linux-imx

/*

 * RTC client/driver for the Maxim/Dallas DS3232/DS3234 Real-Time Clock

 *

 * Copyright (C) 2009-2011 Freescale Semiconductor.

 * Author: Jack Lan <jack.lan@freescale.com>

 * Copyright (C) 2008 MIMOMax Wireless Ltd.

 *

 * This program is free software; you can redistribute  it and/or modify it

 * under  the terms of  the GNU General  Public License as published by the

 * Free Software Foundation;  either version 2 of the  License, or (at your

 * option) any later version.

 */

​

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

​

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/interrupt.h>

#include <linux/i2c.h>

#include <linux/spi/spi.h>

#include <linux/rtc.h>

#include <linux/bcd.h>

#include <linux/slab.h>

#include <linux/regmap.h>

#include <linux/hwmon.h>

​

#define DS3232_REG_SECONDS      0x00

#define DS3232_REG_MINUTES      0x01

#define DS3232_REG_HOURS        0x02

#define DS3232_REG_AMPM         0x02

#define DS3232_REG_DAY          0x03

#define DS3232_REG_DATE         0x04

#define DS3232_REG_MONTH        0x05

#define DS3232_REG_CENTURY      0x05

#define DS3232_REG_YEAR         0x06

#define DS3232_REG_ALARM1       0x07       /* Alarm 1 BASE */

#define DS3232_REG_ALARM2       0x0B       /* Alarm 2 BASE */

#define DS3232_REG_CR           0x0E       /* Control register */

#       define DS3232_REG_CR_nEOSC   0x80

#       define DS3232_REG_CR_INTCN   0x04

#       define DS3232_REG_CR_A2IE    0x02

#       define DS3232_REG_CR_A1IE    0x01

​

#define DS3232_REG_SR           0x0F       /* control/status register */

#       define DS3232_REG_SR_OSF     0x80

#       define DS3232_REG_SR_BSY     0x04

#       define DS3232_REG_SR_A2F     0x02

#       define DS3232_REG_SR_A1F     0x01

​

#define DS3232_REG_TEMPERATURE  0x11

​

struct ds3232 {

    struct device *dev;

    struct regmap *regmap;

    int irq;

    struct rtc_device *rtc;

​

    bool suspended;

};

​

static int ds3232_check_rtc_status(struct device *dev)

{

    struct ds3232 *ds3232 = dev_get_drvdata(dev);

    int ret = 0;

    int control, stat;

​

    ret = regmap_read(ds3232->regmap, DS3232_REG_SR, &stat);

    if (ret)

        return ret;

​

    if (stat & DS3232_REG_SR_OSF)

        dev_warn(dev,

                "oscillator discontinuity flagged, "

                "time unreliable\n");

​

    stat &= ~(DS3232_REG_SR_OSF | DS3232_REG_SR_A1F | DS3232_REG_SR_A2F);

​

    ret = regmap_write(ds3232->regmap, DS3232_REG_SR, stat);

    if (ret)

        return ret;

​

    /* If the alarm is pending, clear it before requesting

     * the interrupt, so an interrupt event isn't reported

     * before everything is initialized.

     */

​

    ret = regmap_read(ds3232->regmap, DS3232_REG_CR, &control);

    if (ret)

        return ret;

​

    control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE);

    control |= DS3232_REG_CR_INTCN;