rtc-tps65910.c

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/*
 * rtc-tps65910.c -- TPS65910 Real Time Clock interface
 *
 * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
 * Author: Venu Byravarasu <[email protected]>
 *
 * Based on original TI driver rtc-twl.c
 *   Copyright (C) 2007 MontaVista Software, Inc
 *   Author: Alexandre Rusev <[email protected]>
 *
 * 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.
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/rtc.h>
#include <linux/bcd.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/mfd/tps65910.h>

struct tps65910_rtc {
    struct rtc_device   *rtc;
    /* To store the list of enabled interrupts */
    u32 irqstat;
};

/* Total number of RTC registers needed to set time*/
#define NUM_TIME_REGS   (TPS65910_YEARS - TPS65910_SECONDS + 1)

static int tps65910_rtc_alarm_irq_enable(struct device *dev, unsigned enabled)
{
    struct tps65910 *tps = dev_get_drvdata(dev->parent);
    u8 val = 0;

    if (enabled)
        val = TPS65910_RTC_INTERRUPTS_IT_ALARM;

    return regmap_write(tps->regmap, TPS65910_RTC_INTERRUPTS, val);
}

/*
 * Gets current tps65910 RTC time and date parameters.
 *
 * The RTC's time/alarm representation is not what gmtime(3) requires
 * Linux to use:
 *
 *  - Months are 1..12 vs Linux 0-11
 *  - Years are 0..99 vs Linux 1900..N (we assume 21st century)
 */
static int tps65910_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
    unsigned char rtc_data[NUM_TIME_REGS];
    struct tps65910 *tps = dev_get_drvdata(dev->parent);
    int ret;

    /* Copy RTC counting registers to static registers or latches */
    ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
        TPS65910_RTC_CTRL_GET_TIME, TPS65910_RTC_CTRL_GET_TIME);
    if (ret < 0) {
        dev_err(dev, "RTC CTRL reg update failed with err:%d\n", ret);
        return ret;
    }

    ret = regmap_bulk_read(tps->regmap, TPS65910_SECONDS, rtc_data,
        NUM_TIME_REGS);
    if (ret < 0) {
        dev_err(dev, "reading from RTC failed with err:%d\n", ret);
        return ret;
    }

    tm->tm_sec = bcd2bin(rtc_data[0]);
    tm->tm_min = bcd2bin(rtc_data[1]);
    tm->tm_hour = bcd2bin(rtc_data[2]);
    tm->tm_mday = bcd2bin(rtc_data[3]);
    tm->tm_mon = bcd2bin(rtc_data[4]) - 1;
    tm->tm_year = bcd2bin(rtc_data[5]) + 100;

    return ret;
}

static int tps65910_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
    unsigned char rtc_data[NUM_TIME_REGS];
    struct tps65910 *tps = dev_get_drvdata(dev->parent);
    int ret;

    rtc_data[0] = bin2bcd(tm->tm_sec);
    rtc_data[1] = bin2bcd(tm->tm_min);
    rtc_data[2] = bin2bcd(tm->tm_hour);
    rtc_data[3] = bin2bcd(tm->tm_mday);
    rtc_data[4] = bin2bcd(tm->tm_mon + 1);
    rtc_data[5] = bin2bcd(tm->tm_year - 100);

    /* Stop RTC while updating the RTC time registers */
    ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
        TPS65910_RTC_CTRL_STOP_RTC, 0);
    if (ret < 0) {
        dev_err(dev, "RTC stop failed with err:%d\n", ret);
        return ret;
    }

    /* update all the time registers in one shot */
    ret = regmap_bulk_write(tps->regmap, TPS65910_SECONDS, rtc_data,
        NUM_TIME_REGS);
    if (ret < 0) {
        dev_err(dev, "rtc_set_time error %d\n", ret);
        return ret;
    }

    /* Start back RTC */
    ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
        TPS65910_RTC_CTRL_STOP_RTC, 1);
    if (ret < 0)
        dev_err(dev, "RTC start failed with err:%d\n", ret);

    return ret;
}

/*
 * Gets current tps65910 RTC alarm time.
 */
static int tps65910_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
    unsigned char alarm_data[NUM_TIME_REGS];
    u32 int_val;
    struct tps65910 *tps = dev_get_drvdata(dev->parent);
    int ret;

    ret = regmap_bulk_read(tps->regmap, TPS65910_SECONDS, alarm_data,
        NUM_TIME_REGS);
    if (ret < 0) {
        dev_err(dev, "rtc_read_alarm error %d\n", ret);
        return ret;
    }

    alm->time.tm_sec = bcd2bin(alarm_data[0]);
    alm->time.tm_min = bcd2bin(alarm_data[1]);
    alm->time.tm_hour = bcd2bin(alarm_data[2]);
    alm->time.tm_mday = bcd2bin(alarm_data[3]);
    alm->time.tm_mon = bcd2bin(alarm_data[4]) - 1;
    alm->time.tm_year = bcd2bin(alarm_data[5]) + 100;

    ret = regmap_read(tps->regmap, TPS65910_RTC_INTERRUPTS, &int_val);
    if (ret < 0)
        return ret;

    if (int_val & TPS65910_RTC_INTERRUPTS_IT_ALARM)
        alm->enabled = 1;

    return ret;
}

static int tps65910_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
    unsigned char alarm_data[NUM_TIME_REGS];
    struct tps65910 *tps = dev_get_drvdata(dev->parent);
    int ret;

    ret = tps65910_rtc_alarm_irq_enable(dev, 0);
    if (ret)
        return ret;

    alarm_data[0] = bin2bcd(alm->time.tm_sec);
    alarm_data[1] = bin2bcd(alm->time.tm_min);
    alarm_data[2] = bin2bcd(alm->time.tm_hour);
    alarm_data[3] = bin2bcd(alm->time.tm_mday);
    alarm_data[4] = bin2bcd(alm->time.tm_mon + 1);
    alarm_data[5] = bin2bcd(alm->time.tm_year - 100);

    /* update all the alarm registers in one shot */
    ret = regmap_bulk_write(tps->regmap, TPS65910_ALARM_SECONDS,
        alarm_data, NUM_TIME_REGS);
    if (ret) {
        dev_err(dev, "rtc_set_alarm error %d\n", ret);
        return ret;
    }

    if (alm->enabled)
        ret = tps65910_rtc_alarm_irq_enable(dev, 1);

    return ret;
}

static irqreturn_t tps65910_rtc_interrupt(int irq, void *rtc)
{
    struct device *dev = rtc;
    unsigned long events = 0;
    struct tps65910 *tps = dev_get_drvdata(dev->parent);
    struct tps65910_rtc *tps_rtc = dev_get_drvdata(dev);
    int ret;
    u32 rtc_reg;

    ret = regmap_read(tps->regmap, TPS65910_RTC_STATUS, &rtc_reg);
    if (ret)
        return IRQ_NONE;

    if (rtc_reg & TPS65910_RTC_STATUS_ALARM)
        events = RTC_IRQF | RTC_AF;

    ret = regmap_write(tps->regmap, TPS65910_RTC_STATUS, rtc_reg);
    if (ret)
        return IRQ_NONE;

    /* Notify RTC core on event */
    rtc_update_irq(tps_rtc->rtc, 1, events);

    return IRQ_HANDLED;
}

static const struct rtc_class_ops tps65910_rtc_ops = {
    .read_time  = tps65910_rtc_read_time,
    .set_time   = tps65910_rtc_set_time,
    .read_alarm = tps65910_rtc_read_alarm,
    .set_alarm  = tps65910_rtc_set_alarm,
    .alarm_irq_enable = tps65910_rtc_alarm_irq_enable,
};

static int __devinit tps65910_rtc_probe(struct platform_device *pdev)
{
    struct tps65910 *tps65910 = NULL;
    struct tps65910_rtc *tps_rtc = NULL;
    int ret;
    int irq;
    u32 rtc_reg;

    tps65910 = dev_get_drvdata(pdev->dev.parent);

    tps_rtc = devm_kzalloc(&pdev->dev, sizeof(struct tps65910_rtc),
            GFP_KERNEL);
    if (!tps_rtc)
        return -ENOMEM;

    /* Clear pending interrupts */
    ret = regmap_read(tps65910->regmap, TPS65910_RTC_STATUS, &rtc_reg);
    if (ret < 0)
        return ret;

    ret = regmap_write(tps65910->regmap, TPS65910_RTC_STATUS, rtc_reg);
    if (ret < 0)
        return ret;

    dev_dbg(&pdev->dev, "Enabling rtc-tps65910.\n");
    rtc_reg = TPS65910_RTC_CTRL_STOP_RTC;
    ret = regmap_write(tps65910->regmap, TPS65910_RTC_CTRL, rtc_reg);
    if (ret < 0)
        return ret;

    irq  = platform_get_irq(pdev, 0);
    if (irq <= 0) {
        dev_warn(&pdev->dev, "Wake up is not possible as irq = %d\n",
            irq);
        return ret;
    }

    ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
        tps65910_rtc_interrupt, IRQF_TRIGGER_LOW,
        "rtc-tps65910", &pdev->dev);
    if (ret < 0) {
        dev_err(&pdev->dev, "IRQ is not free.\n");
        return ret;
    }
    device_init_wakeup(&pdev->dev, 1);

    tps_rtc->rtc = rtc_device_register(pdev->name, &pdev->dev,
        &tps65910_rtc_ops, THIS_MODULE);
    if (IS_ERR(tps_rtc->rtc)) {
        ret = PTR_ERR(tps_rtc->rtc);
        dev_err(&pdev->dev, "RTC device register: err %d\n", ret);
        return ret;
    }

    platform_set_drvdata(pdev, tps_rtc);

    return 0;
}

/*
 * Disable tps65910 RTC interrupts.
 * Sets status flag to free.
 */
static int __devexit tps65910_rtc_remove(struct platform_device *pdev)
{
    /* leave rtc running, but disable irqs */
    struct tps65910_rtc *tps_rtc = platform_get_drvdata(pdev);

    tps65910_rtc_alarm_irq_enable(&pdev->dev, 0);

    rtc_device_unregister(tps_rtc->rtc);
    return 0;
}

#ifdef CONFIG_PM_SLEEP

static int tps65910_rtc_suspend(struct device *dev)
{
    struct tps65910 *tps = dev_get_drvdata(dev->parent);
    u8 alarm = TPS65910_RTC_INTERRUPTS_IT_ALARM;
    int ret;

    /* Store current list of enabled interrupts*/
    ret = regmap_read(tps->regmap, TPS65910_RTC_INTERRUPTS,
        &tps->rtc->irqstat);
    if (ret < 0)
        return ret;

    /* Enable RTC ALARM interrupt only */
    return regmap_write(tps->regmap, TPS65910_RTC_INTERRUPTS, alarm);
}

static int tps65910_rtc_resume(struct device *dev)
{
    struct tps65910 *tps = dev_get_drvdata(dev->parent);

    /* Restore list of enabled interrupts before suspend */
    return regmap_write(tps->regmap, TPS65910_RTC_INTERRUPTS,
        tps->rtc->irqstat);
}

static const struct dev_pm_ops tps65910_rtc_pm_ops = {
    .suspend    = tps65910_rtc_suspend,
    .resume     = tps65910_rtc_resume,
};

#define DEV_PM_OPS     (&tps65910_rtc_pm_ops)
#else
#define DEV_PM_OPS     NULL
#endif

static struct platform_driver tps65910_rtc_driver = {
    .probe      = tps65910_rtc_probe,
    .remove     = __devexit_p(tps65910_rtc_remove),
    .driver     = {
        .owner  = THIS_MODULE,
        .name   = "tps65910-rtc",
        .pm = DEV_PM_OPS,
    },
};

module_platform_driver(tps65910_rtc_driver);
MODULE_ALIAS("platform:rtc-tps65910");
MODULE_AUTHOR("Venu Byravarasu <[email protected]>");
MODULE_LICENSE("GPL");