[net-next-2.6.git] / drivers / rtc / rtc-isl1208.c

/*
 * Intersil ISL1208 rtc class driver
 *
 * Copyright 2005,2006 Hebert Valerio Riedel <hvr@gnu.org>
 *
 *  This program is free software; you can redistribute  it and/or modify it
 *  under  the terms of  the GNU General  Public License as published by the
 *  Free Software Foundation;  either version 2 of the  License, or (at your
 *  option) any later version.
 *
 */

#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/bcd.h>
#include <linux/rtc.h>

#define DRV_VERSION "0.3"

/* Register map */
/* rtc section */
#define ISL1208_REG_SC  0x00
#define ISL1208_REG_MN  0x01
#define ISL1208_REG_HR  0x02
#define ISL1208_REG_HR_MIL     (1<<7)	/* 24h/12h mode */
#define ISL1208_REG_HR_PM      (1<<5)	/* PM/AM bit in 12h mode */
#define ISL1208_REG_DT  0x03
#define ISL1208_REG_MO  0x04
#define ISL1208_REG_YR  0x05
#define ISL1208_REG_DW  0x06
#define ISL1208_RTC_SECTION_LEN 7

/* control/status section */
#define ISL1208_REG_SR  0x07
#define ISL1208_REG_SR_ARST    (1<<7)	/* auto reset */
#define ISL1208_REG_SR_XTOSCB  (1<<6)	/* crystal oscillator */
#define ISL1208_REG_SR_WRTC    (1<<4)	/* write rtc */
#define ISL1208_REG_SR_ALM     (1<<2)	/* alarm */
#define ISL1208_REG_SR_BAT     (1<<1)	/* battery */
#define ISL1208_REG_SR_RTCF    (1<<0)	/* rtc fail */
#define ISL1208_REG_INT 0x08
#define ISL1208_REG_09  0x09	/* reserved */
#define ISL1208_REG_ATR 0x0a
#define ISL1208_REG_DTR 0x0b

/* alarm section */
#define ISL1208_REG_SCA 0x0c
#define ISL1208_REG_MNA 0x0d
#define ISL1208_REG_HRA 0x0e
#define ISL1208_REG_DTA 0x0f
#define ISL1208_REG_MOA 0x10
#define ISL1208_REG_DWA 0x11
#define ISL1208_ALARM_SECTION_LEN 6

/* user section */
#define ISL1208_REG_USR1 0x12
#define ISL1208_REG_USR2 0x13
#define ISL1208_USR_SECTION_LEN 2

static struct i2c_driver isl1208_driver;

/* block read */
static int
isl1208_i2c_read_regs(struct i2c_client *client, u8 reg, u8 buf[],
		      unsigned len)
{
	u8 reg_addr[1] = { reg };
	struct i2c_msg msgs[2] = {
		{client->addr, 0, sizeof(reg_addr), reg_addr}
		,
		{client->addr, I2C_M_RD, len, buf}
	};
	int ret;

	BUG_ON(reg > ISL1208_REG_USR2);
	BUG_ON(reg + len > ISL1208_REG_USR2 + 1);

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

/* block write */
static int
isl1208_i2c_set_regs(struct i2c_client *client, u8 reg, u8 const buf[],
		     unsigned len)
{
	u8 i2c_buf[ISL1208_REG_USR2 + 2];
	struct i2c_msg msgs[1] = {
		{client->addr, 0, len + 1, i2c_buf}
	};
	int ret;

	BUG_ON(reg > ISL1208_REG_USR2);
	BUG_ON(reg + len > ISL1208_REG_USR2 + 1);

	i2c_buf[0] = reg;
	memcpy(&i2c_buf[1], &buf[0], len);

	ret = i2c_transfer(client->adapter, msgs, 1);
	if (ret > 0)
		ret = 0;
	return ret;
}

/* simple check to see wether we have a isl1208 */
static int
isl1208_i2c_validate_client(struct i2c_client *client)
{
	u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
	u8 zero_mask[ISL1208_RTC_SECTION_LEN] = {
		0x80, 0x80, 0x40, 0xc0, 0xe0, 0x00, 0xf8
	};
	int i;
	int ret;

	ret = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
	if (ret < 0)
		return ret;

	for (i = 0; i < ISL1208_RTC_SECTION_LEN; ++i) {
		if (regs[i] & zero_mask[i])	/* check if bits are cleared */
			return -ENODEV;
	}

	return 0;
}

static int
isl1208_i2c_get_sr(struct i2c_client *client)
{
	int sr = i2c_smbus_read_byte_data(client, ISL1208_REG_SR);
	if (sr < 0)
		return -EIO;

	return sr;
}

static int
isl1208_i2c_get_atr(struct i2c_client *client)
{
	int atr = i2c_smbus_read_byte_data(client, ISL1208_REG_ATR);
	if (atr < 0)
		return atr;

	/* The 6bit value in the ATR register controls the load
	 * capacitance C_load * in steps of 0.25pF
	 *
	 * bit (1<<5) of the ATR register is inverted
	 *
	 * C_load(ATR=0x20) =  4.50pF
	 * C_load(ATR=0x00) = 12.50pF
	 * C_load(ATR=0x1f) = 20.25pF
	 *
	 */

	atr &= 0x3f;		/* mask out lsb */
	atr ^= 1 << 5;		/* invert 6th bit */
	atr += 2 * 9;		/* add offset of 4.5pF; unit[atr] = 0.25pF */

	return atr;
}

static int
isl1208_i2c_get_dtr(struct i2c_client *client)
{
	int dtr = i2c_smbus_read_byte_data(client, ISL1208_REG_DTR);
	if (dtr < 0)
		return -EIO;

	/* dtr encodes adjustments of {-60,-40,-20,0,20,40,60} ppm */
	dtr = ((dtr & 0x3) * 20) * (dtr & (1 << 2) ? -1 : 1);

	return dtr;
}

static int
isl1208_i2c_get_usr(struct i2c_client *client)
{
	u8 buf[ISL1208_USR_SECTION_LEN] = { 0, };
	int ret;

	ret = isl1208_i2c_read_regs(client, ISL1208_REG_USR1, buf,
				    ISL1208_USR_SECTION_LEN);
	if (ret < 0)
		return ret;

	return (buf[1] << 8) | buf[0];
}

static int
isl1208_i2c_set_usr(struct i2c_client *client, u16 usr)
{
	u8 buf[ISL1208_USR_SECTION_LEN];

	buf[0] = usr & 0xff;
	buf[1] = (usr >> 8) & 0xff;

	return isl1208_i2c_set_regs(client, ISL1208_REG_USR1, buf,
				    ISL1208_USR_SECTION_LEN);
}

static int
isl1208_rtc_proc(struct device *dev, struct seq_file *seq)
{
	struct i2c_client *const client = to_i2c_client(dev);
	int sr, dtr, atr, usr;

	sr = isl1208_i2c_get_sr(client);
	if (sr < 0) {
		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
		return sr;
	}

	seq_printf(seq, "status_reg\t:%s%s%s%s%s%s (0x%.2x)\n",
		   (sr & ISL1208_REG_SR_RTCF) ? " RTCF" : "",
		   (sr & ISL1208_REG_SR_BAT) ? " BAT" : "",
		   (sr & ISL1208_REG_SR_ALM) ? " ALM" : "",
		   (sr & ISL1208_REG_SR_WRTC) ? " WRTC" : "",
		   (sr & ISL1208_REG_SR_XTOSCB) ? " XTOSCB" : "",
		   (sr & ISL1208_REG_SR_ARST) ? " ARST" : "", sr);

	seq_printf(seq, "batt_status\t: %s\n",
		   (sr & ISL1208_REG_SR_RTCF) ? "bad" : "okay");

	dtr = isl1208_i2c_get_dtr(client);
	if (dtr >= 0 - 1)
		seq_printf(seq, "digital_trim\t: %d ppm\n", dtr);

	atr = isl1208_i2c_get_atr(client);
	if (atr >= 0)
		seq_printf(seq, "analog_trim\t: %d.%.2d pF\n",
			   atr >> 2, (atr & 0x3) * 25);

	usr = isl1208_i2c_get_usr(client);
	if (usr >= 0)
		seq_printf(seq, "user_data\t: 0x%.4x\n", usr);

	return 0;
}

static int
isl1208_i2c_read_time(struct i2c_client *client, struct rtc_time *tm)
{
	int sr;
	u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };

	sr = isl1208_i2c_get_sr(client);
	if (sr < 0) {
		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
		return -EIO;
	}

	sr = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
	if (sr < 0) {
		dev_err(&client->dev, "%s: reading RTC section failed\n",
			__func__);
		return sr;
	}

	tm->tm_sec = bcd2bin(regs[ISL1208_REG_SC]);
	tm->tm_min = bcd2bin(regs[ISL1208_REG_MN]);

	/* HR field has a more complex interpretation */
	{
		const u8 _hr = regs[ISL1208_REG_HR];
		if (_hr & ISL1208_REG_HR_MIL)	/* 24h format */
			tm->tm_hour = bcd2bin(_hr & 0x3f);
		else {
			/* 12h format */
			tm->tm_hour = bcd2bin(_hr & 0x1f);
			if (_hr & ISL1208_REG_HR_PM)	/* PM flag set */
				tm->tm_hour += 12;
		}
	}

	tm->tm_mday = bcd2bin(regs[ISL1208_REG_DT]);
	tm->tm_mon = bcd2bin(regs[ISL1208_REG_MO]) - 1;	/* rtc starts at 1 */
	tm->tm_year = bcd2bin(regs[ISL1208_REG_YR]) + 100;
	tm->tm_wday = bcd2bin(regs[ISL1208_REG_DW]);

	return 0;
}

static int
isl1208_i2c_read_alarm(struct i2c_client *client, struct rtc_wkalrm *alarm)
{
	struct rtc_time *const tm = &alarm->time;
	u8 regs[ISL1208_ALARM_SECTION_LEN] = { 0, };
	int sr;

	sr = isl1208_i2c_get_sr(client);
	if (sr < 0) {
		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
		return sr;
	}

	sr = isl1208_i2c_read_regs(client, ISL1208_REG_SCA, regs,
				   ISL1208_ALARM_SECTION_LEN);
	if (sr < 0) {
		dev_err(&client->dev, "%s: reading alarm section failed\n",
			__func__);
		return sr;
	}

	/* MSB of each alarm register is an enable bit */
	tm->tm_sec = bcd2bin(regs[ISL1208_REG_SCA - ISL1208_REG_SCA] & 0x7f);
	tm->tm_min = bcd2bin(regs[ISL1208_REG_MNA - ISL1208_REG_SCA] & 0x7f);
	tm->tm_hour = bcd2bin(regs[ISL1208_REG_HRA - ISL1208_REG_SCA] & 0x3f);
	tm->tm_mday = bcd2bin(regs[ISL1208_REG_DTA - ISL1208_REG_SCA] & 0x3f);
	tm->tm_mon =
		bcd2bin(regs[ISL1208_REG_MOA - ISL1208_REG_SCA] & 0x1f) - 1;
	tm->tm_wday = bcd2bin(regs[ISL1208_REG_DWA - ISL1208_REG_SCA] & 0x03);

	return 0;
}

static int
isl1208_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
	return isl1208_i2c_read_time(to_i2c_client(dev), tm);
}

static int
isl1208_i2c_set_time(struct i2c_client *client, struct rtc_time const *tm)
{
	int sr;
	u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };

	/* The clock has an 8 bit wide bcd-coded register (they never learn)
	 * for the year. tm_year is an offset from 1900 and we are interested
	 * in the 2000-2099 range, so any value less than 100 is invalid.
	 */
	if (tm->tm_year < 100)
		return -EINVAL;

	regs[ISL1208_REG_SC] = bin2bcd(tm->tm_sec);
	regs[ISL1208_REG_MN] = bin2bcd(tm->tm_min);
	regs[ISL1208_REG_HR] = bin2bcd(tm->tm_hour) | ISL1208_REG_HR_MIL;

	regs[ISL1208_REG_DT] = bin2bcd(tm->tm_mday);
	regs[ISL1208_REG_MO] = bin2bcd(tm->tm_mon + 1);
	regs[ISL1208_REG_YR] = bin2bcd(tm->tm_year - 100);

	regs[ISL1208_REG_DW] = bin2bcd(tm->tm_wday & 7);

	sr = isl1208_i2c_get_sr(client);
	if (sr < 0) {
		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
		return sr;
	}

	/* set WRTC */
	sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR,
				       sr | ISL1208_REG_SR_WRTC);
	if (sr < 0) {
		dev_err(&client->dev, "%s: writing SR failed\n", __func__);
		return sr;
	}

	/* write RTC registers */
	sr = isl1208_i2c_set_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
	if (sr < 0) {
		dev_err(&client->dev, "%s: writing RTC section failed\n",
			__func__);
		return sr;
	}

	/* clear WRTC again */
	sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR,
				       sr & ~ISL1208_REG_SR_WRTC);
	if (sr < 0) {
		dev_err(&client->dev, "%s: writing SR failed\n", __func__);
		return sr;
	}

	return 0;
}


static int
isl1208_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
	return isl1208_i2c_set_time(to_i2c_client(dev), tm);
}

static int
isl1208_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
	return isl1208_i2c_read_alarm(to_i2c_client(dev), alarm);
}

static const struct rtc_class_ops isl1208_rtc_ops = {
	.proc = isl1208_rtc_proc,
	.read_time = isl1208_rtc_read_time,
	.set_time = isl1208_rtc_set_time,
	.read_alarm = isl1208_rtc_read_alarm,
	/*.set_alarm    = isl1208_rtc_set_alarm, */
};

/* sysfs interface */

static ssize_t
isl1208_sysfs_show_atrim(struct device *dev,
			 struct device_attribute *attr, char *buf)
{
	int atr = isl1208_i2c_get_atr(to_i2c_client(dev));
	if (atr < 0)
		return atr;

	return sprintf(buf, "%d.%.2d pF\n", atr >> 2, (atr & 0x3) * 25);
}

static DEVICE_ATTR(atrim, S_IRUGO, isl1208_sysfs_show_atrim, NULL);

static ssize_t
isl1208_sysfs_show_dtrim(struct device *dev,
			 struct device_attribute *attr, char *buf)
{
	int dtr = isl1208_i2c_get_dtr(to_i2c_client(dev));
	if (dtr < 0)
		return dtr;

	return sprintf(buf, "%d ppm\n", dtr);
}

static DEVICE_ATTR(dtrim, S_IRUGO, isl1208_sysfs_show_dtrim, NULL);

static ssize_t
isl1208_sysfs_show_usr(struct device *dev,
		       struct device_attribute *attr, char *buf)
{
	int usr = isl1208_i2c_get_usr(to_i2c_client(dev));
	if (usr < 0)
		return usr;

	return sprintf(buf, "0x%.4x\n", usr);
}

static ssize_t
isl1208_sysfs_store_usr(struct device *dev,
			struct device_attribute *attr,
			const char *buf, size_t count)
{
	int usr = -1;

	if (buf[0] == '0' && (buf[1] == 'x' || buf[1] == 'X')) {
		if (sscanf(buf, "%x", &usr) != 1)
			return -EINVAL;
	} else {
		if (sscanf(buf, "%d", &usr) != 1)
			return -EINVAL;
	}

	if (usr < 0 || usr > 0xffff)
		return -EINVAL;

	return isl1208_i2c_set_usr(to_i2c_client(dev), usr) ? -EIO : count;
}

static DEVICE_ATTR(usr, S_IRUGO | S_IWUSR, isl1208_sysfs_show_usr,
		   isl1208_sysfs_store_usr);

static struct attribute *isl1208_rtc_attrs[] = {
	&dev_attr_atrim.attr,
	&dev_attr_dtrim.attr,
	&dev_attr_usr.attr,
	NULL
};

static const struct attribute_group isl1208_rtc_sysfs_files = {
	.attrs	= isl1208_rtc_attrs,
};

static int
isl1208_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
	int rc = 0;
	struct rtc_device *rtc;

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
		return -ENODEV;

	if (isl1208_i2c_validate_client(client) < 0)
		return -ENODEV;

	dev_info(&client->dev,
		 "chip found, driver version " DRV_VERSION "\n");

	rtc = rtc_device_register(isl1208_driver.driver.name,
				  &client->dev, &isl1208_rtc_ops,
				  THIS_MODULE);
	if (IS_ERR(rtc))
		return PTR_ERR(rtc);

	i2c_set_clientdata(client, rtc);

	rc = isl1208_i2c_get_sr(client);
	if (rc < 0) {
		dev_err(&client->dev, "reading status failed\n");
		goto exit_unregister;
	}

	if (rc & ISL1208_REG_SR_RTCF)
		dev_warn(&client->dev, "rtc power failure detected, "
			 "please set clock.\n");

	rc = sysfs_create_group(&client->dev.kobj, &isl1208_rtc_sysfs_files);
	if (rc)
		goto exit_unregister;

	return 0;

exit_unregister:
	rtc_device_unregister(rtc);

	return rc;
}

static int
isl1208_remove(struct i2c_client *client)
{
	struct rtc_device *rtc = i2c_get_clientdata(client);

	sysfs_remove_group(&client->dev.kobj, &isl1208_rtc_sysfs_files);
	rtc_device_unregister(rtc);

	return 0;
}

static const struct i2c_device_id isl1208_id[] = {
	{ "isl1208", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, isl1208_id);

static struct i2c_driver isl1208_driver = {
	.driver = {
		   .name = "rtc-isl1208",
		   },
	.probe = isl1208_probe,
	.remove = isl1208_remove,
	.id_table = isl1208_id,
};

static int __init
isl1208_init(void)
{
	return i2c_add_driver(&isl1208_driver);
}

static void __exit
isl1208_exit(void)
{
	i2c_del_driver(&isl1208_driver);
}

MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>");
MODULE_DESCRIPTION("Intersil ISL1208 RTC driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);

module_init(isl1208_init);
module_exit(isl1208_exit);
Commit	Line	Data
7e56a7dc HVR	1	/*
	2	* Intersil ISL1208 rtc class driver
	3	*
	4	* Copyright 2005,2006 Hebert Valerio Riedel <hvr@gnu.org>
	5	*
	6	* This program is free software; you can redistribute it and/or modify it
	7	* under the terms of the GNU General Public License as published by the
	8	* Free Software Foundation; either version 2 of the License, or (at your
	9	* option) any later version.
	10	*
	11	*/
	12
	13	#include <linux/module.h>
	14	#include <linux/i2c.h>
	15	#include <linux/bcd.h>
	16	#include <linux/rtc.h>
	17
9edae7bc	18	#define DRV_VERSION "0.3"
7e56a7dc HVR	19
	20	/* Register map */
	21	/* rtc section */
	22	#define ISL1208_REG_SC 0x00
	23	#define ISL1208_REG_MN 0x01
	24	#define ISL1208_REG_HR 0x02
9edae7bc AZ	25	#define ISL1208_REG_HR_MIL (1<<7) /* 24h/12h mode */
9edae7bc AZ	26	#define ISL1208_REG_HR_PM (1<<5) /* PM/AM bit in 12h mode */
7e56a7dc HVR	27	#define ISL1208_REG_DT 0x03
	28	#define ISL1208_REG_MO 0x04
	29	#define ISL1208_REG_YR 0x05
	30	#define ISL1208_REG_DW 0x06
	31	#define ISL1208_RTC_SECTION_LEN 7
	32
	33	/* control/status section */
	34	#define ISL1208_REG_SR 0x07
9edae7bc AZ	35	#define ISL1208_REG_SR_ARST (1<<7) /* auto reset */
	36	#define ISL1208_REG_SR_XTOSCB (1<<6) /* crystal oscillator */
	37	#define ISL1208_REG_SR_WRTC (1<<4) /* write rtc */
	38	#define ISL1208_REG_SR_ALM (1<<2) /* alarm */
	39	#define ISL1208_REG_SR_BAT (1<<1) /* battery */
	40	#define ISL1208_REG_SR_RTCF (1<<0) /* rtc fail */
7e56a7dc	41	#define ISL1208_REG_INT 0x08
9edae7bc	42	#define ISL1208_REG_09 0x09 /* reserved */
7e56a7dc HVR	43	#define ISL1208_REG_ATR 0x0a
	44	#define ISL1208_REG_DTR 0x0b
	45
	46	/* alarm section */
	47	#define ISL1208_REG_SCA 0x0c
	48	#define ISL1208_REG_MNA 0x0d
	49	#define ISL1208_REG_HRA 0x0e
	50	#define ISL1208_REG_DTA 0x0f
	51	#define ISL1208_REG_MOA 0x10
	52	#define ISL1208_REG_DWA 0x11
	53	#define ISL1208_ALARM_SECTION_LEN 6
	54
	55	/* user section */
	56	#define ISL1208_REG_USR1 0x12
	57	#define ISL1208_REG_USR2 0x13
	58	#define ISL1208_USR_SECTION_LEN 2
	59
9edae7bc	60	static struct i2c_driver isl1208_driver;
7e56a7dc HVR	61
	62	/* block read */
	63	static int
	64	isl1208_i2c_read_regs(struct i2c_client *client, u8 reg, u8 buf[],
9edae7bc	65	unsigned len)
7e56a7dc HVR	66	{
	67	u8 reg_addr[1] = { reg };
	68	struct i2c_msg msgs[2] = {
9edae7bc AZ	69	{client->addr, 0, sizeof(reg_addr), reg_addr}
	70	,
	71	{client->addr, I2C_M_RD, len, buf}
7e56a7dc HVR	72	};
	73	int ret;
	74
7e56a7dc HVR	75	BUG_ON(reg > ISL1208_REG_USR2);
	76	BUG_ON(reg + len > ISL1208_REG_USR2 + 1);
	77
	78	ret = i2c_transfer(client->adapter, msgs, 2);
	79	if (ret > 0)
	80	ret = 0;
	81	return ret;
	82	}
	83
	84	/* block write */
	85	static int
	86	isl1208_i2c_set_regs(struct i2c_client *client, u8 reg, u8 const buf[],
9edae7bc	87	unsigned len)
7e56a7dc HVR	88	{
	89	u8 i2c_buf[ISL1208_REG_USR2 + 2];
	90	struct i2c_msg msgs[1] = {
9edae7bc	91	{client->addr, 0, len + 1, i2c_buf}
7e56a7dc HVR	92	};
	93	int ret;
	94
7e56a7dc HVR	95	BUG_ON(reg > ISL1208_REG_USR2);
	96	BUG_ON(reg + len > ISL1208_REG_USR2 + 1);
	97
	98	i2c_buf[0] = reg;
	99	memcpy(&i2c_buf[1], &buf[0], len);
	100
	101	ret = i2c_transfer(client->adapter, msgs, 1);
	102	if (ret > 0)
	103	ret = 0;
	104	return ret;
	105	}
	106
	107	/* simple check to see wether we have a isl1208 */
9edae7bc AZ	108	static int
9edae7bc AZ	109	isl1208_i2c_validate_client(struct i2c_client *client)
7e56a7dc HVR	110	{
	111	u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
	112	u8 zero_mask[ISL1208_RTC_SECTION_LEN] = {
	113	0x80, 0x80, 0x40, 0xc0, 0xe0, 0x00, 0xf8
	114	};
	115	int i;
	116	int ret;
	117
	118	ret = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
	119	if (ret < 0)
	120	return ret;
	121
	122	for (i = 0; i < ISL1208_RTC_SECTION_LEN; ++i) {
9edae7bc	123	if (regs[i] & zero_mask[i]) /* check if bits are cleared */
7e56a7dc HVR	124	return -ENODEV;
	125	}
	126
	127	return 0;
	128	}
	129
9edae7bc AZ	130	static int
9edae7bc AZ	131	isl1208_i2c_get_sr(struct i2c_client *client)
7e56a7dc	132	{
9edae7bc AZ	133	int sr = i2c_smbus_read_byte_data(client, ISL1208_REG_SR);
	134	if (sr < 0)
	135	return -EIO;
	136
	137	return sr;
7e56a7dc HVR	138	}
7e56a7dc HVR	139
9edae7bc AZ	140	static int
9edae7bc AZ	141	isl1208_i2c_get_atr(struct i2c_client *client)
7e56a7dc HVR	142	{
7e56a7dc HVR	143	int atr = i2c_smbus_read_byte_data(client, ISL1208_REG_ATR);
7e56a7dc	144	if (atr < 0)
9edae7bc	145	return atr;
7e56a7dc HVR	146
	147	/* The 6bit value in the ATR register controls the load
	148	* capacitance C_load * in steps of 0.25pF
	149	*
	150	* bit (1<<5) of the ATR register is inverted
	151	*
	152	* C_load(ATR=0x20) = 4.50pF
	153	* C_load(ATR=0x00) = 12.50pF
	154	* C_load(ATR=0x1f) = 20.25pF
	155	*
	156	*/
	157
9edae7bc AZ	158	atr &= 0x3f; /* mask out lsb */
	159	atr ^= 1 << 5; /* invert 6th bit */
	160	atr += 2 * 9; /* add offset of 4.5pF; unit[atr] = 0.25pF */
7e56a7dc HVR	161
	162	return atr;
	163	}
	164
9edae7bc AZ	165	static int
9edae7bc AZ	166	isl1208_i2c_get_dtr(struct i2c_client *client)
7e56a7dc HVR	167	{
7e56a7dc HVR	168	int dtr = i2c_smbus_read_byte_data(client, ISL1208_REG_DTR);
7e56a7dc HVR	169	if (dtr < 0)
	170	return -EIO;
	171
	172	/* dtr encodes adjustments of {-60,-40,-20,0,20,40,60} ppm */
9edae7bc	173	dtr = ((dtr & 0x3) * 20) * (dtr & (1 << 2) ? -1 : 1);
7e56a7dc HVR	174
	175	return dtr;
	176	}
	177
9edae7bc AZ	178	static int
9edae7bc AZ	179	isl1208_i2c_get_usr(struct i2c_client *client)
7e56a7dc HVR	180	{
	181	u8 buf[ISL1208_USR_SECTION_LEN] = { 0, };
	182	int ret;
	183
9edae7bc AZ	184	ret = isl1208_i2c_read_regs(client, ISL1208_REG_USR1, buf,
9edae7bc AZ	185	ISL1208_USR_SECTION_LEN);
7e56a7dc HVR	186	if (ret < 0)
	187	return ret;
	188
	189	return (buf[1] << 8) \| buf[0];
	190	}
	191
9edae7bc AZ	192	static int
9edae7bc AZ	193	isl1208_i2c_set_usr(struct i2c_client *client, u16 usr)
7e56a7dc HVR	194	{
	195	u8 buf[ISL1208_USR_SECTION_LEN];
	196
	197	buf[0] = usr & 0xff;
	198	buf[1] = (usr >> 8) & 0xff;
	199
9edae7bc AZ	200	return isl1208_i2c_set_regs(client, ISL1208_REG_USR1, buf,
9edae7bc AZ	201	ISL1208_USR_SECTION_LEN);
7e56a7dc HVR	202	}
7e56a7dc HVR	203
9edae7bc AZ	204	static int
9edae7bc AZ	205	isl1208_rtc_proc(struct device dev, struct seq_file seq)
7e56a7dc HVR	206	{
	207	struct i2c_client *const client = to_i2c_client(dev);
	208	int sr, dtr, atr, usr;
	209
	210	sr = isl1208_i2c_get_sr(client);
	211	if (sr < 0) {
	212	dev_err(&client->dev, "%s: reading SR failed\n", __func__);
	213	return sr;
	214	}
	215
	216	seq_printf(seq, "status_reg\t:%s%s%s%s%s%s (0x%.2x)\n",
	217	(sr & ISL1208_REG_SR_RTCF) ? " RTCF" : "",
	218	(sr & ISL1208_REG_SR_BAT) ? " BAT" : "",
	219	(sr & ISL1208_REG_SR_ALM) ? " ALM" : "",
	220	(sr & ISL1208_REG_SR_WRTC) ? " WRTC" : "",
	221	(sr & ISL1208_REG_SR_XTOSCB) ? " XTOSCB" : "",
9edae7bc	222	(sr & ISL1208_REG_SR_ARST) ? " ARST" : "", sr);
7e56a7dc HVR	223
	224	seq_printf(seq, "batt_status\t: %s\n",
	225	(sr & ISL1208_REG_SR_RTCF) ? "bad" : "okay");
	226
	227	dtr = isl1208_i2c_get_dtr(client);
9edae7bc	228	if (dtr >= 0 - 1)
7e56a7dc HVR	229	seq_printf(seq, "digital_trim\t: %d ppm\n", dtr);
	230
	231	atr = isl1208_i2c_get_atr(client);
	232	if (atr >= 0)
	233	seq_printf(seq, "analog_trim\t: %d.%.2d pF\n",
9edae7bc	234	atr >> 2, (atr & 0x3) * 25);
7e56a7dc HVR	235
	236	usr = isl1208_i2c_get_usr(client);
	237	if (usr >= 0)
	238	seq_printf(seq, "user_data\t: 0x%.4x\n", usr);
	239
	240	return 0;
	241	}
	242
9edae7bc AZ	243	static int
9edae7bc AZ	244	isl1208_i2c_read_time(struct i2c_client client, struct rtc_time tm)
7e56a7dc HVR	245	{
	246	int sr;
	247	u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
	248
	249	sr = isl1208_i2c_get_sr(client);
	250	if (sr < 0) {
	251	dev_err(&client->dev, "%s: reading SR failed\n", __func__);
	252	return -EIO;
	253	}
	254
	255	sr = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
	256	if (sr < 0) {
	257	dev_err(&client->dev, "%s: reading RTC section failed\n",
	258	__func__);
	259	return sr;
	260	}
	261
fe20ba70 AB	262	tm->tm_sec = bcd2bin(regs[ISL1208_REG_SC]);
fe20ba70 AB	263	tm->tm_min = bcd2bin(regs[ISL1208_REG_MN]);
9edae7bc AZ	264
	265	/* HR field has a more complex interpretation */
	266	{
7e56a7dc	267	const u8 _hr = regs[ISL1208_REG_HR];
9edae7bc	268	if (_hr & ISL1208_REG_HR_MIL) /* 24h format */
fe20ba70	269	tm->tm_hour = bcd2bin(_hr & 0x3f);
9edae7bc AZ	270	else {
9edae7bc AZ	271	/* 12h format */
fe20ba70	272	tm->tm_hour = bcd2bin(_hr & 0x1f);
9edae7bc	273	if (_hr & ISL1208_REG_HR_PM) /* PM flag set */
7e56a7dc HVR	274	tm->tm_hour += 12;
	275	}
	276	}
	277
fe20ba70 AB	278	tm->tm_mday = bcd2bin(regs[ISL1208_REG_DT]);
	279	tm->tm_mon = bcd2bin(regs[ISL1208_REG_MO]) - 1; /* rtc starts at 1 */
	280	tm->tm_year = bcd2bin(regs[ISL1208_REG_YR]) + 100;
	281	tm->tm_wday = bcd2bin(regs[ISL1208_REG_DW]);
7e56a7dc HVR	282
	283	return 0;
	284	}
	285
9edae7bc AZ	286	static int
9edae7bc AZ	287	isl1208_i2c_read_alarm(struct i2c_client client, struct rtc_wkalrm alarm)
7e56a7dc HVR	288	{
	289	struct rtc_time *const tm = &alarm->time;
	290	u8 regs[ISL1208_ALARM_SECTION_LEN] = { 0, };
	291	int sr;
	292
	293	sr = isl1208_i2c_get_sr(client);
	294	if (sr < 0) {
	295	dev_err(&client->dev, "%s: reading SR failed\n", __func__);
	296	return sr;
	297	}
	298
	299	sr = isl1208_i2c_read_regs(client, ISL1208_REG_SCA, regs,
9edae7bc	300	ISL1208_ALARM_SECTION_LEN);
7e56a7dc HVR	301	if (sr < 0) {
	302	dev_err(&client->dev, "%s: reading alarm section failed\n",
	303	__func__);
	304	return sr;
	305	}
	306
	307	/* MSB of each alarm register is an enable bit */
fe20ba70 AB	308	tm->tm_sec = bcd2bin(regs[ISL1208_REG_SCA - ISL1208_REG_SCA] & 0x7f);
	309	tm->tm_min = bcd2bin(regs[ISL1208_REG_MNA - ISL1208_REG_SCA] & 0x7f);
	310	tm->tm_hour = bcd2bin(regs[ISL1208_REG_HRA - ISL1208_REG_SCA] & 0x3f);
	311	tm->tm_mday = bcd2bin(regs[ISL1208_REG_DTA - ISL1208_REG_SCA] & 0x3f);
9edae7bc	312	tm->tm_mon =
fe20ba70 AB	313	bcd2bin(regs[ISL1208_REG_MOA - ISL1208_REG_SCA] & 0x1f) - 1;
fe20ba70 AB	314	tm->tm_wday = bcd2bin(regs[ISL1208_REG_DWA - ISL1208_REG_SCA] & 0x03);
7e56a7dc HVR	315
	316	return 0;
	317	}
	318
9edae7bc AZ	319	static int
9edae7bc AZ	320	isl1208_rtc_read_time(struct device dev, struct rtc_time tm)
7e56a7dc HVR	321	{
	322	return isl1208_i2c_read_time(to_i2c_client(dev), tm);
	323	}
	324
9edae7bc AZ	325	static int
9edae7bc AZ	326	isl1208_i2c_set_time(struct i2c_client client, struct rtc_time const tm)
7e56a7dc HVR	327	{
	328	int sr;
	329	u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
	330
cc6c2ca3 CE	331	/* The clock has an 8 bit wide bcd-coded register (they never learn)
	332	* for the year. tm_year is an offset from 1900 and we are interested
	333	* in the 2000-2099 range, so any value less than 100 is invalid.
	334	*/
	335	if (tm->tm_year < 100)
	336	return -EINVAL;
	337
fe20ba70 AB	338	regs[ISL1208_REG_SC] = bin2bcd(tm->tm_sec);
	339	regs[ISL1208_REG_MN] = bin2bcd(tm->tm_min);
	340	regs[ISL1208_REG_HR] = bin2bcd(tm->tm_hour) \| ISL1208_REG_HR_MIL;
7e56a7dc	341
fe20ba70 AB	342	regs[ISL1208_REG_DT] = bin2bcd(tm->tm_mday);
	343	regs[ISL1208_REG_MO] = bin2bcd(tm->tm_mon + 1);
	344	regs[ISL1208_REG_YR] = bin2bcd(tm->tm_year - 100);
7e56a7dc	345
fe20ba70	346	regs[ISL1208_REG_DW] = bin2bcd(tm->tm_wday & 7);
7e56a7dc HVR	347
	348	sr = isl1208_i2c_get_sr(client);
	349	if (sr < 0) {
	350	dev_err(&client->dev, "%s: reading SR failed\n", __func__);
	351	return sr;
	352	}
	353
	354	/* set WRTC */
9edae7bc	355	sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR,
7e56a7dc HVR	356	sr \| ISL1208_REG_SR_WRTC);
	357	if (sr < 0) {
	358	dev_err(&client->dev, "%s: writing SR failed\n", __func__);
	359	return sr;
	360	}
	361
	362	/* write RTC registers */
	363	sr = isl1208_i2c_set_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
	364	if (sr < 0) {
	365	dev_err(&client->dev, "%s: writing RTC section failed\n",
	366	__func__);
	367	return sr;
	368	}
	369
	370	/* clear WRTC again */
9edae7bc	371	sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR,
7e56a7dc HVR	372	sr & ~ISL1208_REG_SR_WRTC);
	373	if (sr < 0) {
	374	dev_err(&client->dev, "%s: writing SR failed\n", __func__);
	375	return sr;
	376	}
	377
	378	return 0;
	379	}
	380
	381
9edae7bc AZ	382	static int
9edae7bc AZ	383	isl1208_rtc_set_time(struct device dev, struct rtc_time tm)
7e56a7dc HVR	384	{
	385	return isl1208_i2c_set_time(to_i2c_client(dev), tm);
	386	}
	387
9edae7bc AZ	388	static int
9edae7bc AZ	389	isl1208_rtc_read_alarm(struct device dev, struct rtc_wkalrm alarm)
7e56a7dc HVR	390	{
	391	return isl1208_i2c_read_alarm(to_i2c_client(dev), alarm);
	392	}
	393
ff8371ac	394	static const struct rtc_class_ops isl1208_rtc_ops = {
9edae7bc AZ	395	.proc = isl1208_rtc_proc,
	396	.read_time = isl1208_rtc_read_time,
	397	.set_time = isl1208_rtc_set_time,
	398	.read_alarm = isl1208_rtc_read_alarm,
	399	/.set_alarm = isl1208_rtc_set_alarm, /
7e56a7dc HVR	400	};
	401
	402	/* sysfs interface */
	403
9edae7bc AZ	404	static ssize_t
	405	isl1208_sysfs_show_atrim(struct device *dev,
	406	struct device_attribute attr, char buf)
7e56a7dc	407	{
9edae7bc	408	int atr = isl1208_i2c_get_atr(to_i2c_client(dev));
7e56a7dc HVR	409	if (atr < 0)
	410	return atr;
	411
9edae7bc	412	return sprintf(buf, "%d.%.2d pF\n", atr >> 2, (atr & 0x3) * 25);
7e56a7dc	413	}
9edae7bc	414
7e56a7dc HVR	415	static DEVICE_ATTR(atrim, S_IRUGO, isl1208_sysfs_show_atrim, NULL);
7e56a7dc HVR	416
9edae7bc AZ	417	static ssize_t
	418	isl1208_sysfs_show_dtrim(struct device *dev,
	419	struct device_attribute attr, char buf)
7e56a7dc	420	{
9edae7bc	421	int dtr = isl1208_i2c_get_dtr(to_i2c_client(dev));
7e56a7dc HVR	422	if (dtr < 0)
	423	return dtr;
	424
	425	return sprintf(buf, "%d ppm\n", dtr);
	426	}
9edae7bc	427
7e56a7dc HVR	428	static DEVICE_ATTR(dtrim, S_IRUGO, isl1208_sysfs_show_dtrim, NULL);
7e56a7dc HVR	429
9edae7bc AZ	430	static ssize_t
	431	isl1208_sysfs_show_usr(struct device *dev,
	432	struct device_attribute attr, char buf)
7e56a7dc	433	{
9edae7bc	434	int usr = isl1208_i2c_get_usr(to_i2c_client(dev));
7e56a7dc HVR	435	if (usr < 0)
	436	return usr;
	437
	438	return sprintf(buf, "0x%.4x\n", usr);
	439	}
	440
9edae7bc AZ	441	static ssize_t
	442	isl1208_sysfs_store_usr(struct device *dev,
	443	struct device_attribute *attr,
	444	const char *buf, size_t count)
7e56a7dc HVR	445	{
	446	int usr = -1;
	447
	448	if (buf[0] == '0' && (buf[1] == 'x' \|\| buf[1] == 'X')) {
	449	if (sscanf(buf, "%x", &usr) != 1)
	450	return -EINVAL;
	451	} else {
	452	if (sscanf(buf, "%d", &usr) != 1)
	453	return -EINVAL;
	454	}
	455
	456	if (usr < 0 \|\| usr > 0xffff)
	457	return -EINVAL;
	458
	459	return isl1208_i2c_set_usr(to_i2c_client(dev), usr) ? -EIO : count;
	460	}
9edae7bc	461
7e56a7dc HVR	462	static DEVICE_ATTR(usr, S_IRUGO \| S_IWUSR, isl1208_sysfs_show_usr,
	463	isl1208_sysfs_store_usr);
	464
e17ab5cb HS	465	static struct attribute *isl1208_rtc_attrs[] = {
	466	&dev_attr_atrim.attr,
	467	&dev_attr_dtrim.attr,
	468	&dev_attr_usr.attr,
	469	NULL
	470	};
9edae7bc	471
e17ab5cb HS	472	static const struct attribute_group isl1208_rtc_sysfs_files = {
	473	.attrs = isl1208_rtc_attrs,
	474	};
9edae7bc AZ	475
9edae7bc AZ	476	static int
d2653e92	477	isl1208_probe(struct i2c_client client, const struct i2c_device_id id)
9edae7bc AZ	478	{
	479	int rc = 0;
	480	struct rtc_device *rtc;
7e56a7dc	481
9edae7bc AZ	482	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
9edae7bc AZ	483	return -ENODEV;
7e56a7dc	484
9edae7bc AZ	485	if (isl1208_i2c_validate_client(client) < 0)
	486	return -ENODEV;
	487
	488	dev_info(&client->dev,
7e56a7dc HVR	489	"chip found, driver version " DRV_VERSION "\n");
	490
	491	rtc = rtc_device_register(isl1208_driver.driver.name,
9edae7bc AZ	492	&client->dev, &isl1208_rtc_ops,
	493	THIS_MODULE);
	494	if (IS_ERR(rtc))
	495	return PTR_ERR(rtc);
7e56a7dc	496
9edae7bc	497	i2c_set_clientdata(client, rtc);
7e56a7dc	498
9edae7bc	499	rc = isl1208_i2c_get_sr(client);
7e56a7dc	500	if (rc < 0) {
9edae7bc AZ	501	dev_err(&client->dev, "reading status failed\n");
9edae7bc AZ	502	goto exit_unregister;
7e56a7dc HVR	503	}
	504
	505	if (rc & ISL1208_REG_SR_RTCF)
9edae7bc	506	dev_warn(&client->dev, "rtc power failure detected, "
7e56a7dc HVR	507	"please set clock.\n");
7e56a7dc HVR	508
e17ab5cb	509	rc = sysfs_create_group(&client->dev.kobj, &isl1208_rtc_sysfs_files);
9edae7bc AZ	510	if (rc)
9edae7bc AZ	511	goto exit_unregister;
7e56a7dc HVR	512
	513	return 0;
	514
9edae7bc	515	exit_unregister:
7e56a7dc	516	rtc_device_unregister(rtc);
7e56a7dc	517
9edae7bc	518	return rc;
7e56a7dc HVR	519	}
	520
	521	static int
9edae7bc	522	isl1208_remove(struct i2c_client *client)
7e56a7dc	523	{
9edae7bc	524	struct rtc_device *rtc = i2c_get_clientdata(client);
7e56a7dc	525
e17ab5cb	526	sysfs_remove_group(&client->dev.kobj, &isl1208_rtc_sysfs_files);
9edae7bc	527	rtc_device_unregister(rtc);
7e56a7dc HVR	528
	529	return 0;
	530	}
	531
3760f736 JD	532	static const struct i2c_device_id isl1208_id[] = {
	533	{ "isl1208", 0 },
	534	{ }
	535	};
	536	MODULE_DEVICE_TABLE(i2c, isl1208_id);
	537
9edae7bc AZ	538	static struct i2c_driver isl1208_driver = {
	539	.driver = {
	540	.name = "rtc-isl1208",
	541	},
	542	.probe = isl1208_probe,
	543	.remove = isl1208_remove,
3760f736	544	.id_table = isl1208_id,
9edae7bc	545	};
7e56a7dc	546
9edae7bc AZ	547	static int __init
9edae7bc AZ	548	isl1208_init(void)
7e56a7dc HVR	549	{
	550	return i2c_add_driver(&isl1208_driver);
	551	}
	552
9edae7bc AZ	553	static void __exit
9edae7bc AZ	554	isl1208_exit(void)
7e56a7dc HVR	555	{
	556	i2c_del_driver(&isl1208_driver);
	557	}
	558
	559	MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>");
	560	MODULE_DESCRIPTION("Intersil ISL1208 RTC driver");
	561	MODULE_LICENSE("GPL");
	562	MODULE_VERSION(DRV_VERSION);
	563
	564	module_init(isl1208_init);
	565	module_exit(isl1208_exit);