linux/drivers/rtc/rtc-88pm860x.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Real Time Clock driver for Marvell 88PM860x PMIC
   4 *
   5 * Copyright (c) 2010 Marvell International Ltd.
   6 * Author:      Haojian Zhuang <haojian.zhuang@marvell.com>
   7 */
   8
   9#include <linux/kernel.h>
  10#include <linux/module.h>
  11#include <linux/of.h>
  12#include <linux/platform_device.h>
  13#include <linux/slab.h>
  14#include <linux/mutex.h>
  15#include <linux/rtc.h>
  16#include <linux/delay.h>
  17#include <linux/mfd/core.h>
  18#include <linux/mfd/88pm860x.h>
  19
  20#define VRTC_CALIBRATION
  21
  22struct pm860x_rtc_info {
  23        struct pm860x_chip      *chip;
  24        struct i2c_client       *i2c;
  25        struct rtc_device       *rtc_dev;
  26        struct device           *dev;
  27        struct delayed_work     calib_work;
  28
  29        int                     irq;
  30        int                     vrtc;
  31};
  32
  33#define REG_VRTC_MEAS1          0x7D
  34
  35#define REG0_ADDR               0xB0
  36#define REG1_ADDR               0xB2
  37#define REG2_ADDR               0xB4
  38#define REG3_ADDR               0xB6
  39
  40#define REG0_DATA               0xB1
  41#define REG1_DATA               0xB3
  42#define REG2_DATA               0xB5
  43#define REG3_DATA               0xB7
  44
  45/* bit definitions of Measurement Enable Register 2 (0x51) */
  46#define MEAS2_VRTC              (1 << 0)
  47
  48/* bit definitions of RTC Register 1 (0xA0) */
  49#define ALARM_EN                (1 << 3)
  50#define ALARM_WAKEUP            (1 << 4)
  51#define ALARM                   (1 << 5)
  52#define RTC1_USE_XO             (1 << 7)
  53
  54#define VRTC_CALIB_INTERVAL     (HZ * 60 * 10)          /* 10 minutes */
  55
  56static irqreturn_t rtc_update_handler(int irq, void *data)
  57{
  58        struct pm860x_rtc_info *info = (struct pm860x_rtc_info *)data;
  59        int mask;
  60
  61        mask = ALARM | ALARM_WAKEUP;
  62        pm860x_set_bits(info->i2c, PM8607_RTC1, mask | ALARM_EN, mask);
  63        rtc_update_irq(info->rtc_dev, 1, RTC_AF);
  64        return IRQ_HANDLED;
  65}
  66
  67static int pm860x_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
  68{
  69        struct pm860x_rtc_info *info = dev_get_drvdata(dev);
  70
  71        if (enabled)
  72                pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, ALARM_EN);
  73        else
  74                pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, 0);
  75        return 0;
  76}
  77
  78static int pm860x_rtc_read_time(struct device *dev, struct rtc_time *tm)
  79{
  80        struct pm860x_rtc_info *info = dev_get_drvdata(dev);
  81        unsigned char buf[8];
  82        unsigned long ticks, base, data;
  83
  84        pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
  85        dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
  86                buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
  87        base = ((unsigned long)buf[1] << 24) | (buf[3] << 16) |
  88                (buf[5] << 8) | buf[7];
  89
  90        /* load 32-bit read-only counter */
  91        pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
  92        data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
  93                (buf[1] << 8) | buf[0];
  94        ticks = base + data;
  95        dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
  96                base, data, ticks);
  97
  98        rtc_time64_to_tm(ticks, tm);
  99
 100        return 0;
 101}
 102
 103static int pm860x_rtc_set_time(struct device *dev, struct rtc_time *tm)
 104{
 105        struct pm860x_rtc_info *info = dev_get_drvdata(dev);
 106        unsigned char buf[4];
 107        unsigned long ticks, base, data;
 108
 109        ticks = rtc_tm_to_time64(tm);
 110
 111        /* load 32-bit read-only counter */
 112        pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
 113        data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
 114                (buf[1] << 8) | buf[0];
 115        base = ticks - data;
 116        dev_dbg(info->dev, "set base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
 117                base, data, ticks);
 118
 119        pm860x_page_reg_write(info->i2c, REG0_DATA, (base >> 24) & 0xFF);
 120        pm860x_page_reg_write(info->i2c, REG1_DATA, (base >> 16) & 0xFF);
 121        pm860x_page_reg_write(info->i2c, REG2_DATA, (base >> 8) & 0xFF);
 122        pm860x_page_reg_write(info->i2c, REG3_DATA, base & 0xFF);
 123
 124        return 0;
 125}
 126
 127static int pm860x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 128{
 129        struct pm860x_rtc_info *info = dev_get_drvdata(dev);
 130        unsigned char buf[8];
 131        unsigned long ticks, base, data;
 132        int ret;
 133
 134        pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
 135        dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
 136                buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
 137        base = ((unsigned long)buf[1] << 24) | (buf[3] << 16) |
 138                (buf[5] << 8) | buf[7];
 139
 140        pm860x_bulk_read(info->i2c, PM8607_RTC_EXPIRE1, 4, buf);
 141        data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
 142                (buf[1] << 8) | buf[0];
 143        ticks = base + data;
 144        dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
 145                base, data, ticks);
 146
 147        rtc_time64_to_tm(ticks, &alrm->time);
 148        ret = pm860x_reg_read(info->i2c, PM8607_RTC1);
 149        alrm->enabled = (ret & ALARM_EN) ? 1 : 0;
 150        alrm->pending = (ret & (ALARM | ALARM_WAKEUP)) ? 1 : 0;
 151        return 0;
 152}
 153
 154static int pm860x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 155{
 156        struct pm860x_rtc_info *info = dev_get_drvdata(dev);
 157        unsigned long ticks, base, data;
 158        unsigned char buf[8];
 159        int mask;
 160
 161        pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, 0);
 162
 163        pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
 164        dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
 165                buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
 166        base = ((unsigned long)buf[1] << 24) | (buf[3] << 16) |
 167                (buf[5] << 8) | buf[7];
 168
 169        ticks = rtc_tm_to_time64(&alrm->time);
 170        data = ticks - base;
 171
 172        buf[0] = data & 0xff;
 173        buf[1] = (data >> 8) & 0xff;
 174        buf[2] = (data >> 16) & 0xff;
 175        buf[3] = (data >> 24) & 0xff;
 176        pm860x_bulk_write(info->i2c, PM8607_RTC_EXPIRE1, 4, buf);
 177        if (alrm->enabled) {
 178                mask = ALARM | ALARM_WAKEUP | ALARM_EN;
 179                pm860x_set_bits(info->i2c, PM8607_RTC1, mask, mask);
 180        } else {
 181                mask = ALARM | ALARM_WAKEUP | ALARM_EN;
 182                pm860x_set_bits(info->i2c, PM8607_RTC1, mask,
 183                                ALARM | ALARM_WAKEUP);
 184        }
 185        return 0;
 186}
 187
 188static const struct rtc_class_ops pm860x_rtc_ops = {
 189        .read_time      = pm860x_rtc_read_time,
 190        .set_time       = pm860x_rtc_set_time,
 191        .read_alarm     = pm860x_rtc_read_alarm,
 192        .set_alarm      = pm860x_rtc_set_alarm,
 193        .alarm_irq_enable = pm860x_rtc_alarm_irq_enable,
 194};
 195
 196#ifdef VRTC_CALIBRATION
 197static void calibrate_vrtc_work(struct work_struct *work)
 198{
 199        struct pm860x_rtc_info *info = container_of(work,
 200                struct pm860x_rtc_info, calib_work.work);
 201        unsigned char buf[2];
 202        unsigned int sum, data, mean, vrtc_set;
 203        int i;
 204
 205        for (i = 0, sum = 0; i < 16; i++) {
 206                msleep(100);
 207                pm860x_bulk_read(info->i2c, REG_VRTC_MEAS1, 2, buf);
 208                data = (buf[0] << 4) | buf[1];
 209                data = (data * 5400) >> 12;     /* convert to mv */
 210                sum += data;
 211        }
 212        mean = sum >> 4;
 213        vrtc_set = 2700 + (info->vrtc & 0x3) * 200;
 214        dev_dbg(info->dev, "mean:%d, vrtc_set:%d\n", mean, vrtc_set);
 215
 216        sum = pm860x_reg_read(info->i2c, PM8607_RTC_MISC1);
 217        data = sum & 0x3;
 218        if ((mean + 200) < vrtc_set) {
 219                /* try higher voltage */
 220                if (++data == 4)
 221                        goto out;
 222                data = (sum & 0xf8) | (data & 0x3);
 223                pm860x_reg_write(info->i2c, PM8607_RTC_MISC1, data);
 224        } else if ((mean - 200) > vrtc_set) {
 225                /* try lower voltage */
 226                if (data-- == 0)
 227                        goto out;
 228                data = (sum & 0xf8) | (data & 0x3);
 229                pm860x_reg_write(info->i2c, PM8607_RTC_MISC1, data);
 230        } else
 231                goto out;
 232        dev_dbg(info->dev, "set 0x%x to RTC_MISC1\n", data);
 233        /* trigger next calibration since VRTC is updated */
 234        schedule_delayed_work(&info->calib_work, VRTC_CALIB_INTERVAL);
 235        return;
 236out:
 237        /* disable measurement */
 238        pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, 0);
 239        dev_dbg(info->dev, "finish VRTC calibration\n");
 240        return;
 241}
 242#endif
 243
 244#ifdef CONFIG_OF
 245static int pm860x_rtc_dt_init(struct platform_device *pdev,
 246                              struct pm860x_rtc_info *info)
 247{
 248        struct device_node *np = pdev->dev.parent->of_node;
 249        int ret;
 250        if (!np)
 251                return -ENODEV;
 252        np = of_get_child_by_name(np, "rtc");
 253        if (!np) {
 254                dev_err(&pdev->dev, "failed to find rtc node\n");
 255                return -ENODEV;
 256        }
 257        ret = of_property_read_u32(np, "marvell,88pm860x-vrtc", &info->vrtc);
 258        if (ret)
 259                info->vrtc = 0;
 260        of_node_put(np);
 261        return 0;
 262}
 263#else
 264#define pm860x_rtc_dt_init(x, y)        do { } while (0)
 265#endif
 266
 267static int pm860x_rtc_probe(struct platform_device *pdev)
 268{
 269        struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
 270        struct pm860x_rtc_info *info;
 271        int ret;
 272
 273        info = devm_kzalloc(&pdev->dev, sizeof(struct pm860x_rtc_info),
 274                            GFP_KERNEL);
 275        if (!info)
 276                return -ENOMEM;
 277        info->irq = platform_get_irq(pdev, 0);
 278        if (info->irq < 0)
 279                return info->irq;
 280
 281        info->chip = chip;
 282        info->i2c = (chip->id == CHIP_PM8607) ? chip->client : chip->companion;
 283        info->dev = &pdev->dev;
 284        dev_set_drvdata(&pdev->dev, info);
 285
 286        info->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
 287        if (IS_ERR(info->rtc_dev))
 288                return PTR_ERR(info->rtc_dev);
 289
 290        ret = devm_request_threaded_irq(&pdev->dev, info->irq, NULL,
 291                                        rtc_update_handler, IRQF_ONESHOT, "rtc",
 292                                        info);
 293        if (ret < 0) {
 294                dev_err(chip->dev, "Failed to request IRQ: #%d: %d\n",
 295                        info->irq, ret);
 296                return ret;
 297        }
 298
 299        /* set addresses of 32-bit base value for RTC time */
 300        pm860x_page_reg_write(info->i2c, REG0_ADDR, REG0_DATA);
 301        pm860x_page_reg_write(info->i2c, REG1_ADDR, REG1_DATA);
 302        pm860x_page_reg_write(info->i2c, REG2_ADDR, REG2_DATA);
 303        pm860x_page_reg_write(info->i2c, REG3_ADDR, REG3_DATA);
 304
 305        pm860x_rtc_dt_init(pdev, info);
 306
 307        info->rtc_dev->ops = &pm860x_rtc_ops;
 308        info->rtc_dev->range_max = U32_MAX;
 309
 310        ret = devm_rtc_register_device(info->rtc_dev);
 311        if (ret)
 312                return ret;
 313
 314        /*
 315         * enable internal XO instead of internal 3.25MHz clock since it can
 316         * free running in PMIC power-down state.
 317         */
 318        pm860x_set_bits(info->i2c, PM8607_RTC1, RTC1_USE_XO, RTC1_USE_XO);
 319
 320#ifdef VRTC_CALIBRATION
 321        /* <00> -- 2.7V, <01> -- 2.9V, <10> -- 3.1V, <11> -- 3.3V */
 322        pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, MEAS2_VRTC);
 323
 324        /* calibrate VRTC */
 325        INIT_DELAYED_WORK(&info->calib_work, calibrate_vrtc_work);
 326        schedule_delayed_work(&info->calib_work, VRTC_CALIB_INTERVAL);
 327#endif  /* VRTC_CALIBRATION */
 328
 329        device_init_wakeup(&pdev->dev, 1);
 330
 331        return 0;
 332}
 333
 334static int pm860x_rtc_remove(struct platform_device *pdev)
 335{
 336        struct pm860x_rtc_info *info = platform_get_drvdata(pdev);
 337
 338#ifdef VRTC_CALIBRATION
 339        cancel_delayed_work_sync(&info->calib_work);
 340        /* disable measurement */
 341        pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, 0);
 342#endif  /* VRTC_CALIBRATION */
 343
 344        return 0;
 345}
 346
 347#ifdef CONFIG_PM_SLEEP
 348static int pm860x_rtc_suspend(struct device *dev)
 349{
 350        struct platform_device *pdev = to_platform_device(dev);
 351        struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
 352
 353        if (device_may_wakeup(dev))
 354                chip->wakeup_flag |= 1 << PM8607_IRQ_RTC;
 355        return 0;
 356}
 357static int pm860x_rtc_resume(struct device *dev)
 358{
 359        struct platform_device *pdev = to_platform_device(dev);
 360        struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
 361
 362        if (device_may_wakeup(dev))
 363                chip->wakeup_flag &= ~(1 << PM8607_IRQ_RTC);
 364        return 0;
 365}
 366#endif
 367
 368static SIMPLE_DEV_PM_OPS(pm860x_rtc_pm_ops, pm860x_rtc_suspend, pm860x_rtc_resume);
 369
 370static struct platform_driver pm860x_rtc_driver = {
 371        .driver         = {
 372                .name   = "88pm860x-rtc",
 373                .pm     = &pm860x_rtc_pm_ops,
 374        },
 375        .probe          = pm860x_rtc_probe,
 376        .remove         = pm860x_rtc_remove,
 377};
 378
 379module_platform_driver(pm860x_rtc_driver);
 380
 381MODULE_DESCRIPTION("Marvell 88PM860x RTC driver");
 382MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
 383MODULE_LICENSE("GPL");
 384