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/of.h>
  15#include <linux/platform_device.h>
  16#include <linux/slab.h>
  17#include <linux/mutex.h>
  18#include <linux/rtc.h>
  19#include <linux/delay.h>
  20#include <linux/mfd/core.h>
  21#include <linux/mfd/88pm860x.h>
  22
  23#define VRTC_CALIBRATION
  24
  25struct pm860x_rtc_info {
  26        struct pm860x_chip      *chip;
  27        struct i2c_client       *i2c;
  28        struct rtc_device       *rtc_dev;
  29        struct device           *dev;
  30        struct delayed_work     calib_work;
  31
  32        int                     irq;
  33        int                     vrtc;
  34        int                     (*sync)(unsigned int ticks);
  35};
  36
  37#define REG_VRTC_MEAS1          0x7D
  38
  39#define REG0_ADDR               0xB0
  40#define REG1_ADDR               0xB2
  41#define REG2_ADDR               0xB4
  42#define REG3_ADDR               0xB6
  43
  44#define REG0_DATA               0xB1
  45#define REG1_DATA               0xB3
  46#define REG2_DATA               0xB5
  47#define REG3_DATA               0xB7
  48
  49/* bit definitions of Measurement Enable Register 2 (0x51) */
  50#define MEAS2_VRTC              (1 << 0)
  51
  52/* bit definitions of RTC Register 1 (0xA0) */
  53#define ALARM_EN                (1 << 3)
  54#define ALARM_WAKEUP            (1 << 4)
  55#define ALARM                   (1 << 5)
  56#define RTC1_USE_XO             (1 << 7)
  57
  58#define VRTC_CALIB_INTERVAL     (HZ * 60 * 10)          /* 10 minutes */
  59
  60static irqreturn_t rtc_update_handler(int irq, void *data)
  61{
  62        struct pm860x_rtc_info *info = (struct pm860x_rtc_info *)data;
  63        int mask;
  64
  65        mask = ALARM | ALARM_WAKEUP;
  66        pm860x_set_bits(info->i2c, PM8607_RTC1, mask | ALARM_EN, mask);
  67        rtc_update_irq(info->rtc_dev, 1, RTC_AF);
  68        return IRQ_HANDLED;
  69}
  70
  71static int pm860x_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
  72{
  73        struct pm860x_rtc_info *info = dev_get_drvdata(dev);
  74
  75        if (enabled)
  76                pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, ALARM_EN);
  77        else
  78                pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, 0);
  79        return 0;
  80}
  81
  82/*
  83 * Calculate the next alarm time given the requested alarm time mask
  84 * and the current time.
  85 */
  86static void rtc_next_alarm_time(struct rtc_time *next, struct rtc_time *now,
  87                                struct rtc_time *alrm)
  88{
  89        unsigned long next_time;
  90        unsigned long now_time;
  91
  92        next->tm_year = now->tm_year;
  93        next->tm_mon = now->tm_mon;
  94        next->tm_mday = now->tm_mday;
  95        next->tm_hour = alrm->tm_hour;
  96        next->tm_min = alrm->tm_min;
  97        next->tm_sec = alrm->tm_sec;
  98
  99        rtc_tm_to_time(now, &now_time);
 100        rtc_tm_to_time(next, &next_time);
 101
 102        if (next_time < now_time) {
 103                /* Advance one day */
 104                next_time += 60 * 60 * 24;
 105                rtc_time_to_tm(next_time, next);
 106        }
 107}
 108
 109static int pm860x_rtc_read_time(struct device *dev, struct rtc_time *tm)
 110{
 111        struct pm860x_rtc_info *info = dev_get_drvdata(dev);
 112        unsigned char buf[8];
 113        unsigned long ticks, base, data;
 114
 115        pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
 116        dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
 117                buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
 118        base = (buf[1] << 24) | (buf[3] << 16) | (buf[5] << 8) | buf[7];
 119
 120        /* load 32-bit read-only counter */
 121        pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
 122        data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
 123        ticks = base + data;
 124        dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
 125                base, data, ticks);
 126
 127        rtc_time_to_tm(ticks, tm);
 128
 129        return 0;
 130}
 131
 132static int pm860x_rtc_set_time(struct device *dev, struct rtc_time *tm)
 133{
 134        struct pm860x_rtc_info *info = dev_get_drvdata(dev);
 135        unsigned char buf[4];
 136        unsigned long ticks, base, data;
 137
 138        if ((tm->tm_year < 70) || (tm->tm_year > 138)) {
 139                dev_dbg(info->dev, "Set time %d out of range. "
 140                        "Please set time between 1970 to 2038.\n",
 141                        1900 + tm->tm_year);
 142                return -EINVAL;
 143        }
 144        rtc_tm_to_time(tm, &ticks);
 145
 146        /* load 32-bit read-only counter */
 147        pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
 148        data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
 149        base = ticks - data;
 150        dev_dbg(info->dev, "set base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
 151                base, data, ticks);
 152
 153        pm860x_page_reg_write(info->i2c, REG0_DATA, (base >> 24) & 0xFF);
 154        pm860x_page_reg_write(info->i2c, REG1_DATA, (base >> 16) & 0xFF);
 155        pm860x_page_reg_write(info->i2c, REG2_DATA, (base >> 8) & 0xFF);
 156        pm860x_page_reg_write(info->i2c, REG3_DATA, base & 0xFF);
 157
 158        if (info->sync)
 159                info->sync(ticks);
 160        return 0;
 161}
 162
 163static int pm860x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 164{
 165        struct pm860x_rtc_info *info = dev_get_drvdata(dev);
 166        unsigned char buf[8];
 167        unsigned long ticks, base, data;
 168        int ret;
 169
 170        pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
 171        dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
 172                buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
 173        base = (buf[1] << 24) | (buf[3] << 16) | (buf[5] << 8) | buf[7];
 174
 175        pm860x_bulk_read(info->i2c, PM8607_RTC_EXPIRE1, 4, buf);
 176        data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
 177        ticks = base + data;
 178        dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
 179                base, data, ticks);
 180
 181        rtc_time_to_tm(ticks, &alrm->time);
 182        ret = pm860x_reg_read(info->i2c, PM8607_RTC1);
 183        alrm->enabled = (ret & ALARM_EN) ? 1 : 0;
 184        alrm->pending = (ret & (ALARM | ALARM_WAKEUP)) ? 1 : 0;
 185        return 0;
 186}
 187
 188static int pm860x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 189{
 190        struct pm860x_rtc_info *info = dev_get_drvdata(dev);
 191        struct rtc_time now_tm, alarm_tm;
 192        unsigned long ticks, base, data;
 193        unsigned char buf[8];
 194        int mask;
 195
 196        pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, 0);
 197
 198        pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
 199        dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
 200                buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
 201        base = (buf[1] << 24) | (buf[3] << 16) | (buf[5] << 8) | buf[7];
 202
 203        /* load 32-bit read-only counter */
 204        pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
 205        data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
 206        ticks = base + data;
 207        dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
 208                base, data, ticks);
 209
 210        rtc_time_to_tm(ticks, &now_tm);
 211        rtc_next_alarm_time(&alarm_tm, &now_tm, &alrm->time);
 212        /* get new ticks for alarm in 24 hours */
 213        rtc_tm_to_time(&alarm_tm, &ticks);
 214        data = ticks - base;
 215
 216        buf[0] = data & 0xff;
 217        buf[1] = (data >> 8) & 0xff;
 218        buf[2] = (data >> 16) & 0xff;
 219        buf[3] = (data >> 24) & 0xff;
 220        pm860x_bulk_write(info->i2c, PM8607_RTC_EXPIRE1, 4, buf);
 221        if (alrm->enabled) {
 222                mask = ALARM | ALARM_WAKEUP | ALARM_EN;
 223                pm860x_set_bits(info->i2c, PM8607_RTC1, mask, mask);
 224        } else {
 225                mask = ALARM | ALARM_WAKEUP | ALARM_EN;
 226                pm860x_set_bits(info->i2c, PM8607_RTC1, mask,
 227                                ALARM | ALARM_WAKEUP);
 228        }
 229        return 0;
 230}
 231
 232static const struct rtc_class_ops pm860x_rtc_ops = {
 233        .read_time      = pm860x_rtc_read_time,
 234        .set_time       = pm860x_rtc_set_time,
 235        .read_alarm     = pm860x_rtc_read_alarm,
 236        .set_alarm      = pm860x_rtc_set_alarm,
 237        .alarm_irq_enable = pm860x_rtc_alarm_irq_enable,
 238};
 239
 240#ifdef VRTC_CALIBRATION
 241static void calibrate_vrtc_work(struct work_struct *work)
 242{
 243        struct pm860x_rtc_info *info = container_of(work,
 244                struct pm860x_rtc_info, calib_work.work);
 245        unsigned char buf[2];
 246        unsigned int sum, data, mean, vrtc_set;
 247        int i;
 248
 249        for (i = 0, sum = 0; i < 16; i++) {
 250                msleep(100);
 251                pm860x_bulk_read(info->i2c, REG_VRTC_MEAS1, 2, buf);
 252                data = (buf[0] << 4) | buf[1];
 253                data = (data * 5400) >> 12;     /* convert to mv */
 254                sum += data;
 255        }
 256        mean = sum >> 4;
 257        vrtc_set = 2700 + (info->vrtc & 0x3) * 200;
 258        dev_dbg(info->dev, "mean:%d, vrtc_set:%d\n", mean, vrtc_set);
 259
 260        sum = pm860x_reg_read(info->i2c, PM8607_RTC_MISC1);
 261        data = sum & 0x3;
 262        if ((mean + 200) < vrtc_set) {
 263                /* try higher voltage */
 264                if (++data == 4)
 265                        goto out;
 266                data = (sum & 0xf8) | (data & 0x3);
 267                pm860x_reg_write(info->i2c, PM8607_RTC_MISC1, data);
 268        } else if ((mean - 200) > vrtc_set) {
 269                /* try lower voltage */
 270                if (data-- == 0)
 271                        goto out;
 272                data = (sum & 0xf8) | (data & 0x3);
 273                pm860x_reg_write(info->i2c, PM8607_RTC_MISC1, data);
 274        } else
 275                goto out;
 276        dev_dbg(info->dev, "set 0x%x to RTC_MISC1\n", data);
 277        /* trigger next calibration since VRTC is updated */
 278        schedule_delayed_work(&info->calib_work, VRTC_CALIB_INTERVAL);
 279        return;
 280out:
 281        /* disable measurement */
 282        pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, 0);
 283        dev_dbg(info->dev, "finish VRTC calibration\n");
 284        return;
 285}
 286#endif
 287
 288#ifdef CONFIG_OF
 289static int pm860x_rtc_dt_init(struct platform_device *pdev,
 290                              struct pm860x_rtc_info *info)
 291{
 292        struct device_node *np = pdev->dev.parent->of_node;
 293        int ret;
 294        if (!np)
 295                return -ENODEV;
 296        np = of_find_node_by_name(np, "rtc");
 297        if (!np) {
 298                dev_err(&pdev->dev, "failed to find rtc node\n");
 299                return -ENODEV;
 300        }
 301        ret = of_property_read_u32(np, "marvell,88pm860x-vrtc", &info->vrtc);
 302        if (ret)
 303                info->vrtc = 0;
 304        return 0;
 305}
 306#else
 307#define pm860x_rtc_dt_init(x, y)        (-1)
 308#endif
 309
 310static int pm860x_rtc_probe(struct platform_device *pdev)
 311{
 312        struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
 313        struct pm860x_rtc_pdata *pdata = NULL;
 314        struct pm860x_rtc_info *info;
 315        struct rtc_time tm;
 316        unsigned long ticks = 0;
 317        int ret;
 318
 319        pdata = pdev->dev.platform_data;
 320
 321        info = kzalloc(sizeof(struct pm860x_rtc_info), GFP_KERNEL);
 322        if (!info)
 323                return -ENOMEM;
 324        info->irq = platform_get_irq(pdev, 0);
 325        if (info->irq < 0) {
 326                dev_err(&pdev->dev, "No IRQ resource!\n");
 327                ret = -EINVAL;
 328                goto out;
 329        }
 330
 331        info->chip = chip;
 332        info->i2c = (chip->id == CHIP_PM8607) ? chip->client : chip->companion;
 333        info->dev = &pdev->dev;
 334        dev_set_drvdata(&pdev->dev, info);
 335
 336        ret = request_threaded_irq(info->irq, NULL, rtc_update_handler,
 337                                   IRQF_ONESHOT, "rtc", info);
 338        if (ret < 0) {
 339                dev_err(chip->dev, "Failed to request IRQ: #%d: %d\n",
 340                        info->irq, ret);
 341                goto out;
 342        }
 343
 344        /* set addresses of 32-bit base value for RTC time */
 345        pm860x_page_reg_write(info->i2c, REG0_ADDR, REG0_DATA);
 346        pm860x_page_reg_write(info->i2c, REG1_ADDR, REG1_DATA);
 347        pm860x_page_reg_write(info->i2c, REG2_ADDR, REG2_DATA);
 348        pm860x_page_reg_write(info->i2c, REG3_ADDR, REG3_DATA);
 349
 350        ret = pm860x_rtc_read_time(&pdev->dev, &tm);
 351        if (ret < 0) {
 352                dev_err(&pdev->dev, "Failed to read initial time.\n");
 353                goto out_rtc;
 354        }
 355        if ((tm.tm_year < 70) || (tm.tm_year > 138)) {
 356                tm.tm_year = 70;
 357                tm.tm_mon = 0;
 358                tm.tm_mday = 1;
 359                tm.tm_hour = 0;
 360                tm.tm_min = 0;
 361                tm.tm_sec = 0;
 362                ret = pm860x_rtc_set_time(&pdev->dev, &tm);
 363                if (ret < 0) {
 364                        dev_err(&pdev->dev, "Failed to set initial time.\n");
 365                        goto out_rtc;
 366                }
 367        }
 368        rtc_tm_to_time(&tm, &ticks);
 369        if (pm860x_rtc_dt_init(pdev, info)) {
 370                if (pdata && pdata->sync) {
 371                        pdata->sync(ticks);
 372                        info->sync = pdata->sync;
 373                }
 374        }
 375
 376        info->rtc_dev = rtc_device_register("88pm860x-rtc", &pdev->dev,
 377                                            &pm860x_rtc_ops, THIS_MODULE);
 378        ret = PTR_ERR(info->rtc_dev);
 379        if (IS_ERR(info->rtc_dev)) {
 380                dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
 381                goto out_rtc;
 382        }
 383
 384        /*
 385         * enable internal XO instead of internal 3.25MHz clock since it can
 386         * free running in PMIC power-down state.
 387         */
 388        pm860x_set_bits(info->i2c, PM8607_RTC1, RTC1_USE_XO, RTC1_USE_XO);
 389
 390#ifdef VRTC_CALIBRATION
 391        /* <00> -- 2.7V, <01> -- 2.9V, <10> -- 3.1V, <11> -- 3.3V */
 392        if (pm860x_rtc_dt_init(pdev, info)) {
 393                if (pdata && pdata->vrtc)
 394                        info->vrtc = pdata->vrtc & 0x3;
 395                else
 396                        info->vrtc = 1;
 397        }
 398        pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, MEAS2_VRTC);
 399
 400        /* calibrate VRTC */
 401        INIT_DELAYED_WORK(&info->calib_work, calibrate_vrtc_work);
 402        schedule_delayed_work(&info->calib_work, VRTC_CALIB_INTERVAL);
 403#endif  /* VRTC_CALIBRATION */
 404
 405        device_init_wakeup(&pdev->dev, 1);
 406
 407        return 0;
 408out_rtc:
 409        free_irq(info->irq, info);
 410out:
 411        kfree(info);
 412        return ret;
 413}
 414
 415static int pm860x_rtc_remove(struct platform_device *pdev)
 416{
 417        struct pm860x_rtc_info *info = platform_get_drvdata(pdev);
 418
 419#ifdef VRTC_CALIBRATION
 420        flush_scheduled_work();
 421        /* disable measurement */
 422        pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, 0);
 423#endif  /* VRTC_CALIBRATION */
 424
 425        platform_set_drvdata(pdev, NULL);
 426        rtc_device_unregister(info->rtc_dev);
 427        free_irq(info->irq, info);
 428        kfree(info);
 429        return 0;
 430}
 431
 432#ifdef CONFIG_PM_SLEEP
 433static int pm860x_rtc_suspend(struct device *dev)
 434{
 435        struct platform_device *pdev = to_platform_device(dev);
 436        struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
 437
 438        if (device_may_wakeup(dev))
 439                chip->wakeup_flag |= 1 << PM8607_IRQ_RTC;
 440        return 0;
 441}
 442static int pm860x_rtc_resume(struct device *dev)
 443{
 444        struct platform_device *pdev = to_platform_device(dev);
 445        struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
 446
 447        if (device_may_wakeup(dev))
 448                chip->wakeup_flag &= ~(1 << PM8607_IRQ_RTC);
 449        return 0;
 450}
 451#endif
 452
 453static SIMPLE_DEV_PM_OPS(pm860x_rtc_pm_ops, pm860x_rtc_suspend, pm860x_rtc_resume);
 454
 455static struct platform_driver pm860x_rtc_driver = {
 456        .driver         = {
 457                .name   = "88pm860x-rtc",
 458                .owner  = THIS_MODULE,
 459                .pm     = &pm860x_rtc_pm_ops,
 460        },
 461        .probe          = pm860x_rtc_probe,
 462        .remove         = pm860x_rtc_remove,
 463};
 464
 465module_platform_driver(pm860x_rtc_driver);
 466
 467MODULE_DESCRIPTION("Marvell 88PM860x RTC driver");
 468MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
 469MODULE_LICENSE("GPL");
 470
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