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/i2c.h> 17 #include <linux/interrupt.h> 18 #include <linux/kernel.h> 19 #include <linux/module.h> 20 #include <linux/rtc.h> 21 22 #define RV8803_SEC 0x00 23 #define RV8803_MIN 0x01 24 #define RV8803_HOUR 0x02 25 #define RV8803_WEEK 0x03 26 #define RV8803_DAY 0x04 27 #define RV8803_MONTH 0x05 28 #define RV8803_YEAR 0x06 29 #define RV8803_RAM 0x07 30 #define RV8803_ALARM_MIN 0x08 31 #define RV8803_ALARM_HOUR 0x09 32 #define RV8803_ALARM_WEEK_OR_DAY 0x0A 33 #define RV8803_EXT 0x0D 34 #define RV8803_FLAG 0x0E 35 #define RV8803_CTRL 0x0F 36 37 #define RV8803_EXT_WADA BIT(6) 38 39 #define RV8803_FLAG_V1F BIT(0) 40 #define RV8803_FLAG_V2F BIT(1) 41 #define RV8803_FLAG_AF BIT(3) 42 #define RV8803_FLAG_TF BIT(4) 43 #define RV8803_FLAG_UF BIT(5) 44 45 #define RV8803_CTRL_RESET BIT(0) 46 47 #define RV8803_CTRL_EIE BIT(2) 48 #define RV8803_CTRL_AIE BIT(3) 49 #define RV8803_CTRL_TIE BIT(4) 50 #define RV8803_CTRL_UIE BIT(5) 51 52 struct rv8803_data { 53 struct i2c_client *client; 54 struct rtc_device *rtc; 55 struct mutex flags_lock; 56 u8 ctrl; 57 }; 58 59 static irqreturn_t rv8803_handle_irq(int irq, void *dev_id) 60 { 61 struct i2c_client *client = dev_id; 62 struct rv8803_data *rv8803 = i2c_get_clientdata(client); 63 unsigned long events = 0; 64 int flags, try = 0; 65 66 mutex_lock(&rv8803->flags_lock); 67 68 do { 69 flags = i2c_smbus_read_byte_data(client, RV8803_FLAG); 70 try++; 71 } while ((flags == -ENXIO) && (try < 3)); 72 if (flags <= 0) { 73 mutex_unlock(&rv8803->flags_lock); 74 return IRQ_NONE; 75 } 76 77 if (flags & RV8803_FLAG_V1F) 78 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n"); 79 80 if (flags & RV8803_FLAG_V2F) 81 dev_warn(&client->dev, "Voltage low, data loss detected.\n"); 82 83 if (flags & RV8803_FLAG_TF) { 84 flags &= ~RV8803_FLAG_TF; 85 rv8803->ctrl &= ~RV8803_CTRL_TIE; 86 events |= RTC_PF; 87 } 88 89 if (flags & RV8803_FLAG_AF) { 90 flags &= ~RV8803_FLAG_AF; 91 rv8803->ctrl &= ~RV8803_CTRL_AIE; 92 events |= RTC_AF; 93 } 94 95 if (flags & RV8803_FLAG_UF) { 96 flags &= ~RV8803_FLAG_UF; 97 rv8803->ctrl &= ~RV8803_CTRL_UIE; 98 events |= RTC_UF; 99 } 100 101 if (events) { 102 rtc_update_irq(rv8803->rtc, 1, events); 103 i2c_smbus_write_byte_data(client, RV8803_FLAG, flags); 104 i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL, 105 rv8803->ctrl); 106 } 107 108 mutex_unlock(&rv8803->flags_lock); 109 110 return IRQ_HANDLED; 111 } 112 113 static int rv8803_get_time(struct device *dev, struct rtc_time *tm) 114 { 115 struct rv8803_data *rv8803 = dev_get_drvdata(dev); 116 u8 date1[7]; 117 u8 date2[7]; 118 u8 *date = date1; 119 int ret, flags; 120 121 flags = i2c_smbus_read_byte_data(rv8803->client, RV8803_FLAG); 122 if (flags < 0) 123 return flags; 124 125 if (flags & RV8803_FLAG_V2F) { 126 dev_warn(dev, "Voltage low, data is invalid.\n"); 127 return -EINVAL; 128 } 129 130 ret = i2c_smbus_read_i2c_block_data(rv8803->client, RV8803_SEC, 131 7, date); 132 if (ret != 7) 133 return ret < 0 ? ret : -EIO; 134 135 if ((date1[RV8803_SEC] & 0x7f) == bin2bcd(59)) { 136 ret = i2c_smbus_read_i2c_block_data(rv8803->client, RV8803_SEC, 137 7, date2); 138 if (ret != 7) 139 return ret < 0 ? ret : -EIO; 140 141 if ((date2[RV8803_SEC] & 0x7f) != bin2bcd(59)) 142 date = date2; 143 } 144 145 tm->tm_sec = bcd2bin(date[RV8803_SEC] & 0x7f); 146 tm->tm_min = bcd2bin(date[RV8803_MIN] & 0x7f); 147 tm->tm_hour = bcd2bin(date[RV8803_HOUR] & 0x3f); 148 tm->tm_wday = ffs(date[RV8803_WEEK] & 0x7f); 149 tm->tm_mday = bcd2bin(date[RV8803_DAY] & 0x3f); 150 tm->tm_mon = bcd2bin(date[RV8803_MONTH] & 0x1f) - 1; 151 tm->tm_year = bcd2bin(date[RV8803_YEAR]) + 100; 152 153 return rtc_valid_tm(tm); 154 } 155 156 static int rv8803_set_time(struct device *dev, struct rtc_time *tm) 157 { 158 struct rv8803_data *rv8803 = dev_get_drvdata(dev); 159 u8 date[7]; 160 int flags, ret; 161 162 if ((tm->tm_year < 100) || (tm->tm_year > 199)) 163 return -EINVAL; 164 165 date[RV8803_SEC] = bin2bcd(tm->tm_sec); 166 date[RV8803_MIN] = bin2bcd(tm->tm_min); 167 date[RV8803_HOUR] = bin2bcd(tm->tm_hour); 168 date[RV8803_WEEK] = 1 << (tm->tm_wday); 169 date[RV8803_DAY] = bin2bcd(tm->tm_mday); 170 date[RV8803_MONTH] = bin2bcd(tm->tm_mon + 1); 171 date[RV8803_YEAR] = bin2bcd(tm->tm_year - 100); 172 173 ret = i2c_smbus_write_i2c_block_data(rv8803->client, RV8803_SEC, 174 7, date); 175 if (ret < 0) 176 return ret; 177 178 mutex_lock(&rv8803->flags_lock); 179 180 flags = i2c_smbus_read_byte_data(rv8803->client, RV8803_FLAG); 181 if (flags < 0) { 182 mutex_unlock(&rv8803->flags_lock); 183 return flags; 184 } 185 186 ret = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG, 187 flags & ~RV8803_FLAG_V2F); 188 189 mutex_unlock(&rv8803->flags_lock); 190 191 return ret; 192 } 193 194 static int rv8803_get_alarm(struct device *dev, struct rtc_wkalrm *alrm) 195 { 196 struct rv8803_data *rv8803 = dev_get_drvdata(dev); 197 struct i2c_client *client = rv8803->client; 198 u8 alarmvals[3]; 199 int flags, ret; 200 201 ret = i2c_smbus_read_i2c_block_data(client, RV8803_ALARM_MIN, 202 3, alarmvals); 203 if (ret != 3) 204 return ret < 0 ? ret : -EIO; 205 206 flags = i2c_smbus_read_byte_data(client, RV8803_FLAG); 207 if (flags < 0) 208 return flags; 209 210 alrm->time.tm_sec = 0; 211 alrm->time.tm_min = bcd2bin(alarmvals[0] & 0x7f); 212 alrm->time.tm_hour = bcd2bin(alarmvals[1] & 0x3f); 213 alrm->time.tm_wday = -1; 214 alrm->time.tm_mday = bcd2bin(alarmvals[2] & 0x3f); 215 alrm->time.tm_mon = -1; 216 alrm->time.tm_year = -1; 217 218 alrm->enabled = !!(rv8803->ctrl & RV8803_CTRL_AIE); 219 alrm->pending = (flags & RV8803_FLAG_AF) && alrm->enabled; 220 221 return 0; 222 } 223 224 static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 225 { 226 struct i2c_client *client = to_i2c_client(dev); 227 struct rv8803_data *rv8803 = dev_get_drvdata(dev); 228 u8 alarmvals[3]; 229 u8 ctrl[2]; 230 int ret, err; 231 232 /* The alarm has no seconds, round up to nearest minute */ 233 if (alrm->time.tm_sec) { 234 time64_t alarm_time = rtc_tm_to_time64(&alrm->time); 235 236 alarm_time += 60 - alrm->time.tm_sec; 237 rtc_time64_to_tm(alarm_time, &alrm->time); 238 } 239 240 mutex_lock(&rv8803->flags_lock); 241 242 ret = i2c_smbus_read_i2c_block_data(client, RV8803_FLAG, 2, ctrl); 243 if (ret != 2) { 244 mutex_unlock(&rv8803->flags_lock); 245 return ret < 0 ? ret : -EIO; 246 } 247 248 alarmvals[0] = bin2bcd(alrm->time.tm_min); 249 alarmvals[1] = bin2bcd(alrm->time.tm_hour); 250 alarmvals[2] = bin2bcd(alrm->time.tm_mday); 251 252 if (rv8803->ctrl & (RV8803_CTRL_AIE | RV8803_CTRL_UIE)) { 253 rv8803->ctrl &= ~(RV8803_CTRL_AIE | RV8803_CTRL_UIE); 254 err = i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL, 255 rv8803->ctrl); 256 if (err) { 257 mutex_unlock(&rv8803->flags_lock); 258 return err; 259 } 260 } 261 262 ctrl[1] &= ~RV8803_FLAG_AF; 263 err = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG, ctrl[1]); 264 mutex_unlock(&rv8803->flags_lock); 265 if (err) 266 return err; 267 268 err = i2c_smbus_write_i2c_block_data(rv8803->client, RV8803_ALARM_MIN, 269 3, alarmvals); 270 if (err) 271 return err; 272 273 if (alrm->enabled) { 274 if (rv8803->rtc->uie_rtctimer.enabled) 275 rv8803->ctrl |= RV8803_CTRL_UIE; 276 if (rv8803->rtc->aie_timer.enabled) 277 rv8803->ctrl |= RV8803_CTRL_AIE; 278 279 err = i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL, 280 rv8803->ctrl); 281 if (err) 282 return err; 283 } 284 285 return 0; 286 } 287 288 static int rv8803_alarm_irq_enable(struct device *dev, unsigned int enabled) 289 { 290 struct i2c_client *client = to_i2c_client(dev); 291 struct rv8803_data *rv8803 = dev_get_drvdata(dev); 292 int ctrl, flags, err; 293 294 ctrl = rv8803->ctrl; 295 296 if (enabled) { 297 if (rv8803->rtc->uie_rtctimer.enabled) 298 ctrl |= RV8803_CTRL_UIE; 299 if (rv8803->rtc->aie_timer.enabled) 300 ctrl |= RV8803_CTRL_AIE; 301 } else { 302 if (!rv8803->rtc->uie_rtctimer.enabled) 303 ctrl &= ~RV8803_CTRL_UIE; 304 if (!rv8803->rtc->aie_timer.enabled) 305 ctrl &= ~RV8803_CTRL_AIE; 306 } 307 308 mutex_lock(&rv8803->flags_lock); 309 flags = i2c_smbus_read_byte_data(client, RV8803_FLAG); 310 if (flags < 0) { 311 mutex_unlock(&rv8803->flags_lock); 312 return flags; 313 } 314 flags &= ~(RV8803_FLAG_AF | RV8803_FLAG_UF); 315 err = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags); 316 mutex_unlock(&rv8803->flags_lock); 317 if (err) 318 return err; 319 320 if (ctrl != rv8803->ctrl) { 321 rv8803->ctrl = ctrl; 322 err = i2c_smbus_write_byte_data(client, RV8803_CTRL, 323 rv8803->ctrl); 324 if (err) 325 return err; 326 } 327 328 return 0; 329 } 330 331 static int rv8803_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) 332 { 333 struct i2c_client *client = to_i2c_client(dev); 334 struct rv8803_data *rv8803 = dev_get_drvdata(dev); 335 int flags, ret = 0; 336 337 switch (cmd) { 338 case RTC_VL_READ: 339 flags = i2c_smbus_read_byte_data(client, RV8803_FLAG); 340 if (flags < 0) 341 return flags; 342 343 if (flags & RV8803_FLAG_V1F) 344 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n"); 345 346 if (flags & RV8803_FLAG_V2F) 347 dev_warn(&client->dev, "Voltage low, data loss detected.\n"); 348 349 flags &= RV8803_FLAG_V1F | RV8803_FLAG_V2F; 350 351 if (copy_to_user((void __user *)arg, &flags, sizeof(int))) 352 return -EFAULT; 353 354 return 0; 355 356 case RTC_VL_CLR: 357 mutex_lock(&rv8803->flags_lock); 358 flags = i2c_smbus_read_byte_data(client, RV8803_FLAG); 359 if (flags < 0) { 360 mutex_unlock(&rv8803->flags_lock); 361 return flags; 362 } 363 364 flags &= ~(RV8803_FLAG_V1F | RV8803_FLAG_V2F); 365 ret = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags); 366 mutex_unlock(&rv8803->flags_lock); 367 if (ret < 0) 368 return ret; 369 370 return 0; 371 372 default: 373 return -ENOIOCTLCMD; 374 } 375 } 376 377 static ssize_t rv8803_nvram_write(struct file *filp, struct kobject *kobj, 378 struct bin_attribute *attr, 379 char *buf, loff_t off, size_t count) 380 { 381 struct device *dev = kobj_to_dev(kobj); 382 struct i2c_client *client = to_i2c_client(dev); 383 int ret; 384 385 ret = i2c_smbus_write_byte_data(client, RV8803_RAM, buf[0]); 386 if (ret < 0) 387 return ret; 388 389 return 1; 390 } 391 392 static ssize_t rv8803_nvram_read(struct file *filp, struct kobject *kobj, 393 struct bin_attribute *attr, 394 char *buf, loff_t off, size_t count) 395 { 396 struct device *dev = kobj_to_dev(kobj); 397 struct i2c_client *client = to_i2c_client(dev); 398 int ret; 399 400 ret = i2c_smbus_read_byte_data(client, RV8803_RAM); 401 if (ret < 0) 402 return ret; 403 404 buf[0] = ret; 405 406 return 1; 407 } 408 409 static struct bin_attribute rv8803_nvram_attr = { 410 .attr = { 411 .name = "nvram", 412 .mode = S_IRUGO | S_IWUSR, 413 }, 414 .size = 1, 415 .read = rv8803_nvram_read, 416 .write = rv8803_nvram_write, 417 }; 418 419 static struct rtc_class_ops rv8803_rtc_ops = { 420 .read_time = rv8803_get_time, 421 .set_time = rv8803_set_time, 422 .ioctl = rv8803_ioctl, 423 }; 424 425 static int rv8803_probe(struct i2c_client *client, 426 const struct i2c_device_id *id) 427 { 428 struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent); 429 struct rv8803_data *rv8803; 430 int err, flags, try = 0; 431 432 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | 433 I2C_FUNC_SMBUS_I2C_BLOCK)) { 434 dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n"); 435 return -EIO; 436 } 437 438 rv8803 = devm_kzalloc(&client->dev, sizeof(struct rv8803_data), 439 GFP_KERNEL); 440 if (!rv8803) 441 return -ENOMEM; 442 443 mutex_init(&rv8803->flags_lock); 444 rv8803->client = client; 445 i2c_set_clientdata(client, rv8803); 446 447 /* 448 * There is a 60µs window where the RTC may not reply on the i2c bus in 449 * that case, the transfer is not ACKed. In that case, ensure there are 450 * multiple attempts. 451 */ 452 do { 453 flags = i2c_smbus_read_byte_data(client, RV8803_FLAG); 454 try++; 455 } while ((flags == -ENXIO) && (try < 3)); 456 457 if (flags < 0) 458 return flags; 459 460 if (flags & RV8803_FLAG_V1F) 461 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n"); 462 463 if (flags & RV8803_FLAG_V2F) 464 dev_warn(&client->dev, "Voltage low, data loss detected.\n"); 465 466 if (flags & RV8803_FLAG_AF) 467 dev_warn(&client->dev, "An alarm maybe have been missed.\n"); 468 469 if (client->irq > 0) { 470 err = devm_request_threaded_irq(&client->dev, client->irq, 471 NULL, rv8803_handle_irq, 472 IRQF_TRIGGER_LOW | IRQF_ONESHOT, 473 "rv8803", client); 474 if (err) { 475 dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n"); 476 client->irq = 0; 477 } else { 478 rv8803_rtc_ops.read_alarm = rv8803_get_alarm; 479 rv8803_rtc_ops.set_alarm = rv8803_set_alarm; 480 rv8803_rtc_ops.alarm_irq_enable = rv8803_alarm_irq_enable; 481 } 482 } 483 484 rv8803->rtc = devm_rtc_device_register(&client->dev, client->name, 485 &rv8803_rtc_ops, THIS_MODULE); 486 if (IS_ERR(rv8803->rtc)) { 487 dev_err(&client->dev, "unable to register the class device\n"); 488 return PTR_ERR(rv8803->rtc); 489 } 490 491 try = 0; 492 do { 493 err = i2c_smbus_write_byte_data(rv8803->client, RV8803_EXT, 494 RV8803_EXT_WADA); 495 try++; 496 } while ((err == -ENXIO) && (try < 3)); 497 if (err) 498 return err; 499 500 err = device_create_bin_file(&client->dev, &rv8803_nvram_attr); 501 if (err) 502 return err; 503 504 rv8803->rtc->max_user_freq = 1; 505 506 return 0; 507 } 508 509 static int rv8803_remove(struct i2c_client *client) 510 { 511 device_remove_bin_file(&client->dev, &rv8803_nvram_attr); 512 513 return 0; 514 } 515 516 static const struct i2c_device_id rv8803_id[] = { 517 { "rv8803", 0 }, 518 { "rx8900", 0 }, 519 { } 520 }; 521 MODULE_DEVICE_TABLE(i2c, rv8803_id); 522 523 static struct i2c_driver rv8803_driver = { 524 .driver = { 525 .name = "rtc-rv8803", 526 }, 527 .probe = rv8803_probe, 528 .remove = rv8803_remove, 529 .id_table = rv8803_id, 530 }; 531 module_i2c_driver(rv8803_driver); 532 533 MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>"); 534 MODULE_DESCRIPTION("Micro Crystal RV8803 RTC driver"); 535 MODULE_LICENSE("GPL v2"); 536