linux/drivers/rtc/rtc-88pm860x.c
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   1/*
   2 * Real Time Clock driver for Marvell 88PM860x PMIC
   3 *
   4 * Copyright (c) 2010 Marvell International Ltd.
   5 * Author:      Haojian Zhuang <haojian.zhuang@marvell.com>
   6 *
   7 * This program is free software; you can redistribute it and/or modify
   8 * it under the terms of the GNU General Public License version 2 as
   9 * published by the Free Software Foundation.
  10 */
  11
  12#include <linux/kernel.h>
  13#include <linux/module.h>
  14#include <linux/platform_device.h>
  15#include <linux/slab.h>
  16#include <linux/mutex.h>
  17#include <linux/rtc.h>
  18#include <linux/delay.h>
  19#include <linux/mfd/core.h>
  20#include <linux/mfd/88pm860x.h>
  21
  22#define VRTC_CALIBRATION
  23
  24struct pm860x_rtc_info {
  25        struct pm860x_chip      *chip;
  26        struct i2c_client       *i2c;
  27        struct rtc_device       *rtc_dev;
  28        struct device           *dev;
  29        struct delayed_work     calib_work;
  30
  31        int                     irq;
  32        int                     vrtc;
  33        int                     (*sync)(unsigned int ticks);
  34};
  35
  36#define REG_VRTC_MEAS1          0x7D
  37
  38#define REG0_ADDR               0xB0
  39#define REG1_ADDR               0xB2
  40#define REG2_ADDR               0xB4
  41#define REG3_ADDR               0xB6
  42
  43#define REG0_DATA               0xB1
  44#define REG1_DATA               0xB3
  45#define REG2_DATA               0xB5
  46#define REG3_DATA               0xB7
  47
  48/* bit definitions of Measurement Enable Register 2 (0x51) */
  49#define MEAS2_VRTC              (1 << 0)
  50
  51/* bit definitions of RTC Register 1 (0xA0) */
  52#define ALARM_EN                (1 << 3)
  53#define ALARM_WAKEUP            (1 << 4)
  54#define ALARM                   (1 << 5)
  55#define RTC1_USE_XO             (1 << 7)
  56
  57#define VRTC_CALIB_INTERVAL     (HZ * 60 * 10)          /* 10 minutes */
  58
  59static irqreturn_t rtc_update_handler(int irq, void *data)
  60{
  61        struct pm860x_rtc_info *info = (struct pm860x_rtc_info *)data;
  62        int mask;
  63
  64        mask = ALARM | ALARM_WAKEUP;
  65        pm860x_set_bits(info->i2c, PM8607_RTC1, mask | ALARM_EN, mask);
  66        rtc_update_irq(info->rtc_dev, 1, RTC_AF);
  67        return IRQ_HANDLED;
  68}
  69
  70static int pm860x_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
  71{
  72        struct pm860x_rtc_info *info = dev_get_drvdata(dev);
  73
  74        if (enabled)
  75                pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, ALARM_EN);
  76        else
  77                pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, 0);
  78        return 0;
  79}
  80
  81/*
  82 * Calculate the next alarm time given the requested alarm time mask
  83 * and the current time.
  84 */
  85static void rtc_next_alarm_time(struct rtc_time *next, struct rtc_time *now,
  86                                struct rtc_time *alrm)
  87{
  88        unsigned long next_time;
  89        unsigned long now_time;
  90
  91        next->tm_year = now->tm_year;
  92        next->tm_mon = now->tm_mon;
  93        next->tm_mday = now->tm_mday;
  94        next->tm_hour = alrm->tm_hour;
  95        next->tm_min = alrm->tm_min;
  96        next->tm_sec = alrm->tm_sec;
  97
  98        rtc_tm_to_time(now, &now_time);
  99        rtc_tm_to_time(next, &next_time);
 100
 101        if (next_time < now_time) {
 102                /* Advance one day */
 103                next_time += 60 * 60 * 24;
 104                rtc_time_to_tm(next_time, next);
 105        }
 106}
 107
 108static int pm860x_rtc_read_time(struct device *dev, struct rtc_time *tm)
 109{
 110        struct pm860x_rtc_info *info = dev_get_drvdata(dev);
 111        unsigned char buf[8];
 112        unsigned long ticks, base, data;
 113
 114        pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
 115        dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
 116                buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
 117        base = (buf[1] << 24) | (buf[3] << 16) | (buf[5] << 8) | buf[7];
 118
 119        /* load 32-bit read-only counter */
 120        pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
 121        data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
 122        ticks = base + data;
 123        dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
 124                base, data, ticks);
 125
 126        rtc_time_to_tm(ticks, tm);
 127
 128        return 0;
 129}
 130
 131static int pm860x_rtc_set_time(struct device *dev, struct rtc_time *tm)
 132{
 133        struct pm860x_rtc_info *info = dev_get_drvdata(dev);
 134        unsigned char buf[4];
 135        unsigned long ticks, base, data;
 136
 137        if ((tm->tm_year < 70) || (tm->tm_year > 138)) {
 138                dev_dbg(info->dev, "Set time %d out of range. "
 139                        "Please set time between 1970 to 2038.\n",
 140                        1900 + tm->tm_year);
 141                return -EINVAL;
 142        }
 143        rtc_tm_to_time(tm, &ticks);
 144
 145        /* load 32-bit read-only counter */
 146        pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
 147        data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
 148        base = ticks - data;
 149        dev_dbg(info->dev, "set base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
 150                base, data, ticks);
 151
 152        pm860x_page_reg_write(info->i2c, REG0_DATA, (base >> 24) & 0xFF);
 153        pm860x_page_reg_write(info->i2c, REG1_DATA, (base >> 16) & 0xFF);
 154        pm860x_page_reg_write(info->i2c, REG2_DATA, (base >> 8) & 0xFF);
 155        pm860x_page_reg_write(info->i2c, REG3_DATA, base & 0xFF);
 156
 157        if (info->sync)
 158                info->sync(ticks);
 159        return 0;
 160}
 161
 162static int pm860x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 163{
 164        struct pm860x_rtc_info *info = dev_get_drvdata(dev);
 165        unsigned char buf[8];
 166        unsigned long ticks, base, data;
 167        int ret;
 168
 169        pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
 170        dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
 171                buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
 172        base = (buf[1] << 24) | (buf[3] << 16) | (buf[5] << 8) | buf[7];
 173
 174        pm860x_bulk_read(info->i2c, PM8607_RTC_EXPIRE1, 4, buf);
 175        data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
 176        ticks = base + data;
 177        dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
 178                base, data, ticks);
 179
 180        rtc_time_to_tm(ticks, &alrm->time);
 181        ret = pm860x_reg_read(info->i2c, PM8607_RTC1);
 182        alrm->enabled = (ret & ALARM_EN) ? 1 : 0;
 183        alrm->pending = (ret & (ALARM | ALARM_WAKEUP)) ? 1 : 0;
 184        return 0;
 185}
 186
 187static int pm860x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 188{
 189        struct pm860x_rtc_info *info = dev_get_drvdata(dev);
 190        struct rtc_time now_tm, alarm_tm;
 191        unsigned long ticks, base, data;
 192        unsigned char buf[8];
 193        int mask;
 194
 195        pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, 0);
 196
 197        pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
 198        dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
 199                buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
 200        base = (buf[1] << 24) | (buf[3] << 16) | (buf[5] << 8) | buf[7];
 201
 202        /* load 32-bit read-only counter */
 203        pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
 204        data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
 205        ticks = base + data;
 206        dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
 207                base, data, ticks);
 208
 209        rtc_time_to_tm(ticks, &now_tm);
 210        rtc_next_alarm_time(&alarm_tm, &now_tm, &alrm->time);
 211        /* get new ticks for alarm in 24 hours */
 212        rtc_tm_to_time(&alarm_tm, &ticks);
 213        data = ticks - base;
 214
 215        buf[0] = data & 0xff;
 216        buf[1] = (data >> 8) & 0xff;
 217        buf[2] = (data >> 16) & 0xff;
 218        buf[3] = (data >> 24) & 0xff;
 219        pm860x_bulk_write(info->i2c, PM8607_RTC_EXPIRE1, 4, buf);
 220        if (alrm->enabled) {
 221                mask = ALARM | ALARM_WAKEUP | ALARM_EN;
 222                pm860x_set_bits(info->i2c, PM8607_RTC1, mask, mask);
 223        } else {
 224                mask = ALARM | ALARM_WAKEUP | ALARM_EN;
 225                pm860x_set_bits(info->i2c, PM8607_RTC1, mask,
 226                                ALARM | ALARM_WAKEUP);
 227        }
 228        return 0;
 229}
 230
 231static const struct rtc_class_ops pm860x_rtc_ops = {
 232        .read_time      = pm860x_rtc_read_time,
 233        .set_time       = pm860x_rtc_set_time,
 234        .read_alarm     = pm860x_rtc_read_alarm,
 235        .set_alarm      = pm860x_rtc_set_alarm,
 236        .alarm_irq_enable = pm860x_rtc_alarm_irq_enable,
 237};
 238
 239#ifdef VRTC_CALIBRATION
 240static void calibrate_vrtc_work(struct work_struct *work)
 241{
 242        struct pm860x_rtc_info *info = container_of(work,
 243                struct pm860x_rtc_info, calib_work.work);
 244        unsigned char buf[2];
 245        unsigned int sum, data, mean, vrtc_set;
 246        int i;
 247
 248        for (i = 0, sum = 0; i < 16; i++) {
 249                msleep(100);
 250                pm860x_bulk_read(info->i2c, REG_VRTC_MEAS1, 2, buf);
 251                data = (buf[0] << 4) | buf[1];
 252                data = (data * 5400) >> 12;     /* convert to mv */
 253                sum += data;
 254        }
 255        mean = sum >> 4;
 256        vrtc_set = 2700 + (info->vrtc & 0x3) * 200;
 257        dev_dbg(info->dev, "mean:%d, vrtc_set:%d\n", mean, vrtc_set);
 258
 259        sum = pm860x_reg_read(info->i2c, PM8607_RTC_MISC1);
 260        data = sum & 0x3;
 261        if ((mean + 200) < vrtc_set) {
 262                /* try higher voltage */
 263                if (++data == 4)
 264                        goto out;
 265                data = (sum & 0xf8) | (data & 0x3);
 266                pm860x_reg_write(info->i2c, PM8607_RTC_MISC1, data);
 267        } else if ((mean - 200) > vrtc_set) {
 268                /* try lower voltage */
 269                if (data-- == 0)
 270                        goto out;
 271                data = (sum & 0xf8) | (data & 0x3);
 272                pm860x_reg_write(info->i2c, PM8607_RTC_MISC1, data);
 273        } else
 274                goto out;
 275        dev_dbg(info->dev, "set 0x%x to RTC_MISC1\n", data);
 276        /* trigger next calibration since VRTC is updated */
 277        schedule_delayed_work(&info->calib_work, VRTC_CALIB_INTERVAL);
 278        return;
 279out:
 280        /* disable measurement */
 281        pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, 0);
 282        dev_dbg(info->dev, "finish VRTC calibration\n");
 283        return;
 284}
 285#endif
 286
 287static int __devinit pm860x_rtc_probe(struct platform_device *pdev)
 288{
 289        struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
 290        struct pm860x_rtc_pdata *pdata = NULL;
 291        struct pm860x_rtc_info *info;
 292        struct rtc_time tm;
 293        unsigned long ticks = 0;
 294        int ret;
 295
 296        pdata = pdev->dev.platform_data;
 297        if (pdata == NULL)
 298                dev_warn(&pdev->dev, "No platform data!\n");
 299
 300        info = kzalloc(sizeof(struct pm860x_rtc_info), GFP_KERNEL);
 301        if (!info)
 302                return -ENOMEM;
 303        info->irq = platform_get_irq(pdev, 0);
 304        if (info->irq < 0) {
 305                dev_err(&pdev->dev, "No IRQ resource!\n");
 306                ret = -EINVAL;
 307                goto out;
 308        }
 309
 310        info->chip = chip;
 311        info->i2c = (chip->id == CHIP_PM8607) ? chip->client : chip->companion;
 312        info->dev = &pdev->dev;
 313        dev_set_drvdata(&pdev->dev, info);
 314
 315        ret = request_threaded_irq(info->irq, NULL, rtc_update_handler,
 316                                   IRQF_ONESHOT, "rtc", info);
 317        if (ret < 0) {
 318                dev_err(chip->dev, "Failed to request IRQ: #%d: %d\n",
 319                        info->irq, ret);
 320                goto out;
 321        }
 322
 323        /* set addresses of 32-bit base value for RTC time */
 324        pm860x_page_reg_write(info->i2c, REG0_ADDR, REG0_DATA);
 325        pm860x_page_reg_write(info->i2c, REG1_ADDR, REG1_DATA);
 326        pm860x_page_reg_write(info->i2c, REG2_ADDR, REG2_DATA);
 327        pm860x_page_reg_write(info->i2c, REG3_ADDR, REG3_DATA);
 328
 329        ret = pm860x_rtc_read_time(&pdev->dev, &tm);
 330        if (ret < 0) {
 331                dev_err(&pdev->dev, "Failed to read initial time.\n");
 332                goto out_rtc;
 333        }
 334        if ((tm.tm_year < 70) || (tm.tm_year > 138)) {
 335                tm.tm_year = 70;
 336                tm.tm_mon = 0;
 337                tm.tm_mday = 1;
 338                tm.tm_hour = 0;
 339                tm.tm_min = 0;
 340                tm.tm_sec = 0;
 341                ret = pm860x_rtc_set_time(&pdev->dev, &tm);
 342                if (ret < 0) {
 343                        dev_err(&pdev->dev, "Failed to set initial time.\n");
 344                        goto out_rtc;
 345                }
 346        }
 347        rtc_tm_to_time(&tm, &ticks);
 348        if (pdata && pdata->sync) {
 349                pdata->sync(ticks);
 350                info->sync = pdata->sync;
 351        }
 352
 353        info->rtc_dev = rtc_device_register("88pm860x-rtc", &pdev->dev,
 354                                            &pm860x_rtc_ops, THIS_MODULE);
 355        ret = PTR_ERR(info->rtc_dev);
 356        if (IS_ERR(info->rtc_dev)) {
 357                dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
 358                goto out_rtc;
 359        }
 360
 361        /*
 362         * enable internal XO instead of internal 3.25MHz clock since it can
 363         * free running in PMIC power-down state.
 364         */
 365        pm860x_set_bits(info->i2c, PM8607_RTC1, RTC1_USE_XO, RTC1_USE_XO);
 366
 367#ifdef VRTC_CALIBRATION
 368        /* <00> -- 2.7V, <01> -- 2.9V, <10> -- 3.1V, <11> -- 3.3V */
 369        if (pdata && pdata->vrtc)
 370                info->vrtc = pdata->vrtc & 0x3;
 371        else
 372                info->vrtc = 1;
 373        pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, MEAS2_VRTC);
 374
 375        /* calibrate VRTC */
 376        INIT_DELAYED_WORK(&info->calib_work, calibrate_vrtc_work);
 377        schedule_delayed_work(&info->calib_work, VRTC_CALIB_INTERVAL);
 378#endif  /* VRTC_CALIBRATION */
 379
 380        device_init_wakeup(&pdev->dev, 1);
 381
 382        return 0;
 383out_rtc:
 384        free_irq(info->irq, info);
 385out:
 386        kfree(info);
 387        return ret;
 388}
 389
 390static int __devexit pm860x_rtc_remove(struct platform_device *pdev)
 391{
 392        struct pm860x_rtc_info *info = platform_get_drvdata(pdev);
 393
 394#ifdef VRTC_CALIBRATION
 395        flush_scheduled_work();
 396        /* disable measurement */
 397        pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, 0);
 398#endif  /* VRTC_CALIBRATION */
 399
 400        platform_set_drvdata(pdev, NULL);
 401        rtc_device_unregister(info->rtc_dev);
 402        free_irq(info->irq, info);
 403        kfree(info);
 404        return 0;
 405}
 406
 407#ifdef CONFIG_PM_SLEEP
 408static int pm860x_rtc_suspend(struct device *dev)
 409{
 410        struct platform_device *pdev = to_platform_device(dev);
 411        struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
 412
 413        if (device_may_wakeup(dev))
 414                chip->wakeup_flag |= 1 << PM8607_IRQ_RTC;
 415        return 0;
 416}
 417static int pm860x_rtc_resume(struct device *dev)
 418{
 419        struct platform_device *pdev = to_platform_device(dev);
 420        struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
 421
 422        if (device_may_wakeup(dev))
 423                chip->wakeup_flag &= ~(1 << PM8607_IRQ_RTC);
 424        return 0;
 425}
 426#endif
 427
 428static SIMPLE_DEV_PM_OPS(pm860x_rtc_pm_ops, pm860x_rtc_suspend, pm860x_rtc_resume);
 429
 430static struct platform_driver pm860x_rtc_driver = {
 431        .driver         = {
 432                .name   = "88pm860x-rtc",
 433                .owner  = THIS_MODULE,
 434                .pm     = &pm860x_rtc_pm_ops,
 435        },
 436        .probe          = pm860x_rtc_probe,
 437        .remove         = __devexit_p(pm860x_rtc_remove),
 438};
 439
 440module_platform_driver(pm860x_rtc_driver);
 441
 442MODULE_DESCRIPTION("Marvell 88PM860x RTC driver");
 443MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
 444MODULE_LICENSE("GPL");
 445
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