/*
 *  linux/drivers/i2c/chips/rtc8564.c
 *
 *  Copyright (C) 2002-2004 Stefan Eletzhofer
 *
 *	based on linux/drivers/acron/char/pcf8583.c
 *  Copyright (C) 2000 Russell King
 *
 * 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 system3's EPSON RTC 8564 chip
 */
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/rtc.h>		/* get the user-level API */
#include <linux/init.h>

#include "rtc8564.h"

#ifdef DEBUG
# define _DBG(x, fmt, args...) do{ if (debug>=x) printk(KERN_DEBUG"%s: " fmt "\n", __FUNCTION__, ##args); } while(0);
#else
# define _DBG(x, fmt, args...) do { } while(0);
#endif

#define _DBGRTCTM(x, rtctm) if (debug>=x) printk("%s: secs=%d, mins=%d, hours=%d, mday=%d, " \
			"mon=%d, year=%d, wday=%d VL=%d\n", __FUNCTION__, \
			(rtctm).secs, (rtctm).mins, (rtctm).hours, (rtctm).mday, \
			(rtctm).mon, (rtctm).year, (rtctm).wday, (rtctm).vl);

struct rtc8564_data {
	struct i2c_client client;
	u16 ctrl;
};

static inline u8 _rtc8564_ctrl1(struct i2c_client *client)
{
	struct rtc8564_data *data = i2c_get_clientdata(client);
	return data->ctrl & 0xff;
}
static inline u8 _rtc8564_ctrl2(struct i2c_client *client)
{
	struct rtc8564_data *data = i2c_get_clientdata(client);
	return (data->ctrl & 0xff00) >> 8;
}

#define CTRL1(c) _rtc8564_ctrl1(c)
#define CTRL2(c) _rtc8564_ctrl2(c)

#define BCD_TO_BIN(val) (((val)&15) + ((val)>>4)*10)
#define BIN_TO_BCD(val) ((((val)/10)<<4) + (val)%10)

static int debug;;
module_param(debug, int, S_IRUGO | S_IWUSR);

static struct i2c_driver rtc8564_driver;

static unsigned short ignore[] = { I2C_CLIENT_END };
static unsigned short normal_addr[] = { 0x51, I2C_CLIENT_END };

static struct i2c_client_address_data addr_data = {
	.normal_i2c		= normal_addr,
	.probe			= ignore,
	.ignore			= ignore,
};

static int rtc8564_read_mem(struct i2c_client *client, struct mem *mem);
static int rtc8564_write_mem(struct i2c_client *client, struct mem *mem);

static int rtc8564_read(struct i2c_client *client, unsigned char adr,
			unsigned char *buf, unsigned char len)
{
	int ret = -EIO;
	unsigned char addr[1] = { adr };
	struct i2c_msg msgs[2] = {
		{client->addr, 0, 1, addr},
		{client->addr, I2C_M_RD, len, buf}
	};

	_DBG(1, "client=%p, adr=%d, buf=%p, len=%d", client, adr, buf, len);

	if (!buf) {
		ret = -EINVAL;
		goto done;
	}

	ret = i2c_transfer(client->adapter, msgs, 2);
	if (ret == 2) {
		ret = 0;
	}

done:
	return ret;
}

static int rtc8564_write(struct i2c_client *client, unsigned char adr,
			 unsigned char *data, unsigned char len)
{
	int ret = 0;
	unsigned char _data[16];
	struct i2c_msg wr;
	int i;

	if (!data || len > 15) {
		ret = -EINVAL;
		goto done;
	}

	_DBG(1, "client=%p, adr=%d, buf=%p, len=%d", client, adr, data, len);

	_data[0] = adr;
	for (i = 0; i < len; i++) {
		_data[i + 1] = data[i];
		_DBG(5, "data[%d] = 0x%02x (%d)", i, data[i], data[i]);
	}

	wr.addr = client->addr;
	wr.flags = 0;
	wr.len = len + 1;
	wr.buf = _data;

	ret = i2c_transfer(client->adapter, &wr, 1);
	if (ret == 1) {
		ret = 0;
	}

done:
	return ret;
}

static int rtc8564_attach(struct i2c_adapter *adap, int addr, int kind)
{
	int ret;
	struct i2c_client *new_client;
	struct rtc8564_data *d;
	unsigned char data[10];
	unsigned char ad[1] = { 0 };
	struct i2c_msg ctrl_wr[1] = {
		{addr, 0, 2, data}
	};
	struct i2c_msg ctrl_rd[2] = {
		{addr, 0, 1, ad},
		{addr, I2C_M_RD, 2, data}
	};

	d = kmalloc(sizeof(struct rtc8564_data), GFP_KERNEL);
	if (!d) {
		ret = -ENOMEM;
		goto done;
	}
	memset(d, 0, sizeof(struct rtc8564_data));
	new_client = &d->client;

	strlcpy(new_client->name, "RTC8564", I2C_NAME_SIZE);
	i2c_set_clientdata(new_client, d);
	new_client->flags = I2C_CLIENT_ALLOW_USE | I2C_DF_NOTIFY;
	new_client->addr = addr;
	new_client->adapter = adap;
	new_client->driver = &rtc8564_driver;

	_DBG(1, "client=%p", new_client);

	/* init ctrl1 reg */
	data[0] = 0;
	data[1] = 0;
	ret = i2c_transfer(new_client->adapter, ctrl_wr, 1);
	if (ret != 1) {
		printk(KERN_INFO "rtc8564: cant init ctrl1\n");
		ret = -ENODEV;
		goto done;
	}

	/* read back ctrl1 and ctrl2 */
	ret = i2c_transfer(new_client->adapter, ctrl_rd, 2);
	if (ret != 2) {
		printk(KERN_INFO "rtc8564: cant read ctrl\n");
		ret = -ENODEV;
		goto done;
	}

	d->ctrl = data[0] | (data[1] << 8);

	_DBG(1, "RTC8564_REG_CTRL1=%02x, RTC8564_REG_CTRL2=%02x",
	     data[0], data[1]);

	ret = i2c_attach_client(new_client);
done:
	if (ret) {
		kfree(d);
	}
	return ret;
}

static int rtc8564_probe(struct i2c_adapter *adap)
{
	return i2c_probe(adap, &addr_data, rtc8564_attach);
}

static int rtc8564_detach(struct i2c_client *client)
{
	i2c_detach_client(client);
	kfree(i2c_get_clientdata(client));
	return 0;
}

static int rtc8564_get_datetime(struct i2c_client *client, struct rtc_tm *dt)
{
	int ret = -EIO;
	unsigned char buf[15];

	_DBG(1, "client=%p, dt=%p", client, dt);

	if (!dt)
		return -EINVAL;

	memset(buf, 0, sizeof(buf));

	ret = rtc8564_read(client, 0, buf, 15);
	if (ret)
		return ret;

	/* century stored in minute alarm reg */
	dt->year = BCD_TO_BIN(buf[RTC8564_REG_YEAR]);
	dt->year += 100 * BCD_TO_BIN(buf[RTC8564_REG_AL_MIN] & 0x3f);
	dt->mday = BCD_TO_BIN(buf[RTC8564_REG_DAY] & 0x3f);
	dt->wday = BCD_TO_BIN(buf[RTC8564_REG_WDAY] & 7);
	dt->mon = BCD_TO_BIN(buf[RTC8564_REG_MON_CENT] & 0x1f);

	dt->secs = BCD_TO_BIN(buf[RTC8564_REG_SEC] & 0x7f);
	dt->vl = (buf[RTC8564_REG_SEC] & 0x80) == 0x80;
	dt->mins = BCD_TO_BIN(buf[RTC8564_REG_MIN] & 0x7f);
	dt->hours = BCD_TO_BIN(buf[RTC8564_REG_HR] & 0x3f);

	_DBGRTCTM(2, *dt);

	return 0;
}

static int
rtc8564_set_datetime(struct i2c_client *client, struct rtc_tm *dt, int datetoo)
{
	int ret, len = 5;
	unsigned char buf[15];

	_DBG(1, "client=%p, dt=%p", client, dt);

	if (!dt)
		return -EINVAL;

	_DBGRTCTM(2, *dt);

	buf[RTC8564_REG_CTRL1] = CTRL1(client) | RTC8564_CTRL1_STOP;
	buf[RTC8564_REG_CTRL2] = CTRL2(client);
	buf[RTC8564_REG_SEC] = BIN_TO_BCD(dt->secs);
	buf[RTC8564_REG_MIN] = BIN_TO_BCD(dt->mins);
	buf[RTC8564_REG_HR] = BIN_TO_BCD(dt->hours);

	if (datetoo) {
		len += 5;
		buf[RTC8564_REG_DAY] = BIN_TO_BCD(dt->mday);
		buf[RTC8564_REG_WDAY] = BIN_TO_BCD(dt->wday);
		buf[RTC8564_REG_MON_CENT] = BIN_TO_BCD(dt->mon) & 0x1f;
		/* century stored in minute alarm reg */
		buf[RTC8564_REG_YEAR] = BIN_TO_BCD(dt->year % 100);
		buf[RTC8564_REG_AL_MIN] = BIN_TO_BCD(dt->year / 100);
	}

	ret = rtc8564_write(client, 0, buf, len);
	if (ret) {
		_DBG(1, "error writing data! %d", ret);
	}

	buf[RTC8564_REG_CTRL1] = CTRL1(client);
	ret = rtc8564_write(client, 0, buf, 1);
	if (ret) {
		_DBG(1, "error writing data! %d", ret);
	}

	return ret;
}

static int rtc8564_get_ctrl(struct i2c_client *client, unsigned int *ctrl)
{
	struct rtc8564_data *data = i2c_get_clientdata(client);

	if (!ctrl)
		return -1;

	*ctrl = data->ctrl;
	return 0;
}

static int rtc8564_set_ctrl(struct i2c_client *client, unsigned int *ctrl)
{
	struct rtc8564_data *data = i2c_get_clientdata(client);
	unsigned char buf[2];

	if (!ctrl)
		return -1;

	buf[0] = *ctrl & 0xff;
	buf[1] = (*ctrl & 0xff00) >> 8;
	data->ctrl = *ctrl;

	return rtc8564_write(client, 0, buf, 2);
}

static int rtc8564_read_mem(struct i2c_client *client, struct mem *mem)
{

	if (!mem)
		return -EINVAL;

	return rtc8564_read(client, mem->loc, mem->data, mem->nr);
}

static int rtc8564_write_mem(struct i2c_client *client, struct mem *mem)
{

	if (!mem)
		return -EINVAL;

	return rtc8564_write(client, mem->loc, mem->data, mem->nr);
}

static int
rtc8564_command(struct i2c_client *client, unsigned int cmd, void *arg)
{

	_DBG(1, "cmd=%d", cmd);

	switch (cmd) {
	case RTC_GETDATETIME:
		return rtc8564_get_datetime(client, arg);

	case RTC_SETTIME:
		return rtc8564_set_datetime(client, arg, 0);

	case RTC_SETDATETIME:
		return rtc8564_set_datetime(client, arg, 1);

	case RTC_GETCTRL:
		return rtc8564_get_ctrl(client, arg);

	case RTC_SETCTRL:
		return rtc8564_set_ctrl(client, arg);

	case MEM_READ:
		return rtc8564_read_mem(client, arg);

	case MEM_WRITE:
		return rtc8564_write_mem(client, arg);

	default:
		return -EINVAL;
	}
}

static struct i2c_driver rtc8564_driver = {
	.owner		= THIS_MODULE,
	.name		= "RTC8564",
	.id		= I2C_DRIVERID_RTC8564,
	.flags		= I2C_DF_NOTIFY,
	.attach_adapter = rtc8564_probe,
	.detach_client	= rtc8564_detach,
	.command	= rtc8564_command
};

static __init int rtc8564_init(void)
{
	return i2c_add_driver(&rtc8564_driver);
}

static __exit void rtc8564_exit(void)
{
	i2c_del_driver(&rtc8564_driver);
}

MODULE_AUTHOR("Stefan Eletzhofer <Stefan.Eletzhofer@eletztrick.de>");
MODULE_DESCRIPTION("EPSON RTC8564 Driver");
MODULE_LICENSE("GPL");

module_init(rtc8564_init);
module_exit(rtc8564_exit);