/*
   * A driver for the RTC embedded in the Cirrus Logic EP93XX processors
   * Copyright (c) 2006 Tower Technologies
   *
   * Author: Alessandro Zummo <a.zummo@towertech.it>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */
  
  #include <linux/module.h>
  #include <linux/rtc.h>
  #include <linux/platform_device.h>

  #include <linux/io.h>

  #include <linux/gfp.h>

  
  #define EP93XX_RTC_DATA			0x000
  #define EP93XX_RTC_MATCH		0x004
  #define EP93XX_RTC_STATUS		0x008
  #define  EP93XX_RTC_STATUS_INTR		 (1<<0)
  #define EP93XX_RTC_LOAD			0x00C
  #define EP93XX_RTC_CONTROL		0x010
  #define  EP93XX_RTC_CONTROL_MIE		 (1<<0)
  #define EP93XX_RTC_SWCOMP		0x108
  #define  EP93XX_RTC_SWCOMP_DEL_MASK	 0x001f0000
  #define  EP93XX_RTC_SWCOMP_DEL_SHIFT	 16
  #define  EP93XX_RTC_SWCOMP_INT_MASK	 0x0000ffff
  #define  EP93XX_RTC_SWCOMP_INT_SHIFT	 0
  
  #define DRV_VERSION "0.3"

  /*
   * struct device dev.platform_data is used to store our private data
   * because struct rtc_device does not have a variable to hold it.
   */
  struct ep93xx_rtc {
  	void __iomem	*mmio_base;

  	struct rtc_device *rtc;

  };

  static int ep93xx_rtc_get_swcomp(struct device *dev, unsigned short *preload,

  				unsigned short *delete)
  {

  	struct ep93xx_rtc *ep93xx_rtc = dev->platform_data;
  	unsigned long comp;
  
  	comp = __raw_readl(ep93xx_rtc->mmio_base + EP93XX_RTC_SWCOMP);

  
  	if (preload)

  		*preload = (comp & EP93XX_RTC_SWCOMP_INT_MASK)
  				>> EP93XX_RTC_SWCOMP_INT_SHIFT;

  
  	if (delete)

  		*delete = (comp & EP93XX_RTC_SWCOMP_DEL_MASK)
  				>> EP93XX_RTC_SWCOMP_DEL_SHIFT;

  
  	return 0;
  }
  
  static int ep93xx_rtc_read_time(struct device *dev, struct rtc_time *tm)
  {

  	struct ep93xx_rtc *ep93xx_rtc = dev->platform_data;
  	unsigned long time;
  
  	 time = __raw_readl(ep93xx_rtc->mmio_base + EP93XX_RTC_DATA);

  
  	rtc_time_to_tm(time, tm);
  	return 0;
  }
  
  static int ep93xx_rtc_set_mmss(struct device *dev, unsigned long secs)
  {

  	struct ep93xx_rtc *ep93xx_rtc = dev->platform_data;
  
  	__raw_writel(secs + 1, ep93xx_rtc->mmio_base + EP93XX_RTC_LOAD);

  	return 0;
  }

  static int ep93xx_rtc_proc(struct device *dev, struct seq_file *seq)
  {
  	unsigned short preload, delete;

  	ep93xx_rtc_get_swcomp(dev, &preload, &delete);

  	seq_printf(seq, "preload\t\t: %d
  ", preload);
  	seq_printf(seq, "delete\t\t: %d
  ", delete);
  
  	return 0;
  }

  static const struct rtc_class_ops ep93xx_rtc_ops = {

  	.read_time	= ep93xx_rtc_read_time,

  	.set_mmss	= ep93xx_rtc_set_mmss,
  	.proc		= ep93xx_rtc_proc,
  };

  static ssize_t ep93xx_rtc_show_comp_preload(struct device *dev,

  			struct device_attribute *attr, char *buf)
  {
  	unsigned short preload;

  	ep93xx_rtc_get_swcomp(dev, &preload, NULL);

  
  	return sprintf(buf, "%d
  ", preload);
  }

  static DEVICE_ATTR(comp_preload, S_IRUGO, ep93xx_rtc_show_comp_preload, NULL);

  static ssize_t ep93xx_rtc_show_comp_delete(struct device *dev,

  			struct device_attribute *attr, char *buf)
  {
  	unsigned short delete;

  	ep93xx_rtc_get_swcomp(dev, NULL, &delete);

  
  	return sprintf(buf, "%d
  ", delete);
  }

  static DEVICE_ATTR(comp_delete, S_IRUGO, ep93xx_rtc_show_comp_delete, NULL);

  static struct attribute *ep93xx_rtc_attrs[] = {
  	&dev_attr_comp_preload.attr,
  	&dev_attr_comp_delete.attr,
  	NULL
  };
  
  static const struct attribute_group ep93xx_rtc_sysfs_files = {
  	.attrs	= ep93xx_rtc_attrs,
  };

  static int __init ep93xx_rtc_probe(struct platform_device *pdev)

  {

  	struct ep93xx_rtc *ep93xx_rtc;
  	struct resource *res;

  	int err;

  	ep93xx_rtc = devm_kzalloc(&pdev->dev, sizeof(*ep93xx_rtc), GFP_KERNEL);
  	if (!ep93xx_rtc)

  		return -ENOMEM;
  
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

  	if (!res)
  		return -ENXIO;

  	if (!devm_request_mem_region(&pdev->dev, res->start,
  				     resource_size(res), pdev->name))
  		return -EBUSY;

  	ep93xx_rtc->mmio_base = devm_ioremap(&pdev->dev, res->start,
  					     resource_size(res));
  	if (!ep93xx_rtc->mmio_base)
  		return -ENXIO;

  	pdev->dev.platform_data = ep93xx_rtc;

  	platform_set_drvdata(pdev, ep93xx_rtc);

  	ep93xx_rtc->rtc = rtc_device_register(pdev->name,

  				&pdev->dev, &ep93xx_rtc_ops, THIS_MODULE);

  	if (IS_ERR(ep93xx_rtc->rtc)) {
  		err = PTR_ERR(ep93xx_rtc->rtc);

  		goto exit;

  	}

  	err = sysfs_create_group(&pdev->dev.kobj, &ep93xx_rtc_sysfs_files);

  	if (err)
  		goto fail;

  
  	return 0;

  
  fail:

  	rtc_device_unregister(ep93xx_rtc->rtc);

  exit:

  	platform_set_drvdata(pdev, NULL);

  	pdev->dev.platform_data = NULL;

  	return err;

  }

  static int __exit ep93xx_rtc_remove(struct platform_device *pdev)

  {

  	struct ep93xx_rtc *ep93xx_rtc = platform_get_drvdata(pdev);

  	sysfs_remove_group(&pdev->dev.kobj, &ep93xx_rtc_sysfs_files);
  	platform_set_drvdata(pdev, NULL);

  	rtc_device_unregister(ep93xx_rtc->rtc);

  	pdev->dev.platform_data = NULL;

  	return 0;
  }

  /* work with hotplug and coldplug */
  MODULE_ALIAS("platform:ep93xx-rtc");

  static struct platform_driver ep93xx_rtc_driver = {

  	.driver		= {
  		.name	= "ep93xx-rtc",
  		.owner	= THIS_MODULE,
  	},

  	.remove		= __exit_p(ep93xx_rtc_remove),

  };
  
  static int __init ep93xx_rtc_init(void)
  {

          return platform_driver_probe(&ep93xx_rtc_driver, ep93xx_rtc_probe);

  }
  
  static void __exit ep93xx_rtc_exit(void)
  {

  	platform_driver_unregister(&ep93xx_rtc_driver);

  }
  
  MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
  MODULE_DESCRIPTION("EP93XX RTC driver");
  MODULE_LICENSE("GPL");
  MODULE_VERSION(DRV_VERSION);
  
  module_init(ep93xx_rtc_init);
  module_exit(ep93xx_rtc_exit);