linux/drivers/rtc/rtc-rc5t619.c
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   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * drivers/rtc/rtc-rc5t619.c
   4 *
   5 * Real time clock driver for RICOH RC5T619 power management chip.
   6 *
   7 * Copyright (C) 2019 Andreas Kemnade
   8 */
   9
  10#include <linux/kernel.h>
  11#include <linux/device.h>
  12#include <linux/errno.h>
  13#include <linux/init.h>
  14#include <linux/module.h>
  15#include <linux/mfd/rn5t618.h>
  16#include <linux/platform_device.h>
  17#include <linux/regmap.h>
  18#include <linux/bcd.h>
  19#include <linux/rtc.h>
  20#include <linux/slab.h>
  21#include <linux/irqdomain.h>
  22
  23struct rc5t619_rtc {
  24        int                     irq;
  25        struct rtc_device       *rtc;
  26        struct rn5t618 *rn5t618;
  27};
  28
  29#define CTRL1_ALARM_ENABLED 0x40
  30#define CTRL1_24HR 0x20
  31#define CTRL1_PERIODIC_MASK 0xf
  32
  33#define CTRL2_PON 0x10
  34#define CTRL2_ALARM_STATUS 0x80
  35#define CTRL2_CTFG 0x4
  36#define CTRL2_CTC 0x1
  37
  38#define MONTH_CENTFLAG 0x80
  39#define HOUR_PMFLAG 0x20
  40#define MDAY_DAL_EXT 0x80
  41
  42static uint8_t rtc5t619_12hour_bcd2bin(uint8_t hour)
  43{
  44        if (hour & HOUR_PMFLAG) {
  45                hour = bcd2bin(hour & ~HOUR_PMFLAG);
  46                return hour == 12 ? 12 : 12 + hour;
  47        }
  48
  49        hour = bcd2bin(hour);
  50        return hour == 12 ? 0 : hour;
  51}
  52
  53static uint8_t rtc5t619_12hour_bin2bcd(uint8_t hour)
  54{
  55        if (!hour)
  56                return 0x12;
  57
  58        if (hour < 12)
  59                return bin2bcd(hour);
  60
  61        if (hour == 12)
  62                return 0x12 | HOUR_PMFLAG;
  63
  64        return bin2bcd(hour - 12) | HOUR_PMFLAG;
  65}
  66
  67static int rc5t619_rtc_periodic_disable(struct device *dev)
  68{
  69        struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
  70        int err;
  71
  72        /* disable function */
  73        err = regmap_update_bits(rtc->rn5t618->regmap,
  74                                 RN5T618_RTC_CTRL1, CTRL1_PERIODIC_MASK, 0);
  75        if (err < 0)
  76                return err;
  77
  78        /* clear alarm flag and CTFG */
  79        err = regmap_update_bits(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2,
  80                                 CTRL2_ALARM_STATUS | CTRL2_CTFG | CTRL2_CTC,
  81                                 0);
  82        if (err < 0)
  83                return err;
  84
  85        return 0;
  86}
  87
  88/* things to be done once after power on */
  89static int rc5t619_rtc_pon_setup(struct device *dev)
  90{
  91        struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
  92        int err;
  93        unsigned int reg_data;
  94
  95        err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2, &reg_data);
  96        if (err < 0)
  97                return err;
  98
  99        /* clear VDET PON */
 100        reg_data &= ~(CTRL2_PON | CTRL2_CTC | 0x4a);    /* 0101-1011 */
 101        reg_data |= 0x20;       /* 0010-0000 */
 102        err = regmap_write(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2, reg_data);
 103        if (err < 0)
 104                return err;
 105
 106        /* clearing RTC Adjust register */
 107        err = regmap_write(rtc->rn5t618->regmap, RN5T618_RTC_ADJUST, 0);
 108        if (err)
 109                return err;
 110
 111        return regmap_update_bits(rtc->rn5t618->regmap,
 112                                        RN5T618_RTC_CTRL1,
 113                                        CTRL1_24HR, CTRL1_24HR);
 114}
 115
 116static int rc5t619_rtc_read_time(struct device *dev, struct rtc_time *tm)
 117{
 118        struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
 119        u8 buff[7];
 120        int err;
 121        int cent_flag;
 122        unsigned int ctrl1;
 123        unsigned int ctrl2;
 124
 125        err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2, &ctrl2);
 126        if (err < 0)
 127                return err;
 128
 129        if (ctrl2 & CTRL2_PON)
 130                return -EINVAL;
 131
 132        err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL1, &ctrl1);
 133        if (err < 0)
 134                return err;
 135
 136        err = regmap_bulk_read(rtc->rn5t618->regmap, RN5T618_RTC_SECONDS,
 137                               buff, sizeof(buff));
 138        if (err < 0)
 139                return err;
 140
 141        if (buff[5] & MONTH_CENTFLAG)
 142                cent_flag = 1;
 143        else
 144                cent_flag = 0;
 145
 146        tm->tm_sec  = bcd2bin(buff[0]);
 147        tm->tm_min  = bcd2bin(buff[1]);
 148
 149        if (ctrl1 & CTRL1_24HR)
 150                tm->tm_hour = bcd2bin(buff[2]);
 151        else
 152                tm->tm_hour = rtc5t619_12hour_bcd2bin(buff[2]);
 153
 154        tm->tm_wday = bcd2bin(buff[3]);
 155        tm->tm_mday = bcd2bin(buff[4]);
 156        tm->tm_mon  = bcd2bin(buff[5] & 0x1f) - 1; /* back to system 0-11 */
 157        tm->tm_year = bcd2bin(buff[6]) + 100 * cent_flag;
 158
 159        return 0;
 160}
 161
 162static int rc5t619_rtc_set_time(struct device *dev, struct rtc_time *tm)
 163{
 164        struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
 165        u8 buff[7];
 166        int err;
 167        int cent_flag;
 168        unsigned int ctrl1;
 169        unsigned int ctrl2;
 170
 171        err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2, &ctrl2);
 172        if (err < 0)
 173                return err;
 174
 175        if (ctrl2 & CTRL2_PON)
 176                rc5t619_rtc_pon_setup(dev);
 177
 178        err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL1, &ctrl1);
 179        if (err < 0)
 180                return err;
 181
 182        if (tm->tm_year >= 100)
 183                cent_flag = 1;
 184        else
 185                cent_flag = 0;
 186
 187        buff[0] = bin2bcd(tm->tm_sec);
 188        buff[1] = bin2bcd(tm->tm_min);
 189
 190        if (ctrl1 & CTRL1_24HR)
 191                buff[2] = bin2bcd(tm->tm_hour);
 192        else
 193                buff[2] = rtc5t619_12hour_bin2bcd(tm->tm_hour);
 194
 195        buff[3] = bin2bcd(tm->tm_wday);
 196        buff[4] = bin2bcd(tm->tm_mday);
 197        buff[5] = bin2bcd(tm->tm_mon + 1);      /* system set 0-11 */
 198        buff[6] = bin2bcd(tm->tm_year - cent_flag * 100);
 199
 200        if (cent_flag)
 201                buff[5] |= MONTH_CENTFLAG;
 202
 203        err = regmap_bulk_write(rtc->rn5t618->regmap, RN5T618_RTC_SECONDS,
 204                                buff, sizeof(buff));
 205        if (err < 0) {
 206                dev_err(dev, "failed to program new time: %d\n", err);
 207                return err;
 208        }
 209
 210        return 0;
 211}
 212
 213/* 0-disable, 1-enable */
 214static int rc5t619_rtc_alarm_enable(struct device *dev, unsigned int enabled)
 215{
 216        struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
 217
 218        return regmap_update_bits(rtc->rn5t618->regmap,
 219                        RN5T618_RTC_CTRL1,
 220                        CTRL1_ALARM_ENABLED,
 221                        enabled ? CTRL1_ALARM_ENABLED : 0);
 222}
 223
 224static int rc5t619_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 225{
 226        struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
 227        u8 buff[6];
 228        unsigned int buff_cent;
 229        int err;
 230        int cent_flag;
 231        unsigned int ctrl1;
 232
 233        err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL1, &ctrl1);
 234        if (err)
 235                return err;
 236
 237        err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_MONTH, &buff_cent);
 238        if (err < 0) {
 239                dev_err(dev, "failed to read time: %d\n", err);
 240                return err;
 241        }
 242
 243        if (buff_cent & MONTH_CENTFLAG)
 244                cent_flag = 1;
 245        else
 246                cent_flag = 0;
 247
 248        err = regmap_bulk_read(rtc->rn5t618->regmap, RN5T618_RTC_ALARM_Y_SEC,
 249                               buff, sizeof(buff));
 250        if (err)
 251                return err;
 252
 253        buff[3] = buff[3] & 0x3f;
 254
 255        alrm->time.tm_sec  = bcd2bin(buff[0]);
 256        alrm->time.tm_min  = bcd2bin(buff[1]);
 257
 258        if (ctrl1 & CTRL1_24HR)
 259                alrm->time.tm_hour = bcd2bin(buff[2]);
 260        else
 261                alrm->time.tm_hour = rtc5t619_12hour_bcd2bin(buff[2]);
 262
 263        alrm->time.tm_mday = bcd2bin(buff[3]);
 264        alrm->time.tm_mon  = bcd2bin(buff[4]) - 1;
 265        alrm->time.tm_year = bcd2bin(buff[5]) + 100 * cent_flag;
 266        alrm->enabled = !!(ctrl1 & CTRL1_ALARM_ENABLED);
 267        dev_dbg(dev, "read alarm: %ptR\n", &alrm->time);
 268
 269        return 0;
 270}
 271
 272static int rc5t619_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 273{
 274        struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
 275        u8 buff[6];
 276        int err;
 277        int cent_flag;
 278        unsigned int ctrl1;
 279
 280        err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL1, &ctrl1);
 281        if (err)
 282                return err;
 283
 284        err = rc5t619_rtc_alarm_enable(dev, 0);
 285        if (err < 0)
 286                return err;
 287
 288        if (rtc->irq == -1)
 289                return -EINVAL;
 290
 291        if (alrm->enabled == 0)
 292                return 0;
 293
 294        if (alrm->time.tm_year >= 100)
 295                cent_flag = 1;
 296        else
 297                cent_flag = 0;
 298
 299        alrm->time.tm_mon += 1;
 300        buff[0] = bin2bcd(alrm->time.tm_sec);
 301        buff[1] = bin2bcd(alrm->time.tm_min);
 302
 303        if (ctrl1 & CTRL1_24HR)
 304                buff[2] = bin2bcd(alrm->time.tm_hour);
 305        else
 306                buff[2] = rtc5t619_12hour_bin2bcd(alrm->time.tm_hour);
 307
 308        buff[3] = bin2bcd(alrm->time.tm_mday);
 309        buff[4] = bin2bcd(alrm->time.tm_mon);
 310        buff[5] = bin2bcd(alrm->time.tm_year - 100 * cent_flag);
 311        buff[3] |= MDAY_DAL_EXT;
 312
 313        err = regmap_bulk_write(rtc->rn5t618->regmap, RN5T618_RTC_ALARM_Y_SEC,
 314                                buff, sizeof(buff));
 315        if (err < 0)
 316                return err;
 317
 318        return rc5t619_rtc_alarm_enable(dev, alrm->enabled);
 319}
 320
 321static const struct rtc_class_ops rc5t619_rtc_ops = {
 322        .read_time      = rc5t619_rtc_read_time,
 323        .set_time       = rc5t619_rtc_set_time,
 324        .set_alarm      = rc5t619_rtc_set_alarm,
 325        .read_alarm     = rc5t619_rtc_read_alarm,
 326        .alarm_irq_enable = rc5t619_rtc_alarm_enable,
 327};
 328
 329static int rc5t619_rtc_alarm_flag_clr(struct device *dev)
 330{
 331        struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
 332
 333        /* clear alarm-D status bits.*/
 334        return regmap_update_bits(rtc->rn5t618->regmap,
 335                                RN5T618_RTC_CTRL2,
 336                                CTRL2_ALARM_STATUS | CTRL2_CTC, 0);
 337}
 338
 339static irqreturn_t rc5t619_rtc_irq(int irq, void *data)
 340{
 341        struct device *dev = data;
 342        struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
 343
 344        rc5t619_rtc_alarm_flag_clr(dev);
 345
 346        rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
 347        return IRQ_HANDLED;
 348}
 349
 350static int rc5t619_rtc_probe(struct platform_device *pdev)
 351{
 352        struct device *dev = &pdev->dev;
 353        struct rn5t618 *rn5t618 = dev_get_drvdata(pdev->dev.parent);
 354        struct rc5t619_rtc *rtc;
 355        unsigned int ctrl2;
 356        int err;
 357
 358        rtc = devm_kzalloc(dev, sizeof(*rtc), GFP_KERNEL);
 359        if (!rtc)
 360                return -ENOMEM;
 361
 362        rtc->rn5t618 = rn5t618;
 363
 364        dev_set_drvdata(dev, rtc);
 365        rtc->irq = -1;
 366
 367        if (rn5t618->irq_data)
 368                rtc->irq = regmap_irq_get_virq(rn5t618->irq_data,
 369                                               RN5T618_IRQ_RTC);
 370
 371        if (rtc->irq  < 0)
 372                rtc->irq = -1;
 373
 374        err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2, &ctrl2);
 375        if (err < 0)
 376                return err;
 377
 378        /* disable rtc periodic function */
 379        err = rc5t619_rtc_periodic_disable(&pdev->dev);
 380        if (err)
 381                return err;
 382
 383        if (ctrl2 & CTRL2_PON) {
 384                err = rc5t619_rtc_alarm_flag_clr(&pdev->dev);
 385                if (err)
 386                        return err;
 387        }
 388
 389        rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
 390        if (IS_ERR(rtc->rtc)) {
 391                err = PTR_ERR(rtc->rtc);
 392                dev_err(dev, "RTC device register: err %d\n", err);
 393                return err;
 394        }
 395
 396        rtc->rtc->ops = &rc5t619_rtc_ops;
 397        rtc->rtc->range_min = RTC_TIMESTAMP_BEGIN_1900;
 398        rtc->rtc->range_max = RTC_TIMESTAMP_END_2099;
 399
 400        /* set interrupt and enable it */
 401        if (rtc->irq != -1) {
 402                err = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
 403                                                rc5t619_rtc_irq,
 404                                                IRQF_ONESHOT,
 405                                                "rtc-rc5t619",
 406                                                &pdev->dev);
 407                if (err < 0) {
 408                        dev_err(&pdev->dev, "request IRQ:%d fail\n", rtc->irq);
 409                        rtc->irq = -1;
 410
 411                        err = rc5t619_rtc_alarm_enable(&pdev->dev, 0);
 412                        if (err)
 413                                return err;
 414
 415                } else {
 416                        /* enable wake */
 417                        device_init_wakeup(&pdev->dev, 1);
 418                        enable_irq_wake(rtc->irq);
 419                }
 420        } else {
 421                /* system don't want to using alarm interrupt, so close it */
 422                err = rc5t619_rtc_alarm_enable(&pdev->dev, 0);
 423                if (err)
 424                        return err;
 425
 426                dev_warn(&pdev->dev, "rc5t619 interrupt is disabled\n");
 427        }
 428
 429        return rtc_register_device(rtc->rtc);
 430}
 431
 432static struct platform_driver rc5t619_rtc_driver = {
 433        .driver = {
 434                .name   = "rc5t619-rtc",
 435        },
 436        .probe  = rc5t619_rtc_probe,
 437};
 438
 439module_platform_driver(rc5t619_rtc_driver);
 440MODULE_ALIAS("platform:rc5t619-rtc");
 441MODULE_DESCRIPTION("RICOH RC5T619 RTC driver");
 442MODULE_LICENSE("GPL");
 443