/*
   * rtc-as3722.c - Real Time Clock driver for ams AS3722 PMICs
   *
   * Copyright (C) 2013 ams AG
   * Copyright (c) 2013, NVIDIA Corporation. All rights reserved.
   *
   * Author: Florian Lobmaier <florian.lobmaier@ams.com>
   * Author: Laxman Dewangan <ldewangan@nvidia.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.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   */
  
  #include <linux/bcd.h>
  #include <linux/completion.h>
  #include <linux/delay.h>
  #include <linux/interrupt.h>
  #include <linux/ioctl.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/mfd/as3722.h>
  #include <linux/platform_device.h>
  #include <linux/rtc.h>
  #include <linux/time.h>
  
  #define AS3722_RTC_START_YEAR	  2000
  struct as3722_rtc {
  	struct rtc_device	*rtc;
  	struct device		*dev;
  	struct as3722		*as3722;
  	int			alarm_irq;
  	bool			irq_enable;
  };
  
  static void as3722_time_to_reg(u8 *rbuff, struct rtc_time *tm)
  {
  	rbuff[0] = bin2bcd(tm->tm_sec);
  	rbuff[1] = bin2bcd(tm->tm_min);
  	rbuff[2] = bin2bcd(tm->tm_hour);
  	rbuff[3] = bin2bcd(tm->tm_mday);
  	rbuff[4] = bin2bcd(tm->tm_mon);
  	rbuff[5] = bin2bcd(tm->tm_year - (AS3722_RTC_START_YEAR - 1900));
  }
  
  static void as3722_reg_to_time(u8 *rbuff, struct rtc_time *tm)
  {
  	tm->tm_sec = bcd2bin(rbuff[0] & 0x7F);
  	tm->tm_min = bcd2bin(rbuff[1] & 0x7F);
  	tm->tm_hour = bcd2bin(rbuff[2] & 0x3F);
  	tm->tm_mday = bcd2bin(rbuff[3] & 0x3F);
  	tm->tm_mon = bcd2bin(rbuff[4] & 0x1F);
  	tm->tm_year = (AS3722_RTC_START_YEAR - 1900) + bcd2bin(rbuff[5] & 0x7F);
  	return;
  }
  
  static int as3722_rtc_read_time(struct device *dev, struct rtc_time *tm)
  {
  	struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev);
  	struct as3722 *as3722 = as3722_rtc->as3722;
  	u8 as_time_array[6];
  	int ret;
  
  	ret = as3722_block_read(as3722, AS3722_RTC_SECOND_REG,
  			6, as_time_array);
  	if (ret < 0) {
  		dev_err(dev, "RTC_SECOND reg block read failed %d
  ", ret);
  		return ret;
  	}
  	as3722_reg_to_time(as_time_array, tm);
  	return 0;
  }
  
  static int as3722_rtc_set_time(struct device *dev, struct rtc_time *tm)
  {
  	struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev);
  	struct as3722 *as3722 = as3722_rtc->as3722;
  	u8 as_time_array[6];
  	int ret;
  
  	if (tm->tm_year < (AS3722_RTC_START_YEAR - 1900))
  		return -EINVAL;
  
  	as3722_time_to_reg(as_time_array, tm);
  	ret = as3722_block_write(as3722, AS3722_RTC_SECOND_REG, 6,
  			as_time_array);
  	if (ret < 0)
  		dev_err(dev, "RTC_SECOND reg block write failed %d
  ", ret);
  	return ret;
  }
  
  static int as3722_rtc_alarm_irq_enable(struct device *dev,
  		unsigned int enabled)
  {
  	struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev);
  
  	if (enabled && !as3722_rtc->irq_enable) {
  		enable_irq(as3722_rtc->alarm_irq);
  		as3722_rtc->irq_enable = true;
  	} else if (!enabled && as3722_rtc->irq_enable)  {
  		disable_irq(as3722_rtc->alarm_irq);
  		as3722_rtc->irq_enable = false;
  	}
  	return 0;
  }
  
  static int as3722_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  {
  	struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev);
  	struct as3722 *as3722 = as3722_rtc->as3722;
  	u8 as_time_array[6];
  	int ret;
  
  	ret = as3722_block_read(as3722, AS3722_RTC_ALARM_SECOND_REG, 6,
  			as_time_array);
  	if (ret < 0) {
  		dev_err(dev, "RTC_ALARM_SECOND block read failed %d
  ", ret);
  		return ret;
  	}
  
  	as3722_reg_to_time(as_time_array, &alrm->time);
  	return 0;
  }
  
  static int as3722_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  {
  	struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev);
  	struct as3722 *as3722 = as3722_rtc->as3722;
  	u8 as_time_array[6];
  	int ret;
  
  	if (alrm->time.tm_year < (AS3722_RTC_START_YEAR - 1900))
  		return -EINVAL;
  
  	ret = as3722_rtc_alarm_irq_enable(dev, 0);
  	if (ret < 0) {
  		dev_err(dev, "Disable RTC alarm failed
  ");
  		return ret;
  	}
  
  	as3722_time_to_reg(as_time_array, &alrm->time);
  	ret = as3722_block_write(as3722, AS3722_RTC_ALARM_SECOND_REG, 6,
  			as_time_array);
  	if (ret < 0) {
  		dev_err(dev, "RTC_ALARM_SECOND block write failed %d
  ", ret);
  		return ret;
  	}
  
  	if (alrm->enabled)
  		ret = as3722_rtc_alarm_irq_enable(dev, alrm->enabled);
  	return ret;
  }
  
  static irqreturn_t as3722_alarm_irq(int irq, void *data)
  {
  	struct as3722_rtc *as3722_rtc = data;
  
  	rtc_update_irq(as3722_rtc->rtc, 1, RTC_IRQF | RTC_AF);
  	return IRQ_HANDLED;
  }
  
  static const struct rtc_class_ops as3722_rtc_ops = {
  	.read_time = as3722_rtc_read_time,
  	.set_time = as3722_rtc_set_time,
  	.read_alarm = as3722_rtc_read_alarm,
  	.set_alarm = as3722_rtc_set_alarm,
  	.alarm_irq_enable = as3722_rtc_alarm_irq_enable,
  };
  
  static int as3722_rtc_probe(struct platform_device *pdev)
  {
  	struct as3722 *as3722 = dev_get_drvdata(pdev->dev.parent);
  	struct as3722_rtc *as3722_rtc;
  	int ret;
  
  	as3722_rtc = devm_kzalloc(&pdev->dev, sizeof(*as3722_rtc), GFP_KERNEL);
  	if (!as3722_rtc)
  		return -ENOMEM;
  
  	as3722_rtc->as3722 = as3722;
  	as3722_rtc->dev = &pdev->dev;
  	platform_set_drvdata(pdev, as3722_rtc);
  
  	/* Enable the RTC to make sure it is running. */
  	ret = as3722_update_bits(as3722, AS3722_RTC_CONTROL_REG,
  			AS3722_RTC_ON | AS3722_RTC_ALARM_WAKEUP_EN,
  			AS3722_RTC_ON | AS3722_RTC_ALARM_WAKEUP_EN);
  	if (ret < 0) {
  		dev_err(&pdev->dev, "RTC_CONTROL reg write failed: %d
  ", ret);
  		return ret;
  	}
  
  	device_init_wakeup(&pdev->dev, 1);
  
  	as3722_rtc->rtc = devm_rtc_device_register(&pdev->dev, "as3722-rtc",
  				&as3722_rtc_ops, THIS_MODULE);
  	if (IS_ERR(as3722_rtc->rtc)) {
  		ret = PTR_ERR(as3722_rtc->rtc);
  		dev_err(&pdev->dev, "RTC register failed: %d
  ", ret);
  		return ret;
  	}
  
  	as3722_rtc->alarm_irq = platform_get_irq(pdev, 0);
  	dev_info(&pdev->dev, "RTC interrupt %d
  ", as3722_rtc->alarm_irq);
  
  	ret = devm_request_threaded_irq(&pdev->dev, as3722_rtc->alarm_irq, NULL,
  			as3722_alarm_irq, IRQF_ONESHOT | IRQF_EARLY_RESUME,
  			"rtc-alarm", as3722_rtc);
  	if (ret < 0) {
  		dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d
  ",
  				as3722_rtc->alarm_irq, ret);
  		return ret;
  	}
  	disable_irq(as3722_rtc->alarm_irq);
  	return 0;
  }
  
  #ifdef CONFIG_PM_SLEEP
  static int as3722_rtc_suspend(struct device *dev)
  {
  	struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev);
  
  	if (device_may_wakeup(dev))
  		enable_irq_wake(as3722_rtc->alarm_irq);
  
  	return 0;
  }
  
  static int as3722_rtc_resume(struct device *dev)
  {
  	struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev);
  
  	if (device_may_wakeup(dev))
  		disable_irq_wake(as3722_rtc->alarm_irq);
  	return 0;
  }
  #endif
  
  static const struct dev_pm_ops as3722_rtc_pm_ops = {
  	SET_SYSTEM_SLEEP_PM_OPS(as3722_rtc_suspend, as3722_rtc_resume)
  };
  
  static struct platform_driver as3722_rtc_driver = {
  	.probe = as3722_rtc_probe,
  	.driver = {
  		.name = "as3722-rtc",
  		.pm = &as3722_rtc_pm_ops,
  	},
  };
  module_platform_driver(as3722_rtc_driver);
  
  MODULE_DESCRIPTION("RTC driver for AS3722 PMICs");
  MODULE_ALIAS("platform:as3722-rtc");
  MODULE_AUTHOR("Florian Lobmaier <florian.lobmaier@ams.com>");
  MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
  MODULE_LICENSE("GPL");