drivers/rtc/rtc-tps65910.c

   1 /*
   2  * rtc-tps65910.c -- TPS65910 Real Time Clock interface
   3  *
   4  * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
   5  * Author: Venu Byravarasu <vbyravarasu@nvidia.com>
   6  *
   7  * Based on original TI driver rtc-twl.c
   8  *   Copyright (C) 2007 MontaVista Software, Inc
   9  *   Author: Alexandre Rusev <source@mvista.com>
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License
  13  * as published by the Free Software Foundation; either version
  14  * 2 of the License, or (at your option) any later version.
  15  */
  16
  17 #include <linux/kernel.h>
  18 #include <linux/errno.h>
  19 #include <linux/init.h>
  20 #include <linux/module.h>
  21 #include <linux/types.h>
  22 #include <linux/rtc.h>
  23 #include <linux/bcd.h>
  24 #include <linux/math64.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/mfd/tps65910.h>
  28
  29 struct tps65910_rtc {
  30         struct rtc_device       *rtc;
  31         int irq;
  32 };
  33
  34 /* Total number of RTC registers needed to set time*/
  35 #define NUM_TIME_REGS   (TPS65910_YEARS - TPS65910_SECONDS + 1)
  36
  37 /* Total number of RTC registers needed to set compensation registers */
  38 #define NUM_COMP_REGS   (TPS65910_RTC_COMP_MSB - TPS65910_RTC_COMP_LSB + 1)
  39
  40 /* Min and max values supported with 'offset' interface (swapped sign) */
  41 #define MIN_OFFSET      (-277761)
  42 #define MAX_OFFSET      (277778)
  43
  44 /* Number of ticks per hour */
  45 #define TICKS_PER_HOUR  (32768 * 3600)
  46
  47 /* Multiplier for ppb conversions */
  48 #define PPB_MULT        (1000000000LL)
  49
  50 static int tps65910_rtc_alarm_irq_enable(struct device *dev, unsigned enabled)
  51 {
  52         struct tps65910 *tps = dev_get_drvdata(dev->parent);
  53         u8 val = 0;
  54
  55         if (enabled)
  56                 val = TPS65910_RTC_INTERRUPTS_IT_ALARM;
  57
  58         return regmap_write(tps->regmap, TPS65910_RTC_INTERRUPTS, val);
  59 }
  60
  61 /*
  62  * Gets current tps65910 RTC time and date parameters.
  63  *
  64  * The RTC's time/alarm representation is not what gmtime(3) requires
  65  * Linux to use:
  66  *
  67  *  - Months are 1..12 vs Linux 0-11
  68  *  - Years are 0..99 vs Linux 1900..N (we assume 21st century)
  69  */
  70 static int tps65910_rtc_read_time(struct device *dev, struct rtc_time *tm)
  71 {
  72         unsigned char rtc_data[NUM_TIME_REGS];
  73         struct tps65910 *tps = dev_get_drvdata(dev->parent);
  74         int ret;
  75
  76         /* Copy RTC counting registers to static registers or latches */
  77         ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
  78                 TPS65910_RTC_CTRL_GET_TIME, TPS65910_RTC_CTRL_GET_TIME);
  79         if (ret < 0) {
  80                 dev_err(dev, "RTC CTRL reg update failed with err:%d\n", ret);
  81                 return ret;
  82         }
  83
  84         ret = regmap_bulk_read(tps->regmap, TPS65910_SECONDS, rtc_data,
  85                 NUM_TIME_REGS);
  86         if (ret < 0) {
  87                 dev_err(dev, "reading from RTC failed with err:%d\n", ret);
  88                 return ret;
  89         }
  90
  91         tm->tm_sec = bcd2bin(rtc_data[0]);
  92         tm->tm_min = bcd2bin(rtc_data[1]);
  93         tm->tm_hour = bcd2bin(rtc_data[2]);
  94         tm->tm_mday = bcd2bin(rtc_data[3]);
  95         tm->tm_mon = bcd2bin(rtc_data[4]) - 1;
  96         tm->tm_year = bcd2bin(rtc_data[5]) + 100;
  97
  98         return ret;
  99 }
 100
 101 static int tps65910_rtc_set_time(struct device *dev, struct rtc_time *tm)
 102 {
 103         unsigned char rtc_data[NUM_TIME_REGS];
 104         struct tps65910 *tps = dev_get_drvdata(dev->parent);
 105         int ret;
 106
 107         rtc_data[0] = bin2bcd(tm->tm_sec);
 108         rtc_data[1] = bin2bcd(tm->tm_min);
 109         rtc_data[2] = bin2bcd(tm->tm_hour);
 110         rtc_data[3] = bin2bcd(tm->tm_mday);
 111         rtc_data[4] = bin2bcd(tm->tm_mon + 1);
 112         rtc_data[5] = bin2bcd(tm->tm_year - 100);
 113
 114         /* Stop RTC while updating the RTC time registers */
 115         ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
 116                 TPS65910_RTC_CTRL_STOP_RTC, 0);
 117         if (ret < 0) {
 118                 dev_err(dev, "RTC stop failed with err:%d\n", ret);
 119                 return ret;
 120         }
 121
 122         /* update all the time registers in one shot */
 123         ret = regmap_bulk_write(tps->regmap, TPS65910_SECONDS, rtc_data,
 124                 NUM_TIME_REGS);
 125         if (ret < 0) {
 126                 dev_err(dev, "rtc_set_time error %d\n", ret);
 127                 return ret;
 128         }
 129
 130         /* Start back RTC */
 131         ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
 132                 TPS65910_RTC_CTRL_STOP_RTC, 1);
 133         if (ret < 0)
 134                 dev_err(dev, "RTC start failed with err:%d\n", ret);
 135
 136         return ret;
 137 }
 138
 139 /*
 140  * Gets current tps65910 RTC alarm time.
 141  */
 142 static int tps65910_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 143 {
 144         unsigned char alarm_data[NUM_TIME_REGS];
 145         u32 int_val;
 146         struct tps65910 *tps = dev_get_drvdata(dev->parent);
 147         int ret;
 148
 149         ret = regmap_bulk_read(tps->regmap, TPS65910_SECONDS, alarm_data,
 150                 NUM_TIME_REGS);
 151         if (ret < 0) {
 152                 dev_err(dev, "rtc_read_alarm error %d\n", ret);
 153                 return ret;
 154         }
 155
 156         alm->time.tm_sec = bcd2bin(alarm_data[0]);
 157         alm->time.tm_min = bcd2bin(alarm_data[1]);
 158         alm->time.tm_hour = bcd2bin(alarm_data[2]);
 159         alm->time.tm_mday = bcd2bin(alarm_data[3]);
 160         alm->time.tm_mon = bcd2bin(alarm_data[4]) - 1;
 161         alm->time.tm_year = bcd2bin(alarm_data[5]) + 100;
 162
 163         ret = regmap_read(tps->regmap, TPS65910_RTC_INTERRUPTS, &int_val);
 164         if (ret < 0)
 165                 return ret;
 166
 167         if (int_val & TPS65910_RTC_INTERRUPTS_IT_ALARM)
 168                 alm->enabled = 1;
 169
 170         return ret;
 171 }
 172
 173 static int tps65910_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 174 {
 175         unsigned char alarm_data[NUM_TIME_REGS];
 176         struct tps65910 *tps = dev_get_drvdata(dev->parent);
 177         int ret;
 178
 179         ret = tps65910_rtc_alarm_irq_enable(dev, 0);
 180         if (ret)
 181                 return ret;
 182
 183         alarm_data[0] = bin2bcd(alm->time.tm_sec);
 184         alarm_data[1] = bin2bcd(alm->time.tm_min);
 185         alarm_data[2] = bin2bcd(alm->time.tm_hour);
 186         alarm_data[3] = bin2bcd(alm->time.tm_mday);
 187         alarm_data[4] = bin2bcd(alm->time.tm_mon + 1);
 188         alarm_data[5] = bin2bcd(alm->time.tm_year - 100);
 189
 190         /* update all the alarm registers in one shot */
 191         ret = regmap_bulk_write(tps->regmap, TPS65910_ALARM_SECONDS,
 192                 alarm_data, NUM_TIME_REGS);
 193         if (ret) {
 194                 dev_err(dev, "rtc_set_alarm error %d\n", ret);
 195                 return ret;
 196         }
 197
 198         if (alm->enabled)
 199                 ret = tps65910_rtc_alarm_irq_enable(dev, 1);
 200
 201         return ret;
 202 }
 203
 204 static int tps65910_rtc_set_calibration(struct device *dev, int calibration)
 205 {
 206         unsigned char comp_data[NUM_COMP_REGS];
 207         struct tps65910 *tps = dev_get_drvdata(dev->parent);
 208         s16 value;
 209         int ret;
 210
 211         /*
 212          * TPS65910 uses two's complement 16 bit value for compensation for RTC
 213          * crystal inaccuracies. One time every hour when seconds counter
 214          * increments from 0 to 1 compensation value will be added to internal
 215          * RTC counter value.
 216          *
 217          * Compensation value 0x7FFF is prohibited value.
 218          *
 219          * Valid range for compensation value: [-32768 .. 32766]
 220          */
 221         if ((calibration < -32768) || (calibration > 32766)) {
 222                 dev_err(dev, "RTC calibration value out of range: %d\n",
 223                         calibration);
 224                 return -EINVAL;
 225         }
 226
 227         value = (s16)calibration;
 228
 229         comp_data[0] = (u16)value & 0xFF;
 230         comp_data[1] = ((u16)value >> 8) & 0xFF;
 231
 232         /* Update all the compensation registers in one shot */
 233         ret = regmap_bulk_write(tps->regmap, TPS65910_RTC_COMP_LSB,
 234                 comp_data, NUM_COMP_REGS);
 235         if (ret < 0) {
 236                 dev_err(dev, "rtc_set_calibration error: %d\n", ret);
 237                 return ret;
 238         }
 239
 240         /* Enable automatic compensation */
 241         ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
 242                 TPS65910_RTC_CTRL_AUTO_COMP, TPS65910_RTC_CTRL_AUTO_COMP);
 243         if (ret < 0)
 244                 dev_err(dev, "auto_comp enable failed with error: %d\n", ret);
 245
 246         return ret;
 247 }
 248
 249 static int tps65910_rtc_get_calibration(struct device *dev, int *calibration)
 250 {
 251         unsigned char comp_data[NUM_COMP_REGS];
 252         struct tps65910 *tps = dev_get_drvdata(dev->parent);
 253         unsigned int ctrl;
 254         u16 value;
 255         int ret;
 256
 257         ret = regmap_read(tps->regmap, TPS65910_RTC_CTRL, &ctrl);
 258         if (ret < 0)
 259                 return ret;
 260
 261         /* If automatic compensation is not enabled report back zero */
 262         if (!(ctrl & TPS65910_RTC_CTRL_AUTO_COMP)) {
 263                 *calibration = 0;
 264                 return 0;
 265         }
 266
 267         ret = regmap_bulk_read(tps->regmap, TPS65910_RTC_COMP_LSB, comp_data,
 268                 NUM_COMP_REGS);
 269         if (ret < 0) {
 270                 dev_err(dev, "rtc_get_calibration error: %d\n", ret);
 271                 return ret;
 272         }
 273
 274         value = (u16)comp_data[0] | ((u16)comp_data[1] << 8);
 275
 276         *calibration = (s16)value;
 277
 278         return 0;
 279 }
 280
 281 static int tps65910_read_offset(struct device *dev, long *offset)
 282 {
 283         int calibration;
 284         s64 tmp;
 285         int ret;
 286
 287         ret = tps65910_rtc_get_calibration(dev, &calibration);
 288         if (ret < 0)
 289                 return ret;
 290
 291         /* Convert from RTC calibration register format to ppb format */
 292         tmp = calibration * (s64)PPB_MULT;
 293         if (tmp < 0)
 294                 tmp -= TICKS_PER_HOUR / 2LL;
 295         else
 296                 tmp += TICKS_PER_HOUR / 2LL;
 297         tmp = div_s64(tmp, TICKS_PER_HOUR);
 298
 299         /* Offset value operates in negative way, so swap sign */
 300         *offset = (long)-tmp;
 301
 302         return 0;
 303 }
 304
 305 static int tps65910_set_offset(struct device *dev, long offset)
 306 {
 307         int calibration;
 308         s64 tmp;
 309         int ret;
 310
 311         /* Make sure offset value is within supported range */
 312         if (offset < MIN_OFFSET || offset > MAX_OFFSET)
 313                 return -ERANGE;
 314
 315         /* Convert from ppb format to RTC calibration register format */
 316         tmp = offset * (s64)TICKS_PER_HOUR;
 317         if (tmp < 0)
 318                 tmp -= PPB_MULT / 2LL;
 319         else
 320                 tmp += PPB_MULT / 2LL;
 321         tmp = div_s64(tmp, PPB_MULT);
 322
 323         /* Offset value operates in negative way, so swap sign */
 324         calibration = (int)-tmp;
 325
 326         ret = tps65910_rtc_set_calibration(dev, calibration);
 327
 328         return ret;
 329 }
 330
 331 static irqreturn_t tps65910_rtc_interrupt(int irq, void *rtc)
 332 {
 333         struct device *dev = rtc;
 334         unsigned long events = 0;
 335         struct tps65910 *tps = dev_get_drvdata(dev->parent);
 336         struct tps65910_rtc *tps_rtc = dev_get_drvdata(dev);
 337         int ret;
 338         u32 rtc_reg;
 339
 340         ret = regmap_read(tps->regmap, TPS65910_RTC_STATUS, &rtc_reg);
 341         if (ret)
 342                 return IRQ_NONE;
 343
 344         if (rtc_reg & TPS65910_RTC_STATUS_ALARM)
 345                 events = RTC_IRQF | RTC_AF;
 346
 347         ret = regmap_write(tps->regmap, TPS65910_RTC_STATUS, rtc_reg);
 348         if (ret)
 349                 return IRQ_NONE;
 350
 351         /* Notify RTC core on event */
 352         rtc_update_irq(tps_rtc->rtc, 1, events);
 353
 354         return IRQ_HANDLED;
 355 }
 356
 357 static const struct rtc_class_ops tps65910_rtc_ops = {
 358         .read_time      = tps65910_rtc_read_time,
 359         .set_time       = tps65910_rtc_set_time,
 360         .read_alarm     = tps65910_rtc_read_alarm,
 361         .set_alarm      = tps65910_rtc_set_alarm,
 362         .alarm_irq_enable = tps65910_rtc_alarm_irq_enable,
 363         .read_offset    = tps65910_read_offset,
 364         .set_offset     = tps65910_set_offset,
 365 };
 366
 367 static int tps65910_rtc_probe(struct platform_device *pdev)
 368 {
 369         struct tps65910 *tps65910 = NULL;
 370         struct tps65910_rtc *tps_rtc = NULL;
 371         int ret;
 372         int irq;
 373         u32 rtc_reg;
 374
 375         tps65910 = dev_get_drvdata(pdev->dev.parent);
 376
 377         tps_rtc = devm_kzalloc(&pdev->dev, sizeof(struct tps65910_rtc),
 378                         GFP_KERNEL);
 379         if (!tps_rtc)
 380                 return -ENOMEM;
 381
 382         /* Clear pending interrupts */
 383         ret = regmap_read(tps65910->regmap, TPS65910_RTC_STATUS, &rtc_reg);
 384         if (ret < 0)
 385                 return ret;
 386
 387         ret = regmap_write(tps65910->regmap, TPS65910_RTC_STATUS, rtc_reg);
 388         if (ret < 0)
 389                 return ret;
 390
 391         dev_dbg(&pdev->dev, "Enabling rtc-tps65910.\n");
 392
 393         /* Enable RTC digital power domain */
 394         ret = regmap_update_bits(tps65910->regmap, TPS65910_DEVCTRL,
 395                 DEVCTRL_RTC_PWDN_MASK, 0 << DEVCTRL_RTC_PWDN_SHIFT);
 396         if (ret < 0)
 397                 return ret;
 398
 399         rtc_reg = TPS65910_RTC_CTRL_STOP_RTC;
 400         ret = regmap_write(tps65910->regmap, TPS65910_RTC_CTRL, rtc_reg);
 401         if (ret < 0)
 402                 return ret;
 403
 404         platform_set_drvdata(pdev, tps_rtc);
 405
 406         irq  = platform_get_irq(pdev, 0);
 407         if (irq <= 0) {
 408                 dev_warn(&pdev->dev, "Wake up is not possible as irq = %d\n",
 409                         irq);
 410                 return -ENXIO;
 411         }
 412
 413         ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
 414                 tps65910_rtc_interrupt, IRQF_TRIGGER_LOW,
 415                 dev_name(&pdev->dev), &pdev->dev);
 416         if (ret < 0) {
 417                 dev_err(&pdev->dev, "IRQ is not free.\n");
 418                 return ret;
 419         }
 420         tps_rtc->irq = irq;
 421         device_set_wakeup_capable(&pdev->dev, 1);
 422
 423         tps_rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
 424                 &tps65910_rtc_ops, THIS_MODULE);
 425         if (IS_ERR(tps_rtc->rtc)) {
 426                 ret = PTR_ERR(tps_rtc->rtc);
 427                 dev_err(&pdev->dev, "RTC device register: err %d\n", ret);
 428                 return ret;
 429         }
 430
 431         return 0;
 432 }
 433
 434 /*
 435  * Disable tps65910 RTC interrupts.
 436  * Sets status flag to free.
 437  */
 438 static int tps65910_rtc_remove(struct platform_device *pdev)
 439 {
 440         tps65910_rtc_alarm_irq_enable(&pdev->dev, 0);
 441
 442         return 0;
 443 }
 444
 445 #ifdef CONFIG_PM_SLEEP
 446 static int tps65910_rtc_suspend(struct device *dev)
 447 {
 448         struct tps65910_rtc *tps_rtc = dev_get_drvdata(dev);
 449
 450         if (device_may_wakeup(dev))
 451                 enable_irq_wake(tps_rtc->irq);
 452         return 0;
 453 }
 454
 455 static int tps65910_rtc_resume(struct device *dev)
 456 {
 457         struct tps65910_rtc *tps_rtc = dev_get_drvdata(dev);
 458
 459         if (device_may_wakeup(dev))
 460                 disable_irq_wake(tps_rtc->irq);
 461         return 0;
 462 }
 463 #endif
 464
 465 static SIMPLE_DEV_PM_OPS(tps65910_rtc_pm_ops, tps65910_rtc_suspend,
 466                         tps65910_rtc_resume);
 467
 468 static struct platform_driver tps65910_rtc_driver = {
 469         .probe          = tps65910_rtc_probe,
 470         .remove         = tps65910_rtc_remove,
 471         .driver         = {
 472                 .name   = "tps65910-rtc",
 473                 .pm     = &tps65910_rtc_pm_ops,
 474         },
 475 };
 476
 477 module_platform_driver(tps65910_rtc_driver);
 478 MODULE_ALIAS("platform:rtc-tps65910");
 479 MODULE_AUTHOR("Venu Byravarasu <vbyravarasu@nvidia.com>");
 480 MODULE_LICENSE("GPL");