1 /* 2 * Seiko Instruments S-35390A RTC Driver 3 * 4 * Copyright (c) 2007 Byron Bradley 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License 8 * as published by the Free Software Foundation; either version 9 * 2 of the License, or (at your option) any later version. 10 */ 11 12 #include <linux/module.h> 13 #include <linux/rtc.h> 14 #include <linux/i2c.h> 15 #include <linux/bitrev.h> 16 #include <linux/bcd.h> 17 #include <linux/slab.h> 18 #include <linux/delay.h> 19 20 #define S35390A_CMD_STATUS1 0 21 #define S35390A_CMD_STATUS2 1 22 #define S35390A_CMD_TIME1 2 23 #define S35390A_CMD_TIME2 3 24 #define S35390A_CMD_INT2_REG1 5 25 26 #define S35390A_BYTE_YEAR 0 27 #define S35390A_BYTE_MONTH 1 28 #define S35390A_BYTE_DAY 2 29 #define S35390A_BYTE_WDAY 3 30 #define S35390A_BYTE_HOURS 4 31 #define S35390A_BYTE_MINS 5 32 #define S35390A_BYTE_SECS 6 33 34 #define S35390A_ALRM_BYTE_WDAY 0 35 #define S35390A_ALRM_BYTE_HOURS 1 36 #define S35390A_ALRM_BYTE_MINS 2 37 38 /* flags for STATUS1 */ 39 #define S35390A_FLAG_POC 0x01 40 #define S35390A_FLAG_BLD 0x02 41 #define S35390A_FLAG_INT2 0x04 42 #define S35390A_FLAG_24H 0x40 43 #define S35390A_FLAG_RESET 0x80 44 45 /* flag for STATUS2 */ 46 #define S35390A_FLAG_TEST 0x01 47 48 #define S35390A_INT2_MODE_MASK 0xF0 49 50 #define S35390A_INT2_MODE_NOINTR 0x00 51 #define S35390A_INT2_MODE_FREQ 0x10 52 #define S35390A_INT2_MODE_ALARM 0x40 53 #define S35390A_INT2_MODE_PMIN_EDG 0x20 54 55 static const struct i2c_device_id s35390a_id[] = { 56 { "s35390a", 0 }, 57 { } 58 }; 59 MODULE_DEVICE_TABLE(i2c, s35390a_id); 60 61 static const struct of_device_id s35390a_of_match[] = { 62 { .compatible = "s35390a" }, 63 { .compatible = "sii,s35390a" }, 64 { } 65 }; 66 MODULE_DEVICE_TABLE(of, s35390a_of_match); 67 68 struct s35390a { 69 struct i2c_client *client[8]; 70 struct rtc_device *rtc; 71 int twentyfourhour; 72 }; 73 74 static int s35390a_set_reg(struct s35390a *s35390a, int reg, char *buf, int len) 75 { 76 struct i2c_client *client = s35390a->client[reg]; 77 struct i2c_msg msg[] = { 78 { 79 .addr = client->addr, 80 .len = len, 81 .buf = buf 82 }, 83 }; 84 85 if ((i2c_transfer(client->adapter, msg, 1)) != 1) 86 return -EIO; 87 88 return 0; 89 } 90 91 static int s35390a_get_reg(struct s35390a *s35390a, int reg, char *buf, int len) 92 { 93 struct i2c_client *client = s35390a->client[reg]; 94 struct i2c_msg msg[] = { 95 { 96 .addr = client->addr, 97 .flags = I2C_M_RD, 98 .len = len, 99 .buf = buf 100 }, 101 }; 102 103 if ((i2c_transfer(client->adapter, msg, 1)) != 1) 104 return -EIO; 105 106 return 0; 107 } 108 109 /* 110 * Returns <0 on error, 0 if rtc is setup fine and 1 if the chip was reset. 111 * To keep the information if an irq is pending, pass the value read from 112 * STATUS1 to the caller. 113 */ 114 static int s35390a_reset(struct s35390a *s35390a, char *status1) 115 { 116 char buf; 117 int ret; 118 unsigned initcount = 0; 119 120 ret = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, status1, 1); 121 if (ret < 0) 122 return ret; 123 124 if (*status1 & S35390A_FLAG_POC) 125 /* 126 * Do not communicate for 0.5 seconds since the power-on 127 * detection circuit is in operation. 128 */ 129 msleep(500); 130 else if (!(*status1 & S35390A_FLAG_BLD)) 131 /* 132 * If both POC and BLD are unset everything is fine. 133 */ 134 return 0; 135 136 /* 137 * At least one of POC and BLD are set, so reinitialise chip. Keeping 138 * this information in the hardware to know later that the time isn't 139 * valid is unfortunately not possible because POC and BLD are cleared 140 * on read. So the reset is best done now. 141 * 142 * The 24H bit is kept over reset, so set it already here. 143 */ 144 initialize: 145 *status1 = S35390A_FLAG_24H; 146 buf = S35390A_FLAG_RESET | S35390A_FLAG_24H; 147 ret = s35390a_set_reg(s35390a, S35390A_CMD_STATUS1, &buf, 1); 148 149 if (ret < 0) 150 return ret; 151 152 ret = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, &buf, 1); 153 if (ret < 0) 154 return ret; 155 156 if (buf & (S35390A_FLAG_POC | S35390A_FLAG_BLD)) { 157 /* Try up to five times to reset the chip */ 158 if (initcount < 5) { 159 ++initcount; 160 goto initialize; 161 } else 162 return -EIO; 163 } 164 165 return 1; 166 } 167 168 static int s35390a_disable_test_mode(struct s35390a *s35390a) 169 { 170 char buf[1]; 171 172 if (s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf)) < 0) 173 return -EIO; 174 175 if (!(buf[0] & S35390A_FLAG_TEST)) 176 return 0; 177 178 buf[0] &= ~S35390A_FLAG_TEST; 179 return s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf)); 180 } 181 182 static char s35390a_hr2reg(struct s35390a *s35390a, int hour) 183 { 184 if (s35390a->twentyfourhour) 185 return bin2bcd(hour); 186 187 if (hour < 12) 188 return bin2bcd(hour); 189 190 return 0x40 | bin2bcd(hour - 12); 191 } 192 193 static int s35390a_reg2hr(struct s35390a *s35390a, char reg) 194 { 195 unsigned hour; 196 197 if (s35390a->twentyfourhour) 198 return bcd2bin(reg & 0x3f); 199 200 hour = bcd2bin(reg & 0x3f); 201 if (reg & 0x40) 202 hour += 12; 203 204 return hour; 205 } 206 207 static int s35390a_set_datetime(struct i2c_client *client, struct rtc_time *tm) 208 { 209 struct s35390a *s35390a = i2c_get_clientdata(client); 210 int i, err; 211 char buf[7]; 212 213 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d mday=%d, " 214 "mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec, 215 tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year, 216 tm->tm_wday); 217 218 buf[S35390A_BYTE_YEAR] = bin2bcd(tm->tm_year - 100); 219 buf[S35390A_BYTE_MONTH] = bin2bcd(tm->tm_mon + 1); 220 buf[S35390A_BYTE_DAY] = bin2bcd(tm->tm_mday); 221 buf[S35390A_BYTE_WDAY] = bin2bcd(tm->tm_wday); 222 buf[S35390A_BYTE_HOURS] = s35390a_hr2reg(s35390a, tm->tm_hour); 223 buf[S35390A_BYTE_MINS] = bin2bcd(tm->tm_min); 224 buf[S35390A_BYTE_SECS] = bin2bcd(tm->tm_sec); 225 226 /* This chip expects the bits of each byte to be in reverse order */ 227 for (i = 0; i < 7; ++i) 228 buf[i] = bitrev8(buf[i]); 229 230 err = s35390a_set_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf)); 231 232 return err; 233 } 234 235 static int s35390a_get_datetime(struct i2c_client *client, struct rtc_time *tm) 236 { 237 struct s35390a *s35390a = i2c_get_clientdata(client); 238 char buf[7]; 239 int i, err; 240 241 err = s35390a_get_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf)); 242 if (err < 0) 243 return err; 244 245 /* This chip returns the bits of each byte in reverse order */ 246 for (i = 0; i < 7; ++i) 247 buf[i] = bitrev8(buf[i]); 248 249 tm->tm_sec = bcd2bin(buf[S35390A_BYTE_SECS]); 250 tm->tm_min = bcd2bin(buf[S35390A_BYTE_MINS]); 251 tm->tm_hour = s35390a_reg2hr(s35390a, buf[S35390A_BYTE_HOURS]); 252 tm->tm_wday = bcd2bin(buf[S35390A_BYTE_WDAY]); 253 tm->tm_mday = bcd2bin(buf[S35390A_BYTE_DAY]); 254 tm->tm_mon = bcd2bin(buf[S35390A_BYTE_MONTH]) - 1; 255 tm->tm_year = bcd2bin(buf[S35390A_BYTE_YEAR]) + 100; 256 257 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, mday=%d, " 258 "mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec, 259 tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year, 260 tm->tm_wday); 261 262 return rtc_valid_tm(tm); 263 } 264 265 static int s35390a_set_alarm(struct i2c_client *client, struct rtc_wkalrm *alm) 266 { 267 struct s35390a *s35390a = i2c_get_clientdata(client); 268 char buf[3], sts = 0; 269 int err, i; 270 271 dev_dbg(&client->dev, "%s: alm is secs=%d, mins=%d, hours=%d mday=%d, "\ 272 "mon=%d, year=%d, wday=%d\n", __func__, alm->time.tm_sec, 273 alm->time.tm_min, alm->time.tm_hour, alm->time.tm_mday, 274 alm->time.tm_mon, alm->time.tm_year, alm->time.tm_wday); 275 276 /* disable interrupt (which deasserts the irq line) */ 277 err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts)); 278 if (err < 0) 279 return err; 280 281 /* clear pending interrupt (in STATUS1 only), if any */ 282 err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, &sts, sizeof(sts)); 283 if (err < 0) 284 return err; 285 286 if (alm->enabled) 287 sts = S35390A_INT2_MODE_ALARM; 288 else 289 sts = S35390A_INT2_MODE_NOINTR; 290 291 /* This chip expects the bits of each byte to be in reverse order */ 292 sts = bitrev8(sts); 293 294 /* set interupt mode*/ 295 err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts)); 296 if (err < 0) 297 return err; 298 299 if (alm->time.tm_wday != -1) 300 buf[S35390A_ALRM_BYTE_WDAY] = bin2bcd(alm->time.tm_wday) | 0x80; 301 else 302 buf[S35390A_ALRM_BYTE_WDAY] = 0; 303 304 buf[S35390A_ALRM_BYTE_HOURS] = s35390a_hr2reg(s35390a, 305 alm->time.tm_hour) | 0x80; 306 buf[S35390A_ALRM_BYTE_MINS] = bin2bcd(alm->time.tm_min) | 0x80; 307 308 if (alm->time.tm_hour >= 12) 309 buf[S35390A_ALRM_BYTE_HOURS] |= 0x40; 310 311 for (i = 0; i < 3; ++i) 312 buf[i] = bitrev8(buf[i]); 313 314 err = s35390a_set_reg(s35390a, S35390A_CMD_INT2_REG1, buf, 315 sizeof(buf)); 316 317 return err; 318 } 319 320 static int s35390a_read_alarm(struct i2c_client *client, struct rtc_wkalrm *alm) 321 { 322 struct s35390a *s35390a = i2c_get_clientdata(client); 323 char buf[3], sts; 324 int i, err; 325 326 err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts)); 327 if (err < 0) 328 return err; 329 330 if ((bitrev8(sts) & S35390A_INT2_MODE_MASK) != S35390A_INT2_MODE_ALARM) { 331 /* 332 * When the alarm isn't enabled, the register to configure 333 * the alarm time isn't accessible. 334 */ 335 alm->enabled = 0; 336 return 0; 337 } else { 338 alm->enabled = 1; 339 } 340 341 err = s35390a_get_reg(s35390a, S35390A_CMD_INT2_REG1, buf, sizeof(buf)); 342 if (err < 0) 343 return err; 344 345 /* This chip returns the bits of each byte in reverse order */ 346 for (i = 0; i < 3; ++i) 347 buf[i] = bitrev8(buf[i]); 348 349 /* 350 * B0 of the three matching registers is an enable flag. Iff it is set 351 * the configured value is used for matching. 352 */ 353 if (buf[S35390A_ALRM_BYTE_WDAY] & 0x80) 354 alm->time.tm_wday = 355 bcd2bin(buf[S35390A_ALRM_BYTE_WDAY] & ~0x80); 356 357 if (buf[S35390A_ALRM_BYTE_HOURS] & 0x80) 358 alm->time.tm_hour = 359 s35390a_reg2hr(s35390a, 360 buf[S35390A_ALRM_BYTE_HOURS] & ~0x80); 361 362 if (buf[S35390A_ALRM_BYTE_MINS] & 0x80) 363 alm->time.tm_min = bcd2bin(buf[S35390A_ALRM_BYTE_MINS] & ~0x80); 364 365 /* alarm triggers always at s=0 */ 366 alm->time.tm_sec = 0; 367 368 dev_dbg(&client->dev, "%s: alm is mins=%d, hours=%d, wday=%d\n", 369 __func__, alm->time.tm_min, alm->time.tm_hour, 370 alm->time.tm_wday); 371 372 return 0; 373 } 374 375 static int s35390a_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm) 376 { 377 return s35390a_read_alarm(to_i2c_client(dev), alm); 378 } 379 380 static int s35390a_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm) 381 { 382 return s35390a_set_alarm(to_i2c_client(dev), alm); 383 } 384 385 static int s35390a_rtc_read_time(struct device *dev, struct rtc_time *tm) 386 { 387 return s35390a_get_datetime(to_i2c_client(dev), tm); 388 } 389 390 static int s35390a_rtc_set_time(struct device *dev, struct rtc_time *tm) 391 { 392 return s35390a_set_datetime(to_i2c_client(dev), tm); 393 } 394 395 static const struct rtc_class_ops s35390a_rtc_ops = { 396 .read_time = s35390a_rtc_read_time, 397 .set_time = s35390a_rtc_set_time, 398 .set_alarm = s35390a_rtc_set_alarm, 399 .read_alarm = s35390a_rtc_read_alarm, 400 401 }; 402 403 static struct i2c_driver s35390a_driver; 404 405 static int s35390a_probe(struct i2c_client *client, 406 const struct i2c_device_id *id) 407 { 408 int err, err_reset; 409 unsigned int i; 410 struct s35390a *s35390a; 411 struct rtc_time tm; 412 char buf, status1; 413 414 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { 415 err = -ENODEV; 416 goto exit; 417 } 418 419 s35390a = devm_kzalloc(&client->dev, sizeof(struct s35390a), 420 GFP_KERNEL); 421 if (!s35390a) { 422 err = -ENOMEM; 423 goto exit; 424 } 425 426 s35390a->client[0] = client; 427 i2c_set_clientdata(client, s35390a); 428 429 /* This chip uses multiple addresses, use dummy devices for them */ 430 for (i = 1; i < 8; ++i) { 431 s35390a->client[i] = i2c_new_dummy(client->adapter, 432 client->addr + i); 433 if (!s35390a->client[i]) { 434 dev_err(&client->dev, "Address %02x unavailable\n", 435 client->addr + i); 436 err = -EBUSY; 437 goto exit_dummy; 438 } 439 } 440 441 err_reset = s35390a_reset(s35390a, &status1); 442 if (err_reset < 0) { 443 err = err_reset; 444 dev_err(&client->dev, "error resetting chip\n"); 445 goto exit_dummy; 446 } 447 448 if (status1 & S35390A_FLAG_24H) 449 s35390a->twentyfourhour = 1; 450 else 451 s35390a->twentyfourhour = 0; 452 453 if (status1 & S35390A_FLAG_INT2) { 454 /* disable alarm (and maybe test mode) */ 455 buf = 0; 456 err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &buf, 1); 457 if (err < 0) { 458 dev_err(&client->dev, "error disabling alarm"); 459 goto exit_dummy; 460 } 461 } else { 462 err = s35390a_disable_test_mode(s35390a); 463 if (err < 0) { 464 dev_err(&client->dev, "error disabling test mode\n"); 465 goto exit_dummy; 466 } 467 } 468 469 if (err_reset > 0 || s35390a_get_datetime(client, &tm) < 0) 470 dev_warn(&client->dev, "clock needs to be set\n"); 471 472 device_set_wakeup_capable(&client->dev, 1); 473 474 s35390a->rtc = devm_rtc_device_register(&client->dev, 475 s35390a_driver.driver.name, 476 &s35390a_rtc_ops, THIS_MODULE); 477 478 if (IS_ERR(s35390a->rtc)) { 479 err = PTR_ERR(s35390a->rtc); 480 goto exit_dummy; 481 } 482 483 if (status1 & S35390A_FLAG_INT2) 484 rtc_update_irq(s35390a->rtc, 1, RTC_AF); 485 486 return 0; 487 488 exit_dummy: 489 for (i = 1; i < 8; ++i) 490 if (s35390a->client[i]) 491 i2c_unregister_device(s35390a->client[i]); 492 493 exit: 494 return err; 495 } 496 497 static int s35390a_remove(struct i2c_client *client) 498 { 499 unsigned int i; 500 struct s35390a *s35390a = i2c_get_clientdata(client); 501 502 for (i = 1; i < 8; ++i) 503 if (s35390a->client[i]) 504 i2c_unregister_device(s35390a->client[i]); 505 506 return 0; 507 } 508 509 static struct i2c_driver s35390a_driver = { 510 .driver = { 511 .name = "rtc-s35390a", 512 .of_match_table = of_match_ptr(s35390a_of_match), 513 }, 514 .probe = s35390a_probe, 515 .remove = s35390a_remove, 516 .id_table = s35390a_id, 517 }; 518 519 module_i2c_driver(s35390a_driver); 520 521 MODULE_AUTHOR("Byron Bradley <byron.bbradley@gmail.com>"); 522 MODULE_DESCRIPTION("S35390A RTC driver"); 523 MODULE_LICENSE("GPL"); 524