/*
   * Real time clock driver for DA9052
   *
   * Copyright(c) 2012 Dialog Semiconductor Ltd.
   *
   * Author: Dajun Dajun Chen <dajun.chen@diasemi.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/module.h>
  #include <linux/platform_device.h>
  #include <linux/rtc.h>
  #include <linux/err.h>
  
  #include <linux/mfd/da9052/da9052.h>
  #include <linux/mfd/da9052/reg.h>
  
  #define rtc_err(da9052, fmt, ...) \
  		dev_err(da9052->dev, "%s: " fmt, __func__, ##__VA_ARGS__)
  
  struct da9052_rtc {
  	struct rtc_device *rtc;
  	struct da9052 *da9052;
  	int irq;
  };
  
  static int da9052_rtc_enable_alarm(struct da9052 *da9052, bool enable)
  {
  	int ret;
  	if (enable) {
  		ret = da9052_reg_update(da9052, DA9052_ALARM_Y_REG,
  					DA9052_ALARM_Y_ALARM_ON,
  					DA9052_ALARM_Y_ALARM_ON);
  		if (ret != 0)
  			rtc_err(da9052, "Failed to enable ALM: %d
  ", ret);
  	} else {
  		ret = da9052_reg_update(da9052, DA9052_ALARM_Y_REG,
  					DA9052_ALARM_Y_ALARM_ON, 0);
  		if (ret != 0)
  			rtc_err(da9052, "Write error: %d
  ", ret);
  	}
  	return ret;
  }
  
  static irqreturn_t da9052_rtc_irq(int irq, void *data)
  {
  	struct da9052_rtc *rtc = data;
  	int ret;
  
  	ret = da9052_reg_read(rtc->da9052, DA9052_ALARM_MI_REG);
  	if (ret < 0) {
  		rtc_err(rtc->da9052, "Read error: %d
  ", ret);
  		return IRQ_NONE;
  	}
  
  	if (ret & DA9052_ALARMMI_ALARMTYPE) {
  		da9052_rtc_enable_alarm(rtc->da9052, 0);
  		rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
  	} else
  		rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_PF);
  
  	return IRQ_HANDLED;
  }
  
  static int da9052_read_alarm(struct da9052 *da9052, struct rtc_time *rtc_tm)
  {
  	int ret;
  	uint8_t v[5];
  
  	ret = da9052_group_read(da9052, DA9052_ALARM_MI_REG, 5, v);
  	if (ret != 0) {
  		rtc_err(da9052, "Failed to group read ALM: %d
  ", ret);
  		return ret;
  	}
  
  	rtc_tm->tm_year = (v[4] & DA9052_RTC_YEAR) + 100;
  	rtc_tm->tm_mon  = (v[3] & DA9052_RTC_MONTH) - 1;
  	rtc_tm->tm_mday = v[2] & DA9052_RTC_DAY;
  	rtc_tm->tm_hour = v[1] & DA9052_RTC_HOUR;
  	rtc_tm->tm_min  = v[0] & DA9052_RTC_MIN;
  
  	ret = rtc_valid_tm(rtc_tm);
  	if (ret != 0)
  		return ret;
  	return ret;
  }
  
  static int da9052_set_alarm(struct da9052 *da9052, struct rtc_time *rtc_tm)
  {
  	int ret;
  	uint8_t v[3];
  
  	rtc_tm->tm_year -= 100;
  	rtc_tm->tm_mon += 1;
  
  	ret = da9052_reg_update(da9052, DA9052_ALARM_MI_REG,
  				DA9052_RTC_MIN, rtc_tm->tm_min);
  	if (ret != 0) {
  		rtc_err(da9052, "Failed to write ALRM MIN: %d
  ", ret);
  		return ret;
  	}
  
  	v[0] = rtc_tm->tm_hour;
  	v[1] = rtc_tm->tm_mday;
  	v[2] = rtc_tm->tm_mon;
  
  	ret = da9052_group_write(da9052, DA9052_ALARM_H_REG, 3, v);
  	if (ret < 0)
  		return ret;
  
  	ret = da9052_reg_update(da9052, DA9052_ALARM_Y_REG,
  				DA9052_RTC_YEAR, rtc_tm->tm_year);
  	if (ret != 0)
  		rtc_err(da9052, "Failed to write ALRM YEAR: %d
  ", ret);
  
  	return ret;
  }
  
  static int da9052_rtc_get_alarm_status(struct da9052 *da9052)
  {
  	int ret;
  
  	ret = da9052_reg_read(da9052, DA9052_ALARM_Y_REG);
  	if (ret < 0) {
  		rtc_err(da9052, "Failed to read ALM: %d
  ", ret);
  		return ret;
  	}
  	ret &= DA9052_ALARM_Y_ALARM_ON;
  	return (ret > 0) ? 1 : 0;
  }
  
  static int da9052_rtc_read_time(struct device *dev, struct rtc_time *rtc_tm)
  {
  	struct da9052_rtc *rtc = dev_get_drvdata(dev);
  	uint8_t v[6];
  	int ret;
  
  	ret = da9052_group_read(rtc->da9052, DA9052_COUNT_S_REG, 6, v);
  	if (ret < 0) {
  		rtc_err(rtc->da9052, "Failed to read RTC time : %d
  ", ret);
  		return ret;
  	}
  
  	rtc_tm->tm_year = (v[5] & DA9052_RTC_YEAR) + 100;
  	rtc_tm->tm_mon  = (v[4] & DA9052_RTC_MONTH) - 1;
  	rtc_tm->tm_mday = v[3] & DA9052_RTC_DAY;
  	rtc_tm->tm_hour = v[2] & DA9052_RTC_HOUR;
  	rtc_tm->tm_min  = v[1] & DA9052_RTC_MIN;
  	rtc_tm->tm_sec  = v[0] & DA9052_RTC_SEC;
  
  	ret = rtc_valid_tm(rtc_tm);
  	if (ret != 0) {
  		rtc_err(rtc->da9052, "rtc_valid_tm failed: %d
  ", ret);
  		return ret;
  	}
  
  	return 0;
  }
  
  static int da9052_rtc_set_time(struct device *dev, struct rtc_time *tm)
  {
  	struct da9052_rtc *rtc;
  	uint8_t v[6];
  
  	rtc = dev_get_drvdata(dev);
  
  	v[0] = tm->tm_sec;
  	v[1] = tm->tm_min;
  	v[2] = tm->tm_hour;
  	v[3] = tm->tm_mday;
  	v[4] = tm->tm_mon + 1;
  	v[5] = tm->tm_year - 100;
  
  	return da9052_group_write(rtc->da9052, DA9052_COUNT_S_REG, 6, v);
  }
  
  static int da9052_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  {
  	int ret;
  	struct rtc_time *tm = &alrm->time;
  	struct da9052_rtc *rtc = dev_get_drvdata(dev);
  
  	ret = da9052_read_alarm(rtc->da9052, tm);
  
  	if (ret)
  		return ret;
  
  	alrm->enabled = da9052_rtc_get_alarm_status(rtc->da9052);
  
  	return 0;
  }
  
  static int da9052_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  {
  	int ret;
  	struct rtc_time *tm = &alrm->time;
  	struct da9052_rtc *rtc = dev_get_drvdata(dev);
  
  	ret = da9052_rtc_enable_alarm(rtc->da9052, 0);
  	if (ret < 0)
  		return ret;
  
  	ret = da9052_set_alarm(rtc->da9052, tm);
  	if (ret)
  		return ret;
  
  	ret = da9052_rtc_enable_alarm(rtc->da9052, 1);
  
  	return ret;
  }
  
  static int da9052_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
  {
  	struct da9052_rtc *rtc = dev_get_drvdata(dev);
  
  	return da9052_rtc_enable_alarm(rtc->da9052, enabled);
  }
  
  static const struct rtc_class_ops da9052_rtc_ops = {
  	.read_time	= da9052_rtc_read_time,
  	.set_time	= da9052_rtc_set_time,
  	.read_alarm	= da9052_rtc_read_alarm,
  	.set_alarm	= da9052_rtc_set_alarm,
  	.alarm_irq_enable = da9052_rtc_alarm_irq_enable,
  };
  
  static int da9052_rtc_probe(struct platform_device *pdev)
  {
  	struct da9052_rtc *rtc;
  	int ret;
  
  	rtc = devm_kzalloc(&pdev->dev, sizeof(struct da9052_rtc), GFP_KERNEL);
  	if (!rtc)
  		return -ENOMEM;
  
  	rtc->da9052 = dev_get_drvdata(pdev->dev.parent);
  	platform_set_drvdata(pdev, rtc);
  	rtc->irq =  DA9052_IRQ_ALARM;
  	ret = da9052_request_irq(rtc->da9052, rtc->irq, "ALM",
  				da9052_rtc_irq, rtc);
  	if (ret != 0) {
  		rtc_err(rtc->da9052, "irq registration failed: %d
  ", ret);
  		return ret;
  	}
  
  	rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
  				       &da9052_rtc_ops, THIS_MODULE);
  	return PTR_ERR_OR_ZERO(rtc->rtc);
  }
  
  static struct platform_driver da9052_rtc_driver = {
  	.probe	= da9052_rtc_probe,
  	.driver = {
  		.name	= "da9052-rtc",
  		.owner	= THIS_MODULE,
  	},
  };
  
  module_platform_driver(da9052_rtc_driver);
  
  MODULE_AUTHOR("David Dajun Chen <dchen@diasemi.com>");
  MODULE_DESCRIPTION("RTC driver for Dialog DA9052 PMIC");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("platform:da9052-rtc");