regmap_bulk_read(ds3232->regmap, DS3232_REG_ALARM1, buf, 4); 195 if (ret) 196 goto out; 197 198 alarm->time.tm_sec = bcd2bin(buf[0] & 0x7F); 199 alarm->time.tm_min = bcd2bin(buf[1] & 0x7F); 200 alarm->time.tm_hour = bcd2bin(buf[2] & 0x7F); 201 alarm->time.tm_mday = bcd2bin(buf[3] & 0x7F); 202 203 alarm->enabled = !!(control & DS3232_REG_CR_A1IE); 204 alarm->pending = !!(stat & DS3232_REG_SR_A1F); 205 206 ret = 0; 207 out: 208 return ret; 209 } 210 211 /* 212 * linux rtc-module does not support wday alarm 213 * and only 24h time mode supported indeed 214 */ 215 static int ds3232_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) 216 { 217 struct ds3232 *ds3232 = dev_get_drvdata(dev); 218 int control, stat; 219 int ret; 220 u8 buf[4]; 221 222 if (ds3232->irq <= 0) 223 return -EINVAL; 224 225 buf[0] = bin2bcd(alarm->time.tm_sec); 226 buf[1] = bin2bcd(alarm->time.tm_min); 227 buf[2] = bin2bcd(alarm->time.tm_hour); 228 buf[3] = bin2bcd(alarm->time.tm_mday); 229 230 /* clear alarm interrupt enable bit */ 231 ret = regmap_read(ds3232->regmap, DS3232_REG_CR, &control); 232 if (ret) 233 goto out; 234 control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE); 235 ret = regmap_write(ds3232->regmap, DS3232_REG_CR, control); 236 if (ret) 237 goto out; 238 239 /* clear any pending alarm flag */ 240 ret = regmap_read(ds3232->regmap, DS3232_REG_SR, &stat); 241 if (ret) 242 goto out; 243 stat &= ~(DS3232_REG_SR_A1F | DS3232_REG_SR_A2F); 244 ret = regmap_write(ds3232->regmap, DS3232_REG_SR, stat); 245 if (ret) 246 goto out; 247 248 ret = regmap_bulk_write(ds3232->regmap, DS3232_REG_ALARM1, buf, 4); 249 if (ret) 250 goto out; 251 252 if (alarm->enabled) { 253 control |= DS3232_REG_CR_A1IE; 254 ret = regmap_write(ds3232->regmap, DS3232_REG_CR, control); 255 } 256 out: 257 return ret; 258 } 259 260 static int ds3232_update_alarm(struct device *dev, unsigned int enabled) 261 { 262 struct ds3232 *ds3232 = dev_get_drvdata(dev); 263 int control; 264 int ret; 265 266 ret = regmap_read(ds3232->regmap, DS3232_REG_CR, &control); 267 if (ret) 268 return ret; 269 270 if (enabled) 271 /* enable alarm1 interrupt */ 272 control |= DS3232_REG_CR_A1IE; 273 else 274 /* disable alarm1 interrupt */ 275 control &= ~(DS3232_REG_CR_A1IE); 276 ret = regmap_write(ds3232->regmap, DS3232_REG_CR, control); 277 278 return ret; 279 } 280 281 /* 282 * Temperature sensor support for ds3232/ds3234 devices. 283 * A user-initiated temperature conversion is not started by this function, 284 * so the temperature is updated once every 64 seconds. 285 */ 286 static int ds3232_hwmon_read_temp(struct device *dev, long int *mC) 287 { 288 struct ds3232 *ds3232 = dev_get_drvdata(dev); 289 u8 temp_buf[2]; 290 s16 temp; 291 int ret; 292 293 ret = regmap_bulk_read(ds3232->regmap, DS3232_REG_TEMPERATURE, temp_buf, 294 sizeof(temp_buf)); 295 if (ret < 0) 296 return ret; 297 298 /* 299 * Temperature is represented as a 10-bit code with a resolution of 300 * 0.25 degree celsius and encoded in two's complement format. 301 */ 302 temp = (temp_buf[0] << 8) | temp_buf[1]; 303 temp >>= 6; 304 *mC = temp * 250; 305 306 return 0; 307 } 308 309 static umode_t ds3232_hwmon_is_visible(const void *data, 310 enum hwmon_sensor_types type, 311 u32 attr, int channel) 312 { 313 if (type != hwmon_temp) 314 return 0; 315 316 switch (attr) { 317 case hwmon_temp_input: 318 return 0444; 319 default: 320 return 0; 321 } 322 } 323 324 static int ds3232_hwmon_read(struct device *dev, 325 enum hwmon_sensor_types type, 326 u32 attr, int channel, long *temp) 327 { 328 int err; 329 330 switch (attr) { 331 case hwmon_temp_input: 332 err = ds3232_hwmon_read_temp(dev, temp); 333 break; 334 default: 335 err = -EOPNOTSUPP; 336 break; 337 } 338 339 return err; 340 } 341 342 static u32 ds3232_hwmon_chip_config[] = { 343 HWMON_C_REGISTER_TZ, 344 0 345 }; 346 347 static const struct hwmon_channel_info ds3232_hwmon_chip = { 348 .type = hwmon_chip, 349 .config = ds3232_hwmon_chip_config, 350 }; 351 352 static u32 ds3232_hwmon_temp_config[] = { 353 HWMON_T_INPUT, 354 0 355 }; 356 357 static const struct hwmon_channel_info ds3232_hwmon_temp = { 358 .type = hwmon_temp, 359 .config = ds3232_hwmon_temp_config, 360 }; 361 362 static const struct hwmon_channel_info *ds3232_hwmon_info[] = { 363 &ds3232_hwmon_chip, 364 &ds3232_hwmon_temp, 365 NULL 366 }; 367 368 static const struct hwmon_ops ds3232_hwmon_hwmon_ops = { 369 .is_visible = ds3232_hwmon_is_visible, 370 .read = ds3232_hwmon_read, 371 }; 372 373 static const struct hwmon_chip_info ds3232_hwmon_chip_info = { 374 .ops = &ds3232_hwmon_hwmon_ops, 375 .info = ds3232_hwmon_info, 376 }; 377 378 static void ds3232_hwmon_register(struct device *dev, const char *name) 379 { 380 struct ds3232 *ds3232 = dev_get_drvdata(dev); 381 struct device *hwmon_dev; 382 383 if (!IS_ENABLED(CONFIG_RTC_DRV_DS3232_HWMON)) 384 return; 385 386 hwmon_dev = devm_hwmon_device_register_with_info(dev, name, ds3232, 387 &ds3232_hwmon_chip_info, 388 NULL); 389 if (IS_ERR(hwmon_dev)) { 390 dev_err(dev, "unable to register hwmon device %ld\n", 391 PTR_ERR(hwmon_dev)); 392 } 393 } 394 395 static int ds3232_alarm_irq_enable(struct device *dev, unsigned int enabled) 396 { 397 struct ds3232 *ds3232 = dev_get_drvdata(dev); 398 399 if (ds3232->irq <= 0) 400 return -EINVAL; 401 402 return ds3232_update_alarm(dev, enabled); 403 } 404 405 static irqreturn_t ds3232_irq(int irq, void *dev_id) 406 { 407 struct device *dev = dev_id; 408 struct ds3232 *ds3232 = dev_get_drvdata(dev); 409 struct mutex *lock = &ds3232->rtc->ops_lock; 410 int ret; 411 int stat, control; 412 413 mutex_lock(lock); 414 415 ret = regmap_read(ds3232->regmap, DS3232_REG_SR, &stat); 416 if (ret) 417 goto unlock; 418 419 if (stat & DS3232_REG_SR_A1F) { 420 ret = regmap_read(ds3232->regmap, DS3232_REG_CR, &control); 421 if (ret) { 422 dev_warn(ds3232->dev, 423 "Read Control Register error %d\n", ret); 424 } else { 425 /* disable alarm1 interrupt */ 426 control &= ~(DS3232_REG_CR_A1IE); 427 ret = regmap_write(ds3232->regmap, DS3232_REG_CR, 428 control); 429 if (ret) { 430 dev_warn(ds3232->dev, 431 "Write Control Register error %d\n", 432 ret); 433 goto unlock; 434 } 435 436 /* clear the alarm pend flag */ 437 stat &= ~DS3232_REG_SR_A1F; 438 ret = regmap_write(ds3232->regmap, DS3232_REG_SR, stat); 439 if (ret) { 440 dev_warn(ds3232->dev, 441 "Write Status Register error %d\n", 442 ret); 443 goto unlock; 444 } 445 446 rtc_update_irq(ds3232->rtc, 1, RTC_AF | RTC_IRQF); 447 } 448 } 449 450 unlock: 451 mutex_unlock(lock); 452 453 return IRQ_HANDLED; 454 } 455 456 static const struct rtc_class_ops ds3232_rtc_ops = { 457 .read_time = ds3232_read_time, 458 .set_time = ds3232_set_time, 459 .read_alarm = ds3232_read_alarm, 460 .set_alarm = ds3232_set_alarm, 461 .alarm_irq_enable = ds3232_alarm_irq_enable, 462 }; 463 464 static int ds3232_probe(struct device *dev, struct regmap *regmap, int irq, 465 const char *name) 466 { 467 struct ds3232 *ds3232; 468 int ret; 469 470 ds3232 = devm_kzalloc(dev, sizeof(*ds3232), GFP_KERNEL); 471 if (!ds3232) 472 return -ENOMEM; 473 474 ds3232->regmap = regmap; 475 ds3232->irq = irq; 476 ds3232->dev = dev; 477 dev_set_drvdata(dev, ds3232); 478 479 ret = ds3232_check_rtc_status(dev); 480 if (ret) 481 return ret; 482 483 if (ds3232->irq > 0) 484 device_init_wakeup(dev, 1); 485 486 ds3232_hwmon_register(dev, name); 487 488 ds3232->rtc = devm_rtc_device_register(dev, name, &ds3232_rtc_ops, 489 THIS_MODULE); 490 if (IS_ERR(ds3232->rtc)) 491 return PTR_ERR(ds3232->rtc); 492 493 if (ds3232->irq > 0) { 494 ret = devm_request_threaded_irq(dev, ds3232->irq, NULL, 495 ds3232_irq, 496 IRQF_SHARED | IRQF_ONESHOT, 497 name, dev); 498 if (ret) { 499 device_set_wakeup_capable(dev, 0); 500 ds3232->irq = 0; 501 dev_err(dev, "unable to request IRQ\n"); 502 } 503 } 504 505 return 0; 506 } 507 508 #ifdef CONFIG_PM_SLEEP 509 static int ds3232_suspend(struct device *dev) 510 { 511 struct ds3232 *ds3232 = dev_get_drvdata(dev); 512 513 if (device_may_wakeup(dev)) { 514 if (enable_irq_wake(ds3232->irq)) 515 dev_warn_once(dev, "Cannot set wakeup source\n"); 516 } 517 518 return 0; 519 } 520 521 static int ds3232_resume(struct device *dev) 522 { 523 struct ds3232 *ds3232 = dev_get_drvdata(dev); 524 525 if (device_may_wakeup(dev)) 526 disable_irq_wake(ds3232->irq); 527 528 return 0; 529 } 530 #endif 531 532 static const struct dev_pm_ops ds3232_pm_ops = { 533 SET_SYSTEM_SLEEP_PM_OPS(ds3232_suspend, ds3232_resume) 534 }; 535 536 #if IS_ENABLED(CONFIG_I2C) 537 538 static int ds3232_i2c_probe(struct i2c_client *client, 539 const struct i2c_device_id *id) 540 { 541 struct regmap *regmap; 542 static const struct regmap_config config = { 543 .reg_bits = 8, 544 .val_bits = 8, 545 .max_register = 0x13, 546 }; 547 548 regmap = devm_regmap_init_i2c(client, &config); 549 if (IS_ERR(regmap)) { 550 dev_err(&client->dev, "%s: regmap allocation failed: %ld\n", 551 __func__, PTR_ERR(regmap)); 552 return PTR_ERR(regmap); 553 } 554 555 return ds3232_probe(&client->dev, regmap, client->irq, client->name); 556 } 557 558 static const struct i2c_device_id ds3232_id[] = { 559 { "ds3232", 0 }, 560 { } 561 }; 562 MODULE_DEVICE_TABLE(i2c, ds3232_id); 563 564 static const struct of_device_id ds3232_of_match[] = { 565 { .compatible = "dallas,ds3232" }, 566 { } 567 }; 568 MODULE_DEVICE_TABLE(of, ds3232_of_match); 569 570 static struct i2c_driver ds3232_driver = { 571 .driver = { 572 .name = "rtc-ds3232", 573 .of_match_table = of_match_ptr(ds3232_of_match), 574 .pm = &ds3232_pm_ops, 575 }, 576 .probe = ds3232_i2c_probe, 577 .id_table = ds3232_id, 578 }; 579 580 static int ds3232_register_driver(void) 581 { 582 return i2c_add_driver(&ds3232_driver); 583 } 584 585 static void ds3232_unregister_driver(void) 586 { 587 i2c_del_driver(&ds3232_driver); 588 } 589 590 #else 591 592 static int ds3232_register_driver(void) 593 { 594 return 0; 595 } 596 597 static void ds3232_unregister_driver(void) 598 { 599 } 600 601 #endif 602 603 #if IS_ENABLED(CONFIG_SPI_MASTER) 604 605 static int ds3234_probe(struct spi_device *spi) 606 { 607 int res; 608 unsigned int tmp; 609 static const struct regmap_config config = { 610 .reg_bits = 8, 611 .val_bits = 8, 612 .max_register = 0x13, 613 .write_flag_mask = 0x80, 614 }; 615 struct regmap *regmap; 616 617 regmap = devm_regmap_init_spi(spi, &config); 618 if (IS_ERR(regmap)) { 619 dev_err(&spi->dev, "%s: regmap allocation failed: %ld\n", 620 __func__, PTR_ERR(regmap)); 621 return PTR_ERR(regmap); 622 } 623 624 spi->mode = SPI_MODE_3; 625 spi->bits_per_word = 8; 626 spi_setup(spi); 627 628 res = regmap_read(regmap, DS3232_REG_SECONDS, &tmp); 629 if (res) 630 return res; 631 632 /* Control settings 633 * 634 * CONTROL_REG 635 * BIT 7 6 5 4 3 2 1 0 636 * EOSC BBSQW CONV RS2 RS1 INTCN A2IE A1IE 637 * 638 * 0 0 0 1 1 1 0 0 639 * 640 * CONTROL_STAT_REG 641 * BIT 7 6 5 4 3 2 1 0 642 * OSF BB32kHz CRATE1 CRATE0 EN32kHz BSY A2F A1F 643 * 644 * 1 0 0 0 1 0 0 0 645 */ 646 res = regmap_read(regmap, DS3232_REG_CR, &tmp); 647 if (res) 648 return res; 649 res = regmap_write(regmap, DS3232_REG_CR, tmp & 0x1c); 650 if (res) 651 return res; 652 653 res = regmap_read(regmap, DS3232_REG_SR, &tmp); 654 if (res) 655 return res; 656 res = regmap_write(regmap, DS3232_REG_SR, tmp & 0x88); 657 if (res) 658 return res; 659 660 /* Print our settings */ 661 res = regmap_read(regmap, DS3232_REG_CR, &tmp); 662 if (res) 663 return res; 664 dev_info(&spi->dev, "Control Reg: 0x%02x\n", tmp); 665 666 res = regmap_read(regmap, DS3232_REG_SR, &tmp); 667 if (res) 668 return res; 669 dev_info(&spi->dev, "Ctrl/Stat Reg: 0x%02x\n", tmp); 670 671 return ds3232_probe(&spi->dev, regmap, spi->irq, "ds3234"); 672 } 673 674 static struct spi_driver ds3234_driver = { 675 .driver = { 676 .name = "ds3234", 677 }, 678 .probe = ds3234_probe, 679 }; 680 681 static int ds3234_register_driver(void) 682 { 683 return spi_register_driver(&ds3234_driver); 684 } 685 686 static void ds3234_unregister_driver(void) 687 { 688 spi_unregister_driver(&ds3234_driver); 689 } 690 691 #else 692 693 static int ds3234_register_driver(void) 694 { 695 return 0; 696 } 697 698 static void ds3234_unregister_driver(void) 699 { 700 } 701 702 #endif 703 704 static int __init ds323x_init(void) 705 { 706 int ret; 707 708 ret = ds3232_register_driver(); 709 if (ret) { 710 pr_err("Failed to register ds3232 driver: %d\n", ret); 711 return ret; 712 } 713 714 ret = ds3234_register_driver(); 715 if (ret) { 716 pr_err("Failed to register ds3234 driver: %d\n", ret); 717 ds3232_unregister_driver(); 718 } 719 720 return ret; 721 } 722 module_init(ds323x_init) 723 724 static void __exit ds323x_exit(void) 725 { 726 ds3234_unregister_driver(); 727 ds3232_unregister_driver(); 728 } 729 module_exit(ds323x_exit) 730 731 MODULE_AUTHOR("Srikanth Srinivasan <srikanth.srinivasan@freescale.com>"); 732 MODULE_AUTHOR("Dennis Aberilla <denzzzhome@yahoo.com>"); 733 MODULE_DESCRIPTION("Maxim/Dallas DS3232/DS3234 RTC Driver"); 734 MODULE_LICENSE("GPL"); 735 MODULE_ALIAS("spi:ds3234"); 736