drivers/rtc/rtc-nct3018y.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (c) 2022 Nuvoton Technology Corporation
   3
   4 #include <linux/bcd.h>
   5 #include <linux/clk-provider.h>
   6 #include <linux/err.h>
   7 #include <linux/i2c.h>
   8 #include <linux/module.h>
   9 #include <linux/of.h>
  10 #include <linux/rtc.h>
  11 #include <linux/slab.h>
  12
  13 #define NCT3018Y_REG_SC         0x00 /* seconds */
  14 #define NCT3018Y_REG_SCA        0x01 /* alarm */
  15 #define NCT3018Y_REG_MN         0x02
  16 #define NCT3018Y_REG_MNA        0x03 /* alarm */
  17 #define NCT3018Y_REG_HR         0x04
  18 #define NCT3018Y_REG_HRA        0x05 /* alarm */
  19 #define NCT3018Y_REG_DW         0x06
  20 #define NCT3018Y_REG_DM         0x07
  21 #define NCT3018Y_REG_MO         0x08
  22 #define NCT3018Y_REG_YR         0x09
  23 #define NCT3018Y_REG_CTRL       0x0A /* timer control */
  24 #define NCT3018Y_REG_ST         0x0B /* status */
  25 #define NCT3018Y_REG_CLKO       0x0C /* clock out */
  26
  27 #define NCT3018Y_BIT_AF         BIT(7)
  28 #define NCT3018Y_BIT_ST         BIT(7)
  29 #define NCT3018Y_BIT_DM         BIT(6)
  30 #define NCT3018Y_BIT_HF         BIT(5)
  31 #define NCT3018Y_BIT_DSM        BIT(4)
  32 #define NCT3018Y_BIT_AIE        BIT(3)
  33 #define NCT3018Y_BIT_OFIE       BIT(2)
  34 #define NCT3018Y_BIT_CIE        BIT(1)
  35 #define NCT3018Y_BIT_TWO        BIT(0)
  36
  37 #define NCT3018Y_REG_BAT_MASK           0x07
  38 #define NCT3018Y_REG_CLKO_F_MASK        0x03 /* frequenc mask */
  39 #define NCT3018Y_REG_CLKO_CKE           0x80 /* clock out enabled */
  40
  41 struct nct3018y {
  42         struct rtc_device *rtc;
  43         struct i2c_client *client;
  44 #ifdef CONFIG_COMMON_CLK
  45         struct clk_hw clkout_hw;
  46 #endif
  47 };
  48
  49 static int nct3018y_set_alarm_mode(struct i2c_client *client, bool on)
  50 {
  51         int err, flags;
  52
  53         dev_dbg(&client->dev, "%s:on:%d\n", __func__, on);
  54
  55         flags =  i2c_smbus_read_byte_data(client, NCT3018Y_REG_CTRL);
  56         if (flags < 0) {
  57                 dev_dbg(&client->dev,
  58                         "Failed to read NCT3018Y_REG_CTRL\n");
  59                 return flags;
  60         }
  61
  62         if (on)
  63                 flags |= NCT3018Y_BIT_AIE;
  64         else
  65                 flags &= ~NCT3018Y_BIT_AIE;
  66
  67         flags |= NCT3018Y_BIT_CIE;
  68         err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_CTRL, flags);
  69         if (err < 0) {
  70                 dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_CTRL\n");
  71                 return err;
  72         }
  73
  74         flags =  i2c_smbus_read_byte_data(client, NCT3018Y_REG_ST);
  75         if (flags < 0) {
  76                 dev_dbg(&client->dev,
  77                         "Failed to read NCT3018Y_REG_ST\n");
  78                 return flags;
  79         }
  80
  81         flags &= ~(NCT3018Y_BIT_AF);
  82         err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_ST, flags);
  83         if (err < 0) {
  84                 dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_ST\n");
  85                 return err;
  86         }
  87
  88         return 0;
  89 }
  90
  91 static int nct3018y_get_alarm_mode(struct i2c_client *client, unsigned char *alarm_enable,
  92                                    unsigned char *alarm_flag)
  93 {
  94         int flags;
  95
  96         if (alarm_enable) {
  97                 dev_dbg(&client->dev, "%s:NCT3018Y_REG_CTRL\n", __func__);
  98                 flags =  i2c_smbus_read_byte_data(client, NCT3018Y_REG_CTRL);
  99                 if (flags < 0)
 100                         return flags;
 101                 *alarm_enable = flags & NCT3018Y_BIT_AIE;
 102         }
 103
 104         if (alarm_flag) {
 105                 dev_dbg(&client->dev, "%s:NCT3018Y_REG_ST\n", __func__);
 106                 flags =  i2c_smbus_read_byte_data(client, NCT3018Y_REG_ST);
 107                 if (flags < 0)
 108                         return flags;
 109                 *alarm_flag = flags & NCT3018Y_BIT_AF;
 110         }
 111
 112         dev_dbg(&client->dev, "%s:alarm_enable:%x alarm_flag:%x\n",
 113                 __func__, *alarm_enable, *alarm_flag);
 114
 115         return 0;
 116 }
 117
 118 static irqreturn_t nct3018y_irq(int irq, void *dev_id)
 119 {
 120         struct nct3018y *nct3018y = i2c_get_clientdata(dev_id);
 121         struct i2c_client *client = nct3018y->client;
 122         int err;
 123         unsigned char alarm_flag;
 124         unsigned char alarm_enable;
 125
 126         dev_dbg(&client->dev, "%s:irq:%d\n", __func__, irq);
 127         err = nct3018y_get_alarm_mode(nct3018y->client, &alarm_enable, &alarm_flag);
 128         if (err)
 129                 return IRQ_NONE;
 130
 131         if (alarm_flag) {
 132                 dev_dbg(&client->dev, "%s:alarm flag:%x\n",
 133                         __func__, alarm_flag);
 134                 rtc_update_irq(nct3018y->rtc, 1, RTC_IRQF | RTC_AF);
 135                 nct3018y_set_alarm_mode(nct3018y->client, 0);
 136                 dev_dbg(&client->dev, "%s:IRQ_HANDLED\n", __func__);
 137                 return IRQ_HANDLED;
 138         }
 139
 140         return IRQ_NONE;
 141 }
 142
 143 /*
 144  * In the routines that deal directly with the nct3018y hardware, we use
 145  * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
 146  */
 147 static int nct3018y_rtc_read_time(struct device *dev, struct rtc_time *tm)
 148 {
 149         struct i2c_client *client = to_i2c_client(dev);
 150         unsigned char buf[10];
 151         int err;
 152
 153         err = i2c_smbus_read_i2c_block_data(client, NCT3018Y_REG_ST, 1, buf);
 154         if (err < 0)
 155                 return err;
 156
 157         if (!buf[0]) {
 158                 dev_dbg(&client->dev, " voltage <=1.7, date/time is not reliable.\n");
 159                 return -EINVAL;
 160         }
 161
 162         err = i2c_smbus_read_i2c_block_data(client, NCT3018Y_REG_SC, sizeof(buf), buf);
 163         if (err < 0)
 164                 return err;
 165
 166         tm->tm_sec = bcd2bin(buf[0] & 0x7F);
 167         tm->tm_min = bcd2bin(buf[2] & 0x7F);
 168         tm->tm_hour = bcd2bin(buf[4] & 0x3F);
 169         tm->tm_wday = buf[6] & 0x07;
 170         tm->tm_mday = bcd2bin(buf[7] & 0x3F);
 171         tm->tm_mon = bcd2bin(buf[8] & 0x1F) - 1;
 172         tm->tm_year = bcd2bin(buf[9]) + 100;
 173
 174         return 0;
 175 }
 176
 177 static int nct3018y_rtc_set_time(struct device *dev, struct rtc_time *tm)
 178 {
 179         struct i2c_client *client = to_i2c_client(dev);
 180         unsigned char buf[4] = {0};
 181         int err;
 182
 183         buf[0] = bin2bcd(tm->tm_sec);
 184         err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_SC, buf[0]);
 185         if (err < 0) {
 186                 dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_SC\n");
 187                 return err;
 188         }
 189
 190         buf[0] = bin2bcd(tm->tm_min);
 191         err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_MN, buf[0]);
 192         if (err < 0) {
 193                 dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_MN\n");
 194                 return err;
 195         }
 196
 197         buf[0] = bin2bcd(tm->tm_hour);
 198         err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_HR, buf[0]);
 199         if (err < 0) {
 200                 dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_HR\n");
 201                 return err;
 202         }
 203
 204         buf[0] = tm->tm_wday & 0x07;
 205         buf[1] = bin2bcd(tm->tm_mday);
 206         buf[2] = bin2bcd(tm->tm_mon + 1);
 207         buf[3] = bin2bcd(tm->tm_year - 100);
 208         err = i2c_smbus_write_i2c_block_data(client, NCT3018Y_REG_DW,
 209                                              sizeof(buf), buf);
 210         if (err < 0) {
 211                 dev_dbg(&client->dev, "Unable to write for day and mon and year\n");
 212                 return -EIO;
 213         }
 214
 215         return err;
 216 }
 217
 218 static int nct3018y_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm)
 219 {
 220         struct i2c_client *client = to_i2c_client(dev);
 221         unsigned char buf[5];
 222         int err;
 223
 224         err = i2c_smbus_read_i2c_block_data(client, NCT3018Y_REG_SCA,
 225                                             sizeof(buf), buf);
 226         if (err < 0) {
 227                 dev_dbg(&client->dev, "Unable to read date\n");
 228                 return -EIO;
 229         }
 230
 231         dev_dbg(&client->dev, "%s: raw data is sec=%02x, min=%02x hr=%02x\n",
 232                 __func__, buf[0], buf[2], buf[4]);
 233
 234         tm->time.tm_sec = bcd2bin(buf[0] & 0x7F);
 235         tm->time.tm_min = bcd2bin(buf[2] & 0x7F);
 236         tm->time.tm_hour = bcd2bin(buf[4] & 0x3F);
 237
 238         err = nct3018y_get_alarm_mode(client, &tm->enabled, &tm->pending);
 239         if (err < 0)
 240                 return err;
 241
 242         dev_dbg(&client->dev, "%s:s=%d m=%d, hr=%d, enabled=%d, pending=%d\n",
 243                 __func__, tm->time.tm_sec, tm->time.tm_min,
 244                 tm->time.tm_hour, tm->enabled, tm->pending);
 245
 246         return 0;
 247 }
 248
 249 static int nct3018y_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm)
 250 {
 251         struct i2c_client *client = to_i2c_client(dev);
 252         int err;
 253
 254         dev_dbg(dev, "%s, sec=%d, min=%d hour=%d tm->enabled:%d\n",
 255                 __func__, tm->time.tm_sec, tm->time.tm_min, tm->time.tm_hour,
 256                 tm->enabled);
 257
 258         err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_SCA, bin2bcd(tm->time.tm_sec));
 259         if (err < 0) {
 260                 dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_SCA\n");
 261                 return err;
 262         }
 263
 264         err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_MNA, bin2bcd(tm->time.tm_min));
 265         if (err < 0) {
 266                 dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_MNA\n");
 267                 return err;
 268         }
 269
 270         err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_HRA, bin2bcd(tm->time.tm_hour));
 271         if (err < 0) {
 272                 dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_HRA\n");
 273                 return err;
 274         }
 275
 276         return nct3018y_set_alarm_mode(client, tm->enabled);
 277 }
 278
 279 static int nct3018y_irq_enable(struct device *dev, unsigned int enabled)
 280 {
 281         dev_dbg(dev, "%s: alarm enable=%d\n", __func__, enabled);
 282
 283         return nct3018y_set_alarm_mode(to_i2c_client(dev), enabled);
 284 }
 285
 286 static int nct3018y_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 287 {
 288         struct i2c_client *client = to_i2c_client(dev);
 289         int status, flags = 0;
 290
 291         switch (cmd) {
 292         case RTC_VL_READ:
 293                 status = i2c_smbus_read_byte_data(client, NCT3018Y_REG_ST);
 294                 if (status < 0)
 295                         return status;
 296
 297                 if (!(status & NCT3018Y_REG_BAT_MASK))
 298                         flags |= RTC_VL_DATA_INVALID;
 299
 300                 return put_user(flags, (unsigned int __user *)arg);
 301
 302         default:
 303                 return -ENOIOCTLCMD;
 304         }
 305 }
 306
 307 #ifdef CONFIG_COMMON_CLK
 308 /*
 309  * Handling of the clkout
 310  */
 311
 312 #define clkout_hw_to_nct3018y(_hw) container_of(_hw, struct nct3018y, clkout_hw)
 313
 314 static const int clkout_rates[] = {
 315         32768,
 316         1024,
 317         32,
 318         1,
 319 };
 320
 321 static unsigned long nct3018y_clkout_recalc_rate(struct clk_hw *hw,
 322                                                  unsigned long parent_rate)
 323 {
 324         struct nct3018y *nct3018y = clkout_hw_to_nct3018y(hw);
 325         struct i2c_client *client = nct3018y->client;
 326         int flags;
 327
 328         flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CLKO);
 329         if (flags < 0)
 330                 return 0;
 331
 332         flags &= NCT3018Y_REG_CLKO_F_MASK;
 333         return clkout_rates[flags];
 334 }
 335
 336 static long nct3018y_clkout_round_rate(struct clk_hw *hw, unsigned long rate,
 337                                        unsigned long *prate)
 338 {
 339         int i;
 340
 341         for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
 342                 if (clkout_rates[i] <= rate)
 343                         return clkout_rates[i];
 344
 345         return 0;
 346 }
 347
 348 static int nct3018y_clkout_set_rate(struct clk_hw *hw, unsigned long rate,
 349                                     unsigned long parent_rate)
 350 {
 351         struct nct3018y *nct3018y = clkout_hw_to_nct3018y(hw);
 352         struct i2c_client *client = nct3018y->client;
 353         int i, flags;
 354
 355         flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CLKO);
 356         if (flags < 0)
 357                 return flags;
 358
 359         for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
 360                 if (clkout_rates[i] == rate) {
 361                         flags &= ~NCT3018Y_REG_CLKO_F_MASK;
 362                         flags |= i;
 363                         return i2c_smbus_write_byte_data(client, NCT3018Y_REG_CLKO, flags);
 364                 }
 365
 366         return -EINVAL;
 367 }
 368
 369 static int nct3018y_clkout_control(struct clk_hw *hw, bool enable)
 370 {
 371         struct nct3018y *nct3018y = clkout_hw_to_nct3018y(hw);
 372         struct i2c_client *client = nct3018y->client;
 373         int flags;
 374
 375         flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CLKO);
 376         if (flags < 0)
 377                 return flags;
 378
 379         if (enable)
 380                 flags |= NCT3018Y_REG_CLKO_CKE;
 381         else
 382                 flags &= ~NCT3018Y_REG_CLKO_CKE;
 383
 384         return i2c_smbus_write_byte_data(client, NCT3018Y_REG_CLKO, flags);
 385 }
 386
 387 static int nct3018y_clkout_prepare(struct clk_hw *hw)
 388 {
 389         return nct3018y_clkout_control(hw, 1);
 390 }
 391
 392 static void nct3018y_clkout_unprepare(struct clk_hw *hw)
 393 {
 394         nct3018y_clkout_control(hw, 0);
 395 }
 396
 397 static int nct3018y_clkout_is_prepared(struct clk_hw *hw)
 398 {
 399         struct nct3018y *nct3018y = clkout_hw_to_nct3018y(hw);
 400         struct i2c_client *client = nct3018y->client;
 401         int flags;
 402
 403         flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CLKO);
 404         if (flags < 0)
 405                 return flags;
 406
 407         return flags & NCT3018Y_REG_CLKO_CKE;
 408 }
 409
 410 static const struct clk_ops nct3018y_clkout_ops = {
 411         .prepare = nct3018y_clkout_prepare,
 412         .unprepare = nct3018y_clkout_unprepare,
 413         .is_prepared = nct3018y_clkout_is_prepared,
 414         .recalc_rate = nct3018y_clkout_recalc_rate,
 415         .round_rate = nct3018y_clkout_round_rate,
 416         .set_rate = nct3018y_clkout_set_rate,
 417 };
 418
 419 static struct clk *nct3018y_clkout_register_clk(struct nct3018y *nct3018y)
 420 {
 421         struct i2c_client *client = nct3018y->client;
 422         struct device_node *node = client->dev.of_node;
 423         struct clk *clk;
 424         struct clk_init_data init;
 425
 426         init.name = "nct3018y-clkout";
 427         init.ops = &nct3018y_clkout_ops;
 428         init.flags = 0;
 429         init.parent_names = NULL;
 430         init.num_parents = 0;
 431         nct3018y->clkout_hw.init = &init;
 432
 433         /* optional override of the clockname */
 434         of_property_read_string(node, "clock-output-names", &init.name);
 435
 436         /* register the clock */
 437         clk = devm_clk_register(&client->dev, &nct3018y->clkout_hw);
 438
 439         if (!IS_ERR(clk))
 440                 of_clk_add_provider(node, of_clk_src_simple_get, clk);
 441
 442         return clk;
 443 }
 444 #endif
 445
 446 static const struct rtc_class_ops nct3018y_rtc_ops = {
 447         .read_time      = nct3018y_rtc_read_time,
 448         .set_time       = nct3018y_rtc_set_time,
 449         .read_alarm     = nct3018y_rtc_read_alarm,
 450         .set_alarm      = nct3018y_rtc_set_alarm,
 451         .alarm_irq_enable = nct3018y_irq_enable,
 452         .ioctl          = nct3018y_ioctl,
 453 };
 454
 455 static int nct3018y_probe(struct i2c_client *client)
 456 {
 457         struct nct3018y *nct3018y;
 458         int err, flags;
 459
 460         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
 461                                      I2C_FUNC_SMBUS_BYTE |
 462                                      I2C_FUNC_SMBUS_BLOCK_DATA))
 463                 return -ENODEV;
 464
 465         nct3018y = devm_kzalloc(&client->dev, sizeof(struct nct3018y),
 466                                 GFP_KERNEL);
 467         if (!nct3018y)
 468                 return -ENOMEM;
 469
 470         i2c_set_clientdata(client, nct3018y);
 471         nct3018y->client = client;
 472         device_set_wakeup_capable(&client->dev, 1);
 473
 474         flags = i2c_smbus_read_byte_data(client, NCT3018Y_REG_CTRL);
 475         if (flags < 0) {
 476                 dev_dbg(&client->dev, "%s: read error\n", __func__);
 477                 return flags;
 478         } else if (flags & NCT3018Y_BIT_TWO) {
 479                 dev_dbg(&client->dev, "%s: NCT3018Y_BIT_TWO is set\n", __func__);
 480         }
 481
 482         flags = NCT3018Y_BIT_TWO;
 483         err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_CTRL, flags);
 484         if (err < 0) {
 485                 dev_dbg(&client->dev, "Unable to write NCT3018Y_REG_CTRL\n");
 486                 return err;
 487         }
 488
 489         flags = 0;
 490         err = i2c_smbus_write_byte_data(client, NCT3018Y_REG_ST, flags);
 491         if (err < 0) {
 492                 dev_dbg(&client->dev, "%s: write error\n", __func__);
 493                 return err;
 494         }
 495
 496         nct3018y->rtc = devm_rtc_allocate_device(&client->dev);
 497         if (IS_ERR(nct3018y->rtc))
 498                 return PTR_ERR(nct3018y->rtc);
 499
 500         nct3018y->rtc->ops = &nct3018y_rtc_ops;
 501         nct3018y->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
 502         nct3018y->rtc->range_max = RTC_TIMESTAMP_END_2099;
 503
 504         if (client->irq > 0) {
 505                 err = devm_request_threaded_irq(&client->dev, client->irq,
 506                                                 NULL, nct3018y_irq,
 507                                                 IRQF_ONESHOT | IRQF_TRIGGER_FALLING,
 508                                                 "nct3018y", client);
 509                 if (err) {
 510                         dev_dbg(&client->dev, "unable to request IRQ %d\n", client->irq);
 511                         return err;
 512                 }
 513         } else {
 514                 clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, nct3018y->rtc->features);
 515                 clear_bit(RTC_FEATURE_ALARM, nct3018y->rtc->features);
 516         }
 517
 518 #ifdef CONFIG_COMMON_CLK
 519         /* register clk in common clk framework */
 520         nct3018y_clkout_register_clk(nct3018y);
 521 #endif
 522
 523         return devm_rtc_register_device(nct3018y->rtc);
 524 }
 525
 526 static const struct i2c_device_id nct3018y_id[] = {
 527         { "nct3018y", 0 },
 528         { }
 529 };
 530 MODULE_DEVICE_TABLE(i2c, nct3018y_id);
 531
 532 static const struct of_device_id nct3018y_of_match[] = {
 533         { .compatible = "nuvoton,nct3018y" },
 534         {}
 535 };
 536 MODULE_DEVICE_TABLE(of, nct3018y_of_match);
 537
 538 static struct i2c_driver nct3018y_driver = {
 539         .driver         = {
 540                 .name   = "rtc-nct3018y",
 541                 .of_match_table = of_match_ptr(nct3018y_of_match),
 542         },
 543         .probe          = nct3018y_probe,
 544         .id_table       = nct3018y_id,
 545 };
 546
 547 module_i2c_driver(nct3018y_driver);
 548
 549 MODULE_AUTHOR("Medad CChien <ctcchien@nuvoton.com>");
 550 MODULE_AUTHOR("Mia Lin <mimi05633@gmail.com>");
 551 MODULE_DESCRIPTION("Nuvoton NCT3018Y RTC driver");
 552 MODULE_LICENSE("GPL");