linux/drivers/rtc/rtc-tps6586x.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * rtc-tps6586x.c: RTC driver for TI PMIC TPS6586X
   4 *
   5 * Copyright (c) 2012, NVIDIA Corporation.
   6 *
   7 * Author: Laxman Dewangan <ldewangan@nvidia.com>
   8 */
   9
  10#include <linux/device.h>
  11#include <linux/err.h>
  12#include <linux/init.h>
  13#include <linux/irq.h>
  14#include <linux/kernel.h>
  15#include <linux/mfd/tps6586x.h>
  16#include <linux/module.h>
  17#include <linux/platform_device.h>
  18#include <linux/pm_runtime.h>
  19#include <linux/rtc.h>
  20#include <linux/slab.h>
  21
  22#define RTC_CTRL                        0xc0
  23#define POR_RESET_N                     BIT(7)
  24#define OSC_SRC_SEL                     BIT(6)
  25#define RTC_ENABLE                      BIT(5)  /* enables alarm */
  26#define RTC_BUF_ENABLE                  BIT(4)  /* 32 KHz buffer enable */
  27#define PRE_BYPASS                      BIT(3)  /* 0=1KHz or 1=32KHz updates */
  28#define CL_SEL_MASK                     (BIT(2)|BIT(1))
  29#define CL_SEL_POS                      1
  30#define RTC_ALARM1_HI                   0xc1
  31#define RTC_COUNT4                      0xc6
  32
  33/* start a PMU RTC access by reading the register prior to the RTC_COUNT4 */
  34#define RTC_COUNT4_DUMMYREAD            0xc5
  35
  36/*only 14-bits width in second*/
  37#define ALM1_VALID_RANGE_IN_SEC         0x3FFF
  38
  39#define TPS6586X_RTC_CL_SEL_1_5PF       0x0
  40#define TPS6586X_RTC_CL_SEL_6_5PF       0x1
  41#define TPS6586X_RTC_CL_SEL_7_5PF       0x2
  42#define TPS6586X_RTC_CL_SEL_12_5PF      0x3
  43
  44struct tps6586x_rtc {
  45        struct device           *dev;
  46        struct rtc_device       *rtc;
  47        int                     irq;
  48        bool                    irq_en;
  49};
  50
  51static inline struct device *to_tps6586x_dev(struct device *dev)
  52{
  53        return dev->parent;
  54}
  55
  56static int tps6586x_rtc_read_time(struct device *dev, struct rtc_time *tm)
  57{
  58        struct device *tps_dev = to_tps6586x_dev(dev);
  59        unsigned long long ticks = 0;
  60        time64_t seconds;
  61        u8 buff[6];
  62        int ret;
  63        int i;
  64
  65        ret = tps6586x_reads(tps_dev, RTC_COUNT4_DUMMYREAD, sizeof(buff), buff);
  66        if (ret < 0) {
  67                dev_err(dev, "read counter failed with err %d\n", ret);
  68                return ret;
  69        }
  70
  71        for (i = 1; i < sizeof(buff); i++) {
  72                ticks <<= 8;
  73                ticks |= buff[i];
  74        }
  75
  76        seconds = ticks >> 10;
  77        rtc_time64_to_tm(seconds, tm);
  78
  79        return 0;
  80}
  81
  82static int tps6586x_rtc_set_time(struct device *dev, struct rtc_time *tm)
  83{
  84        struct device *tps_dev = to_tps6586x_dev(dev);
  85        unsigned long long ticks;
  86        time64_t seconds;
  87        u8 buff[5];
  88        int ret;
  89
  90        seconds = rtc_tm_to_time64(tm);
  91
  92        ticks = (unsigned long long)seconds << 10;
  93        buff[0] = (ticks >> 32) & 0xff;
  94        buff[1] = (ticks >> 24) & 0xff;
  95        buff[2] = (ticks >> 16) & 0xff;
  96        buff[3] = (ticks >> 8) & 0xff;
  97        buff[4] = ticks & 0xff;
  98
  99        /* Disable RTC before changing time */
 100        ret = tps6586x_clr_bits(tps_dev, RTC_CTRL, RTC_ENABLE);
 101        if (ret < 0) {
 102                dev_err(dev, "failed to clear RTC_ENABLE\n");
 103                return ret;
 104        }
 105
 106        ret = tps6586x_writes(tps_dev, RTC_COUNT4, sizeof(buff), buff);
 107        if (ret < 0) {
 108                dev_err(dev, "failed to program new time\n");
 109                return ret;
 110        }
 111
 112        /* Enable RTC */
 113        ret = tps6586x_set_bits(tps_dev, RTC_CTRL, RTC_ENABLE);
 114        if (ret < 0) {
 115                dev_err(dev, "failed to set RTC_ENABLE\n");
 116                return ret;
 117        }
 118        return 0;
 119}
 120
 121static int tps6586x_rtc_alarm_irq_enable(struct device *dev,
 122                         unsigned int enabled)
 123{
 124        struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
 125
 126        if (enabled && !rtc->irq_en) {
 127                enable_irq(rtc->irq);
 128                rtc->irq_en = true;
 129        } else if (!enabled && rtc->irq_en)  {
 130                disable_irq(rtc->irq);
 131                rtc->irq_en = false;
 132        }
 133        return 0;
 134}
 135
 136static int tps6586x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 137{
 138        struct device *tps_dev = to_tps6586x_dev(dev);
 139        time64_t seconds;
 140        unsigned long ticks;
 141        unsigned long rtc_current_time;
 142        unsigned long long rticks = 0;
 143        u8 buff[3];
 144        u8 rbuff[6];
 145        int ret;
 146        int i;
 147
 148        seconds = rtc_tm_to_time64(&alrm->time);
 149
 150        ret = tps6586x_rtc_alarm_irq_enable(dev, alrm->enabled);
 151        if (ret < 0) {
 152                dev_err(dev, "can't set alarm irq, err %d\n", ret);
 153                return ret;
 154        }
 155
 156        ret = tps6586x_reads(tps_dev, RTC_COUNT4_DUMMYREAD,
 157                        sizeof(rbuff), rbuff);
 158        if (ret < 0) {
 159                dev_err(dev, "read counter failed with err %d\n", ret);
 160                return ret;
 161        }
 162
 163        for (i = 1; i < sizeof(rbuff); i++) {
 164                rticks <<= 8;
 165                rticks |= rbuff[i];
 166        }
 167
 168        rtc_current_time = rticks >> 10;
 169        if ((seconds - rtc_current_time) > ALM1_VALID_RANGE_IN_SEC)
 170                seconds = rtc_current_time - 1;
 171
 172        ticks = (unsigned long long)seconds << 10;
 173        buff[0] = (ticks >> 16) & 0xff;
 174        buff[1] = (ticks >> 8) & 0xff;
 175        buff[2] = ticks & 0xff;
 176
 177        ret = tps6586x_writes(tps_dev, RTC_ALARM1_HI, sizeof(buff), buff);
 178        if (ret)
 179                dev_err(dev, "programming alarm failed with err %d\n", ret);
 180
 181        return ret;
 182}
 183
 184static int tps6586x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 185{
 186        struct device *tps_dev = to_tps6586x_dev(dev);
 187        unsigned long ticks;
 188        time64_t seconds;
 189        u8 buff[3];
 190        int ret;
 191
 192        ret = tps6586x_reads(tps_dev, RTC_ALARM1_HI, sizeof(buff), buff);
 193        if (ret) {
 194                dev_err(dev, "read RTC_ALARM1_HI failed with err %d\n", ret);
 195                return ret;
 196        }
 197
 198        ticks = (buff[0] << 16) | (buff[1] << 8) | buff[2];
 199        seconds = ticks >> 10;
 200
 201        rtc_time64_to_tm(seconds, &alrm->time);
 202        return 0;
 203}
 204
 205static const struct rtc_class_ops tps6586x_rtc_ops = {
 206        .read_time      = tps6586x_rtc_read_time,
 207        .set_time       = tps6586x_rtc_set_time,
 208        .set_alarm      = tps6586x_rtc_set_alarm,
 209        .read_alarm     = tps6586x_rtc_read_alarm,
 210        .alarm_irq_enable = tps6586x_rtc_alarm_irq_enable,
 211};
 212
 213static irqreturn_t tps6586x_rtc_irq(int irq, void *data)
 214{
 215        struct tps6586x_rtc *rtc = data;
 216
 217        rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
 218        return IRQ_HANDLED;
 219}
 220
 221static int tps6586x_rtc_probe(struct platform_device *pdev)
 222{
 223        struct device *tps_dev = to_tps6586x_dev(&pdev->dev);
 224        struct tps6586x_rtc *rtc;
 225        int ret;
 226
 227        rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
 228        if (!rtc)
 229                return -ENOMEM;
 230
 231        rtc->dev = &pdev->dev;
 232        rtc->irq = platform_get_irq(pdev, 0);
 233
 234        /* 1 kHz tick mode, enable tick counting */
 235        ret = tps6586x_update(tps_dev, RTC_CTRL,
 236                RTC_ENABLE | OSC_SRC_SEL |
 237                ((TPS6586X_RTC_CL_SEL_1_5PF << CL_SEL_POS) & CL_SEL_MASK),
 238                RTC_ENABLE | OSC_SRC_SEL | PRE_BYPASS | CL_SEL_MASK);
 239        if (ret < 0) {
 240                dev_err(&pdev->dev, "unable to start counter\n");
 241                return ret;
 242        }
 243
 244        device_init_wakeup(&pdev->dev, 1);
 245
 246        platform_set_drvdata(pdev, rtc);
 247        rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
 248        if (IS_ERR(rtc->rtc)) {
 249                ret = PTR_ERR(rtc->rtc);
 250                goto fail_rtc_register;
 251        }
 252
 253        rtc->rtc->ops = &tps6586x_rtc_ops;
 254        rtc->rtc->range_max = (1ULL << 30) - 1; /* 30-bit seconds */
 255        rtc->rtc->start_secs = mktime64(2009, 1, 1, 0, 0, 0);
 256        rtc->rtc->set_start_time = true;
 257
 258        irq_set_status_flags(rtc->irq, IRQ_NOAUTOEN);
 259
 260        ret = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
 261                                tps6586x_rtc_irq,
 262                                IRQF_ONESHOT,
 263                                dev_name(&pdev->dev), rtc);
 264        if (ret < 0) {
 265                dev_err(&pdev->dev, "request IRQ(%d) failed with ret %d\n",
 266                                rtc->irq, ret);
 267                goto fail_rtc_register;
 268        }
 269
 270        ret = devm_rtc_register_device(rtc->rtc);
 271        if (ret)
 272                goto fail_rtc_register;
 273
 274        return 0;
 275
 276fail_rtc_register:
 277        tps6586x_update(tps_dev, RTC_CTRL, 0,
 278                RTC_ENABLE | OSC_SRC_SEL | PRE_BYPASS | CL_SEL_MASK);
 279        return ret;
 280};
 281
 282static int tps6586x_rtc_remove(struct platform_device *pdev)
 283{
 284        struct device *tps_dev = to_tps6586x_dev(&pdev->dev);
 285
 286        tps6586x_update(tps_dev, RTC_CTRL, 0,
 287                RTC_ENABLE | OSC_SRC_SEL | PRE_BYPASS | CL_SEL_MASK);
 288        return 0;
 289}
 290
 291#ifdef CONFIG_PM_SLEEP
 292static int tps6586x_rtc_suspend(struct device *dev)
 293{
 294        struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
 295
 296        if (device_may_wakeup(dev))
 297                enable_irq_wake(rtc->irq);
 298        return 0;
 299}
 300
 301static int tps6586x_rtc_resume(struct device *dev)
 302{
 303        struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
 304
 305        if (device_may_wakeup(dev))
 306                disable_irq_wake(rtc->irq);
 307        return 0;
 308}
 309#endif
 310
 311static SIMPLE_DEV_PM_OPS(tps6586x_pm_ops, tps6586x_rtc_suspend,
 312                        tps6586x_rtc_resume);
 313
 314static struct platform_driver tps6586x_rtc_driver = {
 315        .driver = {
 316                .name   = "tps6586x-rtc",
 317                .pm     = &tps6586x_pm_ops,
 318        },
 319        .probe  = tps6586x_rtc_probe,
 320        .remove = tps6586x_rtc_remove,
 321};
 322module_platform_driver(tps6586x_rtc_driver);
 323
 324MODULE_ALIAS("platform:tps6586x-rtc");
 325MODULE_DESCRIPTION("TI TPS6586x RTC driver");
 326MODULE_AUTHOR("Laxman dewangan <ldewangan@nvidia.com>");
 327MODULE_LICENSE("GPL v2");
 328