// SPDX-License-Identifier: GPL-2.0

  /*
   * A driver for the RTC embedded in the Cirrus Logic EP93XX processors
   * Copyright (c) 2006 Tower Technologies
   *
   * Author: Alessandro Zummo <a.zummo@towertech.it>

   */
  
  #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		 BIT(0)

  #define EP93XX_RTC_LOAD			0x00C
  #define EP93XX_RTC_CONTROL		0x010

  #define  EP93XX_RTC_CONTROL_MIE		 BIT(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

  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_get_platdata(dev);

  	unsigned long comp;

  	comp = 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_get_platdata(dev);

  	unsigned long time;

  	time = readl(ep93xx_rtc->mmio_base + EP93XX_RTC_DATA);

  	rtc_time64_to_tm(time, tm);

  	return 0;
  }

  static int ep93xx_rtc_set_time(struct device *dev, struct rtc_time *tm)

  {

  	struct ep93xx_rtc *ep93xx_rtc = dev_get_platdata(dev);

  	unsigned long secs = rtc_tm_to_time64(tm);

  	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_time	= ep93xx_rtc_set_time,

  	.proc		= ep93xx_rtc_proc,
  };

  static ssize_t comp_preload_show(struct device *dev,
  				 struct device_attribute *attr, char *buf)

  {
  	unsigned short preload;

  	ep93xx_rtc_get_swcomp(dev->parent, &preload, NULL);

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

  static DEVICE_ATTR_RO(comp_preload);

  static ssize_t comp_delete_show(struct device *dev,
  				struct device_attribute *attr, char *buf)

  {
  	unsigned short delete;

  	ep93xx_rtc_get_swcomp(dev->parent, NULL, &delete);

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

  static DEVICE_ATTR_RO(comp_delete);

  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 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);

  	ep93xx_rtc->mmio_base = devm_ioremap_resource(&pdev->dev, res);
  	if (IS_ERR(ep93xx_rtc->mmio_base))
  		return PTR_ERR(ep93xx_rtc->mmio_base);

  	platform_set_drvdata(pdev, ep93xx_rtc);

  	ep93xx_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);

  	if (IS_ERR(ep93xx_rtc->rtc))
  		return PTR_ERR(ep93xx_rtc->rtc);

  	ep93xx_rtc->rtc->ops = &ep93xx_rtc_ops;

  	ep93xx_rtc->rtc->range_max = U32_MAX;

  	err = rtc_add_group(ep93xx_rtc->rtc, &ep93xx_rtc_sysfs_files);

  	if (err)
  		return err;

  	return rtc_register_device(ep93xx_rtc->rtc);

  }

  static struct platform_driver ep93xx_rtc_driver = {

  	.driver		= {
  		.name	= "ep93xx-rtc",

  	},

  	.probe		= ep93xx_rtc_probe,

  };

  module_platform_driver(ep93xx_rtc_driver);

  
  MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
  MODULE_DESCRIPTION("EP93XX RTC driver");
  MODULE_LICENSE("GPL");

  MODULE_ALIAS("platform:ep93xx-rtc");