/*
   * Ricoh RS5C313 RTC device/driver
   *  Copyright (C) 2007 Nobuhiro Iwamatsu
   *
   *  2005-09-19 modifed by kogiidena
   *
   * Based on the old drivers/char/rs5c313_rtc.c  by:
   *  Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>
   *  Copyright (C) 1999 Tetsuya Okada & Niibe Yutaka
   *
   * Based on code written by Paul Gortmaker.
   *  Copyright (C) 1996 Paul Gortmaker
   *
   * This file is subject to the terms and conditions of the GNU General Public
   * License.  See the file "COPYING" in the main directory of this archive
   * for more details.
   *
   * Based on other minimal char device drivers, like Alan's
   * watchdog, Ted's random, etc. etc.
   *
   *	1.07	Paul Gortmaker.
   *	1.08	Miquel van Smoorenburg: disallow certain things on the
   *		DEC Alpha as the CMOS clock is also used for other things.
   *	1.09	Nikita Schmidt: epoch support and some Alpha cleanup.
   *	1.09a	Pete Zaitcev: Sun SPARC
   *	1.09b	Jeff Garzik: Modularize, init cleanup
   *	1.09c	Jeff Garzik: SMP cleanup
   *	1.10    Paul Barton-Davis: add support for async I/O
   *	1.10a	Andrea Arcangeli: Alpha updates
   *	1.10b	Andrew Morton: SMP lock fix
   *	1.10c	Cesar Barros: SMP locking fixes and cleanup
   *	1.10d	Paul Gortmaker: delete paranoia check in rtc_exit
   *	1.10e	Maciej W. Rozycki: Handle DECstation's year weirdness.
   *      1.11    Takashi Iwai: Kernel access functions
   *			      rtc_register/rtc_unregister/rtc_control
   *      1.11a   Daniele Bellucci: Audit create_proc_read_entry in rtc_init
   *	1.12	Venkatesh Pallipadi: Hooks for emulating rtc on HPET base-timer
   *		CONFIG_HPET_EMULATE_RTC
   *	1.13	Nobuhiro Iwamatsu: Updata driver.
   */

  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

  #include <linux/module.h>
  #include <linux/err.h>
  #include <linux/rtc.h>
  #include <linux/platform_device.h>
  #include <linux/bcd.h>
  #include <linux/delay.h>

  #include <linux/io.h>

  
  #define DRV_NAME	"rs5c313"

  
  #ifdef CONFIG_SH_LANDISK
  /*****************************************************/
  /* LANDISK dependence part of RS5C313                */
  /*****************************************************/
  
  #define SCSMR1		0xFFE00000
  #define SCSCR1		0xFFE00008
  #define SCSMR1_CA	0x80
  #define SCSCR1_CKE	0x03
  #define SCSPTR1		0xFFE0001C
  #define SCSPTR1_EIO	0x80
  #define SCSPTR1_SPB1IO	0x08
  #define SCSPTR1_SPB1DT	0x04
  #define SCSPTR1_SPB0IO	0x02
  #define SCSPTR1_SPB0DT	0x01
  
  #define SDA_OEN		SCSPTR1_SPB1IO
  #define SDA		SCSPTR1_SPB1DT
  #define SCL_OEN		SCSPTR1_SPB0IO
  #define SCL		SCSPTR1_SPB0DT
  
  /* RICOH RS5C313 CE port */
  #define RS5C313_CE	0xB0000003
  
  /* RICOH RS5C313 CE port bit */
  #define RS5C313_CE_RTCCE	0x02
  
  /* SCSPTR1 data */
  unsigned char scsptr1_data;

  #define RS5C313_CEENABLE    __raw_writeb(RS5C313_CE_RTCCE, RS5C313_CE);
  #define RS5C313_CEDISABLE   __raw_writeb(0x00, RS5C313_CE)
  #define RS5C313_MISCOP      __raw_writeb(0x02, 0xB0000008)

  
  static void rs5c313_init_port(void)
  {
  	/* Set SCK as I/O port and Initialize SCSPTR1 data & I/O port. */

  	__raw_writeb(__raw_readb(SCSMR1) & ~SCSMR1_CA, SCSMR1);
  	__raw_writeb(__raw_readb(SCSCR1) & ~SCSCR1_CKE, SCSCR1);

  
  	/* And Initialize SCL for RS5C313 clock */

  	scsptr1_data = __raw_readb(SCSPTR1) | SCL;	/* SCL:H */
  	__raw_writeb(scsptr1_data, SCSPTR1);
  	scsptr1_data = __raw_readb(SCSPTR1) | SCL_OEN;	/* SCL output enable */
  	__raw_writeb(scsptr1_data, SCSPTR1);

  	RS5C313_CEDISABLE;	/* CE:L */
  }
  
  static void rs5c313_write_data(unsigned char data)
  {
  	int i;
  
  	for (i = 0; i < 8; i++) {
  		/* SDA:Write Data */
  		scsptr1_data = (scsptr1_data & ~SDA) |
  				((((0x80 >> i) & data) >> (7 - i)) << 2);

  		__raw_writeb(scsptr1_data, SCSPTR1);

  		if (i == 0) {
  			scsptr1_data |= SDA_OEN;	/* SDA:output enable */

  			__raw_writeb(scsptr1_data, SCSPTR1);

  		}
  		ndelay(700);
  		scsptr1_data &= ~SCL;	/* SCL:L */

  		__raw_writeb(scsptr1_data, SCSPTR1);

  		ndelay(700);
  		scsptr1_data |= SCL;	/* SCL:H */

  		__raw_writeb(scsptr1_data, SCSPTR1);

  	}
  
  	scsptr1_data &= ~SDA_OEN;	/* SDA:output disable */

  	__raw_writeb(scsptr1_data, SCSPTR1);

  }
  
  static unsigned char rs5c313_read_data(void)
  {
  	int i;

  	unsigned char data = 0;

  
  	for (i = 0; i < 8; i++) {
  		ndelay(700);
  		/* SDA:Read Data */

  		data |= ((__raw_readb(SCSPTR1) & SDA) >> 2) << (7 - i);

  		scsptr1_data &= ~SCL;	/* SCL:L */

  		__raw_writeb(scsptr1_data, SCSPTR1);

  		ndelay(700);
  		scsptr1_data |= SCL;	/* SCL:H */

  		__raw_writeb(scsptr1_data, SCSPTR1);

  	}
  	return data & 0x0F;
  }
  
  #endif /* CONFIG_SH_LANDISK */
  
  /*****************************************************/
  /* machine independence part of RS5C313              */
  /*****************************************************/
  
  /* RICOH RS5C313 address */
  #define RS5C313_ADDR_SEC	0x00
  #define RS5C313_ADDR_SEC10	0x01
  #define RS5C313_ADDR_MIN	0x02
  #define RS5C313_ADDR_MIN10	0x03
  #define RS5C313_ADDR_HOUR	0x04
  #define RS5C313_ADDR_HOUR10	0x05
  #define RS5C313_ADDR_WEEK	0x06
  #define RS5C313_ADDR_INTINTVREG	0x07
  #define RS5C313_ADDR_DAY	0x08
  #define RS5C313_ADDR_DAY10	0x09
  #define RS5C313_ADDR_MON	0x0A
  #define RS5C313_ADDR_MON10	0x0B
  #define RS5C313_ADDR_YEAR	0x0C
  #define RS5C313_ADDR_YEAR10	0x0D
  #define RS5C313_ADDR_CNTREG	0x0E
  #define RS5C313_ADDR_TESTREG	0x0F
  
  /* RICOH RS5C313 control register */
  #define RS5C313_CNTREG_ADJ_BSY	0x01
  #define RS5C313_CNTREG_WTEN_XSTP	0x02
  #define RS5C313_CNTREG_12_24	0x04
  #define RS5C313_CNTREG_CTFG	0x08
  
  /* RICOH RS5C313 test register */
  #define RS5C313_TESTREG_TEST	0x01
  
  /* RICOH RS5C313 control bit */
  #define RS5C313_CNTBIT_READ	0x40
  #define RS5C313_CNTBIT_AD	0x20
  #define RS5C313_CNTBIT_DT	0x10
  
  static unsigned char rs5c313_read_reg(unsigned char addr)
  {
  
  	rs5c313_write_data(addr | RS5C313_CNTBIT_READ | RS5C313_CNTBIT_AD);
  	return rs5c313_read_data();
  }
  
  static void rs5c313_write_reg(unsigned char addr, unsigned char data)
  {
  	data &= 0x0f;
  	rs5c313_write_data(addr | RS5C313_CNTBIT_AD);
  	rs5c313_write_data(data | RS5C313_CNTBIT_DT);
  	return;
  }

  static inline unsigned char rs5c313_read_cntreg(void)

  {
  	return rs5c313_read_reg(RS5C313_ADDR_CNTREG);
  }
  
  static inline void rs5c313_write_cntreg(unsigned char data)
  {
  	rs5c313_write_reg(RS5C313_ADDR_CNTREG, data);
  }
  
  static inline void rs5c313_write_intintvreg(unsigned char data)
  {
  	rs5c313_write_reg(RS5C313_ADDR_INTINTVREG, data);
  }
  
  static int rs5c313_rtc_read_time(struct device *dev, struct rtc_time *tm)
  {
  	int data;

  	int cnt;

  	cnt = 0;

  	while (1) {
  		RS5C313_CEENABLE;	/* CE:H */
  
  		/* Initialize control reg. 24 hour */
  		rs5c313_write_cntreg(0x04);
  
  		if (!(rs5c313_read_cntreg() & RS5C313_CNTREG_ADJ_BSY))
  			break;
  
  		RS5C313_CEDISABLE;
  		ndelay(700);	/* CE:L */

  		if (cnt++ > 100) {

  			dev_err(dev, "%s: timeout error
  ", __func__);

  			return -EIO;
  		}

  	}
  
  	data = rs5c313_read_reg(RS5C313_ADDR_SEC);
  	data |= (rs5c313_read_reg(RS5C313_ADDR_SEC10) << 4);

  	tm->tm_sec = bcd2bin(data);

  
  	data = rs5c313_read_reg(RS5C313_ADDR_MIN);
  	data |= (rs5c313_read_reg(RS5C313_ADDR_MIN10) << 4);

  	tm->tm_min = bcd2bin(data);

  
  	data = rs5c313_read_reg(RS5C313_ADDR_HOUR);
  	data |= (rs5c313_read_reg(RS5C313_ADDR_HOUR10) << 4);

  	tm->tm_hour = bcd2bin(data);

  
  	data = rs5c313_read_reg(RS5C313_ADDR_DAY);
  	data |= (rs5c313_read_reg(RS5C313_ADDR_DAY10) << 4);

  	tm->tm_mday = bcd2bin(data);

  
  	data = rs5c313_read_reg(RS5C313_ADDR_MON);
  	data |= (rs5c313_read_reg(RS5C313_ADDR_MON10) << 4);

  	tm->tm_mon = bcd2bin(data) - 1;

  
  	data = rs5c313_read_reg(RS5C313_ADDR_YEAR);
  	data |= (rs5c313_read_reg(RS5C313_ADDR_YEAR10) << 4);

  	tm->tm_year = bcd2bin(data);

  
  	if (tm->tm_year < 70)
  		tm->tm_year += 100;
  
  	data = rs5c313_read_reg(RS5C313_ADDR_WEEK);

  	tm->tm_wday = bcd2bin(data);

  
  	RS5C313_CEDISABLE;
  	ndelay(700);		/* CE:L */
  
  	return 0;
  }
  
  static int rs5c313_rtc_set_time(struct device *dev, struct rtc_time *tm)
  {
  	int data;

  	int cnt;

  	cnt = 0;

  	/* busy check. */
  	while (1) {
  		RS5C313_CEENABLE;	/* CE:H */
  
  		/* Initiatlize control reg. 24 hour */
  		rs5c313_write_cntreg(0x04);
  
  		if (!(rs5c313_read_cntreg() & RS5C313_CNTREG_ADJ_BSY))
  			break;
  		RS5C313_MISCOP;
  		RS5C313_CEDISABLE;
  		ndelay(700);	/* CE:L */

  
  		if (cnt++ > 100) {

  			dev_err(dev, "%s: timeout error
  ", __func__);

  			return -EIO;
  		}

  	}

  	data = bin2bcd(tm->tm_sec);

  	rs5c313_write_reg(RS5C313_ADDR_SEC, data);
  	rs5c313_write_reg(RS5C313_ADDR_SEC10, (data >> 4));

  	data = bin2bcd(tm->tm_min);

  	rs5c313_write_reg(RS5C313_ADDR_MIN, data);

  	rs5c313_write_reg(RS5C313_ADDR_MIN10, (data >> 4));

  	data = bin2bcd(tm->tm_hour);

  	rs5c313_write_reg(RS5C313_ADDR_HOUR, data);
  	rs5c313_write_reg(RS5C313_ADDR_HOUR10, (data >> 4));

  	data = bin2bcd(tm->tm_mday);

  	rs5c313_write_reg(RS5C313_ADDR_DAY, data);

  	rs5c313_write_reg(RS5C313_ADDR_DAY10, (data >> 4));

  	data = bin2bcd(tm->tm_mon + 1);

  	rs5c313_write_reg(RS5C313_ADDR_MON, data);
  	rs5c313_write_reg(RS5C313_ADDR_MON10, (data >> 4));

  	data = bin2bcd(tm->tm_year % 100);

  	rs5c313_write_reg(RS5C313_ADDR_YEAR, data);
  	rs5c313_write_reg(RS5C313_ADDR_YEAR10, (data >> 4));

  	data = bin2bcd(tm->tm_wday);

  	rs5c313_write_reg(RS5C313_ADDR_WEEK, data);
  
  	RS5C313_CEDISABLE;	/* CE:H */
  	ndelay(700);
  
  	return 0;
  }
  
  static void rs5c313_check_xstp_bit(void)
  {
  	struct rtc_time tm;

  	int cnt;

  
  	RS5C313_CEENABLE;	/* CE:H */
  	if (rs5c313_read_cntreg() & RS5C313_CNTREG_WTEN_XSTP) {
  		/* INT interval reg. OFF */
  		rs5c313_write_intintvreg(0x00);
  		/* Initialize control reg. 24 hour & adjust */
  		rs5c313_write_cntreg(0x07);
  
  		/* busy check. */

  		for (cnt = 0; cnt < 100; cnt++) {
  			if (!(rs5c313_read_cntreg() & RS5C313_CNTREG_ADJ_BSY))
  				break;

  			RS5C313_MISCOP;

  		}

  
  		memset(&tm, 0, sizeof(struct rtc_time));

  		tm.tm_mday	= 1;
  		tm.tm_mon	= 1 - 1;
  		tm.tm_year	= 2000 - 1900;

  
  		rs5c313_rtc_set_time(NULL, &tm);

  		pr_err("invalid value, resetting to 1 Jan 2000
  ");

  	}
  	RS5C313_CEDISABLE;
  	ndelay(700);		/* CE:L */
  }
  
  static const struct rtc_class_ops rs5c313_rtc_ops = {
  	.read_time = rs5c313_rtc_read_time,
  	.set_time = rs5c313_rtc_set_time,
  };
  
  static int rs5c313_rtc_probe(struct platform_device *pdev)
  {

  	struct rtc_device *rtc = devm_rtc_device_register(&pdev->dev, "rs5c313",

  				&rs5c313_rtc_ops, THIS_MODULE);
  
  	if (IS_ERR(rtc))
  		return PTR_ERR(rtc);
  
  	platform_set_drvdata(pdev, rtc);

  	return 0;

  }

  static struct platform_driver rs5c313_rtc_platform_driver = {
  	.driver         = {
  		.name   = DRV_NAME,

  	},

  	.probe	= rs5c313_rtc_probe,

  };
  
  static int __init rs5c313_rtc_init(void)
  {
  	int err;
  
  	err = platform_driver_register(&rs5c313_rtc_platform_driver);
  	if (err)
  		return err;
  
  	rs5c313_init_port();
  	rs5c313_check_xstp_bit();
  
  	return 0;
  }
  
  static void __exit rs5c313_rtc_exit(void)
  {

  	platform_driver_unregister(&rs5c313_rtc_platform_driver);

  }
  
  module_init(rs5c313_rtc_init);
  module_exit(rs5c313_rtc_exit);

  MODULE_AUTHOR("kogiidena , Nobuhiro Iwamatsu <iwamatsu@nigauri.org>");
  MODULE_DESCRIPTION("Ricoh RS5C313 RTC device driver");
  MODULE_LICENSE("GPL");

  MODULE_ALIAS("platform:" DRV_NAME);