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