rtc-rx8025.c

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/*
 * Driver for Epson's RTC module RX-8025 SA/NB
 *
 * Copyright (C) 2009 Wolfgang Grandegger <[email protected]>
 *
 * Copyright (C) 2005 by Digi International Inc.
 * All rights reserved.
 *
 * Modified by fengjh at rising.com.cn
 * <http://lists.lm-sensors.org/mailman/listinfo/lm-sensors>
 * 2006.11
 *
 * Code cleanup by Sergei Poselenov, <[email protected]>
 * Converted to new style by Wolfgang Grandegger <[email protected]>
 * Alarm and periodic interrupt added by Dmitry Rakhchev <[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/slab.h>
#include <linux/init.h>
#include <linux/bcd.h>
#include <linux/i2c.h>
#include <linux/list.h>
#include <linux/rtc.h>

/* Register definitions */
#define RX8025_REG_SEC      0x00
#define RX8025_REG_MIN      0x01
#define RX8025_REG_HOUR     0x02
#define RX8025_REG_WDAY     0x03
#define RX8025_REG_MDAY     0x04
#define RX8025_REG_MONTH    0x05
#define RX8025_REG_YEAR     0x06
#define RX8025_REG_DIGOFF   0x07
#define RX8025_REG_ALWMIN   0x08
#define RX8025_REG_ALWHOUR  0x09
#define RX8025_REG_ALWWDAY  0x0a
#define RX8025_REG_ALDMIN   0x0b
#define RX8025_REG_ALDHOUR  0x0c
/* 0x0d is reserved */
#define RX8025_REG_CTRL1    0x0e
#define RX8025_REG_CTRL2    0x0f

#define RX8025_BIT_CTRL1_CT (7 << 0)
/* 1 Hz periodic level irq */
#define RX8025_BIT_CTRL1_CT_1HZ 4
#define RX8025_BIT_CTRL1_TEST   (1 << 3)
#define RX8025_BIT_CTRL1_1224   (1 << 5)
#define RX8025_BIT_CTRL1_DALE   (1 << 6)
#define RX8025_BIT_CTRL1_WALE   (1 << 7)

#define RX8025_BIT_CTRL2_DAFG   (1 << 0)
#define RX8025_BIT_CTRL2_WAFG   (1 << 1)
#define RX8025_BIT_CTRL2_CTFG   (1 << 2)
#define RX8025_BIT_CTRL2_PON    (1 << 4)
#define RX8025_BIT_CTRL2_XST    (1 << 5)
#define RX8025_BIT_CTRL2_VDET   (1 << 6)

/* Clock precision adjustment */
#define RX8025_ADJ_RESOLUTION   3050 /* in ppb */
#define RX8025_ADJ_DATA_MAX 62
#define RX8025_ADJ_DATA_MIN -62

static const struct i2c_device_id rx8025_id[] = {
    { "rx8025", 0 },
    { }
};
MODULE_DEVICE_TABLE(i2c, rx8025_id);

struct rx8025_data {
    struct i2c_client *client;
    struct rtc_device *rtc;
    struct work_struct work;
    u8 ctrl1;
    unsigned exiting:1;
};

static int rx8025_read_reg(struct i2c_client *client, int number, u8 *value)
{
    int ret = i2c_smbus_read_byte_data(client, (number << 4) | 0x08);

    if (ret < 0) {
        dev_err(&client->dev, "Unable to read register #%d\n", number);
        return ret;
    }

    *value = ret;
    return 0;
}

static int rx8025_read_regs(struct i2c_client *client,
                int number, u8 length, u8 *values)
{
    int ret = i2c_smbus_read_i2c_block_data(client, (number << 4) | 0x08,
                        length, values);

    if (ret != length) {
        dev_err(&client->dev, "Unable to read registers #%d..#%d\n",
            number, number + length - 1);
        return ret < 0 ? ret : -EIO;
    }

    return 0;
}

static int rx8025_write_reg(struct i2c_client *client, int number, u8 value)
{
    int ret = i2c_smbus_write_byte_data(client, number << 4, value);

    if (ret)
        dev_err(&client->dev, "Unable to write register #%d\n",
            number);

    return ret;
}

static int rx8025_write_regs(struct i2c_client *client,
                 int number, u8 length, u8 *values)
{
    int ret = i2c_smbus_write_i2c_block_data(client, (number << 4) | 0x08,
                         length, values);

    if (ret)
        dev_err(&client->dev, "Unable to write registers #%d..#%d\n",
            number, number + length - 1);

    return ret;
}

static irqreturn_t rx8025_irq(int irq, void *dev_id)
{
    struct i2c_client *client = dev_id;
    struct rx8025_data *rx8025 = i2c_get_clientdata(client);

    disable_irq_nosync(irq);
    schedule_work(&rx8025->work);
    return IRQ_HANDLED;
}

static void rx8025_work(struct work_struct *work)
{
    struct rx8025_data *rx8025 = container_of(work, struct rx8025_data,
                          work);
    struct i2c_client *client = rx8025->client;
    struct mutex *lock = &rx8025->rtc->ops_lock;
    u8 status;

    mutex_lock(lock);

    if (rx8025_read_reg(client, RX8025_REG_CTRL2, &status))
        goto out;

    if (!(status & RX8025_BIT_CTRL2_XST))
        dev_warn(&client->dev, "Oscillation stop was detected,"
             "you may have to readjust the clock\n");

    if (status & RX8025_BIT_CTRL2_CTFG) {
        /* periodic */
        status &= ~RX8025_BIT_CTRL2_CTFG;
        local_irq_disable();
        rtc_update_irq(rx8025->rtc, 1, RTC_PF | RTC_IRQF);
        local_irq_enable();
    }

    if (status & RX8025_BIT_CTRL2_DAFG) {
        /* alarm */
        status &= RX8025_BIT_CTRL2_DAFG;
        if (rx8025_write_reg(client, RX8025_REG_CTRL1,
                     rx8025->ctrl1 & ~RX8025_BIT_CTRL1_DALE))
            goto out;
        local_irq_disable();
        rtc_update_irq(rx8025->rtc, 1, RTC_AF | RTC_IRQF);
        local_irq_enable();
    }

    /* acknowledge IRQ */
    rx8025_write_reg(client, RX8025_REG_CTRL2,
             status | RX8025_BIT_CTRL2_XST);

out:
    if (!rx8025->exiting)
        enable_irq(client->irq);

    mutex_unlock(lock);
}

static int rx8025_get_time(struct device *dev, struct rtc_time *dt)
{
    struct rx8025_data *rx8025 = dev_get_drvdata(dev);
    u8 date[7];
    int err;

    err = rx8025_read_regs(rx8025->client, RX8025_REG_SEC, 7, date);
    if (err)
        return err;

    dev_dbg(dev, "%s: read 0x%02x 0x%02x "
        "0x%02x 0x%02x 0x%02x 0x%02x 0x%02x\n", __func__,
        date[0], date[1], date[2], date[3], date[4],
        date[5], date[6]);

    dt->tm_sec = bcd2bin(date[RX8025_REG_SEC] & 0x7f);
    dt->tm_min = bcd2bin(date[RX8025_REG_MIN] & 0x7f);
    if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
        dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x3f);
    else
        dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x1f) % 12
            + (date[RX8025_REG_HOUR] & 0x20 ? 12 : 0);

    dt->tm_mday = bcd2bin(date[RX8025_REG_MDAY] & 0x3f);
    dt->tm_mon = bcd2bin(date[RX8025_REG_MONTH] & 0x1f) - 1;
    dt->tm_year = bcd2bin(date[RX8025_REG_YEAR]);

    if (dt->tm_year < 70)
        dt->tm_year += 100;

    dev_dbg(dev, "%s: date %ds %dm %dh %dmd %dm %dy\n", __func__,
        dt->tm_sec, dt->tm_min, dt->tm_hour,
        dt->tm_mday, dt->tm_mon, dt->tm_year);

    return rtc_valid_tm(dt);
}

static int rx8025_set_time(struct device *dev, struct rtc_time *dt)
{
    struct rx8025_data *rx8025 = dev_get_drvdata(dev);
    u8 date[7];

    /*
     * BUG: The HW assumes every year that is a multiple of 4 to be a leap
     * year.  Next time this is wrong is 2100, which will not be a leap
     * year.
     */

    /*
     * Here the read-only bits are written as "0".  I'm not sure if that
     * is sound.
     */
    date[RX8025_REG_SEC] = bin2bcd(dt->tm_sec);
    date[RX8025_REG_MIN] = bin2bcd(dt->tm_min);
    if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
        date[RX8025_REG_HOUR] = bin2bcd(dt->tm_hour);
    else
        date[RX8025_REG_HOUR] = (dt->tm_hour >= 12 ? 0x20 : 0)
            | bin2bcd((dt->tm_hour + 11) % 12 + 1);

    date[RX8025_REG_WDAY] = bin2bcd(dt->tm_wday);
    date[RX8025_REG_MDAY] = bin2bcd(dt->tm_mday);
    date[RX8025_REG_MONTH] = bin2bcd(dt->tm_mon + 1);
    date[RX8025_REG_YEAR] = bin2bcd(dt->tm_year % 100);

    dev_dbg(dev,
        "%s: write 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x\n",
        __func__,
        date[0], date[1], date[2], date[3], date[4], date[5], date[6]);

    return rx8025_write_regs(rx8025->client, RX8025_REG_SEC, 7, date);
}

static int rx8025_init_client(struct i2c_client *client, int *need_reset)
{
    struct rx8025_data *rx8025 = i2c_get_clientdata(client);
    u8 ctrl[2], ctrl2;
    int need_clear = 0;
    int err;

    err = rx8025_read_regs(rx8025->client, RX8025_REG_CTRL1, 2, ctrl);
    if (err)
        goto out;

    /* Keep test bit zero ! */
    rx8025->ctrl1 = ctrl[0] & ~RX8025_BIT_CTRL1_TEST;

    if (ctrl[1] & RX8025_BIT_CTRL2_PON) {
        dev_warn(&client->dev, "power-on reset was detected, "
             "you may have to readjust the clock\n");
        *need_reset = 1;
    }

    if (ctrl[1] & RX8025_BIT_CTRL2_VDET) {
        dev_warn(&client->dev, "a power voltage drop was detected, "
             "you may have to readjust the clock\n");
        *need_reset = 1;
    }

    if (!(ctrl[1] & RX8025_BIT_CTRL2_XST)) {
        dev_warn(&client->dev, "Oscillation stop was detected,"
             "you may have to readjust the clock\n");
        *need_reset = 1;
    }

    if (ctrl[1] & (RX8025_BIT_CTRL2_DAFG | RX8025_BIT_CTRL2_WAFG)) {
        dev_warn(&client->dev, "Alarm was detected\n");
        need_clear = 1;
    }

    if (!(ctrl[1] & RX8025_BIT_CTRL2_CTFG))
        need_clear = 1;

    if (*need_reset || need_clear) {
        ctrl2 = ctrl[0];
        ctrl2 &= ~(RX8025_BIT_CTRL2_PON | RX8025_BIT_CTRL2_VDET |
               RX8025_BIT_CTRL2_CTFG | RX8025_BIT_CTRL2_WAFG |
               RX8025_BIT_CTRL2_DAFG);
        ctrl2 |= RX8025_BIT_CTRL2_XST;

        err = rx8025_write_reg(client, RX8025_REG_CTRL2, ctrl2);
    }
out:
    return err;
}

/* Alarm support */
static int rx8025_read_alarm(struct device *dev, struct rtc_wkalrm *t)
{
    struct rx8025_data *rx8025 = dev_get_drvdata(dev);
    struct i2c_client *client = rx8025->client;
    u8 ctrl2, ald[2];
    int err;

    if (client->irq <= 0)
        return -EINVAL;

    err = rx8025_read_regs(client, RX8025_REG_ALDMIN, 2, ald);
    if (err)
        return err;

    err = rx8025_read_reg(client, RX8025_REG_CTRL2, &ctrl2);
    if (err)
        return err;

    dev_dbg(dev, "%s: read alarm 0x%02x 0x%02x ctrl2 %02x\n",
        __func__, ald[0], ald[1], ctrl2);

    /* Hardware alarms precision is 1 minute! */
    t->time.tm_sec = 0;
    t->time.tm_min = bcd2bin(ald[0] & 0x7f);
    if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
        t->time.tm_hour = bcd2bin(ald[1] & 0x3f);
    else
        t->time.tm_hour = bcd2bin(ald[1] & 0x1f) % 12
            + (ald[1] & 0x20 ? 12 : 0);

    t->time.tm_wday = -1;
    t->time.tm_mday = -1;
    t->time.tm_mon = -1;
    t->time.tm_year = -1;

    dev_dbg(dev, "%s: date: %ds %dm %dh %dmd %dm %dy\n",
        __func__,
        t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
        t->time.tm_mday, t->time.tm_mon, t->time.tm_year);
    t->enabled = !!(rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE);
    t->pending = (ctrl2 & RX8025_BIT_CTRL2_DAFG) && t->enabled;

    return err;
}

static int rx8025_set_alarm(struct device *dev, struct rtc_wkalrm *t)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct rx8025_data *rx8025 = dev_get_drvdata(dev);
    u8 ald[2];
    int err;

    if (client->irq <= 0)
        return -EINVAL;

    /* Hardware alarm precision is 1 minute! */
    ald[0] = bin2bcd(t->time.tm_min);
    if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
        ald[1] = bin2bcd(t->time.tm_hour);
    else
        ald[1] = (t->time.tm_hour >= 12 ? 0x20 : 0)
            | bin2bcd((t->time.tm_hour + 11) % 12 + 1);

    dev_dbg(dev, "%s: write 0x%02x 0x%02x\n", __func__, ald[0], ald[1]);

    if (rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE) {
        rx8025->ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
        err = rx8025_write_reg(rx8025->client, RX8025_REG_CTRL1,
                       rx8025->ctrl1);
        if (err)
            return err;
    }
    err = rx8025_write_regs(rx8025->client, RX8025_REG_ALDMIN, 2, ald);
    if (err)
        return err;

    if (t->enabled) {
        rx8025->ctrl1 |= RX8025_BIT_CTRL1_DALE;
        err = rx8025_write_reg(rx8025->client, RX8025_REG_CTRL1,
                       rx8025->ctrl1);
        if (err)
            return err;
    }

    return 0;
}

static int rx8025_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
    struct rx8025_data *rx8025 = dev_get_drvdata(dev);
    u8 ctrl1;
    int err;

    ctrl1 = rx8025->ctrl1;
    if (enabled)
        ctrl1 |= RX8025_BIT_CTRL1_DALE;
    else
        ctrl1 &= ~RX8025_BIT_CTRL1_DALE;

    if (ctrl1 != rx8025->ctrl1) {
        rx8025->ctrl1 = ctrl1;
        err = rx8025_write_reg(rx8025->client, RX8025_REG_CTRL1,
                       rx8025->ctrl1);
        if (err)
            return err;
    }
    return 0;
}

static struct rtc_class_ops rx8025_rtc_ops = {
    .read_time = rx8025_get_time,
    .set_time = rx8025_set_time,
    .read_alarm = rx8025_read_alarm,
    .set_alarm = rx8025_set_alarm,
    .alarm_irq_enable = rx8025_alarm_irq_enable,
};

/*
 * Clock precision adjustment support
 *
 * According to the RX8025 SA/NB application manual the frequency and
 * temperature characteristics can be approximated using the following
 * equation:
 *
 *   df = a * (ut - t)**2
 *
 *   df: Frequency deviation in any temperature
 *   a : Coefficient = (-35 +-5) * 10**-9
 *   ut: Ultimate temperature in degree = +25 +-5 degree
 *   t : Any temperature in degree
 *
 * Note that the clock adjustment in ppb must be entered (which is
 * the negative value of the deviation).
 */
static int rx8025_get_clock_adjust(struct device *dev, int *adj)
{
    struct i2c_client *client = to_i2c_client(dev);
    u8 digoff;
    int err;

    err = rx8025_read_reg(client, RX8025_REG_DIGOFF, &digoff);
    if (err)
        return err;

    *adj = digoff >= 64 ? digoff - 128 : digoff;
    if (*adj > 0)
        (*adj)--;
    *adj *= -RX8025_ADJ_RESOLUTION;

    return 0;
}

static int rx8025_set_clock_adjust(struct device *dev, int adj)
{
    struct i2c_client *client = to_i2c_client(dev);
    u8 digoff;
    int err;

    adj /= -RX8025_ADJ_RESOLUTION;
    if (adj > RX8025_ADJ_DATA_MAX)
        adj = RX8025_ADJ_DATA_MAX;
    else if (adj < RX8025_ADJ_DATA_MIN)
        adj = RX8025_ADJ_DATA_MIN;
    else if (adj > 0)
        adj++;
    else if (adj < 0)
        adj += 128;
    digoff = adj;

    err = rx8025_write_reg(client, RX8025_REG_DIGOFF, digoff);
    if (err)
        return err;

    dev_dbg(dev, "%s: write 0x%02x\n", __func__, digoff);

    return 0;
}

static ssize_t rx8025_sysfs_show_clock_adjust(struct device *dev,
                          struct device_attribute *attr,
                          char *buf)
{
    int err, adj;

    err = rx8025_get_clock_adjust(dev, &adj);
    if (err)
        return err;

    return sprintf(buf, "%d\n", adj);
}

static ssize_t rx8025_sysfs_store_clock_adjust(struct device *dev,
                           struct device_attribute *attr,
                           const char *buf, size_t count)
{
    int adj, err;

    if (sscanf(buf, "%i", &adj) != 1)
        return -EINVAL;

    err = rx8025_set_clock_adjust(dev, adj);

    return err ? err : count;
}

static DEVICE_ATTR(clock_adjust_ppb, S_IRUGO | S_IWUSR,
           rx8025_sysfs_show_clock_adjust,
           rx8025_sysfs_store_clock_adjust);

static int rx8025_sysfs_register(struct device *dev)
{
    return device_create_file(dev, &dev_attr_clock_adjust_ppb);
}

static void rx8025_sysfs_unregister(struct device *dev)
{
    device_remove_file(dev, &dev_attr_clock_adjust_ppb);
}

static int __devinit rx8025_probe(struct i2c_client *client,
                  const struct i2c_device_id *id)
{
    struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
    struct rx8025_data *rx8025;
    int err, need_reset = 0;

    if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
                     | I2C_FUNC_SMBUS_I2C_BLOCK)) {
        dev_err(&adapter->dev,
            "doesn't support required functionality\n");
        err = -EIO;
        goto errout;
    }

    rx8025 = kzalloc(sizeof(*rx8025), GFP_KERNEL);
    if (!rx8025) {
        dev_err(&adapter->dev, "failed to alloc memory\n");
        err = -ENOMEM;
        goto errout;
    }

    rx8025->client = client;
    i2c_set_clientdata(client, rx8025);
    INIT_WORK(&rx8025->work, rx8025_work);

    err = rx8025_init_client(client, &need_reset);
    if (err)
        goto errout_free;

    if (need_reset) {
        struct rtc_time tm;
        dev_info(&client->dev,
             "bad conditions detected, resetting date\n");
        rtc_time_to_tm(0, &tm); /* 1970/1/1 */
        rx8025_set_time(&client->dev, &tm);
    }

    rx8025->rtc = rtc_device_register(client->name, &client->dev,
                      &rx8025_rtc_ops, THIS_MODULE);
    if (IS_ERR(rx8025->rtc)) {
        err = PTR_ERR(rx8025->rtc);
        dev_err(&client->dev, "unable to register the class device\n");
        goto errout_free;
    }

    if (client->irq > 0) {
        dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
        err = request_irq(client->irq, rx8025_irq,
                  0, "rx8025", client);
        if (err) {
            dev_err(&client->dev, "unable to request IRQ\n");
            goto errout_reg;
        }
    }

    rx8025->rtc->irq_freq = 1;
    rx8025->rtc->max_user_freq = 1;

    err = rx8025_sysfs_register(&client->dev);
    if (err)
        goto errout_irq;

    return 0;

errout_irq:
    if (client->irq > 0)
        free_irq(client->irq, client);

errout_reg:
    rtc_device_unregister(rx8025->rtc);

errout_free:
    kfree(rx8025);

errout:
    dev_err(&adapter->dev, "probing for rx8025 failed\n");
    return err;
}

static int __devexit rx8025_remove(struct i2c_client *client)
{
    struct rx8025_data *rx8025 = i2c_get_clientdata(client);
    struct mutex *lock = &rx8025->rtc->ops_lock;

    if (client->irq > 0) {
        mutex_lock(lock);
        rx8025->exiting = 1;
        mutex_unlock(lock);

        free_irq(client->irq, client);
        cancel_work_sync(&rx8025->work);
    }

    rx8025_sysfs_unregister(&client->dev);
    rtc_device_unregister(rx8025->rtc);
    kfree(rx8025);
    return 0;
}

static struct i2c_driver rx8025_driver = {
    .driver = {
        .name = "rtc-rx8025",
        .owner = THIS_MODULE,
    },
    .probe      = rx8025_probe,
    .remove     = __devexit_p(rx8025_remove),
    .id_table   = rx8025_id,
};

module_i2c_driver(rx8025_driver);

MODULE_AUTHOR("Wolfgang Grandegger <[email protected]>");
MODULE_DESCRIPTION("RX-8025 SA/NB RTC driver");
MODULE_LICENSE("GPL");