drivers/rtc/rtc-pcf85363.c

   1 /*
   2  * drivers/rtc/rtc-pcf85363.c
   3  *
   4  * Driver for NXP PCF85363 real-time clock.
   5  *
   6  * Copyright (C) 2017 Eric Nelson
   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  * Based loosely on rtc-8583 by Russell King, Wolfram Sang and Juergen Beisert
  13  */
  14 #include <linux/module.h>
  15 #include <linux/i2c.h>
  16 #include <linux/slab.h>
  17 #include <linux/rtc.h>
  18 #include <linux/init.h>
  19 #include <linux/err.h>
  20 #include <linux/errno.h>
  21 #include <linux/bcd.h>
  22 #include <linux/of.h>
  23 #include <linux/of_device.h>
  24 #include <linux/regmap.h>
  25
  26 /*
  27  * Date/Time registers
  28  */
  29 #define DT_100THS       0x00
  30 #define DT_SECS         0x01
  31 #define DT_MINUTES      0x02
  32 #define DT_HOURS        0x03
  33 #define DT_DAYS         0x04
  34 #define DT_WEEKDAYS     0x05
  35 #define DT_MONTHS       0x06
  36 #define DT_YEARS        0x07
  37
  38 /*
  39  * Alarm registers
  40  */
  41 #define DT_SECOND_ALM1  0x08
  42 #define DT_MINUTE_ALM1  0x09
  43 #define DT_HOUR_ALM1    0x0a
  44 #define DT_DAY_ALM1     0x0b
  45 #define DT_MONTH_ALM1   0x0c
  46 #define DT_MINUTE_ALM2  0x0d
  47 #define DT_HOUR_ALM2    0x0e
  48 #define DT_WEEKDAY_ALM2 0x0f
  49 #define DT_ALARM_EN     0x10
  50
  51 /*
  52  * Time stamp registers
  53  */
  54 #define DT_TIMESTAMP1   0x11
  55 #define DT_TIMESTAMP2   0x17
  56 #define DT_TIMESTAMP3   0x1d
  57 #define DT_TS_MODE      0x23
  58
  59 /*
  60  * control registers
  61  */
  62 #define CTRL_OFFSET     0x24
  63 #define CTRL_OSCILLATOR 0x25
  64 #define CTRL_BATTERY    0x26
  65 #define CTRL_PIN_IO     0x27
  66 #define CTRL_FUNCTION   0x28
  67 #define CTRL_INTA_EN    0x29
  68 #define CTRL_INTB_EN    0x2a
  69 #define CTRL_FLAGS      0x2b
  70 #define CTRL_RAMBYTE    0x2c
  71 #define CTRL_WDOG       0x2d
  72 #define CTRL_STOP_EN    0x2e
  73 #define CTRL_RESETS     0x2f
  74 #define CTRL_RAM        0x40
  75
  76 #define ALRM_SEC_A1E    BIT(0)
  77 #define ALRM_MIN_A1E    BIT(1)
  78 #define ALRM_HR_A1E     BIT(2)
  79 #define ALRM_DAY_A1E    BIT(3)
  80 #define ALRM_MON_A1E    BIT(4)
  81 #define ALRM_MIN_A2E    BIT(5)
  82 #define ALRM_HR_A2E     BIT(6)
  83 #define ALRM_DAY_A2E    BIT(7)
  84
  85 #define INT_WDIE        BIT(0)
  86 #define INT_BSIE        BIT(1)
  87 #define INT_TSRIE       BIT(2)
  88 #define INT_A2IE        BIT(3)
  89 #define INT_A1IE        BIT(4)
  90 #define INT_OIE         BIT(5)
  91 #define INT_PIE         BIT(6)
  92 #define INT_ILP         BIT(7)
  93
  94 #define FLAGS_TSR1F     BIT(0)
  95 #define FLAGS_TSR2F     BIT(1)
  96 #define FLAGS_TSR3F     BIT(2)
  97 #define FLAGS_BSF       BIT(3)
  98 #define FLAGS_WDF       BIT(4)
  99 #define FLAGS_A1F       BIT(5)
 100 #define FLAGS_A2F       BIT(6)
 101 #define FLAGS_PIF       BIT(7)
 102
 103 #define PIN_IO_INTAPM   GENMASK(1, 0)
 104 #define PIN_IO_INTA_CLK 0
 105 #define PIN_IO_INTA_BAT 1
 106 #define PIN_IO_INTA_OUT 2
 107 #define PIN_IO_INTA_HIZ 3
 108
 109 #define STOP_EN_STOP    BIT(0)
 110
 111 #define RESET_CPR       0xa4
 112
 113 #define NVRAM_SIZE      0x40
 114
 115 static struct i2c_driver pcf85363_driver;
 116
 117 struct pcf85363 {
 118         struct device           *dev;
 119         struct rtc_device       *rtc;
 120         struct regmap           *regmap;
 121 };
 122
 123 static int pcf85363_rtc_read_time(struct device *dev, struct rtc_time *tm)
 124 {
 125         struct pcf85363 *pcf85363 = dev_get_drvdata(dev);
 126         unsigned char buf[DT_YEARS + 1];
 127         int ret, len = sizeof(buf);
 128
 129         /* read the RTC date and time registers all at once */
 130         ret = regmap_bulk_read(pcf85363->regmap, DT_100THS, buf, len);
 131         if (ret) {
 132                 dev_err(dev, "%s: error %d\n", __func__, ret);
 133                 return ret;
 134         }
 135
 136         tm->tm_year = bcd2bin(buf[DT_YEARS]);
 137         /* adjust for 1900 base of rtc_time */
 138         tm->tm_year += 100;
 139
 140         tm->tm_wday = buf[DT_WEEKDAYS] & 7;
 141         buf[DT_SECS] &= 0x7F;
 142         tm->tm_sec = bcd2bin(buf[DT_SECS]);
 143         buf[DT_MINUTES] &= 0x7F;
 144         tm->tm_min = bcd2bin(buf[DT_MINUTES]);
 145         tm->tm_hour = bcd2bin(buf[DT_HOURS]);
 146         tm->tm_mday = bcd2bin(buf[DT_DAYS]);
 147         tm->tm_mon = bcd2bin(buf[DT_MONTHS]) - 1;
 148
 149         return 0;
 150 }
 151
 152 static int pcf85363_rtc_set_time(struct device *dev, struct rtc_time *tm)
 153 {
 154         struct pcf85363 *pcf85363 = dev_get_drvdata(dev);
 155         unsigned char tmp[11];
 156         unsigned char *buf = &tmp[2];
 157         int ret;
 158
 159         tmp[0] = STOP_EN_STOP;
 160         tmp[1] = RESET_CPR;
 161
 162         buf[DT_100THS] = 0;
 163         buf[DT_SECS] = bin2bcd(tm->tm_sec);
 164         buf[DT_MINUTES] = bin2bcd(tm->tm_min);
 165         buf[DT_HOURS] = bin2bcd(tm->tm_hour);
 166         buf[DT_DAYS] = bin2bcd(tm->tm_mday);
 167         buf[DT_WEEKDAYS] = tm->tm_wday;
 168         buf[DT_MONTHS] = bin2bcd(tm->tm_mon + 1);
 169         buf[DT_YEARS] = bin2bcd(tm->tm_year % 100);
 170
 171         ret = regmap_bulk_write(pcf85363->regmap, CTRL_STOP_EN,
 172                                 tmp, sizeof(tmp));
 173         if (ret)
 174                 return ret;
 175
 176         return regmap_write(pcf85363->regmap, CTRL_STOP_EN, 0);
 177 }
 178
 179 static int pcf85363_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 180 {
 181         struct pcf85363 *pcf85363 = dev_get_drvdata(dev);
 182         unsigned char buf[DT_MONTH_ALM1 - DT_SECOND_ALM1 + 1];
 183         unsigned int val;
 184         int ret;
 185
 186         ret = regmap_bulk_read(pcf85363->regmap, DT_SECOND_ALM1, buf,
 187                                sizeof(buf));
 188         if (ret)
 189                 return ret;
 190
 191         alrm->time.tm_sec = bcd2bin(buf[0]);
 192         alrm->time.tm_min = bcd2bin(buf[1]);
 193         alrm->time.tm_hour = bcd2bin(buf[2]);
 194         alrm->time.tm_mday = bcd2bin(buf[3]);
 195         alrm->time.tm_mon = bcd2bin(buf[4]) - 1;
 196
 197         ret = regmap_read(pcf85363->regmap, CTRL_INTA_EN, &val);
 198         if (ret)
 199                 return ret;
 200
 201         alrm->enabled =  !!(val & INT_A1IE);
 202
 203         return 0;
 204 }
 205
 206 static int _pcf85363_rtc_alarm_irq_enable(struct pcf85363 *pcf85363, unsigned
 207                                           int enabled)
 208 {
 209         unsigned int alarm_flags = ALRM_SEC_A1E | ALRM_MIN_A1E | ALRM_HR_A1E |
 210                                    ALRM_DAY_A1E | ALRM_MON_A1E;
 211         int ret;
 212
 213         ret = regmap_update_bits(pcf85363->regmap, DT_ALARM_EN, alarm_flags,
 214                                  enabled ? alarm_flags : 0);
 215         if (ret)
 216                 return ret;
 217
 218         ret = regmap_update_bits(pcf85363->regmap, CTRL_INTA_EN,
 219                                  INT_A1IE, enabled ? INT_A1IE : 0);
 220
 221         if (ret || enabled)
 222                 return ret;
 223
 224         /* clear current flags */
 225         return regmap_update_bits(pcf85363->regmap, CTRL_FLAGS, FLAGS_A1F, 0);
 226 }
 227
 228 static int pcf85363_rtc_alarm_irq_enable(struct device *dev,
 229                                          unsigned int enabled)
 230 {
 231         struct pcf85363 *pcf85363 = dev_get_drvdata(dev);
 232
 233         return _pcf85363_rtc_alarm_irq_enable(pcf85363, enabled);
 234 }
 235
 236 static int pcf85363_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 237 {
 238         struct pcf85363 *pcf85363 = dev_get_drvdata(dev);
 239         unsigned char buf[DT_MONTH_ALM1 - DT_SECOND_ALM1 + 1];
 240         int ret;
 241
 242         buf[0] = bin2bcd(alrm->time.tm_sec);
 243         buf[1] = bin2bcd(alrm->time.tm_min);
 244         buf[2] = bin2bcd(alrm->time.tm_hour);
 245         buf[3] = bin2bcd(alrm->time.tm_mday);
 246         buf[4] = bin2bcd(alrm->time.tm_mon + 1);
 247
 248         /*
 249          * Disable the alarm interrupt before changing the value to avoid
 250          * spurious interrupts
 251          */
 252         ret = _pcf85363_rtc_alarm_irq_enable(pcf85363, 0);
 253         if (ret)
 254                 return ret;
 255
 256         ret = regmap_bulk_write(pcf85363->regmap, DT_SECOND_ALM1, buf,
 257                                 sizeof(buf));
 258         if (ret)
 259                 return ret;
 260
 261         return _pcf85363_rtc_alarm_irq_enable(pcf85363, alrm->enabled);
 262 }
 263
 264 static irqreturn_t pcf85363_rtc_handle_irq(int irq, void *dev_id)
 265 {
 266         struct pcf85363 *pcf85363 = i2c_get_clientdata(dev_id);
 267         unsigned int flags;
 268         int err;
 269
 270         err = regmap_read(pcf85363->regmap, CTRL_FLAGS, &flags);
 271         if (err)
 272                 return IRQ_NONE;
 273
 274         if (flags & FLAGS_A1F) {
 275                 rtc_update_irq(pcf85363->rtc, 1, RTC_IRQF | RTC_AF);
 276                 regmap_update_bits(pcf85363->regmap, CTRL_FLAGS, FLAGS_A1F, 0);
 277                 return IRQ_HANDLED;
 278         }
 279
 280         return IRQ_NONE;
 281 }
 282
 283 static const struct rtc_class_ops rtc_ops = {
 284         .read_time      = pcf85363_rtc_read_time,
 285         .set_time       = pcf85363_rtc_set_time,
 286 };
 287
 288 static const struct rtc_class_ops rtc_ops_alarm = {
 289         .read_time      = pcf85363_rtc_read_time,
 290         .set_time       = pcf85363_rtc_set_time,
 291         .read_alarm     = pcf85363_rtc_read_alarm,
 292         .set_alarm      = pcf85363_rtc_set_alarm,
 293         .alarm_irq_enable = pcf85363_rtc_alarm_irq_enable,
 294 };
 295
 296 static int pcf85363_nvram_read(void *priv, unsigned int offset, void *val,
 297                                size_t bytes)
 298 {
 299         struct pcf85363 *pcf85363 = priv;
 300
 301         return regmap_bulk_read(pcf85363->regmap, CTRL_RAM + offset,
 302                                 val, bytes);
 303 }
 304
 305 static int pcf85363_nvram_write(void *priv, unsigned int offset, void *val,
 306                                 size_t bytes)
 307 {
 308         struct pcf85363 *pcf85363 = priv;
 309
 310         return regmap_bulk_write(pcf85363->regmap, CTRL_RAM + offset,
 311                                  val, bytes);
 312 }
 313
 314 static const struct regmap_config regmap_config = {
 315         .reg_bits = 8,
 316         .val_bits = 8,
 317         .max_register = 0x7f,
 318 };
 319
 320 static int pcf85363_probe(struct i2c_client *client,
 321                           const struct i2c_device_id *id)
 322 {
 323         struct pcf85363 *pcf85363;
 324         struct nvmem_config nvmem_cfg = {
 325                 .name = "pcf85363-",
 326                 .word_size = 1,
 327                 .stride = 1,
 328                 .size = NVRAM_SIZE,
 329                 .reg_read = pcf85363_nvram_read,
 330                 .reg_write = pcf85363_nvram_write,
 331         };
 332         int ret;
 333
 334         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 335                 return -ENODEV;
 336
 337         pcf85363 = devm_kzalloc(&client->dev, sizeof(struct pcf85363),
 338                                 GFP_KERNEL);
 339         if (!pcf85363)
 340                 return -ENOMEM;
 341
 342         pcf85363->regmap = devm_regmap_init_i2c(client, &regmap_config);
 343         if (IS_ERR(pcf85363->regmap)) {
 344                 dev_err(&client->dev, "regmap allocation failed\n");
 345                 return PTR_ERR(pcf85363->regmap);
 346         }
 347
 348         pcf85363->dev = &client->dev;
 349         i2c_set_clientdata(client, pcf85363);
 350
 351         pcf85363->rtc = devm_rtc_allocate_device(pcf85363->dev);
 352         if (IS_ERR(pcf85363->rtc))
 353                 return PTR_ERR(pcf85363->rtc);
 354
 355         pcf85363->rtc->ops = &rtc_ops;
 356
 357         if (client->irq > 0) {
 358                 regmap_write(pcf85363->regmap, CTRL_FLAGS, 0);
 359                 regmap_update_bits(pcf85363->regmap, CTRL_PIN_IO,
 360                                    PIN_IO_INTA_OUT, PIN_IO_INTAPM);
 361                 ret = devm_request_threaded_irq(pcf85363->dev, client->irq,
 362                                                 NULL, pcf85363_rtc_handle_irq,
 363                                                 IRQF_TRIGGER_LOW | IRQF_ONESHOT,
 364                                                 "pcf85363", client);
 365                 if (ret)
 366                         dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
 367                 else
 368                         pcf85363->rtc->ops = &rtc_ops_alarm;
 369         }
 370
 371         ret = rtc_register_device(pcf85363->rtc);
 372
 373         nvmem_cfg.priv = pcf85363;
 374         rtc_nvmem_register(pcf85363->rtc, &nvmem_cfg);
 375
 376         return ret;
 377 }
 378
 379 static const struct of_device_id dev_ids[] = {
 380         { .compatible = "nxp,pcf85363" },
 381         {}
 382 };
 383 MODULE_DEVICE_TABLE(of, dev_ids);
 384
 385 static struct i2c_driver pcf85363_driver = {
 386         .driver = {
 387                 .name   = "pcf85363",
 388                 .of_match_table = of_match_ptr(dev_ids),
 389         },
 390         .probe  = pcf85363_probe,
 391 };
 392
 393 module_i2c_driver(pcf85363_driver);
 394
 395 MODULE_AUTHOR("Eric Nelson");
 396 MODULE_DESCRIPTION("pcf85363 I2C RTC driver");
 397 MODULE_LICENSE("GPL");