drivers/rtc/rtc-tps65910.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * rtc-tps65910.c -- TPS65910 Real Time Clock interface
   4  *
   5  * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
   6  * Author: Venu Byravarasu <vbyravarasu@nvidia.com>
   7  *
   8  * Based on original TI driver rtc-twl.c
   9  *   Copyright (C) 2007 MontaVista Software, Inc
  10  *   Author: Alexandre Rusev <source@mvista.com>
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/errno.h>
  15 #include <linux/init.h>
  16 #include <linux/module.h>
  17 #include <linux/types.h>
  18 #include <linux/rtc.h>
  19 #include <linux/bcd.h>
  20 #include <linux/math64.h>
  21 #include <linux/property.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/mfd/tps65910.h>
  25
  26 struct tps65910_rtc {
  27         struct rtc_device       *rtc;
  28         int irq;
  29 };
  30
  31 /* Total number of RTC registers needed to set time*/
  32 #define NUM_TIME_REGS   (TPS65910_YEARS - TPS65910_SECONDS + 1)
  33
  34 /* Total number of RTC registers needed to set compensation registers */
  35 #define NUM_COMP_REGS   (TPS65910_RTC_COMP_MSB - TPS65910_RTC_COMP_LSB + 1)
  36
  37 /* Min and max values supported with 'offset' interface (swapped sign) */
  38 #define MIN_OFFSET      (-277761)
  39 #define MAX_OFFSET      (277778)
  40
  41 /* Number of ticks per hour */
  42 #define TICKS_PER_HOUR  (32768 * 3600)
  43
  44 /* Multiplier for ppb conversions */
  45 #define PPB_MULT        (1000000000LL)
  46
  47 static int tps65910_rtc_alarm_irq_enable(struct device *dev,
  48                                          unsigned int enabled)
  49 {
  50         struct tps65910 *tps = dev_get_drvdata(dev->parent);
  51         u8 val = 0;
  52
  53         if (enabled)
  54                 val = TPS65910_RTC_INTERRUPTS_IT_ALARM;
  55
  56         return regmap_write(tps->regmap, TPS65910_RTC_INTERRUPTS, val);
  57 }
  58
  59 /*
  60  * Gets current tps65910 RTC time and date parameters.
  61  *
  62  * The RTC's time/alarm representation is not what gmtime(3) requires
  63  * Linux to use:
  64  *
  65  *  - Months are 1..12 vs Linux 0-11
  66  *  - Years are 0..99 vs Linux 1900..N (we assume 21st century)
  67  */
  68 static int tps65910_rtc_read_time(struct device *dev, struct rtc_time *tm)
  69 {
  70         unsigned char rtc_data[NUM_TIME_REGS];
  71         struct tps65910 *tps = dev_get_drvdata(dev->parent);
  72         int ret;
  73
  74         /* Copy RTC counting registers to static registers or latches */
  75         ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
  76                 TPS65910_RTC_CTRL_GET_TIME, TPS65910_RTC_CTRL_GET_TIME);
  77         if (ret < 0) {
  78                 dev_err(dev, "RTC CTRL reg update failed with err:%d\n", ret);
  79                 return ret;
  80         }
  81
  82         ret = regmap_bulk_read(tps->regmap, TPS65910_SECONDS, rtc_data,
  83                 NUM_TIME_REGS);
  84         if (ret < 0) {
  85                 dev_err(dev, "reading from RTC failed with err:%d\n", ret);
  86                 return ret;
  87         }
  88
  89         tm->tm_sec = bcd2bin(rtc_data[0]);
  90         tm->tm_min = bcd2bin(rtc_data[1]);
  91         tm->tm_hour = bcd2bin(rtc_data[2]);
  92         tm->tm_mday = bcd2bin(rtc_data[3]);
  93         tm->tm_mon = bcd2bin(rtc_data[4]) - 1;
  94         tm->tm_year = bcd2bin(rtc_data[5]) + 100;
  95
  96         return ret;
  97 }
  98
  99 static int tps65910_rtc_set_time(struct device *dev, struct rtc_time *tm)
 100 {
 101         unsigned char rtc_data[NUM_TIME_REGS];
 102         struct tps65910 *tps = dev_get_drvdata(dev->parent);
 103         int ret;
 104
 105         rtc_data[0] = bin2bcd(tm->tm_sec);
 106         rtc_data[1] = bin2bcd(tm->tm_min);
 107         rtc_data[2] = bin2bcd(tm->tm_hour);
 108         rtc_data[3] = bin2bcd(tm->tm_mday);
 109         rtc_data[4] = bin2bcd(tm->tm_mon + 1);
 110         rtc_data[5] = bin2bcd(tm->tm_year - 100);
 111
 112         /* Stop RTC while updating the RTC time registers */
 113         ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
 114                 TPS65910_RTC_CTRL_STOP_RTC, 0);
 115         if (ret < 0) {
 116                 dev_err(dev, "RTC stop failed with err:%d\n", ret);
 117                 return ret;
 118         }
 119
 120         /* update all the time registers in one shot */
 121         ret = regmap_bulk_write(tps->regmap, TPS65910_SECONDS, rtc_data,
 122                 NUM_TIME_REGS);
 123         if (ret < 0) {
 124                 dev_err(dev, "rtc_set_time error %d\n", ret);
 125                 return ret;
 126         }
 127
 128         /* Start back RTC */
 129         ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
 130                 TPS65910_RTC_CTRL_STOP_RTC, 1);
 131         if (ret < 0)
 132                 dev_err(dev, "RTC start failed with err:%d\n", ret);
 133
 134         return ret;
 135 }
 136
 137 /*
 138  * Gets current tps65910 RTC alarm time.
 139  */
 140 static int tps65910_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 141 {
 142         unsigned char alarm_data[NUM_TIME_REGS];
 143         u32 int_val;
 144         struct tps65910 *tps = dev_get_drvdata(dev->parent);
 145         int ret;
 146
 147         ret = regmap_bulk_read(tps->regmap, TPS65910_ALARM_SECONDS, alarm_data,
 148                 NUM_TIME_REGS);
 149         if (ret < 0) {
 150                 dev_err(dev, "rtc_read_alarm error %d\n", ret);
 151                 return ret;
 152         }
 153
 154         alm->time.tm_sec = bcd2bin(alarm_data[0]);
 155         alm->time.tm_min = bcd2bin(alarm_data[1]);
 156         alm->time.tm_hour = bcd2bin(alarm_data[2]);
 157         alm->time.tm_mday = bcd2bin(alarm_data[3]);
 158         alm->time.tm_mon = bcd2bin(alarm_data[4]) - 1;
 159         alm->time.tm_year = bcd2bin(alarm_data[5]) + 100;
 160
 161         ret = regmap_read(tps->regmap, TPS65910_RTC_INTERRUPTS, &int_val);
 162         if (ret < 0)
 163                 return ret;
 164
 165         if (int_val & TPS65910_RTC_INTERRUPTS_IT_ALARM)
 166                 alm->enabled = 1;
 167
 168         return ret;
 169 }
 170
 171 static int tps65910_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 172 {
 173         unsigned char alarm_data[NUM_TIME_REGS];
 174         struct tps65910 *tps = dev_get_drvdata(dev->parent);
 175         int ret;
 176
 177         ret = tps65910_rtc_alarm_irq_enable(dev, 0);
 178         if (ret)
 179                 return ret;
 180
 181         alarm_data[0] = bin2bcd(alm->time.tm_sec);
 182         alarm_data[1] = bin2bcd(alm->time.tm_min);
 183         alarm_data[2] = bin2bcd(alm->time.tm_hour);
 184         alarm_data[3] = bin2bcd(alm->time.tm_mday);
 185         alarm_data[4] = bin2bcd(alm->time.tm_mon + 1);
 186         alarm_data[5] = bin2bcd(alm->time.tm_year - 100);
 187
 188         /* update all the alarm registers in one shot */
 189         ret = regmap_bulk_write(tps->regmap, TPS65910_ALARM_SECONDS,
 190                 alarm_data, NUM_TIME_REGS);
 191         if (ret) {
 192                 dev_err(dev, "rtc_set_alarm error %d\n", ret);
 193                 return ret;
 194         }
 195
 196         if (alm->enabled)
 197                 ret = tps65910_rtc_alarm_irq_enable(dev, 1);
 198
 199         return ret;
 200 }
 201
 202 static int tps65910_rtc_set_calibration(struct device *dev, int calibration)
 203 {
 204         unsigned char comp_data[NUM_COMP_REGS];
 205         struct tps65910 *tps = dev_get_drvdata(dev->parent);
 206         s16 value;
 207         int ret;
 208
 209         /*
 210          * TPS65910 uses two's complement 16 bit value for compensation for RTC
 211          * crystal inaccuracies. One time every hour when seconds counter
 212          * increments from 0 to 1 compensation value will be added to internal
 213          * RTC counter value.
 214          *
 215          * Compensation value 0x7FFF is prohibited value.
 216          *
 217          * Valid range for compensation value: [-32768 .. 32766]
 218          */
 219         if ((calibration < -32768) || (calibration > 32766)) {
 220                 dev_err(dev, "RTC calibration value out of range: %d\n",
 221                         calibration);
 222                 return -EINVAL;
 223         }
 224
 225         value = (s16)calibration;
 226
 227         comp_data[0] = (u16)value & 0xFF;
 228         comp_data[1] = ((u16)value >> 8) & 0xFF;
 229
 230         /* Update all the compensation registers in one shot */
 231         ret = regmap_bulk_write(tps->regmap, TPS65910_RTC_COMP_LSB,
 232                 comp_data, NUM_COMP_REGS);
 233         if (ret < 0) {
 234                 dev_err(dev, "rtc_set_calibration error: %d\n", ret);
 235                 return ret;
 236         }
 237
 238         /* Enable automatic compensation */
 239         ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
 240                 TPS65910_RTC_CTRL_AUTO_COMP, TPS65910_RTC_CTRL_AUTO_COMP);
 241         if (ret < 0)
 242                 dev_err(dev, "auto_comp enable failed with error: %d\n", ret);
 243
 244         return ret;
 245 }
 246
 247 static int tps65910_rtc_get_calibration(struct device *dev, int *calibration)
 248 {
 249         unsigned char comp_data[NUM_COMP_REGS];
 250         struct tps65910 *tps = dev_get_drvdata(dev->parent);
 251         unsigned int ctrl;
 252         u16 value;
 253         int ret;
 254
 255         ret = regmap_read(tps->regmap, TPS65910_RTC_CTRL, &ctrl);
 256         if (ret < 0)
 257                 return ret;
 258
 259         /* If automatic compensation is not enabled report back zero */
 260         if (!(ctrl & TPS65910_RTC_CTRL_AUTO_COMP)) {
 261                 *calibration = 0;
 262                 return 0;
 263         }
 264
 265         ret = regmap_bulk_read(tps->regmap, TPS65910_RTC_COMP_LSB, comp_data,
 266                 NUM_COMP_REGS);
 267         if (ret < 0) {
 268                 dev_err(dev, "rtc_get_calibration error: %d\n", ret);
 269                 return ret;
 270         }
 271
 272         value = (u16)comp_data[0] | ((u16)comp_data[1] << 8);
 273
 274         *calibration = (s16)value;
 275
 276         return 0;
 277 }
 278
 279 static int tps65910_read_offset(struct device *dev, long *offset)
 280 {
 281         int calibration;
 282         s64 tmp;
 283         int ret;
 284
 285         ret = tps65910_rtc_get_calibration(dev, &calibration);
 286         if (ret < 0)
 287                 return ret;
 288
 289         /* Convert from RTC calibration register format to ppb format */
 290         tmp = calibration * (s64)PPB_MULT;
 291         if (tmp < 0)
 292                 tmp -= TICKS_PER_HOUR / 2LL;
 293         else
 294                 tmp += TICKS_PER_HOUR / 2LL;
 295         tmp = div_s64(tmp, TICKS_PER_HOUR);
 296
 297         /* Offset value operates in negative way, so swap sign */
 298         *offset = (long)-tmp;
 299
 300         return 0;
 301 }
 302
 303 static int tps65910_set_offset(struct device *dev, long offset)
 304 {
 305         int calibration;
 306         s64 tmp;
 307         int ret;
 308
 309         /* Make sure offset value is within supported range */
 310         if (offset < MIN_OFFSET || offset > MAX_OFFSET)
 311                 return -ERANGE;
 312
 313         /* Convert from ppb format to RTC calibration register format */
 314         tmp = offset * (s64)TICKS_PER_HOUR;
 315         if (tmp < 0)
 316                 tmp -= PPB_MULT / 2LL;
 317         else
 318                 tmp += PPB_MULT / 2LL;
 319         tmp = div_s64(tmp, PPB_MULT);
 320
 321         /* Offset value operates in negative way, so swap sign */
 322         calibration = (int)-tmp;
 323
 324         ret = tps65910_rtc_set_calibration(dev, calibration);
 325
 326         return ret;
 327 }
 328
 329 static irqreturn_t tps65910_rtc_interrupt(int irq, void *rtc)
 330 {
 331         struct device *dev = rtc;
 332         unsigned long events = 0;
 333         struct tps65910 *tps = dev_get_drvdata(dev->parent);
 334         struct tps65910_rtc *tps_rtc = dev_get_drvdata(dev);
 335         int ret;
 336         u32 rtc_reg;
 337
 338         ret = regmap_read(tps->regmap, TPS65910_RTC_STATUS, &rtc_reg);
 339         if (ret)
 340                 return IRQ_NONE;
 341
 342         if (rtc_reg & TPS65910_RTC_STATUS_ALARM)
 343                 events = RTC_IRQF | RTC_AF;
 344
 345         ret = regmap_write(tps->regmap, TPS65910_RTC_STATUS, rtc_reg);
 346         if (ret)
 347                 return IRQ_NONE;
 348
 349         /* Notify RTC core on event */
 350         rtc_update_irq(tps_rtc->rtc, 1, events);
 351
 352         return IRQ_HANDLED;
 353 }
 354
 355 static const struct rtc_class_ops tps65910_rtc_ops = {
 356         .read_time      = tps65910_rtc_read_time,
 357         .set_time       = tps65910_rtc_set_time,
 358         .read_alarm     = tps65910_rtc_read_alarm,
 359         .set_alarm      = tps65910_rtc_set_alarm,
 360         .alarm_irq_enable = tps65910_rtc_alarm_irq_enable,
 361         .read_offset    = tps65910_read_offset,
 362         .set_offset     = tps65910_set_offset,
 363 };
 364
 365 static int tps65910_rtc_probe(struct platform_device *pdev)
 366 {
 367         struct tps65910 *tps65910 = NULL;
 368         struct tps65910_rtc *tps_rtc = NULL;
 369         int ret;
 370         int irq;
 371         u32 rtc_reg;
 372
 373         tps65910 = dev_get_drvdata(pdev->dev.parent);
 374
 375         tps_rtc = devm_kzalloc(&pdev->dev, sizeof(struct tps65910_rtc),
 376                         GFP_KERNEL);
 377         if (!tps_rtc)
 378                 return -ENOMEM;
 379
 380         tps_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
 381         if (IS_ERR(tps_rtc->rtc))
 382                 return PTR_ERR(tps_rtc->rtc);
 383
 384         /* Clear pending interrupts */
 385         ret = regmap_read(tps65910->regmap, TPS65910_RTC_STATUS, &rtc_reg);
 386         if (ret < 0)
 387                 return ret;
 388
 389         ret = regmap_write(tps65910->regmap, TPS65910_RTC_STATUS, rtc_reg);
 390         if (ret < 0)
 391                 return ret;
 392
 393         dev_dbg(&pdev->dev, "Enabling rtc-tps65910.\n");
 394
 395         /* Enable RTC digital power domain */
 396         ret = regmap_update_bits(tps65910->regmap, TPS65910_DEVCTRL,
 397                 DEVCTRL_RTC_PWDN_MASK, 0 << DEVCTRL_RTC_PWDN_SHIFT);
 398         if (ret < 0)
 399                 return ret;
 400
 401         rtc_reg = TPS65910_RTC_CTRL_STOP_RTC;
 402         ret = regmap_write(tps65910->regmap, TPS65910_RTC_CTRL, rtc_reg);
 403         if (ret < 0)
 404                 return ret;
 405
 406         platform_set_drvdata(pdev, tps_rtc);
 407
 408         irq  = platform_get_irq(pdev, 0);
 409         if (irq <= 0) {
 410                 dev_warn(&pdev->dev, "Wake up is not possible as irq = %d\n",
 411                         irq);
 412                 return -ENXIO;
 413         }
 414
 415         ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
 416                 tps65910_rtc_interrupt, IRQF_TRIGGER_LOW,
 417                 dev_name(&pdev->dev), &pdev->dev);
 418         if (ret < 0)
 419                 irq = -1;
 420
 421         tps_rtc->irq = irq;
 422         if (irq != -1) {
 423                 if (device_property_present(tps65910->dev, "wakeup-source"))
 424                         device_init_wakeup(&pdev->dev, 1);
 425                 else
 426                         device_set_wakeup_capable(&pdev->dev, 1);
 427         } else {
 428                 clear_bit(RTC_FEATURE_ALARM, tps_rtc->rtc->features);
 429         }
 430
 431         tps_rtc->rtc->ops = &tps65910_rtc_ops;
 432         tps_rtc->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
 433         tps_rtc->rtc->range_max = RTC_TIMESTAMP_END_2099;
 434
 435         return devm_rtc_register_device(tps_rtc->rtc);
 436 }
 437
 438 #ifdef CONFIG_PM_SLEEP
 439 static int tps65910_rtc_suspend(struct device *dev)
 440 {
 441         struct tps65910_rtc *tps_rtc = dev_get_drvdata(dev);
 442
 443         if (device_may_wakeup(dev))
 444                 enable_irq_wake(tps_rtc->irq);
 445         return 0;
 446 }
 447
 448 static int tps65910_rtc_resume(struct device *dev)
 449 {
 450         struct tps65910_rtc *tps_rtc = dev_get_drvdata(dev);
 451
 452         if (device_may_wakeup(dev))
 453                 disable_irq_wake(tps_rtc->irq);
 454         return 0;
 455 }
 456 #endif
 457
 458 static SIMPLE_DEV_PM_OPS(tps65910_rtc_pm_ops, tps65910_rtc_suspend,
 459                         tps65910_rtc_resume);
 460
 461 static struct platform_driver tps65910_rtc_driver = {
 462         .probe          = tps65910_rtc_probe,
 463         .driver         = {
 464                 .name   = "tps65910-rtc",
 465                 .pm     = &tps65910_rtc_pm_ops,
 466         },
 467 };
 468
 469 module_platform_driver(tps65910_rtc_driver);
 470 MODULE_ALIAS("platform:tps65910-rtc");
 471 MODULE_AUTHOR("Venu Byravarasu <vbyravarasu@nvidia.com>");
 472 MODULE_LICENSE("GPL");