1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Seiko Instruments S-35390A RTC Driver 4 * 5 * Copyright (c) 2007 Byron Bradley 6 */ 7 8 #include <linux/module.h> 9 #include <linux/rtc.h> 10 #include <linux/i2c.h> 11 #include <linux/bitrev.h> 12 #include <linux/bcd.h> 13 #include <linux/slab.h> 14 #include <linux/delay.h> 15 16 #define S35390A_CMD_STATUS1 0 17 #define S35390A_CMD_STATUS2 1 18 #define S35390A_CMD_TIME1 2 19 #define S35390A_CMD_TIME2 3 20 #define S35390A_CMD_INT2_REG1 5 21 22 #define S35390A_BYTE_YEAR 0 23 #define S35390A_BYTE_MONTH 1 24 #define S35390A_BYTE_DAY 2 25 #define S35390A_BYTE_WDAY 3 26 #define S35390A_BYTE_HOURS 4 27 #define S35390A_BYTE_MINS 5 28 #define S35390A_BYTE_SECS 6 29 30 #define S35390A_ALRM_BYTE_WDAY 0 31 #define S35390A_ALRM_BYTE_HOURS 1 32 #define S35390A_ALRM_BYTE_MINS 2 33 34 /* flags for STATUS1 */ 35 #define S35390A_FLAG_POC 0x01 36 #define S35390A_FLAG_BLD 0x02 37 #define S35390A_FLAG_INT2 0x04 38 #define S35390A_FLAG_24H 0x40 39 #define S35390A_FLAG_RESET 0x80 40 41 /* flag for STATUS2 */ 42 #define S35390A_FLAG_TEST 0x01 43 44 #define S35390A_INT2_MODE_MASK 0xF0 45 46 #define S35390A_INT2_MODE_NOINTR 0x00 47 #define S35390A_INT2_MODE_FREQ 0x10 48 #define S35390A_INT2_MODE_ALARM 0x40 49 #define S35390A_INT2_MODE_PMIN_EDG 0x20 50 51 static const struct i2c_device_id s35390a_id[] = { 52 { "s35390a", 0 }, 53 { } 54 }; 55 MODULE_DEVICE_TABLE(i2c, s35390a_id); 56 57 static const struct of_device_id s35390a_of_match[] = { 58 { .compatible = "s35390a" }, 59 { .compatible = "sii,s35390a" }, 60 { } 61 }; 62 MODULE_DEVICE_TABLE(of, s35390a_of_match); 63 64 struct s35390a { 65 struct i2c_client *client[8]; 66 struct rtc_device *rtc; 67 int twentyfourhour; 68 }; 69 70 static int s35390a_set_reg(struct s35390a *s35390a, int reg, char *buf, int len) 71 { 72 struct i2c_client *client = s35390a->client[reg]; 73 struct i2c_msg msg[] = { 74 { 75 .addr = client->addr, 76 .len = len, 77 .buf = buf 78 }, 79 }; 80 81 if ((i2c_transfer(client->adapter, msg, 1)) != 1) 82 return -EIO; 83 84 return 0; 85 } 86 87 static int s35390a_get_reg(struct s35390a *s35390a, int reg, char *buf, int len) 88 { 89 struct i2c_client *client = s35390a->client[reg]; 90 struct i2c_msg msg[] = { 91 { 92 .addr = client->addr, 93 .flags = I2C_M_RD, 94 .len = len, 95 .buf = buf 96 }, 97 }; 98 99 if ((i2c_transfer(client->adapter, msg, 1)) != 1) 100 return -EIO; 101 102 return 0; 103 } 104 105 static int s35390a_init(struct s35390a *s35390a) 106 { 107 u8 buf; 108 int ret; 109 unsigned initcount = 0; 110 111 /* 112 * At least one of POC and BLD are set, so reinitialise chip. Keeping 113 * this information in the hardware to know later that the time isn't 114 * valid is unfortunately not possible because POC and BLD are cleared 115 * on read. So the reset is best done now. 116 * 117 * The 24H bit is kept over reset, so set it already here. 118 */ 119 initialize: 120 buf = S35390A_FLAG_RESET | S35390A_FLAG_24H; 121 ret = s35390a_set_reg(s35390a, S35390A_CMD_STATUS1, &buf, 1); 122 123 if (ret < 0) 124 return ret; 125 126 ret = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, &buf, 1); 127 if (ret < 0) 128 return ret; 129 130 if (buf & (S35390A_FLAG_POC | S35390A_FLAG_BLD)) { 131 /* Try up to five times to reset the chip */ 132 if (initcount < 5) { 133 ++initcount; 134 goto initialize; 135 } else 136 return -EIO; 137 } 138 139 return 1; 140 } 141 142 /* 143 * Returns <0 on error, 0 if rtc is setup fine and 1 if the chip was reset. 144 * To keep the information if an irq is pending, pass the value read from 145 * STATUS1 to the caller. 146 */ 147 static int s35390a_read_status(struct s35390a *s35390a, char *status1) 148 { 149 int ret; 150 151 ret = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, status1, 1); 152 if (ret < 0) 153 return ret; 154 155 if (*status1 & S35390A_FLAG_POC) { 156 /* 157 * Do not communicate for 0.5 seconds since the power-on 158 * detection circuit is in operation. 159 */ 160 msleep(500); 161 return 1; 162 } else if (*status1 & S35390A_FLAG_BLD) 163 return 1; 164 /* 165 * If both POC and BLD are unset everything is fine. 166 */ 167 return 0; 168 } 169 170 static int s35390a_disable_test_mode(struct s35390a *s35390a) 171 { 172 char buf[1]; 173 174 if (s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf)) < 0) 175 return -EIO; 176 177 if (!(buf[0] & S35390A_FLAG_TEST)) 178 return 0; 179 180 buf[0] &= ~S35390A_FLAG_TEST; 181 return s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf)); 182 } 183 184 static char s35390a_hr2reg(struct s35390a *s35390a, int hour) 185 { 186 if (s35390a->twentyfourhour) 187 return bin2bcd(hour); 188 189 if (hour < 12) 190 return bin2bcd(hour); 191 192 return 0x40 | bin2bcd(hour - 12); 193 } 194 195 static int s35390a_reg2hr(struct s35390a *s35390a, char reg) 196 { 197 unsigned hour; 198 199 if (s35390a->twentyfourhour) 200 return bcd2bin(reg & 0x3f); 201 202 hour = bcd2bin(reg & 0x3f); 203 if (reg & 0x40) 204 hour += 12; 205 206 return hour; 207 } 208 209 static int s35390a_rtc_set_time(struct device *dev, struct rtc_time *tm) 210 { 211 struct i2c_client *client = to_i2c_client(dev); 212 struct s35390a *s35390a = i2c_get_clientdata(client); 213 int i, err; 214 char buf[7], status; 215 216 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d mday=%d, " 217 "mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec, 218 tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year, 219 tm->tm_wday); 220 221 if (s35390a_read_status(s35390a, &status) == 1) 222 s35390a_init(s35390a); 223 224 buf[S35390A_BYTE_YEAR] = bin2bcd(tm->tm_year - 100); 225 buf[S35390A_BYTE_MONTH] = bin2bcd(tm->tm_mon + 1); 226 buf[S35390A_BYTE_DAY] = bin2bcd(tm->tm_mday); 227 buf[S35390A_BYTE_WDAY] = bin2bcd(tm->tm_wday); 228 buf[S35390A_BYTE_HOURS] = s35390a_hr2reg(s35390a, tm->tm_hour); 229 buf[S35390A_BYTE_MINS] = bin2bcd(tm->tm_min); 230 buf[S35390A_BYTE_SECS] = bin2bcd(tm->tm_sec); 231 232 /* This chip expects the bits of each byte to be in reverse order */ 233 for (i = 0; i < 7; ++i) 234 buf[i] = bitrev8(buf[i]); 235 236 err = s35390a_set_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf)); 237 238 return err; 239 } 240 241 static int s35390a_rtc_read_time(struct device *dev, struct rtc_time *tm) 242 { 243 struct i2c_client *client = to_i2c_client(dev); 244 struct s35390a *s35390a = i2c_get_clientdata(client); 245 char buf[7], status; 246 int i, err; 247 248 if (s35390a_read_status(s35390a, &status) == 1) 249 return -EINVAL; 250 251 err = s35390a_get_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf)); 252 if (err < 0) 253 return err; 254 255 /* This chip returns the bits of each byte in reverse order */ 256 for (i = 0; i < 7; ++i) 257 buf[i] = bitrev8(buf[i]); 258 259 tm->tm_sec = bcd2bin(buf[S35390A_BYTE_SECS]); 260 tm->tm_min = bcd2bin(buf[S35390A_BYTE_MINS]); 261 tm->tm_hour = s35390a_reg2hr(s35390a, buf[S35390A_BYTE_HOURS]); 262 tm->tm_wday = bcd2bin(buf[S35390A_BYTE_WDAY]); 263 tm->tm_mday = bcd2bin(buf[S35390A_BYTE_DAY]); 264 tm->tm_mon = bcd2bin(buf[S35390A_BYTE_MONTH]) - 1; 265 tm->tm_year = bcd2bin(buf[S35390A_BYTE_YEAR]) + 100; 266 267 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, mday=%d, " 268 "mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec, 269 tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year, 270 tm->tm_wday); 271 272 return 0; 273 } 274 275 static int s35390a_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm) 276 { 277 struct i2c_client *client = to_i2c_client(dev); 278 struct s35390a *s35390a = i2c_get_clientdata(client); 279 char buf[3], sts = 0; 280 int err, i; 281 282 dev_dbg(&client->dev, "%s: alm is secs=%d, mins=%d, hours=%d mday=%d, "\ 283 "mon=%d, year=%d, wday=%d\n", __func__, alm->time.tm_sec, 284 alm->time.tm_min, alm->time.tm_hour, alm->time.tm_mday, 285 alm->time.tm_mon, alm->time.tm_year, alm->time.tm_wday); 286 287 /* disable interrupt (which deasserts the irq line) */ 288 err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts)); 289 if (err < 0) 290 return err; 291 292 /* clear pending interrupt (in STATUS1 only), if any */ 293 err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, &sts, sizeof(sts)); 294 if (err < 0) 295 return err; 296 297 if (alm->enabled) 298 sts = S35390A_INT2_MODE_ALARM; 299 else 300 sts = S35390A_INT2_MODE_NOINTR; 301 302 /* This chip expects the bits of each byte to be in reverse order */ 303 sts = bitrev8(sts); 304 305 /* set interupt mode*/ 306 err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts)); 307 if (err < 0) 308 return err; 309 310 if (alm->time.tm_wday != -1) 311 buf[S35390A_ALRM_BYTE_WDAY] = bin2bcd(alm->time.tm_wday) | 0x80; 312 else 313 buf[S35390A_ALRM_BYTE_WDAY] = 0; 314 315 buf[S35390A_ALRM_BYTE_HOURS] = s35390a_hr2reg(s35390a, 316 alm->time.tm_hour) | 0x80; 317 buf[S35390A_ALRM_BYTE_MINS] = bin2bcd(alm->time.tm_min) | 0x80; 318 319 if (alm->time.tm_hour >= 12) 320 buf[S35390A_ALRM_BYTE_HOURS] |= 0x40; 321 322 for (i = 0; i < 3; ++i) 323 buf[i] = bitrev8(buf[i]); 324 325 err = s35390a_set_reg(s35390a, S35390A_CMD_INT2_REG1, buf, 326 sizeof(buf)); 327 328 return err; 329 } 330 331 static int s35390a_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm) 332 { 333 struct i2c_client *client = to_i2c_client(dev); 334 struct s35390a *s35390a = i2c_get_clientdata(client); 335 char buf[3], sts; 336 int i, err; 337 338 err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts)); 339 if (err < 0) 340 return err; 341 342 if ((bitrev8(sts) & S35390A_INT2_MODE_MASK) != S35390A_INT2_MODE_ALARM) { 343 /* 344 * When the alarm isn't enabled, the register to configure 345 * the alarm time isn't accessible. 346 */ 347 alm->enabled = 0; 348 return 0; 349 } else { 350 alm->enabled = 1; 351 } 352 353 err = s35390a_get_reg(s35390a, S35390A_CMD_INT2_REG1, buf, sizeof(buf)); 354 if (err < 0) 355 return err; 356 357 /* This chip returns the bits of each byte in reverse order */ 358 for (i = 0; i < 3; ++i) 359 buf[i] = bitrev8(buf[i]); 360 361 /* 362 * B0 of the three matching registers is an enable flag. Iff it is set 363 * the configured value is used for matching. 364 */ 365 if (buf[S35390A_ALRM_BYTE_WDAY] & 0x80) 366 alm->time.tm_wday = 367 bcd2bin(buf[S35390A_ALRM_BYTE_WDAY] & ~0x80); 368 369 if (buf[S35390A_ALRM_BYTE_HOURS] & 0x80) 370 alm->time.tm_hour = 371 s35390a_reg2hr(s35390a, 372 buf[S35390A_ALRM_BYTE_HOURS] & ~0x80); 373 374 if (buf[S35390A_ALRM_BYTE_MINS] & 0x80) 375 alm->time.tm_min = bcd2bin(buf[S35390A_ALRM_BYTE_MINS] & ~0x80); 376 377 /* alarm triggers always at s=0 */ 378 alm->time.tm_sec = 0; 379 380 dev_dbg(&client->dev, "%s: alm is mins=%d, hours=%d, wday=%d\n", 381 __func__, alm->time.tm_min, alm->time.tm_hour, 382 alm->time.tm_wday); 383 384 return 0; 385 } 386 387 static int s35390a_rtc_ioctl(struct device *dev, unsigned int cmd, 388 unsigned long arg) 389 { 390 struct i2c_client *client = to_i2c_client(dev); 391 struct s35390a *s35390a = i2c_get_clientdata(client); 392 char sts; 393 int err; 394 395 switch (cmd) { 396 case RTC_VL_READ: 397 /* s35390a_reset set lowvoltage flag and init RTC if needed */ 398 err = s35390a_read_status(s35390a, &sts); 399 if (err < 0) 400 return err; 401 if (copy_to_user((void __user *)arg, &err, sizeof(int))) 402 return -EFAULT; 403 break; 404 case RTC_VL_CLR: 405 /* update flag and clear register */ 406 err = s35390a_init(s35390a); 407 if (err < 0) 408 return err; 409 break; 410 default: 411 return -ENOIOCTLCMD; 412 } 413 414 return 0; 415 } 416 417 static const struct rtc_class_ops s35390a_rtc_ops = { 418 .read_time = s35390a_rtc_read_time, 419 .set_time = s35390a_rtc_set_time, 420 .set_alarm = s35390a_rtc_set_alarm, 421 .read_alarm = s35390a_rtc_read_alarm, 422 .ioctl = s35390a_rtc_ioctl, 423 }; 424 425 static struct i2c_driver s35390a_driver; 426 427 static int s35390a_probe(struct i2c_client *client, 428 const struct i2c_device_id *id) 429 { 430 int err, err_read; 431 unsigned int i; 432 struct s35390a *s35390a; 433 char buf, status1; 434 435 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { 436 err = -ENODEV; 437 goto exit; 438 } 439 440 s35390a = devm_kzalloc(&client->dev, sizeof(struct s35390a), 441 GFP_KERNEL); 442 if (!s35390a) { 443 err = -ENOMEM; 444 goto exit; 445 } 446 447 s35390a->client[0] = client; 448 i2c_set_clientdata(client, s35390a); 449 450 /* This chip uses multiple addresses, use dummy devices for them */ 451 for (i = 1; i < 8; ++i) { 452 s35390a->client[i] = i2c_new_dummy(client->adapter, 453 client->addr + i); 454 if (!s35390a->client[i]) { 455 dev_err(&client->dev, "Address %02x unavailable\n", 456 client->addr + i); 457 err = -EBUSY; 458 goto exit_dummy; 459 } 460 } 461 462 err_read = s35390a_read_status(s35390a, &status1); 463 if (err_read < 0) { 464 err = err_read; 465 dev_err(&client->dev, "error resetting chip\n"); 466 goto exit_dummy; 467 } 468 469 if (status1 & S35390A_FLAG_24H) 470 s35390a->twentyfourhour = 1; 471 else 472 s35390a->twentyfourhour = 0; 473 474 if (status1 & S35390A_FLAG_INT2) { 475 /* disable alarm (and maybe test mode) */ 476 buf = 0; 477 err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &buf, 1); 478 if (err < 0) { 479 dev_err(&client->dev, "error disabling alarm"); 480 goto exit_dummy; 481 } 482 } else { 483 err = s35390a_disable_test_mode(s35390a); 484 if (err < 0) { 485 dev_err(&client->dev, "error disabling test mode\n"); 486 goto exit_dummy; 487 } 488 } 489 490 device_set_wakeup_capable(&client->dev, 1); 491 492 s35390a->rtc = devm_rtc_device_register(&client->dev, 493 s35390a_driver.driver.name, 494 &s35390a_rtc_ops, THIS_MODULE); 495 496 if (IS_ERR(s35390a->rtc)) { 497 err = PTR_ERR(s35390a->rtc); 498 goto exit_dummy; 499 } 500 501 if (status1 & S35390A_FLAG_INT2) 502 rtc_update_irq(s35390a->rtc, 1, RTC_AF); 503 504 return 0; 505 506 exit_dummy: 507 for (i = 1; i < 8; ++i) 508 if (s35390a->client[i]) 509 i2c_unregister_device(s35390a->client[i]); 510 511 exit: 512 return err; 513 } 514 515 static int s35390a_remove(struct i2c_client *client) 516 { 517 unsigned int i; 518 struct s35390a *s35390a = i2c_get_clientdata(client); 519 520 for (i = 1; i < 8; ++i) 521 if (s35390a->client[i]) 522 i2c_unregister_device(s35390a->client[i]); 523 524 return 0; 525 } 526 527 static struct i2c_driver s35390a_driver = { 528 .driver = { 529 .name = "rtc-s35390a", 530 .of_match_table = of_match_ptr(s35390a_of_match), 531 }, 532 .probe = s35390a_probe, 533 .remove = s35390a_remove, 534 .id_table = s35390a_id, 535 }; 536 537 module_i2c_driver(s35390a_driver); 538 539 MODULE_AUTHOR("Byron Bradley <byron.bbradley@gmail.com>"); 540 MODULE_DESCRIPTION("S35390A RTC driver"); 541 MODULE_LICENSE("GPL"); 542