/* drivers/rtc/rtc-v3020.c
   *
   * Copyright (C) 2006 8D Technologies inc.
   * Copyright (C) 2004 Compulab Ltd.
   *
   * 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.
   *
   * Driver for the V3020 RTC
   *
   * Changelog:
   *
   *  10-May-2006: Raphael Assenat <raph@8d.com>
   *				- Converted to platform driver
   *				- Use the generic rtc class
   *
   *  ??-???-2004: Someone at Compulab
   *  			- Initial driver creation.
   *
   */
  #include <linux/platform_device.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/rtc.h>
  #include <linux/types.h>
  #include <linux/bcd.h>
  #include <linux/rtc-v3020.h>

  #include <linux/delay.h>

  
  #include <asm/io.h>
  
  #undef DEBUG
  
  struct v3020 {
  	void __iomem *ioaddress;
  	int leftshift;
  	struct rtc_device *rtc;
  };
  
  static void v3020_set_reg(struct v3020 *chip, unsigned char address,
  			unsigned char data)
  {
  	int i;
  	unsigned char tmp;
  
  	tmp = address;
  	for (i = 0; i < 4; i++) {
  		writel((tmp & 1) << chip->leftshift, chip->ioaddress);
  		tmp >>= 1;

  		udelay(1);

  	}
  
  	/* Commands dont have data */
  	if (!V3020_IS_COMMAND(address)) {
  		for (i = 0; i < 8; i++) {
  			writel((data & 1) << chip->leftshift, chip->ioaddress);
  			data >>= 1;

  			udelay(1);

  		}
  	}
  }
  
  static unsigned char v3020_get_reg(struct v3020 *chip, unsigned char address)
  {
  	unsigned int data=0;
  	int i;
  
  	for (i = 0; i < 4; i++) {
  		writel((address & 1) << chip->leftshift, chip->ioaddress);
  		address >>= 1;

  		udelay(1);

  	}
  
  	for (i = 0; i < 8; i++) {
  		data >>= 1;
  		if (readl(chip->ioaddress) & (1 << chip->leftshift))
  			data |= 0x80;

  		udelay(1);

  	}
  
  	return data;
  }
  
  static int v3020_read_time(struct device *dev, struct rtc_time *dt)
  {
  	struct v3020 *chip = dev_get_drvdata(dev);
  	int tmp;
  
  	/* Copy the current time to ram... */
  	v3020_set_reg(chip, V3020_CMD_CLOCK2RAM, 0);
  
  	/* ...and then read constant values. */
  	tmp = v3020_get_reg(chip, V3020_SECONDS);

  	dt->tm_sec	= bcd2bin(tmp);

  	tmp = v3020_get_reg(chip, V3020_MINUTES);

  	dt->tm_min	= bcd2bin(tmp);

  	tmp = v3020_get_reg(chip, V3020_HOURS);

  	dt->tm_hour	= bcd2bin(tmp);

  	tmp = v3020_get_reg(chip, V3020_MONTH_DAY);

  	dt->tm_mday	= bcd2bin(tmp);

  	tmp = v3020_get_reg(chip, V3020_MONTH);

  	dt->tm_mon    = bcd2bin(tmp) - 1;

  	tmp = v3020_get_reg(chip, V3020_WEEK_DAY);

  	dt->tm_wday	= bcd2bin(tmp);

  	tmp = v3020_get_reg(chip, V3020_YEAR);

  	dt->tm_year = bcd2bin(tmp)+100;

  
  #ifdef DEBUG

  	printk("
  %s : Read RTC values
  ",__func__);

  	printk("tm_hour: %i
  ",dt->tm_hour);
  	printk("tm_min : %i
  ",dt->tm_min);
  	printk("tm_sec : %i
  ",dt->tm_sec);
  	printk("tm_year: %i
  ",dt->tm_year);
  	printk("tm_mon : %i
  ",dt->tm_mon);
  	printk("tm_mday: %i
  ",dt->tm_mday);
  	printk("tm_wday: %i
  ",dt->tm_wday);
  #endif
  
  	return 0;
  }
  
  
  static int v3020_set_time(struct device *dev, struct rtc_time *dt)
  {
  	struct v3020 *chip = dev_get_drvdata(dev);
  
  #ifdef DEBUG

  	printk("
  %s : Setting RTC values
  ",__func__);

  	printk("tm_sec : %i
  ",dt->tm_sec);
  	printk("tm_min : %i
  ",dt->tm_min);
  	printk("tm_hour: %i
  ",dt->tm_hour);
  	printk("tm_mday: %i
  ",dt->tm_mday);
  	printk("tm_wday: %i
  ",dt->tm_wday);
  	printk("tm_year: %i
  ",dt->tm_year);
  #endif
  
  	/* Write all the values to ram... */

  	v3020_set_reg(chip, V3020_SECONDS, 	bin2bcd(dt->tm_sec));
  	v3020_set_reg(chip, V3020_MINUTES, 	bin2bcd(dt->tm_min));
  	v3020_set_reg(chip, V3020_HOURS, 	bin2bcd(dt->tm_hour));
  	v3020_set_reg(chip, V3020_MONTH_DAY,	bin2bcd(dt->tm_mday));
  	v3020_set_reg(chip, V3020_MONTH,     bin2bcd(dt->tm_mon + 1));
  	v3020_set_reg(chip, V3020_WEEK_DAY, 	bin2bcd(dt->tm_wday));
  	v3020_set_reg(chip, V3020_YEAR, 	bin2bcd(dt->tm_year % 100));

  
  	/* ...and set the clock. */
  	v3020_set_reg(chip, V3020_CMD_RAM2CLOCK, 0);
  
  	/* Compulab used this delay here. I dont know why,
  	 * the datasheet does not specify a delay. */
  	/*mdelay(5);*/
  
  	return 0;
  }

  static const struct rtc_class_ops v3020_rtc_ops = {

  	.read_time	= v3020_read_time,
  	.set_time	= v3020_set_time,
  };
  
  static int rtc_probe(struct platform_device *pdev)
  {
  	struct v3020_platform_data *pdata = pdev->dev.platform_data;
  	struct v3020 *chip;
  	struct rtc_device *rtc;
  	int retval = -EBUSY;
  	int i;
  	int temp;
  
  	if (pdev->num_resources != 1)
  		return -EBUSY;
  
  	if (pdev->resource[0].flags != IORESOURCE_MEM)
  		return -EBUSY;

  	chip = kzalloc(sizeof *chip, GFP_KERNEL);
  	if (!chip)
  		return -ENOMEM;
  
  	chip->leftshift = pdata->leftshift;
  	chip->ioaddress = ioremap(pdev->resource[0].start, 1);
  	if (chip->ioaddress == NULL)
  		goto err_chip;
  
  	/* Make sure the v3020 expects a communication cycle
  	 * by reading 8 times */
  	for (i = 0; i < 8; i++)
  		temp = readl(chip->ioaddress);
  
  	/* Test chip by doing a write/read sequence
  	 * to the chip ram */
  	v3020_set_reg(chip, V3020_SECONDS, 0x33);
  	if(v3020_get_reg(chip, V3020_SECONDS) != 0x33) {
  		retval = -ENODEV;
  		goto err_io;
  	}
  
  	/* Make sure frequency measurment mode, test modes, and lock
  	 * are all disabled */
  	v3020_set_reg(chip, V3020_STATUS_0, 0x0);

  	dev_info(&pdev->dev, "Chip available at physical address 0x%llx,"

  		"data connected to D%d
  ",

  		(unsigned long long)pdev->resource[0].start,

  		chip->leftshift);
  
  	platform_set_drvdata(pdev, chip);
  
  	rtc = rtc_device_register("v3020",
  				&pdev->dev, &v3020_rtc_ops, THIS_MODULE);
  	if (IS_ERR(rtc)) {
  		retval = PTR_ERR(rtc);
  		goto err_io;
  	}
  	chip->rtc = rtc;
  
  	return 0;
  
  err_io:
  	iounmap(chip->ioaddress);
  err_chip:
  	kfree(chip);
  
  	return retval;
  }
  
  static int rtc_remove(struct platform_device *dev)
  {
  	struct v3020 *chip = platform_get_drvdata(dev);
  	struct rtc_device *rtc = chip->rtc;
  
  	if (rtc)
  		rtc_device_unregister(rtc);
  
  	iounmap(chip->ioaddress);
  	kfree(chip);
  
  	return 0;
  }
  
  static struct platform_driver rtc_device_driver = {
  	.probe	= rtc_probe,
  	.remove = rtc_remove,
  	.driver = {
  		.name	= "v3020",
  		.owner	= THIS_MODULE,
  	},
  };
  
  static __init int v3020_init(void)
  {
  	return platform_driver_register(&rtc_device_driver);
  }
  
  static __exit void v3020_exit(void)
  {
  	platform_driver_unregister(&rtc_device_driver);
  }
  
  module_init(v3020_init);
  module_exit(v3020_exit);
  
  MODULE_DESCRIPTION("V3020 RTC");
  MODULE_AUTHOR("Raphael Assenat");
  MODULE_LICENSE("GPL");

  MODULE_ALIAS("platform:v3020");