text: /*
   * Real time clock driver for DA9055
   *
   * 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/mfd/da9055/core.h>
  #include <linux/mfd/da9055/reg.h>
  #include <linux/mfd/da9055/pdata.h>
  
  struct da9055_rtc {
  	struct rtc_device *rtc;
  	struct da9055 *da9055;
  	int alarm_enable;
  };
  
  static int da9055_rtc_enable_alarm(struct da9055_rtc *rtc, bool enable)
  {
  	int ret;
  	if (enable) {
  		ret = da9055_reg_update(rtc->da9055, DA9055_REG_ALARM_Y,
  					DA9055_RTC_ALM_EN,
  					DA9055_RTC_ALM_EN);
  		if (ret != 0)
  			dev_err(rtc->da9055->dev, "Failed to enable ALM: %d\n",
  				ret);
  		rtc->alarm_enable = 1;
  	} else {
  		ret = da9055_reg_update(rtc->da9055, DA9055_REG_ALARM_Y,
  					DA9055_RTC_ALM_EN, 0);
  		if (ret != 0)
  			dev_err(rtc->da9055->dev,
  				"Failed to disable ALM: %d\n", ret);
  		rtc->alarm_enable = 0;
  	}
  	return ret;
  }
  
  static irqreturn_t da9055_rtc_alm_irq(int irq, void *data)
  {
  	struct da9055_rtc *rtc = data;
  
  	da9055_rtc_enable_alarm(rtc, 0);
  	rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
  
  	return IRQ_HANDLED;
  }
  
  static int da9055_read_alarm(struct da9055 *da9055, struct rtc_time *rtc_tm)
  {
  	int ret;
  	uint8_t v[5];
  
  	ret = da9055_group_read(da9055, DA9055_REG_ALARM_MI, 5, v);
  	if (ret != 0) {
  		dev_err(da9055->dev, "Failed to group read ALM: %d\n", ret);
  		return ret;
  	}
  
  	rtc_tm->tm_year = (v[4] & DA9055_RTC_ALM_YEAR) + 100;
  	rtc_tm->tm_mon  = (v[3] & DA9055_RTC_ALM_MONTH) - 1;
  	rtc_tm->tm_mday = v[2] & DA9055_RTC_ALM_DAY;
  	rtc_tm->tm_hour = v[1] & DA9055_RTC_ALM_HOUR;
  	rtc_tm->tm_min  = v[0] & DA9055_RTC_ALM_MIN;
  
  	return rtc_valid_tm(rtc_tm);
  }
  
  static int da9055_set_alarm(struct da9055 *da9055, struct rtc_time *rtc_tm)
  {
  	int ret;
  	uint8_t v[2];
  
  	rtc_tm->tm_year -= 100;
  	rtc_tm->tm_mon += 1;
  
  	ret = da9055_reg_update(da9055, DA9055_REG_ALARM_MI,
  				DA9055_RTC_ALM_MIN, rtc_tm->tm_min);
  	if (ret != 0) {
  		dev_err(da9055->dev, "Failed to write ALRM MIN: %d\n", ret);
  		return ret;
  	}
  
  	v[0] = rtc_tm->tm_hour;
  	v[1] = rtc_tm->tm_mday;
  
  	ret = da9055_group_write(da9055, DA9055_REG_ALARM_H, 2, v);
  	if (ret < 0)
  		return ret;
  
  	ret = da9055_reg_update(da9055, DA9055_REG_ALARM_MO,
  				DA9055_RTC_ALM_MONTH, rtc_tm->tm_mon);
  	if (ret < 0)
  		dev_err(da9055->dev, "Failed to write ALM Month:%d\n", ret);
  
  	ret = da9055_reg_update(da9055, DA9055_REG_ALARM_Y,
  				DA9055_RTC_ALM_YEAR, rtc_tm->tm_year);
  	if (ret < 0)
  		dev_err(da9055->dev, "Failed to write ALM Year:%d\n", ret);
  
  	return ret;
  }
  
  static int da9055_rtc_get_alarm_status(struct da9055 *da9055)
  {
  	int ret;
  
  	ret = da9055_reg_read(da9055, DA9055_REG_ALARM_Y);
  	if (ret < 0) {
  		dev_err(da9055->dev, "Failed to read ALM: %d\n", ret);
  		return ret;
  	}
  	ret &= DA9055_RTC_ALM_EN;
  	return (ret > 0) ? 1 : 0;
  }
  
  static int da9055_rtc_read_time(struct device *dev, struct rtc_time *rtc_tm)
  {
  	struct da9055_rtc *rtc = dev_get_drvdata(dev);
  	uint8_t v[6];
  	int ret;
  
  	ret = da9055_reg_read(rtc->da9055, DA9055_REG_COUNT_S);
  	if (ret < 0)
  		return ret;
  
  	/*
  	 * Registers are only valid when RTC_READ
  	 * status bit is asserted
  	 */
  	if (!(ret & DA9055_RTC_READ))
  		return -EBUSY;
  
  	ret = da9055_group_read(rtc->da9055, DA9055_REG_COUNT_S, 6, v);
  	if (ret < 0) {
  		dev_err(rtc->da9055->dev, "Failed to read RTC time : %d\n",
  			ret);
  		return ret;
  	}
  
  	rtc_tm->tm_year = (v[5] & DA9055_RTC_YEAR) + 100;
  	rtc_tm->tm_mon  = (v[4] & DA9055_RTC_MONTH) - 1;
  	rtc_tm->tm_mday = v[3] & DA9055_RTC_DAY;
  	rtc_tm->tm_hour = v[2] & DA9055_RTC_HOUR;
  	rtc_tm->tm_min  = v[1] & DA9055_RTC_MIN;
  	rtc_tm->tm_sec  = v[0] & DA9055_RTC_SEC;
  
  	return rtc_valid_tm(rtc_tm);
  }
  
  static int da9055_rtc_set_time(struct device *dev, struct rtc_time *tm)
  {
  	struct da9055_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 da9055_group_write(rtc->da9055, DA9055_REG_COUNT_S, 6, v);
  }
  
  static int da9055_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  {
  	int ret;
  	struct rtc_time *tm = &alrm->time;
  	struct da9055_rtc *rtc = dev_get_drvdata(dev);
  
  	ret = da9055_read_alarm(rtc->da9055, tm);
  
  	if (ret)
  		return ret;
  
  	alrm->enabled = da9055_rtc_get_alarm_status(rtc->da9055);
  
  	return 0;
  }
  
  static int da9055_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  {
  	int ret;
  	struct rtc_time *tm = &alrm->time;
  	struct da9055_rtc *rtc = dev_get_drvdata(dev);
  
  	ret = da9055_rtc_enable_alarm(rtc, 0);
  	if (ret < 0)
  		return ret;
  
  	ret = da9055_set_alarm(rtc->da9055, tm);
  	if (ret)
  		return ret;
  
  	ret = da9055_rtc_enable_alarm(rtc, 1);
  
  	return ret;
  }
  
  static int da9055_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
  {
  	struct da9055_rtc *rtc = dev_get_drvdata(dev);
  
  	return da9055_rtc_enable_alarm(rtc, enabled);
  }
  
  static const struct rtc_class_ops da9055_rtc_ops = {
  	.read_time	= da9055_rtc_read_time,
  	.set_time	= da9055_rtc_set_time,
  	.read_alarm	= da9055_rtc_read_alarm,
  	.set_alarm	= da9055_rtc_set_alarm,
  	.alarm_irq_enable = da9055_rtc_alarm_irq_enable,
  };
  
  static int da9055_rtc_device_init(struct da9055 *da9055,
  					struct da9055_pdata *pdata)
  {
  	int ret;
  
  	/* Enable RTC and the internal Crystal */
  	ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_B,
  				DA9055_RTC_EN, DA9055_RTC_EN);
  	if (ret < 0)
  		return ret;
  	ret = da9055_reg_update(da9055, DA9055_REG_EN_32K,
  				DA9055_CRYSTAL_EN, DA9055_CRYSTAL_EN);
  	if (ret < 0)
  		return ret;
  
  	/* Enable RTC in Power Down mode */
  	ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_B,
  				DA9055_RTC_MODE_PD, DA9055_RTC_MODE_PD);
  	if (ret < 0)
  		return ret;
  
  	/* Enable RTC in Reset mode */
  	if (pdata && pdata->reset_enable) {
  		ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_B,
  					DA9055_RTC_MODE_SD,
  					DA9055_RTC_MODE_SD <<
  					DA9055_RTC_MODE_SD_SHIFT);
  		if (ret < 0)
  			return ret;
  	}
  
  	/* Disable the RTC TICK ALM */
  	ret = da9055_reg_update(da9055, DA9055_REG_ALARM_MO,
  				DA9055_RTC_TICK_WAKE_MASK, 0);
  	if (ret < 0)
  		return ret;
  
  	return 0;
  }
  
  static int da9055_rtc_probe(struct platform_device *pdev)
  {
  	struct da9055_rtc *rtc;
  	struct da9055_pdata *pdata = NULL;
  	int ret, alm_irq;
  
  	rtc = devm_kzalloc(&pdev->dev, sizeof(struct da9055_rtc), GFP_KERNEL);
  	if (!rtc)
  		return -ENOMEM;
  
  	rtc->da9055 = dev_get_drvdata(pdev->dev.parent);
  	pdata = dev_get_platdata(rtc->da9055->dev);
  	platform_set_drvdata(pdev, rtc);
  
  	ret = da9055_rtc_device_init(rtc->da9055, pdata);
  	if (ret < 0)
  		goto err_rtc;
  
  	ret = da9055_reg_read(rtc->da9055, DA9055_REG_ALARM_Y);
  	if (ret < 0)
  		goto err_rtc;
  
  	if (ret & DA9055_RTC_ALM_EN)
  		rtc->alarm_enable = 1;
  
  	device_init_wakeup(&pdev->dev, 1);
  
  	rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
  					&da9055_rtc_ops, THIS_MODULE);
  	if (IS_ERR(rtc->rtc)) {
  		ret = PTR_ERR(rtc->rtc);
  		goto err_rtc;
  	}
  
  	alm_irq = platform_get_irq_byname(pdev, "ALM");
  	if (alm_irq < 0)
  		return alm_irq;
  
  	ret = devm_request_threaded_irq(&pdev->dev, alm_irq, NULL,
  					da9055_rtc_alm_irq,
  					IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
  					"ALM", rtc);
  	if (ret != 0)
  		dev_err(rtc->da9055->dev, "irq registration failed: %d\n", ret);
  
  err_rtc:
  	return ret;
  
  }
  
  #ifdef CONFIG_PM
  /* Turn off the alarm if it should not be a wake source. */
  static int da9055_rtc_suspend(struct device *dev)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct da9055_rtc *rtc = dev_get_drvdata(&pdev->dev);
  	int ret;
  
  	if (!device_may_wakeup(&pdev->dev)) {
  		/* Disable the ALM IRQ */
  		ret = da9055_rtc_enable_alarm(rtc, 0);
  		if (ret < 0)
  			dev_err(&pdev->dev, "Failed to disable RTC ALM\n");
  	}
  
  	return 0;
  }
  
  /* Enable the alarm if it should be enabled (in case it was disabled to
   * prevent use as a wake source).
   */
  static int da9055_rtc_resume(struct device *dev)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct da9055_rtc *rtc = dev_get_drvdata(&pdev->dev);
  	int ret;
  
  	if (!device_may_wakeup(&pdev->dev)) {
  		if (rtc->alarm_enable) {
  			ret = da9055_rtc_enable_alarm(rtc, 1);
  			if (ret < 0)
  				dev_err(&pdev->dev,
  					"Failed to restart RTC ALM\n");
  		}
  	}
  
  	return 0;
  }
  
  /* Unconditionally disable the alarm */
  static int da9055_rtc_freeze(struct device *dev)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct da9055_rtc *rtc = dev_get_drvdata(&pdev->dev);
  	int ret;
  
  	ret = da9055_rtc_enable_alarm(rtc, 0);
  	if (ret < 0)
  		dev_err(&pdev->dev, "Failed to freeze RTC ALMs\n");
  
  	return 0;
  
  }
  #else
  #define da9055_rtc_suspend NULL
  #define da9055_rtc_resume NULL
  #define da9055_rtc_freeze NULL
  #endif
  
  static const struct dev_pm_ops da9055_rtc_pm_ops = {
  	.suspend = da9055_rtc_suspend,
  	.resume = da9055_rtc_resume,
  
  	.freeze = da9055_rtc_freeze,
  	.thaw = da9055_rtc_resume,
  	.restore = da9055_rtc_resume,
  
  	.poweroff = da9055_rtc_suspend,
  };
  
  static struct platform_driver da9055_rtc_driver = {
  	.probe  = da9055_rtc_probe,
  	.driver = {
  		.name   = "da9055-rtc",
  		.owner  = THIS_MODULE,
  		.pm = &da9055_rtc_pm_ops,
  	},
  };
  
  module_platform_driver(da9055_rtc_driver);
  
  MODULE_AUTHOR("David Dajun Chen <dchen@diasemi.com>");
  MODULE_DESCRIPTION("RTC driver for Dialog DA9055 PMIC");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("platform:da9055-rtc");
  