/*
   * rtc-tps65910.c -- TPS65910 Real Time Clock interface
   *
   * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
   * Author: Venu Byravarasu <vbyravarasu@nvidia.com>
   *
   * Based on original TI driver rtc-twl.c
   *   Copyright (C) 2007 MontaVista Software, Inc
   *   Author: Alexandre Rusev <source@mvista.com>
   *
   * 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;

  	int irq;

  };
  
  /* 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
  ", 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
  ", 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
  ", 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
  ", 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
  ", 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
  ", 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
  ", 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 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.
  ");

  
  	/* Enable RTC digital power domain */
  	ret = regmap_update_bits(tps65910->regmap, TPS65910_DEVCTRL,
  		DEVCTRL_RTC_PWDN_MASK, 0 << DEVCTRL_RTC_PWDN_SHIFT);
  	if (ret < 0)
  		return ret;

  	rtc_reg = TPS65910_RTC_CTRL_STOP_RTC;
  	ret = regmap_write(tps65910->regmap, TPS65910_RTC_CTRL, rtc_reg);
  	if (ret < 0)
  		return ret;

  	platform_set_drvdata(pdev, tps_rtc);

  	irq  = platform_get_irq(pdev, 0);

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

  		return -ENXIO;

  	}

  	ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,

  		tps65910_rtc_interrupt, IRQF_TRIGGER_LOW,

  		dev_name(&pdev->dev), &pdev->dev);

  	if (ret < 0) {
  		dev_err(&pdev->dev, "IRQ is not free.
  ");
  		return ret;
  	}

  	tps_rtc->irq = irq;
  	device_set_wakeup_capable(&pdev->dev, 1);

  	tps_rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,

  		&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
  ", ret);
  		return ret;
  	}

  	return 0;
  }
  
  /*
   * Disable tps65910 RTC interrupts.
   * Sets status flag to free.
   */

  static int tps65910_rtc_remove(struct platform_device *pdev)

  {

  	tps65910_rtc_alarm_irq_enable(&pdev->dev, 0);

  	return 0;
  }
  
  #ifdef CONFIG_PM_SLEEP

  static int tps65910_rtc_suspend(struct device *dev)
  {

  	struct tps65910_rtc *tps_rtc = dev_get_drvdata(dev);

  	if (device_may_wakeup(dev))
  		enable_irq_wake(tps_rtc->irq);

  	return 0;

  }
  
  static int tps65910_rtc_resume(struct device *dev)
  {

  	struct tps65910_rtc *tps_rtc = dev_get_drvdata(dev);
  
  	if (device_may_wakeup(dev))
  		disable_irq_wake(tps_rtc->irq);

  	return 0;

  }

  #endif

  static SIMPLE_DEV_PM_OPS(tps65910_rtc_pm_ops, tps65910_rtc_suspend,
  			tps65910_rtc_resume);

  static struct platform_driver tps65910_rtc_driver = {
  	.probe		= tps65910_rtc_probe,

  	.remove		= tps65910_rtc_remove,

  	.driver		= {

  		.name	= "tps65910-rtc",

  		.pm	= &tps65910_rtc_pm_ops,

  	},
  };
  
  module_platform_driver(tps65910_rtc_driver);
  MODULE_ALIAS("platform:rtc-tps65910");
  MODULE_AUTHOR("Venu Byravarasu <vbyravarasu@nvidia.com>");
  MODULE_LICENSE("GPL");