1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * rtc-ds1305.c -- driver for DS1305 and DS1306 SPI RTC chips 4 * 5 * Copyright (C) 2008 David Brownell 6 */ 7#include <linux/kernel.h> 8#include <linux/init.h> 9#include <linux/bcd.h> 10#include <linux/slab.h> 11#include <linux/rtc.h> 12#include <linux/workqueue.h> 13 14#include <linux/spi/spi.h> 15#include <linux/spi/ds1305.h> 16#include <linux/module.h> 17 18 19/* 20 * Registers ... mask DS1305_WRITE into register address to write, 21 * otherwise you're reading it. All non-bitmask values are BCD. 22 */ 23#define DS1305_WRITE 0x80 24 25 26/* RTC date/time ... the main special cases are that we: 27 * - Need fancy "hours" encoding in 12hour mode 28 * - Don't rely on the "day-of-week" field (or tm_wday) 29 * - Are a 21st-century clock (2000 <= year < 2100) 30 */ 31#define DS1305_RTC_LEN 7 /* bytes for RTC regs */ 32 33#define DS1305_SEC 0x00 /* register addresses */ 34#define DS1305_MIN 0x01 35#define DS1305_HOUR 0x02 36# define DS1305_HR_12 0x40 /* set == 12 hr mode */ 37# define DS1305_HR_PM 0x20 /* set == PM (12hr mode) */ 38#define DS1305_WDAY 0x03 39#define DS1305_MDAY 0x04 40#define DS1305_MON 0x05 41#define DS1305_YEAR 0x06 42 43 44/* The two alarms have only sec/min/hour/wday fields (ALM_LEN). 45 * DS1305_ALM_DISABLE disables a match field (some combos are bad). 46 * 47 * NOTE that since we don't use WDAY, we limit ourselves to alarms 48 * only one day into the future (vs potentially up to a week). 49 * 50 * NOTE ALSO that while we could generate once-a-second IRQs (UIE), we 51 * don't currently support them. We'd either need to do it only when 52 * no alarm is pending (not the standard model), or to use the second 53 * alarm (implying that this is a DS1305 not DS1306, *and* that either 54 * it's wired up a second IRQ we know, or that INTCN is set) 55 */ 56#define DS1305_ALM_LEN 4 /* bytes for ALM regs */ 57#define DS1305_ALM_DISABLE 0x80 58 59#define DS1305_ALM0(r) (0x07 + (r)) /* register addresses */ 60#define DS1305_ALM1(r) (0x0b + (r)) 61 62 63/* three control registers */ 64#define DS1305_CONTROL_LEN 3 /* bytes of control regs */ 65 66#define DS1305_CONTROL 0x0f /* register addresses */ 67# define DS1305_nEOSC 0x80 /* low enables oscillator */ 68# define DS1305_WP 0x40 /* write protect */ 69# define DS1305_INTCN 0x04 /* clear == only int0 used */ 70# define DS1306_1HZ 0x04 /* enable 1Hz output */ 71# define DS1305_AEI1 0x02 /* enable ALM1 IRQ */ 72# define DS1305_AEI0 0x01 /* enable ALM0 IRQ */ 73#define DS1305_STATUS 0x10 74/* status has just AEIx bits, mirrored as IRQFx */ 75#define DS1305_TRICKLE 0x11 76/* trickle bits are defined in <linux/spi/ds1305.h> */ 77 78/* a bunch of NVRAM */ 79#define DS1305_NVRAM_LEN 96 /* bytes of NVRAM */ 80 81#define DS1305_NVRAM 0x20 /* register addresses */ 82 83 84struct ds1305 { 85 struct spi_device *spi; 86 struct rtc_device *rtc; 87 88 struct work_struct work; 89 90 unsigned long flags; 91#define FLAG_EXITING 0 92 93 bool hr12; 94 u8 ctrl[DS1305_CONTROL_LEN]; 95}; 96 97 98/*----------------------------------------------------------------------*/ 99 100/* 101 * Utilities ... tolerate 12-hour AM/PM notation in case of non-Linux 102 * software (like a bootloader) which may require it. 103 */ 104 105static unsigned bcd2hour(u8 bcd) 106{ 107 if (bcd & DS1305_HR_12) { 108 unsigned hour = 0; 109 110 bcd &= ~DS1305_HR_12; 111 if (bcd & DS1305_HR_PM) { 112 hour = 12; 113 bcd &= ~DS1305_HR_PM; 114 } 115 hour += bcd2bin(bcd); 116 return hour - 1; 117 } 118 return bcd2bin(bcd); 119} 120 121static u8 hour2bcd(bool hr12, int hour) 122{ 123 if (hr12) { 124 hour++; 125 if (hour <= 12) 126 return DS1305_HR_12 | bin2bcd(hour); 127 hour -= 12; 128 return DS1305_HR_12 | DS1305_HR_PM | bin2bcd(hour); 129 } 130 return bin2bcd(hour); 131} 132 133/*----------------------------------------------------------------------*/ 134 135/* 136 * Interface to RTC framework 137 */ 138 139static int ds1305_alarm_irq_enable(struct device *dev, unsigned int enabled) 140{ 141 struct ds1305 *ds1305 = dev_get_drvdata(dev); 142 u8 buf[2]; 143 long err = -EINVAL; 144 145 buf[0] = DS1305_WRITE | DS1305_CONTROL; 146 buf[1] = ds1305->ctrl[0]; 147 148 if (enabled) { 149 if (ds1305->ctrl[0] & DS1305_AEI0) 150 goto done; 151 buf[1] |= DS1305_AEI0; 152 } else { 153 if (!(buf[1] & DS1305_AEI0)) 154 goto done; 155 buf[1] &= ~DS1305_AEI0; 156 } 157 err = spi_write_then_read(ds1305->spi, buf, sizeof(buf), NULL, 0); 158 if (err >= 0) 159 ds1305->ctrl[0] = buf[1]; 160done: 161 return err; 162 163} 164 165 166/* 167 * Get/set of date and time is pretty normal. 168 */ 169 170static int ds1305_get_time(struct device *dev, struct rtc_time *time) 171{ 172 struct ds1305 *ds1305 = dev_get_drvdata(dev); 173 u8 addr = DS1305_SEC; 174 u8 buf[DS1305_RTC_LEN]; 175 int status; 176 177 /* Use write-then-read to get all the date/time registers 178 * since dma from stack is nonportable 179 */ 180 status = spi_write_then_read(ds1305->spi, &addr, sizeof(addr), 181 buf, sizeof(buf)); 182 if (status < 0) 183 return status; 184 185 dev_vdbg(dev, "%s: %3ph, %4ph\n", "read", &buf[0], &buf[3]); 186 187 /* Decode the registers */ 188 time->tm_sec = bcd2bin(buf[DS1305_SEC]); 189 time->tm_min = bcd2bin(buf[DS1305_MIN]); 190 time->tm_hour = bcd2hour(buf[DS1305_HOUR]); 191 time->tm_wday = buf[DS1305_WDAY] - 1; 192 time->tm_mday = bcd2bin(buf[DS1305_MDAY]); 193 time->tm_mon = bcd2bin(buf[DS1305_MON]) - 1; 194 time->tm_year = bcd2bin(buf[DS1305_YEAR]) + 100; 195 196 dev_vdbg(dev, "%s secs=%d, mins=%d, " 197 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n", 198 "read", time->tm_sec, time->tm_min, 199 time->tm_hour, time->tm_mday, 200 time->tm_mon, time->tm_year, time->tm_wday); 201 202 return 0; 203} 204 205static int ds1305_set_time(struct device *dev, struct rtc_time *time) 206{ 207 struct ds1305 *ds1305 = dev_get_drvdata(dev); 208 u8 buf[1 + DS1305_RTC_LEN]; 209 u8 *bp = buf; 210 211 dev_vdbg(dev, "%s secs=%d, mins=%d, " 212 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n", 213 "write", time->tm_sec, time->tm_min, 214 time->tm_hour, time->tm_mday, 215 time->tm_mon, time->tm_year, time->tm_wday); 216 217 /* Write registers starting at the first time/date address. */ 218 *bp++ = DS1305_WRITE | DS1305_SEC; 219 220 *bp++ = bin2bcd(time->tm_sec); 221 *bp++ = bin2bcd(time->tm_min); 222 *bp++ = hour2bcd(ds1305->hr12, time->tm_hour); 223 *bp++ = (time->tm_wday < 7) ? (time->tm_wday + 1) : 1; 224 *bp++ = bin2bcd(time->tm_mday); 225 *bp++ = bin2bcd(time->tm_mon + 1); 226 *bp++ = bin2bcd(time->tm_year - 100); 227 228 dev_dbg(dev, "%s: %3ph, %4ph\n", "write", &buf[1], &buf[4]); 229 230 /* use write-then-read since dma from stack is nonportable */ 231 return spi_write_then_read(ds1305->spi, buf, sizeof(buf), 232 NULL, 0); 233} 234 235/* 236 * Get/set of alarm is a bit funky: 237 * 238 * - First there's the inherent raciness of getting the (partitioned) 239 * status of an alarm that could trigger while we're reading parts 240 * of that status. 241 * 242 * - Second there's its limited range (we could increase it a bit by 243 * relying on WDAY), which means it will easily roll over. 244 * 245 * - Third there's the choice of two alarms and alarm signals. 246 * Here we use ALM0 and expect that nINT0 (open drain) is used; 247 * that's the only real option for DS1306 runtime alarms, and is 248 * natural on DS1305. 249 * 250 * - Fourth, there's also ALM1, and a second interrupt signal: 251 * + On DS1305 ALM1 uses nINT1 (when INTCN=1) else nINT0; 252 * + On DS1306 ALM1 only uses INT1 (an active high pulse) 253 * and it won't work when VCC1 is active. 254 * 255 * So to be most general, we should probably set both alarms to the 256 * same value, letting ALM1 be the wakeup event source on DS1306 257 * and handling several wiring options on DS1305. 258 * 259 * - Fifth, we support the polled mode (as well as possible; why not?) 260 * even when no interrupt line is wired to an IRQ. 261 */ 262 263/* 264 * Context: caller holds rtc->ops_lock (to protect ds1305->ctrl) 265 */ 266static int ds1305_get_alarm(struct device *dev, struct rtc_wkalrm *alm) 267{ 268 struct ds1305 *ds1305 = dev_get_drvdata(dev); 269 struct spi_device *spi = ds1305->spi; 270 u8 addr; 271 int status; 272 u8 buf[DS1305_ALM_LEN]; 273 274 /* Refresh control register cache BEFORE reading ALM0 registers, 275 * since reading alarm registers acks any pending IRQ. That 276 * makes returning "pending" status a bit of a lie, but that bit 277 * of EFI status is at best fragile anyway (given IRQ handlers). 278 */ 279 addr = DS1305_CONTROL; 280 status = spi_write_then_read(spi, &addr, sizeof(addr), 281 ds1305->ctrl, sizeof(ds1305->ctrl)); 282 if (status < 0) 283 return status; 284 285 alm->enabled = !!(ds1305->ctrl[0] & DS1305_AEI0); 286 alm->pending = !!(ds1305->ctrl[1] & DS1305_AEI0); 287 288 /* get and check ALM0 registers */ 289 addr = DS1305_ALM0(DS1305_SEC); 290 status = spi_write_then_read(spi, &addr, sizeof(addr), 291 buf, sizeof(buf)); 292 if (status < 0) 293 return status; 294 295 dev_vdbg(dev, "%s: %02x %02x %02x %02x\n", 296 "alm0 read", buf[DS1305_SEC], buf[DS1305_MIN], 297 buf[DS1305_HOUR], buf[DS1305_WDAY]); 298 299 if ((DS1305_ALM_DISABLE & buf[DS1305_SEC]) 300 || (DS1305_ALM_DISABLE & buf[DS1305_MIN]) 301 || (DS1305_ALM_DISABLE & buf[DS1305_HOUR])) 302 return -EIO; 303 304 /* Stuff these values into alm->time and let RTC framework code 305 * fill in the rest ... and also handle rollover to tomorrow when 306 * that's needed. 307 */ 308 alm->time.tm_sec = bcd2bin(buf[DS1305_SEC]); 309 alm->time.tm_min = bcd2bin(buf[DS1305_MIN]); 310 alm->time.tm_hour = bcd2hour(buf[DS1305_HOUR]); 311 312 return 0; 313} 314 315/* 316 * Context: caller holds rtc->ops_lock (to protect ds1305->ctrl) 317 */ 318static int ds1305_set_alarm(struct device *dev, struct rtc_wkalrm *alm) 319{ 320 struct ds1305 *ds1305 = dev_get_drvdata(dev); 321 struct spi_device *spi = ds1305->spi; 322 unsigned long now, later; 323 struct rtc_time tm; 324 int status; 325 u8 buf[1 + DS1305_ALM_LEN]; 326 327 /* convert desired alarm to time_t */ 328 later = rtc_tm_to_time64(&alm->time); 329 330 /* Read current time as time_t */ 331 status = ds1305_get_time(dev, &tm); 332 if (status < 0) 333 return status; 334 now = rtc_tm_to_time64(&tm); 335 336 /* make sure alarm fires within the next 24 hours */ 337 if (later <= now) 338 return -EINVAL; 339 if ((later - now) > ds1305->rtc->alarm_offset_max) 340 return -ERANGE; 341 342 /* disable alarm if needed */ 343 if (ds1305->ctrl[0] & DS1305_AEI0) { 344 ds1305->ctrl[0] &= ~DS1305_AEI0; 345 346 buf[0] = DS1305_WRITE | DS1305_CONTROL; 347 buf[1] = ds1305->ctrl[0]; 348 status = spi_write_then_read(ds1305->spi, buf, 2, NULL, 0); 349 if (status < 0) 350 return status; 351 } 352 353 /* write alarm */ 354 buf[0] = DS1305_WRITE | DS1305_ALM0(DS1305_SEC); 355 buf[1 + DS1305_SEC] = bin2bcd(alm->time.tm_sec); 356 buf[1 + DS1305_MIN] = bin2bcd(alm->time.tm_min); 357 buf[1 + DS1305_HOUR] = hour2bcd(ds1305->hr12, alm->time.tm_hour); 358 buf[1 + DS1305_WDAY] = DS1305_ALM_DISABLE; 359 360 dev_dbg(dev, "%s: %02x %02x %02x %02x\n", 361 "alm0 write", buf[1 + DS1305_SEC], buf[1 + DS1305_MIN], 362 buf[1 + DS1305_HOUR], buf[1 + DS1305_WDAY]); 363 364 status = spi_write_then_read(spi, buf, sizeof(buf), NULL, 0); 365 if (status < 0) 366 return status; 367 368 /* enable alarm if requested */ 369 if (alm->enabled) { 370 ds1305->ctrl[0] |= DS1305_AEI0; 371 372 buf[0] = DS1305_WRITE | DS1305_CONTROL; 373 buf[1] = ds1305->ctrl[0]; 374 status = spi_write_then_read(ds1305->spi, buf, 2, NULL, 0); 375 } 376 377 return status; 378} 379 380#ifdef CONFIG_PROC_FS 381 382static int ds1305_proc(struct device *dev, struct seq_file *seq) 383{ 384 struct ds1305 *ds1305 = dev_get_drvdata(dev); 385 char *diodes = "no"; 386 char *resistors = ""; 387 388 /* ctrl[2] is treated as read-only; no locking needed */ 389 if ((ds1305->ctrl[2] & 0xf0) == DS1305_TRICKLE_MAGIC) { 390 switch (ds1305->ctrl[2] & 0x0c) { 391 case DS1305_TRICKLE_DS2: 392 diodes = "2 diodes, "; 393 break; 394 case DS1305_TRICKLE_DS1: 395 diodes = "1 diode, "; 396 break; 397 default: 398 goto done; 399 } 400 switch (ds1305->ctrl[2] & 0x03) { 401 case DS1305_TRICKLE_2K: 402 resistors = "2k Ohm"; 403 break; 404 case DS1305_TRICKLE_4K: 405 resistors = "4k Ohm"; 406 break; 407 case DS1305_TRICKLE_8K: 408 resistors = "8k Ohm"; 409 break; 410 default: 411 diodes = "no"; 412 break; 413 } 414 } 415 416done: 417 seq_printf(seq, "trickle_charge\t: %s%s\n", diodes, resistors); 418 419 return 0; 420} 421 422#else 423#define ds1305_proc NULL 424#endif 425 426static const struct rtc_class_ops ds1305_ops = { 427 .read_time = ds1305_get_time, 428 .set_time = ds1305_set_time, 429 .read_alarm = ds1305_get_alarm, 430 .set_alarm = ds1305_set_alarm, 431 .proc = ds1305_proc, 432 .alarm_irq_enable = ds1305_alarm_irq_enable, 433}; 434 435static void ds1305_work(struct work_struct *work) 436{ 437 struct ds1305 *ds1305 = container_of(work, struct ds1305, work); 438 struct spi_device *spi = ds1305->spi; 439 u8 buf[3]; 440 int status; 441 442 /* lock to protect ds1305->ctrl */ 443 rtc_lock(ds1305->rtc); 444 445 /* Disable the IRQ, and clear its status ... for now, we "know" 446 * that if more than one alarm is active, they're in sync. 447 * Note that reading ALM data registers also clears IRQ status. 448 */ 449 ds1305->ctrl[0] &= ~(DS1305_AEI1 | DS1305_AEI0); 450 ds1305->ctrl[1] = 0; 451 452 buf[0] = DS1305_WRITE | DS1305_CONTROL; 453 buf[1] = ds1305->ctrl[0]; 454 buf[2] = 0; 455 456 status = spi_write_then_read(spi, buf, sizeof(buf), 457 NULL, 0); 458 if (status < 0) 459 dev_dbg(&spi->dev, "clear irq --> %d\n", status); 460 461 rtc_unlock(ds1305->rtc); 462 463 if (!test_bit(FLAG_EXITING, &ds1305->flags)) 464 enable_irq(spi->irq); 465 466 rtc_update_irq(ds1305->rtc, 1, RTC_AF | RTC_IRQF); 467} 468 469/* 470 * This "real" IRQ handler hands off to a workqueue mostly to allow 471 * mutex locking for ds1305->ctrl ... unlike I2C, we could issue async 472 * I/O requests in IRQ context (to clear the IRQ status). 473 */ 474static irqreturn_t ds1305_irq(int irq, void *p) 475{ 476 struct ds1305 *ds1305 = p; 477 478 disable_irq(irq); 479 schedule_work(&ds1305->work); 480 return IRQ_HANDLED; 481} 482 483/*----------------------------------------------------------------------*/ 484 485/* 486 * Interface for NVRAM 487 */ 488 489static void msg_init(struct spi_message *m, struct spi_transfer *x, 490 u8 *addr, size_t count, char *tx, char *rx) 491{ 492 spi_message_init(m); 493 memset(x, 0, 2 * sizeof(*x)); 494 495 x->tx_buf = addr; 496 x->len = 1; 497 spi_message_add_tail(x, m); 498 499 x++; 500 501 x->tx_buf = tx; 502 x->rx_buf = rx; 503 x->len = count; 504 spi_message_add_tail(x, m); 505} 506 507static int ds1305_nvram_read(void *priv, unsigned int off, void *buf, 508 size_t count) 509{ 510 struct ds1305 *ds1305 = priv; 511 struct spi_device *spi = ds1305->spi; 512 u8 addr; 513 struct spi_message m; 514 struct spi_transfer x[2]; 515 516 addr = DS1305_NVRAM + off; 517 msg_init(&m, x, &addr, count, NULL, buf); 518 519 return spi_sync(spi, &m); 520} 521 522static int ds1305_nvram_write(void *priv, unsigned int off, void *buf, 523 size_t count) 524{ 525 struct ds1305 *ds1305 = priv; 526 struct spi_device *spi = ds1305->spi; 527 u8 addr; 528 struct spi_message m; 529 struct spi_transfer x[2]; 530 531 addr = (DS1305_WRITE | DS1305_NVRAM) + off; 532 msg_init(&m, x, &addr, count, buf, NULL); 533 534 return spi_sync(spi, &m); 535} 536 537/*----------------------------------------------------------------------*/ 538 539/* 540 * Interface to SPI stack 541 */ 542 543static int ds1305_probe(struct spi_device *spi) 544{ 545 struct ds1305 *ds1305; 546 int status; 547 u8 addr, value; 548 struct ds1305_platform_data *pdata = dev_get_platdata(&spi->dev); 549 bool write_ctrl = false; 550 struct nvmem_config ds1305_nvmem_cfg = { 551 .name = "ds1305_nvram", 552 .word_size = 1, 553 .stride = 1, 554 .size = DS1305_NVRAM_LEN, 555 .reg_read = ds1305_nvram_read, 556 .reg_write = ds1305_nvram_write, 557 }; 558 559 /* Sanity check board setup data. This may be hooked up 560 * in 3wire mode, but we don't care. Note that unless 561 * there's an inverter in place, this needs SPI_CS_HIGH! 562 */ 563 if ((spi->bits_per_word && spi->bits_per_word != 8) 564 || (spi->max_speed_hz > 2000000) 565 || !(spi->mode & SPI_CPHA)) 566 return -EINVAL; 567 568 /* set up driver data */ 569 ds1305 = devm_kzalloc(&spi->dev, sizeof(*ds1305), GFP_KERNEL); 570 if (!ds1305) 571 return -ENOMEM; 572 ds1305->spi = spi; 573 spi_set_drvdata(spi, ds1305); 574 575 /* read and cache control registers */ 576 addr = DS1305_CONTROL; 577 status = spi_write_then_read(spi, &addr, sizeof(addr), 578 ds1305->ctrl, sizeof(ds1305->ctrl)); 579 if (status < 0) { 580 dev_dbg(&spi->dev, "can't %s, %d\n", 581 "read", status); 582 return status; 583 } 584 585 dev_dbg(&spi->dev, "ctrl %s: %3ph\n", "read", ds1305->ctrl); 586 587 /* Sanity check register values ... partially compensating for the 588 * fact that SPI has no device handshake. A pullup on MISO would 589 * make these tests fail; but not all systems will have one. If 590 * some register is neither 0x00 nor 0xff, a chip is likely there. 591 */ 592 if ((ds1305->ctrl[0] & 0x38) != 0 || (ds1305->ctrl[1] & 0xfc) != 0) { 593 dev_dbg(&spi->dev, "RTC chip is not present\n"); 594 return -ENODEV; 595 } 596 if (ds1305->ctrl[2] == 0) 597 dev_dbg(&spi->dev, "chip may not be present\n"); 598 599 /* enable writes if needed ... if we were paranoid it would 600 * make sense to enable them only when absolutely necessary. 601 */ 602 if (ds1305->ctrl[0] & DS1305_WP) { 603 u8 buf[2]; 604 605 ds1305->ctrl[0] &= ~DS1305_WP; 606 607 buf[0] = DS1305_WRITE | DS1305_CONTROL; 608 buf[1] = ds1305->ctrl[0]; 609 status = spi_write_then_read(spi, buf, sizeof(buf), NULL, 0); 610 611 dev_dbg(&spi->dev, "clear WP --> %d\n", status); 612 if (status < 0) 613 return status; 614 } 615 616 /* on DS1305, maybe start oscillator; like most low power 617 * oscillators, it may take a second to stabilize 618 */ 619 if (ds1305->ctrl[0] & DS1305_nEOSC) { 620 ds1305->ctrl[0] &= ~DS1305_nEOSC; 621 write_ctrl = true; 622 dev_warn(&spi->dev, "SET TIME!\n"); 623 } 624 625 /* ack any pending IRQs */ 626 if (ds1305->ctrl[1]) { 627 ds1305->ctrl[1] = 0; 628 write_ctrl = true; 629 } 630 631 /* this may need one-time (re)init */ 632 if (pdata) { 633 /* maybe enable trickle charge */ 634 if (((ds1305->ctrl[2] & 0xf0) != DS1305_TRICKLE_MAGIC)) { 635 ds1305->ctrl[2] = DS1305_TRICKLE_MAGIC 636 | pdata->trickle; 637 write_ctrl = true; 638 } 639 640 /* on DS1306, configure 1 Hz signal */ 641 if (pdata->is_ds1306) { 642 if (pdata->en_1hz) { 643 if (!(ds1305->ctrl[0] & DS1306_1HZ)) { 644 ds1305->ctrl[0] |= DS1306_1HZ; 645 write_ctrl = true; 646 } 647 } else { 648 if (ds1305->ctrl[0] & DS1306_1HZ) { 649 ds1305->ctrl[0] &= ~DS1306_1HZ; 650 write_ctrl = true; 651 } 652 } 653 } 654 } 655 656 if (write_ctrl) { 657 u8 buf[4]; 658 659 buf[0] = DS1305_WRITE | DS1305_CONTROL; 660 buf[1] = ds1305->ctrl[0]; 661 buf[2] = ds1305->ctrl[1]; 662 buf[3] = ds1305->ctrl[2]; 663 status = spi_write_then_read(spi, buf, sizeof(buf), NULL, 0); 664 if (status < 0) { 665 dev_dbg(&spi->dev, "can't %s, %d\n", 666 "write", status); 667 return status; 668 } 669 670 dev_dbg(&spi->dev, "ctrl %s: %3ph\n", "write", ds1305->ctrl); 671 } 672 673 /* see if non-Linux software set up AM/PM mode */ 674 addr = DS1305_HOUR; 675 status = spi_write_then_read(spi, &addr, sizeof(addr), 676 &value, sizeof(value)); 677 if (status < 0) { 678 dev_dbg(&spi->dev, "read HOUR --> %d\n", status); 679 return status; 680 } 681 682 ds1305->hr12 = (DS1305_HR_12 & value) != 0; 683 if (ds1305->hr12) 684 dev_dbg(&spi->dev, "AM/PM\n"); 685 686 /* register RTC ... from here on, ds1305->ctrl needs locking */ 687 ds1305->rtc = devm_rtc_allocate_device(&spi->dev); 688 if (IS_ERR(ds1305->rtc)) 689 return PTR_ERR(ds1305->rtc); 690 691 ds1305->rtc->ops = &ds1305_ops; 692 ds1305->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000; 693 ds1305->rtc->range_max = RTC_TIMESTAMP_END_2099; 694 ds1305->rtc->alarm_offset_max = 24 * 60 * 60; 695 696 ds1305_nvmem_cfg.priv = ds1305; 697 status = devm_rtc_register_device(ds1305->rtc); 698 if (status) 699 return status; 700 701 devm_rtc_nvmem_register(ds1305->rtc, &ds1305_nvmem_cfg); 702 703 /* Maybe set up alarm IRQ; be ready to handle it triggering right 704 * away. NOTE that we don't share this. The signal is active low, 705 * and we can't ack it before a SPI message delay. We temporarily 706 * disable the IRQ until it's acked, which lets us work with more 707 * IRQ trigger modes (not all IRQ controllers can do falling edge). 708 */ 709 if (spi->irq) { 710 INIT_WORK(&ds1305->work, ds1305_work); 711 status = devm_request_irq(&spi->dev, spi->irq, ds1305_irq, 712 0, dev_name(&ds1305->rtc->dev), ds1305); 713 if (status < 0) { 714 dev_err(&spi->dev, "request_irq %d --> %d\n", 715 spi->irq, status); 716 } else { 717 device_set_wakeup_capable(&spi->dev, 1); 718 } 719 } 720 721 return 0; 722} 723 724static void ds1305_remove(struct spi_device *spi) 725{ 726 struct ds1305 *ds1305 = spi_get_drvdata(spi); 727 728 /* carefully shut down irq and workqueue, if present */ 729 if (spi->irq) { 730 set_bit(FLAG_EXITING, &ds1305->flags); 731 devm_free_irq(&spi->dev, spi->irq, ds1305); 732 cancel_work_sync(&ds1305->work); 733 } 734} 735 736static struct spi_driver ds1305_driver = { 737 .driver.name = "rtc-ds1305", 738 .probe = ds1305_probe, 739 .remove = ds1305_remove, 740 /* REVISIT add suspend/resume */ 741}; 742 743module_spi_driver(ds1305_driver); 744 745MODULE_DESCRIPTION("RTC driver for DS1305 and DS1306 chips"); 746MODULE_LICENSE("GPL"); 747MODULE_ALIAS("spi:rtc-ds1305"); 748