rtc-88pm860x.c

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/*
 * Real Time Clock driver for Marvell 88PM860x PMIC
 *
 * Copyright (c) 2010 Marvell International Ltd.
 * Author:  Haojian Zhuang <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/rtc.h>
#include <linux/delay.h>
#include <linux/mfd/core.h>
#include <linux/mfd/88pm860x.h>

#define VRTC_CALIBRATION

struct pm860x_rtc_info {
    struct pm860x_chip  *chip;
    struct i2c_client   *i2c;
    struct rtc_device   *rtc_dev;
    struct device       *dev;
    struct delayed_work calib_work;

    int         irq;
    int         vrtc;
    int         (*sync)(unsigned int ticks);
};

#define REG_VRTC_MEAS1      0x7D

#define REG0_ADDR       0xB0
#define REG1_ADDR       0xB2
#define REG2_ADDR       0xB4
#define REG3_ADDR       0xB6

#define REG0_DATA       0xB1
#define REG1_DATA       0xB3
#define REG2_DATA       0xB5
#define REG3_DATA       0xB7

/* bit definitions of Measurement Enable Register 2 (0x51) */
#define MEAS2_VRTC      (1 << 0)

/* bit definitions of RTC Register 1 (0xA0) */
#define ALARM_EN        (1 << 3)
#define ALARM_WAKEUP        (1 << 4)
#define ALARM           (1 << 5)
#define RTC1_USE_XO     (1 << 7)

#define VRTC_CALIB_INTERVAL (HZ * 60 * 10)      /* 10 minutes */

static irqreturn_t rtc_update_handler(int irq, void *data)
{
    struct pm860x_rtc_info *info = (struct pm860x_rtc_info *)data;
    int mask;

    mask = ALARM | ALARM_WAKEUP;
    pm860x_set_bits(info->i2c, PM8607_RTC1, mask | ALARM_EN, mask);
    rtc_update_irq(info->rtc_dev, 1, RTC_AF);
    return IRQ_HANDLED;
}

static int pm860x_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
    struct pm860x_rtc_info *info = dev_get_drvdata(dev);

    if (enabled)
        pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, ALARM_EN);
    else
        pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, 0);
    return 0;
}

/*
 * Calculate the next alarm time given the requested alarm time mask
 * and the current time.
 */
static void rtc_next_alarm_time(struct rtc_time *next, struct rtc_time *now,
                struct rtc_time *alrm)
{
    unsigned long next_time;
    unsigned long now_time;

    next->tm_year = now->tm_year;
    next->tm_mon = now->tm_mon;
    next->tm_mday = now->tm_mday;
    next->tm_hour = alrm->tm_hour;
    next->tm_min = alrm->tm_min;
    next->tm_sec = alrm->tm_sec;

    rtc_tm_to_time(now, &now_time);
    rtc_tm_to_time(next, &next_time);

    if (next_time < now_time) {
        /* Advance one day */
        next_time += 60 * 60 * 24;
        rtc_time_to_tm(next_time, next);
    }
}

static int pm860x_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
    struct pm860x_rtc_info *info = dev_get_drvdata(dev);
    unsigned char buf[8];
    unsigned long ticks, base, data;

    pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
    dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
        buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
    base = (buf[1] << 24) | (buf[3] << 16) | (buf[5] << 8) | buf[7];

    /* load 32-bit read-only counter */
    pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
    data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
    ticks = base + data;
    dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
        base, data, ticks);

    rtc_time_to_tm(ticks, tm);

    return 0;
}

static int pm860x_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
    struct pm860x_rtc_info *info = dev_get_drvdata(dev);
    unsigned char buf[4];
    unsigned long ticks, base, data;

    if ((tm->tm_year < 70) || (tm->tm_year > 138)) {
        dev_dbg(info->dev, "Set time %d out of range. "
            "Please set time between 1970 to 2038.\n",
            1900 + tm->tm_year);
        return -EINVAL;
    }
    rtc_tm_to_time(tm, &ticks);

    /* load 32-bit read-only counter */
    pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
    data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
    base = ticks - data;
    dev_dbg(info->dev, "set base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
        base, data, ticks);

    pm860x_page_reg_write(info->i2c, REG0_DATA, (base >> 24) & 0xFF);
    pm860x_page_reg_write(info->i2c, REG1_DATA, (base >> 16) & 0xFF);
    pm860x_page_reg_write(info->i2c, REG2_DATA, (base >> 8) & 0xFF);
    pm860x_page_reg_write(info->i2c, REG3_DATA, base & 0xFF);

    if (info->sync)
        info->sync(ticks);
    return 0;
}

static int pm860x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
    struct pm860x_rtc_info *info = dev_get_drvdata(dev);
    unsigned char buf[8];
    unsigned long ticks, base, data;
    int ret;

    pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
    dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
        buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
    base = (buf[1] << 24) | (buf[3] << 16) | (buf[5] << 8) | buf[7];

    pm860x_bulk_read(info->i2c, PM8607_RTC_EXPIRE1, 4, buf);
    data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
    ticks = base + data;
    dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
        base, data, ticks);

    rtc_time_to_tm(ticks, &alrm->time);
    ret = pm860x_reg_read(info->i2c, PM8607_RTC1);
    alrm->enabled = (ret & ALARM_EN) ? 1 : 0;
    alrm->pending = (ret & (ALARM | ALARM_WAKEUP)) ? 1 : 0;
    return 0;
}

static int pm860x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
    struct pm860x_rtc_info *info = dev_get_drvdata(dev);
    struct rtc_time now_tm, alarm_tm;
    unsigned long ticks, base, data;
    unsigned char buf[8];
    int mask;

    pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, 0);

    pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
    dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
        buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
    base = (buf[1] << 24) | (buf[3] << 16) | (buf[5] << 8) | buf[7];

    /* load 32-bit read-only counter */
    pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
    data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
    ticks = base + data;
    dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
        base, data, ticks);

    rtc_time_to_tm(ticks, &now_tm);
    rtc_next_alarm_time(&alarm_tm, &now_tm, &alrm->time);
    /* get new ticks for alarm in 24 hours */
    rtc_tm_to_time(&alarm_tm, &ticks);
    data = ticks - base;

    buf[0] = data & 0xff;
    buf[1] = (data >> 8) & 0xff;
    buf[2] = (data >> 16) & 0xff;
    buf[3] = (data >> 24) & 0xff;
    pm860x_bulk_write(info->i2c, PM8607_RTC_EXPIRE1, 4, buf);
    if (alrm->enabled) {
        mask = ALARM | ALARM_WAKEUP | ALARM_EN;
        pm860x_set_bits(info->i2c, PM8607_RTC1, mask, mask);
    } else {
        mask = ALARM | ALARM_WAKEUP | ALARM_EN;
        pm860x_set_bits(info->i2c, PM8607_RTC1, mask,
                ALARM | ALARM_WAKEUP);
    }
    return 0;
}

static const struct rtc_class_ops pm860x_rtc_ops = {
    .read_time  = pm860x_rtc_read_time,
    .set_time   = pm860x_rtc_set_time,
    .read_alarm = pm860x_rtc_read_alarm,
    .set_alarm  = pm860x_rtc_set_alarm,
    .alarm_irq_enable = pm860x_rtc_alarm_irq_enable,
};

#ifdef VRTC_CALIBRATION
static void calibrate_vrtc_work(struct work_struct *work)
{
    struct pm860x_rtc_info *info = container_of(work,
        struct pm860x_rtc_info, calib_work.work);
    unsigned char buf[2];
    unsigned int sum, data, mean, vrtc_set;
    int i;

    for (i = 0, sum = 0; i < 16; i++) {
        msleep(100);
        pm860x_bulk_read(info->i2c, REG_VRTC_MEAS1, 2, buf);
        data = (buf[0] << 4) | buf[1];
        data = (data * 5400) >> 12; /* convert to mv */
        sum += data;
    }
    mean = sum >> 4;
    vrtc_set = 2700 + (info->vrtc & 0x3) * 200;
    dev_dbg(info->dev, "mean:%d, vrtc_set:%d\n", mean, vrtc_set);

    sum = pm860x_reg_read(info->i2c, PM8607_RTC_MISC1);
    data = sum & 0x3;
    if ((mean + 200) < vrtc_set) {
        /* try higher voltage */
        if (++data == 4)
            goto out;
        data = (sum & 0xf8) | (data & 0x3);
        pm860x_reg_write(info->i2c, PM8607_RTC_MISC1, data);
    } else if ((mean - 200) > vrtc_set) {
        /* try lower voltage */
        if (data-- == 0)
            goto out;
        data = (sum & 0xf8) | (data & 0x3);
        pm860x_reg_write(info->i2c, PM8607_RTC_MISC1, data);
    } else
        goto out;
    dev_dbg(info->dev, "set 0x%x to RTC_MISC1\n", data);
    /* trigger next calibration since VRTC is updated */
    schedule_delayed_work(&info->calib_work, VRTC_CALIB_INTERVAL);
    return;
out:
    /* disable measurement */
    pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, 0);
    dev_dbg(info->dev, "finish VRTC calibration\n");
    return;
}
#endif

#ifdef CONFIG_OF
static int __devinit pm860x_rtc_dt_init(struct platform_device *pdev,
                    struct pm860x_rtc_info *info)
{
    struct device_node *np = pdev->dev.parent->of_node;
    int ret;
    if (!np)
        return -ENODEV;
    np = of_find_node_by_name(np, "rtc");
    if (!np) {
        dev_err(&pdev->dev, "failed to find rtc node\n");
        return -ENODEV;
    }
    ret = of_property_read_u32(np, "marvell,88pm860x-vrtc", &info->vrtc);
    if (ret)
        info->vrtc = 0;
    return 0;
}
#else
#define pm860x_rtc_dt_init(x, y)    (-1)
#endif

static int __devinit pm860x_rtc_probe(struct platform_device *pdev)
{
    struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
    struct pm860x_rtc_pdata *pdata = NULL;
    struct pm860x_rtc_info *info;
    struct rtc_time tm;
    unsigned long ticks = 0;
    int ret;

    pdata = pdev->dev.platform_data;

    info = kzalloc(sizeof(struct pm860x_rtc_info), GFP_KERNEL);
    if (!info)
        return -ENOMEM;
    info->irq = platform_get_irq(pdev, 0);
    if (info->irq < 0) {
        dev_err(&pdev->dev, "No IRQ resource!\n");
        ret = -EINVAL;
        goto out;
    }

    info->chip = chip;
    info->i2c = (chip->id == CHIP_PM8607) ? chip->client : chip->companion;
    info->dev = &pdev->dev;
    dev_set_drvdata(&pdev->dev, info);

    ret = request_threaded_irq(info->irq, NULL, rtc_update_handler,
                   IRQF_ONESHOT, "rtc", info);
    if (ret < 0) {
        dev_err(chip->dev, "Failed to request IRQ: #%d: %d\n",
            info->irq, ret);
        goto out;
    }

    /* set addresses of 32-bit base value for RTC time */
    pm860x_page_reg_write(info->i2c, REG0_ADDR, REG0_DATA);
    pm860x_page_reg_write(info->i2c, REG1_ADDR, REG1_DATA);
    pm860x_page_reg_write(info->i2c, REG2_ADDR, REG2_DATA);
    pm860x_page_reg_write(info->i2c, REG3_ADDR, REG3_DATA);

    ret = pm860x_rtc_read_time(&pdev->dev, &tm);
    if (ret < 0) {
        dev_err(&pdev->dev, "Failed to read initial time.\n");
        goto out_rtc;
    }
    if ((tm.tm_year < 70) || (tm.tm_year > 138)) {
        tm.tm_year = 70;
        tm.tm_mon = 0;
        tm.tm_mday = 1;
        tm.tm_hour = 0;
        tm.tm_min = 0;
        tm.tm_sec = 0;
        ret = pm860x_rtc_set_time(&pdev->dev, &tm);
        if (ret < 0) {
            dev_err(&pdev->dev, "Failed to set initial time.\n");
            goto out_rtc;
        }
    }
    rtc_tm_to_time(&tm, &ticks);
    if (pm860x_rtc_dt_init(pdev, info)) {
        if (pdata && pdata->sync) {
            pdata->sync(ticks);
            info->sync = pdata->sync;
        }
    }

    info->rtc_dev = rtc_device_register("88pm860x-rtc", &pdev->dev,
                        &pm860x_rtc_ops, THIS_MODULE);
    ret = PTR_ERR(info->rtc_dev);
    if (IS_ERR(info->rtc_dev)) {
        dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
        goto out_rtc;
    }

    /*
     * enable internal XO instead of internal 3.25MHz clock since it can
     * free running in PMIC power-down state.
     */
    pm860x_set_bits(info->i2c, PM8607_RTC1, RTC1_USE_XO, RTC1_USE_XO);

#ifdef VRTC_CALIBRATION
    /* <00> -- 2.7V, <01> -- 2.9V, <10> -- 3.1V, <11> -- 3.3V */
    if (pm860x_rtc_dt_init(pdev, info)) {
        if (pdata && pdata->vrtc)
            info->vrtc = pdata->vrtc & 0x3;
        else
            info->vrtc = 1;
    }
    pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, MEAS2_VRTC);

    /* calibrate VRTC */
    INIT_DELAYED_WORK(&info->calib_work, calibrate_vrtc_work);
    schedule_delayed_work(&info->calib_work, VRTC_CALIB_INTERVAL);
#endif  /* VRTC_CALIBRATION */

    device_init_wakeup(&pdev->dev, 1);

    return 0;
out_rtc:
    free_irq(info->irq, info);
out:
    kfree(info);
    return ret;
}

static int __devexit pm860x_rtc_remove(struct platform_device *pdev)
{
    struct pm860x_rtc_info *info = platform_get_drvdata(pdev);

#ifdef VRTC_CALIBRATION
    flush_scheduled_work();
    /* disable measurement */
    pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, 0);
#endif  /* VRTC_CALIBRATION */

    platform_set_drvdata(pdev, NULL);
    rtc_device_unregister(info->rtc_dev);
    free_irq(info->irq, info);
    kfree(info);
    return 0;
}

#ifdef CONFIG_PM_SLEEP
static int pm860x_rtc_suspend(struct device *dev)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);

    if (device_may_wakeup(dev))
        chip->wakeup_flag |= 1 << PM8607_IRQ_RTC;
    return 0;
}
static int pm860x_rtc_resume(struct device *dev)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);

    if (device_may_wakeup(dev))
        chip->wakeup_flag &= ~(1 << PM8607_IRQ_RTC);
    return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(pm860x_rtc_pm_ops, pm860x_rtc_suspend, pm860x_rtc_resume);

static struct platform_driver pm860x_rtc_driver = {
    .driver     = {
        .name   = "88pm860x-rtc",
        .owner  = THIS_MODULE,
        .pm = &pm860x_rtc_pm_ops,
    },
    .probe      = pm860x_rtc_probe,
    .remove     = __devexit_p(pm860x_rtc_remove),
};

module_platform_driver(pm860x_rtc_driver);

MODULE_DESCRIPTION("Marvell 88PM860x RTC driver");
MODULE_AUTHOR("Haojian Zhuang <[email protected]>");
MODULE_LICENSE("GPL");