/*
   * RTC driver for Maxim MAX8997
   *
   * Copyright (C) 2013 Samsung Electronics Co.Ltd
   *
   *  based on rtc-max8998.c
   *
   *  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/slab.h>
  #include <linux/rtc.h>
  #include <linux/delay.h>
  #include <linux/mutex.h>
  #include <linux/module.h>
  #include <linux/platform_device.h>
  #include <linux/mfd/max8997-private.h>
  #include <linux/irqdomain.h>
  
  /* Module parameter for WTSR function control */
  static int wtsr_en = 1;
  module_param(wtsr_en, int, 0444);

  MODULE_PARM_DESC(wtsr_en, "Watchdog Timeout & Software Reset (default=on)");

  /* Module parameter for SMPL function control */
  static int smpl_en = 1;
  module_param(smpl_en, int, 0444);
  MODULE_PARM_DESC(smpl_en, "Sudden Momentary Power Loss (default=on)");
  
  /* RTC Control Register */
  #define BCD_EN_SHIFT			0
  #define BCD_EN_MASK			(1 << BCD_EN_SHIFT)
  #define MODEL24_SHIFT			1
  #define MODEL24_MASK			(1 << MODEL24_SHIFT)
  /* RTC Update Register1 */
  #define RTC_UDR_SHIFT			0
  #define RTC_UDR_MASK			(1 << RTC_UDR_SHIFT)
  /* WTSR and SMPL Register */
  #define WTSRT_SHIFT			0
  #define SMPLT_SHIFT			2
  #define WTSR_EN_SHIFT			6
  #define SMPL_EN_SHIFT			7
  #define WTSRT_MASK			(3 << WTSRT_SHIFT)
  #define SMPLT_MASK			(3 << SMPLT_SHIFT)
  #define WTSR_EN_MASK			(1 << WTSR_EN_SHIFT)
  #define SMPL_EN_MASK			(1 << SMPL_EN_SHIFT)
  /* RTC Hour register */
  #define HOUR_PM_SHIFT			6
  #define HOUR_PM_MASK			(1 << HOUR_PM_SHIFT)
  /* RTC Alarm Enable */
  #define ALARM_ENABLE_SHIFT		7
  #define ALARM_ENABLE_MASK		(1 << ALARM_ENABLE_SHIFT)
  
  enum {
  	RTC_SEC = 0,
  	RTC_MIN,
  	RTC_HOUR,
  	RTC_WEEKDAY,
  	RTC_MONTH,
  	RTC_YEAR,
  	RTC_DATE,
  	RTC_NR_TIME
  };
  
  struct max8997_rtc_info {
  	struct device		*dev;
  	struct max8997_dev	*max8997;
  	struct i2c_client	*rtc;
  	struct rtc_device	*rtc_dev;
  	struct mutex		lock;
  	int virq;
  	int rtc_24hr_mode;
  };
  
  static void max8997_rtc_data_to_tm(u8 *data, struct rtc_time *tm,
  				   int rtc_24hr_mode)
  {
  	tm->tm_sec = data[RTC_SEC] & 0x7f;
  	tm->tm_min = data[RTC_MIN] & 0x7f;
  	if (rtc_24hr_mode)
  		tm->tm_hour = data[RTC_HOUR] & 0x1f;
  	else {
  		tm->tm_hour = data[RTC_HOUR] & 0x0f;
  		if (data[RTC_HOUR] & HOUR_PM_MASK)
  			tm->tm_hour += 12;
  	}
  
  	tm->tm_wday = fls(data[RTC_WEEKDAY] & 0x7f) - 1;
  	tm->tm_mday = data[RTC_DATE] & 0x1f;
  	tm->tm_mon = (data[RTC_MONTH] & 0x0f) - 1;
  	tm->tm_year = (data[RTC_YEAR] & 0x7f) + 100;
  	tm->tm_yday = 0;
  	tm->tm_isdst = 0;
  }
  
  static int max8997_rtc_tm_to_data(struct rtc_time *tm, u8 *data)
  {
  	data[RTC_SEC] = tm->tm_sec;
  	data[RTC_MIN] = tm->tm_min;
  	data[RTC_HOUR] = tm->tm_hour;
  	data[RTC_WEEKDAY] = 1 << tm->tm_wday;
  	data[RTC_DATE] = tm->tm_mday;
  	data[RTC_MONTH] = tm->tm_mon + 1;

  	data[RTC_YEAR] = tm->tm_year > 100 ? (tm->tm_year - 100) : 0;

  
  	if (tm->tm_year < 100) {

  		pr_warn("RTC cannot handle the year %d.  Assume it's 2000.
  ",
  			1900 + tm->tm_year);

  		return -EINVAL;
  	}
  	return 0;
  }
  
  static inline int max8997_rtc_set_update_reg(struct max8997_rtc_info *info)
  {
  	int ret;
  
  	ret = max8997_write_reg(info->rtc, MAX8997_RTC_UPDATE1,
  						RTC_UDR_MASK);
  	if (ret < 0)
  		dev_err(info->dev, "%s: fail to write update reg(%d)
  ",
  				__func__, ret);
  	else {
  		/* Minimum 16ms delay required before RTC update.
  		 * Otherwise, we may read and update based on out-of-date
  		 * value */
  		msleep(20);
  	}
  
  	return ret;
  }
  
  static int max8997_rtc_read_time(struct device *dev, struct rtc_time *tm)
  {
  	struct max8997_rtc_info *info = dev_get_drvdata(dev);
  	u8 data[RTC_NR_TIME];
  	int ret;
  
  	mutex_lock(&info->lock);
  	ret = max8997_bulk_read(info->rtc, MAX8997_RTC_SEC, RTC_NR_TIME, data);
  	mutex_unlock(&info->lock);
  
  	if (ret < 0) {
  		dev_err(info->dev, "%s: fail to read time reg(%d)
  ", __func__,
  				ret);
  		return ret;
  	}
  
  	max8997_rtc_data_to_tm(data, tm, info->rtc_24hr_mode);
  
  	return rtc_valid_tm(tm);
  }
  
  static int max8997_rtc_set_time(struct device *dev, struct rtc_time *tm)
  {
  	struct max8997_rtc_info *info = dev_get_drvdata(dev);
  	u8 data[RTC_NR_TIME];
  	int ret;
  
  	ret = max8997_rtc_tm_to_data(tm, data);
  	if (ret < 0)
  		return ret;
  
  	mutex_lock(&info->lock);
  
  	ret = max8997_bulk_write(info->rtc, MAX8997_RTC_SEC, RTC_NR_TIME, data);
  	if (ret < 0) {
  		dev_err(info->dev, "%s: fail to write time reg(%d)
  ", __func__,
  				ret);
  		goto out;
  	}
  
  	ret = max8997_rtc_set_update_reg(info);
  out:
  	mutex_unlock(&info->lock);
  	return ret;
  }
  
  static int max8997_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  {
  	struct max8997_rtc_info *info = dev_get_drvdata(dev);
  	u8 data[RTC_NR_TIME];
  	u8 val;
  	int i, ret;
  
  	mutex_lock(&info->lock);
  
  	ret = max8997_bulk_read(info->rtc, MAX8997_RTC_ALARM1_SEC, RTC_NR_TIME,
  			data);
  	if (ret < 0) {
  		dev_err(info->dev, "%s:%d fail to read alarm reg(%d)
  ",
  				__func__, __LINE__, ret);
  		goto out;
  	}
  
  	max8997_rtc_data_to_tm(data, &alrm->time, info->rtc_24hr_mode);
  
  	alrm->enabled = 0;
  	for (i = 0; i < RTC_NR_TIME; i++) {
  		if (data[i] & ALARM_ENABLE_MASK) {
  			alrm->enabled = 1;
  			break;
  		}
  	}
  
  	alrm->pending = 0;
  	ret = max8997_read_reg(info->max8997->i2c, MAX8997_REG_STATUS1, &val);
  	if (ret < 0) {
  		dev_err(info->dev, "%s:%d fail to read status1 reg(%d)
  ",
  				__func__, __LINE__, ret);
  		goto out;
  	}
  
  	if (val & (1 << 4)) /* RTCA1 */
  		alrm->pending = 1;
  
  out:
  	mutex_unlock(&info->lock);
  	return 0;
  }
  
  static int max8997_rtc_stop_alarm(struct max8997_rtc_info *info)
  {
  	u8 data[RTC_NR_TIME];
  	int ret, i;
  
  	if (!mutex_is_locked(&info->lock))
  		dev_warn(info->dev, "%s: should have mutex locked
  ", __func__);
  
  	ret = max8997_bulk_read(info->rtc, MAX8997_RTC_ALARM1_SEC, RTC_NR_TIME,
  				data);
  	if (ret < 0) {
  		dev_err(info->dev, "%s: fail to read alarm reg(%d)
  ",
  				__func__, ret);
  		goto out;
  	}
  
  	for (i = 0; i < RTC_NR_TIME; i++)
  		data[i] &= ~ALARM_ENABLE_MASK;
  
  	ret = max8997_bulk_write(info->rtc, MAX8997_RTC_ALARM1_SEC, RTC_NR_TIME,
  				 data);
  	if (ret < 0) {
  		dev_err(info->dev, "%s: fail to write alarm reg(%d)
  ",
  				__func__, ret);
  		goto out;
  	}
  
  	ret = max8997_rtc_set_update_reg(info);
  out:
  	return ret;
  }
  
  static int max8997_rtc_start_alarm(struct max8997_rtc_info *info)
  {
  	u8 data[RTC_NR_TIME];
  	int ret;
  
  	if (!mutex_is_locked(&info->lock))
  		dev_warn(info->dev, "%s: should have mutex locked
  ", __func__);
  
  	ret = max8997_bulk_read(info->rtc, MAX8997_RTC_ALARM1_SEC, RTC_NR_TIME,
  				data);
  	if (ret < 0) {
  		dev_err(info->dev, "%s: fail to read alarm reg(%d)
  ",
  				__func__, ret);
  		goto out;
  	}
  
  	data[RTC_SEC] |= (1 << ALARM_ENABLE_SHIFT);
  	data[RTC_MIN] |= (1 << ALARM_ENABLE_SHIFT);
  	data[RTC_HOUR] |= (1 << ALARM_ENABLE_SHIFT);
  	data[RTC_WEEKDAY] &= ~ALARM_ENABLE_MASK;
  	if (data[RTC_MONTH] & 0xf)
  		data[RTC_MONTH] |= (1 << ALARM_ENABLE_SHIFT);
  	if (data[RTC_YEAR] & 0x7f)
  		data[RTC_YEAR] |= (1 << ALARM_ENABLE_SHIFT);
  	if (data[RTC_DATE] & 0x1f)
  		data[RTC_DATE] |= (1 << ALARM_ENABLE_SHIFT);
  
  	ret = max8997_bulk_write(info->rtc, MAX8997_RTC_ALARM1_SEC, RTC_NR_TIME,
  				 data);
  	if (ret < 0) {
  		dev_err(info->dev, "%s: fail to write alarm reg(%d)
  ",
  				__func__, ret);
  		goto out;
  	}
  
  	ret = max8997_rtc_set_update_reg(info);
  out:
  	return ret;
  }
  static int max8997_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  {
  	struct max8997_rtc_info *info = dev_get_drvdata(dev);
  	u8 data[RTC_NR_TIME];
  	int ret;
  
  	ret = max8997_rtc_tm_to_data(&alrm->time, data);
  	if (ret < 0)
  		return ret;
  
  	dev_info(info->dev, "%s: %d-%02d-%02d %02d:%02d:%02d
  ", __func__,
  			data[RTC_YEAR] + 2000, data[RTC_MONTH], data[RTC_DATE],
  			data[RTC_HOUR], data[RTC_MIN], data[RTC_SEC]);
  
  	mutex_lock(&info->lock);
  
  	ret = max8997_rtc_stop_alarm(info);
  	if (ret < 0)
  		goto out;
  
  	ret = max8997_bulk_write(info->rtc, MAX8997_RTC_ALARM1_SEC, RTC_NR_TIME,
  				data);
  	if (ret < 0) {
  		dev_err(info->dev, "%s: fail to write alarm reg(%d)
  ",
  				__func__, ret);
  		goto out;
  	}
  
  	ret = max8997_rtc_set_update_reg(info);
  	if (ret < 0)
  		goto out;
  
  	if (alrm->enabled)
  		ret = max8997_rtc_start_alarm(info);
  out:
  	mutex_unlock(&info->lock);
  	return ret;
  }
  
  static int max8997_rtc_alarm_irq_enable(struct device *dev,
  					unsigned int enabled)
  {
  	struct max8997_rtc_info *info = dev_get_drvdata(dev);
  	int ret;
  
  	mutex_lock(&info->lock);
  	if (enabled)
  		ret = max8997_rtc_start_alarm(info);
  	else
  		ret = max8997_rtc_stop_alarm(info);
  	mutex_unlock(&info->lock);
  
  	return ret;
  }
  
  static irqreturn_t max8997_rtc_alarm_irq(int irq, void *data)
  {
  	struct max8997_rtc_info *info = data;
  
  	dev_info(info->dev, "%s:irq(%d)
  ", __func__, irq);
  
  	rtc_update_irq(info->rtc_dev, 1, RTC_IRQF | RTC_AF);
  
  	return IRQ_HANDLED;
  }
  
  static const struct rtc_class_ops max8997_rtc_ops = {
  	.read_time = max8997_rtc_read_time,
  	.set_time = max8997_rtc_set_time,
  	.read_alarm = max8997_rtc_read_alarm,
  	.set_alarm = max8997_rtc_set_alarm,
  	.alarm_irq_enable = max8997_rtc_alarm_irq_enable,
  };
  
  static void max8997_rtc_enable_wtsr(struct max8997_rtc_info *info, bool enable)
  {
  	int ret;
  	u8 val, mask;
  
  	if (!wtsr_en)
  		return;
  
  	if (enable)
  		val = (1 << WTSR_EN_SHIFT) | (3 << WTSRT_SHIFT);
  	else
  		val = 0;
  
  	mask = WTSR_EN_MASK | WTSRT_MASK;
  
  	dev_info(info->dev, "%s: %s WTSR
  ", __func__,
  			enable ? "enable" : "disable");
  
  	ret = max8997_update_reg(info->rtc, MAX8997_RTC_WTSR_SMPL, val, mask);
  	if (ret < 0) {
  		dev_err(info->dev, "%s: fail to update WTSR reg(%d)
  ",
  				__func__, ret);
  		return;
  	}
  
  	max8997_rtc_set_update_reg(info);
  }
  
  static void max8997_rtc_enable_smpl(struct max8997_rtc_info *info, bool enable)
  {
  	int ret;
  	u8 val, mask;
  
  	if (!smpl_en)
  		return;
  
  	if (enable)
  		val = (1 << SMPL_EN_SHIFT) | (0 << SMPLT_SHIFT);
  	else
  		val = 0;
  
  	mask = SMPL_EN_MASK | SMPLT_MASK;
  
  	dev_info(info->dev, "%s: %s SMPL
  ", __func__,
  			enable ? "enable" : "disable");
  
  	ret = max8997_update_reg(info->rtc, MAX8997_RTC_WTSR_SMPL, val, mask);
  	if (ret < 0) {
  		dev_err(info->dev, "%s: fail to update SMPL reg(%d)
  ",
  				__func__, ret);
  		return;
  	}
  
  	max8997_rtc_set_update_reg(info);
  
  	val = 0;
  	max8997_read_reg(info->rtc, MAX8997_RTC_WTSR_SMPL, &val);

  	pr_info("WTSR_SMPL(0x%02x)
  ", val);

  }
  
  static int max8997_rtc_init_reg(struct max8997_rtc_info *info)
  {
  	u8 data[2];
  	int ret;
  
  	/* Set RTC control register : Binary mode, 24hour mdoe */
  	data[0] = (1 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);
  	data[1] = (0 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);
  
  	info->rtc_24hr_mode = 1;
  
  	ret = max8997_bulk_write(info->rtc, MAX8997_RTC_CTRLMASK, 2, data);
  	if (ret < 0) {
  		dev_err(info->dev, "%s: fail to write controlm reg(%d)
  ",
  				__func__, ret);
  		return ret;
  	}
  
  	ret = max8997_rtc_set_update_reg(info);
  	return ret;
  }
  
  static int max8997_rtc_probe(struct platform_device *pdev)
  {
  	struct max8997_dev *max8997 = dev_get_drvdata(pdev->dev.parent);
  	struct max8997_rtc_info *info;
  	int ret, virq;
  
  	info = devm_kzalloc(&pdev->dev, sizeof(struct max8997_rtc_info),
  			GFP_KERNEL);
  	if (!info)
  		return -ENOMEM;
  
  	mutex_init(&info->lock);
  	info->dev = &pdev->dev;
  	info->max8997 = max8997;
  	info->rtc = max8997->rtc;
  
  	platform_set_drvdata(pdev, info);
  
  	ret = max8997_rtc_init_reg(info);
  
  	if (ret < 0) {
  		dev_err(&pdev->dev, "Failed to initialize RTC reg:%d
  ", ret);
  		return ret;
  	}
  
  	max8997_rtc_enable_wtsr(info, true);
  	max8997_rtc_enable_smpl(info, true);
  
  	device_init_wakeup(&pdev->dev, 1);

  	info->rtc_dev = devm_rtc_device_register(&pdev->dev, "max8997-rtc",
  					&max8997_rtc_ops, THIS_MODULE);

  
  	if (IS_ERR(info->rtc_dev)) {
  		ret = PTR_ERR(info->rtc_dev);
  		dev_err(&pdev->dev, "Failed to register RTC device: %d
  ", ret);
  		return ret;
  	}
  
  	virq = irq_create_mapping(max8997->irq_domain, MAX8997_PMICIRQ_RTCA1);
  	if (!virq) {
  		dev_err(&pdev->dev, "Failed to create mapping alarm IRQ
  ");

  		ret = -ENXIO;

  		goto err_out;
  	}
  	info->virq = virq;

  	ret = devm_request_threaded_irq(&pdev->dev, virq, NULL,
  				max8997_rtc_alarm_irq, 0,

  				"rtc-alarm0", info);

  	if (ret < 0)

  		dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d
  ",
  			info->virq, ret);

  
  err_out:

  	return ret;
  }

  static void max8997_rtc_shutdown(struct platform_device *pdev)
  {
  	struct max8997_rtc_info *info = platform_get_drvdata(pdev);
  
  	max8997_rtc_enable_wtsr(info, false);
  	max8997_rtc_enable_smpl(info, false);
  }
  
  static const struct platform_device_id rtc_id[] = {
  	{ "max8997-rtc", 0 },
  	{},
  };

  MODULE_DEVICE_TABLE(platform, rtc_id);

  
  static struct platform_driver max8997_rtc_driver = {
  	.driver		= {
  		.name	= "max8997-rtc",

  	},
  	.probe		= max8997_rtc_probe,

  	.shutdown	= max8997_rtc_shutdown,
  	.id_table	= rtc_id,
  };
  
  module_platform_driver(max8997_rtc_driver);
  
  MODULE_DESCRIPTION("Maxim MAX8997 RTC driver");
  MODULE_AUTHOR("<ms925.kim@samsung.com>");
  MODULE_LICENSE("GPL");