[deliverable/linux.git] / drivers / i2c / chips / ds1337.c

/*
 *  linux/drivers/i2c/chips/ds1337.c
 *
 *  Copyright (C) 2005 James Chapman <jchapman@katalix.com>
 *
 *	based on linux/drivers/acorn/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 Dallas Semiconductor DS1337 real time clock chip
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/i2c-sensor.h>
#include <linux/string.h>
#include <linux/rtc.h>		/* get the user-level API */
#include <linux/bcd.h>
#include <linux/list.h>

/* Device registers */
#define DS1337_REG_HOUR		2
#define DS1337_REG_DAY		3
#define DS1337_REG_DATE		4
#define DS1337_REG_MONTH	5
#define DS1337_REG_CONTROL	14
#define DS1337_REG_STATUS	15

/* FIXME - how do we export these interface constants? */
#define DS1337_GET_DATE		0
#define DS1337_SET_DATE		1

/*
 * Functions declaration
 */
static unsigned short normal_i2c[] = { 0x68, I2C_CLIENT_END };
static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END };

SENSORS_INSMOD_1(ds1337);

static int ds1337_attach_adapter(struct i2c_adapter *adapter);
static int ds1337_detect(struct i2c_adapter *adapter, int address, int kind);
static void ds1337_init_client(struct i2c_client *client);
static int ds1337_detach_client(struct i2c_client *client);
static int ds1337_command(struct i2c_client *client, unsigned int cmd,
			  void *arg);

/*
 * Driver data (common to all clients)
 */
static struct i2c_driver ds1337_driver = {
	.owner		= THIS_MODULE,
	.name		= "ds1337",
	.flags		= I2C_DF_NOTIFY,
	.attach_adapter	= ds1337_attach_adapter,
	.detach_client	= ds1337_detach_client,
	.command	= ds1337_command,
};

/*
 * Client data (each client gets its own)
 */
struct ds1337_data {
	struct i2c_client client;
	struct list_head list;
	int id;
};

/*
 * Internal variables
 */
static int ds1337_id;
static LIST_HEAD(ds1337_clients);

static inline int ds1337_read(struct i2c_client *client, u8 reg, u8 *value)
{
	s32 tmp = i2c_smbus_read_byte_data(client, reg);

	if (tmp < 0)
		return -EIO;

	*value = tmp;

	return 0;
}

/*
 * Chip access functions
 */
static int ds1337_get_datetime(struct i2c_client *client, struct rtc_time *dt)
{
	int result;
	u8 buf[7];
	u8 val;
	struct i2c_msg msg[2];
	u8 offs = 0;

	if (!dt) {
		dev_dbg(&client->dev, "%s: EINVAL: dt=NULL\n", __FUNCTION__);
		return -EINVAL;
	}

	msg[0].addr = client->addr;
	msg[0].flags = 0;
	msg[0].len = 1;
	msg[0].buf = &offs;

	msg[1].addr = client->addr;
	msg[1].flags = I2C_M_RD;
	msg[1].len = sizeof(buf);
	msg[1].buf = &buf[0];

	result = i2c_transfer(client->adapter, msg, 2);

	dev_dbg(&client->dev, "%s: [%d] %02x %02x %02x %02x %02x %02x %02x\n",
		__FUNCTION__, result, buf[0], buf[1], buf[2], buf[3],
		buf[4], buf[5], buf[6]);

	if (result >= 0) {
		dt->tm_sec = BCD2BIN(buf[0]);
		dt->tm_min = BCD2BIN(buf[1]);
		val = buf[2] & 0x3f;
		dt->tm_hour = BCD2BIN(val);
		dt->tm_wday = BCD2BIN(buf[3]) - 1;
		dt->tm_mday = BCD2BIN(buf[4]);
		val = buf[5] & 0x7f;
		dt->tm_mon = BCD2BIN(val) - 1;
		dt->tm_year = BCD2BIN(buf[6]);
		if (buf[5] & 0x80)
			dt->tm_year += 100;

		dev_dbg(&client->dev, "%s: secs=%d, mins=%d, "
			"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
			__FUNCTION__, dt->tm_sec, dt->tm_min,
			dt->tm_hour, dt->tm_mday,
			dt->tm_mon, dt->tm_year, dt->tm_wday);
	} else {
		dev_err(&client->dev, "error reading data! %d\n", result);
		result = -EIO;
	}

	return result;
}

static int ds1337_set_datetime(struct i2c_client *client, struct rtc_time *dt)
{
	int result;
	u8 buf[8];
	u8 val;
	struct i2c_msg msg[1];

	if (!dt) {
		dev_dbg(&client->dev, "%s: EINVAL: dt=NULL\n", __FUNCTION__);
		return -EINVAL;
	}

	dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
		"mday=%d, mon=%d, year=%d, wday=%d\n", __FUNCTION__,
		dt->tm_sec, dt->tm_min, dt->tm_hour,
		dt->tm_mday, dt->tm_mon, dt->tm_year, dt->tm_wday);

	buf[0] = 0;		/* reg offset */
	buf[1] = BIN2BCD(dt->tm_sec);
	buf[2] = BIN2BCD(dt->tm_min);
	buf[3] = BIN2BCD(dt->tm_hour) | (1 << 6);
	buf[4] = BIN2BCD(dt->tm_wday) + 1;
	buf[5] = BIN2BCD(dt->tm_mday);
	buf[6] = BIN2BCD(dt->tm_mon) + 1;
	val = dt->tm_year;
	if (val >= 100) {
		val -= 100;
		buf[6] |= (1 << 7);
	}
	buf[7] = BIN2BCD(val);

	msg[0].addr = client->addr;
	msg[0].flags = 0;
	msg[0].len = sizeof(buf);
	msg[0].buf = &buf[0];

	result = i2c_transfer(client->adapter, msg, 1);
	if (result < 0) {
		dev_err(&client->dev, "error writing data! %d\n", result);
		result = -EIO;
	} else {
		result = 0;
	}

	return result;
}

static int ds1337_command(struct i2c_client *client, unsigned int cmd,
			  void *arg)
{
	dev_dbg(&client->dev, "%s: cmd=%d\n", __FUNCTION__, cmd);

	switch (cmd) {
	case DS1337_GET_DATE:
		return ds1337_get_datetime(client, arg);

	case DS1337_SET_DATE:
		return ds1337_set_datetime(client, arg);

	default:
		return -EINVAL;
	}
}

/*
 * Public API for access to specific device. Useful for low-level
 * RTC access from kernel code.
 */
int ds1337_do_command(int id, int cmd, void *arg)
{
	struct list_head *walk;
	struct list_head *tmp;
	struct ds1337_data *data;

	list_for_each_safe(walk, tmp, &ds1337_clients) {
		data = list_entry(walk, struct ds1337_data, list);
		if (data->id == id)
			return ds1337_command(&data->client, cmd, arg);
	}

	return -ENODEV;
}

static int ds1337_attach_adapter(struct i2c_adapter *adapter)
{
	return i2c_detect(adapter, &addr_data, ds1337_detect);
}

/*
 * The following function does more than just detection. If detection
 * succeeds, it also registers the new chip.
 */
static int ds1337_detect(struct i2c_adapter *adapter, int address, int kind)
{
	struct i2c_client *new_client;
	struct ds1337_data *data;
	int err = 0;
	const char *name = "";

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
				     I2C_FUNC_I2C))
		goto exit;

	if (!(data = kmalloc(sizeof(struct ds1337_data), GFP_KERNEL))) {
		err = -ENOMEM;
		goto exit;
	}
	memset(data, 0, sizeof(struct ds1337_data));
	INIT_LIST_HEAD(&data->list);

	/* The common I2C client data is placed right before the
	 * DS1337-specific data. 
	 */
	new_client = &data->client;
	i2c_set_clientdata(new_client, data);
	new_client->addr = address;
	new_client->adapter = adapter;
	new_client->driver = &ds1337_driver;
	new_client->flags = 0;

	/*
	 * Now we do the remaining detection. A negative kind means that
	 * the driver was loaded with no force parameter (default), so we
	 * must both detect and identify the chip. A zero kind means that
	 * the driver was loaded with the force parameter, the detection
	 * step shall be skipped. A positive kind means that the driver
	 * was loaded with the force parameter and a given kind of chip is
	 * requested, so both the detection and the identification steps
	 * are skipped.
	 *
	 * For detection, we read registers that are most likely to cause
	 * detection failure, i.e. those that have more bits with fixed
	 * or reserved values.
	 */

	/* Default to an DS1337 if forced */
	if (kind == 0)
		kind = ds1337;

	if (kind < 0) {		/* detection and identification */
		u8 data;

		/* Check that status register bits 6-2 are zero */
		if ((ds1337_read(new_client, DS1337_REG_STATUS, &data) < 0) ||
		    (data & 0x7c))
			goto exit_free;

		/* Check for a valid day register value */
		if ((ds1337_read(new_client, DS1337_REG_DAY, &data) < 0) ||
		    (data == 0) || (data & 0xf8))
			goto exit_free;

		/* Check for a valid date register value */
		if ((ds1337_read(new_client, DS1337_REG_DATE, &data) < 0) ||
		    (data == 0) || (data & 0xc0) || ((data & 0x0f) > 9) ||
		    (data >= 0x32))
			goto exit_free;

		/* Check for a valid month register value */
		if ((ds1337_read(new_client, DS1337_REG_MONTH, &data) < 0) ||
		    (data == 0) || (data & 0x60) || ((data & 0x0f) > 9) ||
		    ((data >= 0x13) && (data <= 0x19)))
			goto exit_free;

		/* Check that control register bits 6-5 are zero */
		if ((ds1337_read(new_client, DS1337_REG_CONTROL, &data) < 0) ||
		    (data & 0x60))
			goto exit_free;

		kind = ds1337;
	}

	if (kind == ds1337)
		name = "ds1337";

	/* We can fill in the remaining client fields */
	strlcpy(new_client->name, name, I2C_NAME_SIZE);

	/* Tell the I2C layer a new client has arrived */
	if ((err = i2c_attach_client(new_client)))
		goto exit_free;

	/* Initialize the DS1337 chip */
	ds1337_init_client(new_client);

	/* Add client to local list */
	data->id = ds1337_id++;
	list_add(&data->list, &ds1337_clients);

	return 0;

exit_free:
	kfree(data);
exit:
	return err;
}

static void ds1337_init_client(struct i2c_client *client)
{
	s32 val;

	/* Ensure that device is set in 24-hour mode */
	val = i2c_smbus_read_byte_data(client, DS1337_REG_HOUR);
	if ((val >= 0) && (val & (1 << 6)) == 0)
		i2c_smbus_write_byte_data(client, DS1337_REG_HOUR,
					  val | (1 << 6));
}

static int ds1337_detach_client(struct i2c_client *client)
{
	int err;
	struct ds1337_data *data = i2c_get_clientdata(client);

	if ((err = i2c_detach_client(client))) {
		dev_err(&client->dev, "Client deregistration failed, "
			"client not detached.\n");
		return err;
	}

	list_del(&data->list);
	kfree(data);
	return 0;
}

static int __init ds1337_init(void)
{
	return i2c_add_driver(&ds1337_driver);
}

static void __exit ds1337_exit(void)
{
	i2c_del_driver(&ds1337_driver);
}

MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
MODULE_DESCRIPTION("DS1337 RTC driver");
MODULE_LICENSE("GPL");

module_init(ds1337_init);
module_exit(ds1337_exit);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/drivers/i2c/chips/ds1337.c
	3	*
	4	* Copyright (C) 2005 James Chapman <jchapman@katalix.com>
	5	*
3e9d0ba1	6	* based on linux/drivers/acorn/char/pcf8583.c
1da177e4 LT	7	* Copyright (C) 2000 Russell King
	8	*
	9	* This program is free software; you can redistribute it and/or modify
	10	* it under the terms of the GNU General Public License version 2 as
	11	* published by the Free Software Foundation.
	12	*
	13	* Driver for Dallas Semiconductor DS1337 real time clock chip
	14	*/
	15
	16	#include <linux/config.h>
	17	#include <linux/module.h>
	18	#include <linux/init.h>
	19	#include <linux/slab.h>
	20	#include <linux/i2c.h>
	21	#include <linux/i2c-sensor.h>
	22	#include <linux/string.h>
	23	#include <linux/rtc.h> /* get the user-level API */
	24	#include <linux/bcd.h>
	25	#include <linux/list.h>
	26
	27	/* Device registers */
	28	#define DS1337_REG_HOUR 2
	29	#define DS1337_REG_DAY 3
	30	#define DS1337_REG_DATE 4
	31	#define DS1337_REG_MONTH 5
	32	#define DS1337_REG_CONTROL 14
	33	#define DS1337_REG_STATUS 15
	34
	35	/* FIXME - how do we export these interface constants? */
	36	#define DS1337_GET_DATE 0
	37	#define DS1337_SET_DATE 1
	38
	39	/*
	40	* Functions declaration
	41	*/
	42	static unsigned short normal_i2c[] = { 0x68, I2C_CLIENT_END };
	43	static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END };
	44
	45	SENSORS_INSMOD_1(ds1337);
	46
	47	static int ds1337_attach_adapter(struct i2c_adapter *adapter);
	48	static int ds1337_detect(struct i2c_adapter *adapter, int address, int kind);
	49	static void ds1337_init_client(struct i2c_client *client);
	50	static int ds1337_detach_client(struct i2c_client *client);
	51	static int ds1337_command(struct i2c_client *client, unsigned int cmd,
	52	void *arg);
	53
	54	/*
	55	* Driver data (common to all clients)
	56	*/
	57	static struct i2c_driver ds1337_driver = {
	58	.owner = THIS_MODULE,
	59	.name = "ds1337",
	60	.flags = I2C_DF_NOTIFY,
	61	.attach_adapter = ds1337_attach_adapter,
	62	.detach_client = ds1337_detach_client,
	63	.command = ds1337_command,
	64	};
	65
	66	/*
	67	* Client data (each client gets its own)
	68	*/
	69	struct ds1337_data {
	70	struct i2c_client client;
71	struct list_head list;
72	int id;
73	};
74
75	/*
76	* Internal variables
77	*/
78	static int ds1337_id;
79	static LIST_HEAD(ds1337_clients);
80
81	static inline int ds1337_read(struct i2c_client client, u8 reg, u8 value)
82	{
83	s32 tmp = i2c_smbus_read_byte_data(client, reg);
84
85	if (tmp < 0)
86	return -EIO;
87
88	*value = tmp;
89
90	return 0;
91	}
92
93	/*
94	* Chip access functions
95	*/
96	static int ds1337_get_datetime(struct i2c_client client, struct rtc_time dt)
97	{
1da177e4 LT	98	int result;
	99	u8 buf[7];
	100	u8 val;
	101	struct i2c_msg msg[2];
	102	u8 offs = 0;
	103
	104	if (!dt) {
d01b79d0	105	dev_dbg(&client->dev, "%s: EINVAL: dt=NULL\n", __FUNCTION__);
1da177e4 LT	106	return -EINVAL;
	107	}
	108
	109	msg[0].addr = client->addr;
	110	msg[0].flags = 0;
	111	msg[0].len = 1;
	112	msg[0].buf = &offs;
	113
	114	msg[1].addr = client->addr;
	115	msg[1].flags = I2C_M_RD;
	116	msg[1].len = sizeof(buf);
	117	msg[1].buf = &buf[0];
	118
3e9d0ba1	119	result = i2c_transfer(client->adapter, msg, 2);
1da177e4	120
d01b79d0	121	dev_dbg(&client->dev, "%s: [%d] %02x %02x %02x %02x %02x %02x %02x\n",
1da177e4 LT	122	__FUNCTION__, result, buf[0], buf[1], buf[2], buf[3],
	123	buf[4], buf[5], buf[6]);
	124
	125	if (result >= 0) {
6069ffde LM	126	dt->tm_sec = BCD2BIN(buf[0]);
6069ffde LM	127	dt->tm_min = BCD2BIN(buf[1]);
1da177e4	128	val = buf[2] & 0x3f;
6069ffde LM	129	dt->tm_hour = BCD2BIN(val);
	130	dt->tm_wday = BCD2BIN(buf[3]) - 1;
	131	dt->tm_mday = BCD2BIN(buf[4]);
1da177e4	132	val = buf[5] & 0x7f;
0b46e334 LM	133	dt->tm_mon = BCD2BIN(val) - 1;
0b46e334 LM	134	dt->tm_year = BCD2BIN(buf[6]);
1da177e4 LT	135	if (buf[5] & 0x80)
	136	dt->tm_year += 100;
	137
d01b79d0	138	dev_dbg(&client->dev, "%s: secs=%d, mins=%d, "
1da177e4 LT	139	"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
	140	__FUNCTION__, dt->tm_sec, dt->tm_min,
	141	dt->tm_hour, dt->tm_mday,
	142	dt->tm_mon, dt->tm_year, dt->tm_wday);
	143	} else {
d01b79d0	144	dev_err(&client->dev, "error reading data! %d\n", result);
1da177e4 LT	145	result = -EIO;
	146	}
	147
	148	return result;
	149	}
	150
	151	static int ds1337_set_datetime(struct i2c_client client, struct rtc_time dt)
	152	{
1da177e4 LT	153	int result;
	154	u8 buf[8];
	155	u8 val;
	156	struct i2c_msg msg[1];
	157
	158	if (!dt) {
d01b79d0	159	dev_dbg(&client->dev, "%s: EINVAL: dt=NULL\n", __FUNCTION__);
1da177e4 LT	160	return -EINVAL;
	161	}
	162
d01b79d0	163	dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
1da177e4 LT	164	"mday=%d, mon=%d, year=%d, wday=%d\n", __FUNCTION__,
	165	dt->tm_sec, dt->tm_min, dt->tm_hour,
	166	dt->tm_mday, dt->tm_mon, dt->tm_year, dt->tm_wday);
	167
	168	buf[0] = 0; /* reg offset */
6069ffde LM	169	buf[1] = BIN2BCD(dt->tm_sec);
	170	buf[2] = BIN2BCD(dt->tm_min);
	171	buf[3] = BIN2BCD(dt->tm_hour) \| (1 << 6);
	172	buf[4] = BIN2BCD(dt->tm_wday) + 1;
	173	buf[5] = BIN2BCD(dt->tm_mday);
0b46e334 LM	174	buf[6] = BIN2BCD(dt->tm_mon) + 1;
	175	val = dt->tm_year;
	176	if (val >= 100) {
	177	val -= 100;
1da177e4	178	buf[6] \|= (1 << 7);
1da177e4	179	}
6069ffde	180	buf[7] = BIN2BCD(val);
1da177e4 LT	181
	182	msg[0].addr = client->addr;
	183	msg[0].flags = 0;
	184	msg[0].len = sizeof(buf);
	185	msg[0].buf = &buf[0];
	186
3e9d0ba1	187	result = i2c_transfer(client->adapter, msg, 1);
1da177e4	188	if (result < 0) {
d01b79d0	189	dev_err(&client->dev, "error writing data! %d\n", result);
1da177e4 LT	190	result = -EIO;
	191	} else {
	192	result = 0;
	193	}
	194
	195	return result;
	196	}
	197
	198	static int ds1337_command(struct i2c_client *client, unsigned int cmd,
	199	void *arg)
	200	{
d01b79d0	201	dev_dbg(&client->dev, "%s: cmd=%d\n", __FUNCTION__, cmd);
1da177e4 LT	202
	203	switch (cmd) {
	204	case DS1337_GET_DATE:
	205	return ds1337_get_datetime(client, arg);
	206
	207	case DS1337_SET_DATE:
	208	return ds1337_set_datetime(client, arg);
	209
	210	default:
	211	return -EINVAL;
	212	}
	213	}
	214
	215	/*
	216	* Public API for access to specific device. Useful for low-level
	217	* RTC access from kernel code.
	218	*/
	219	int ds1337_do_command(int id, int cmd, void *arg)
	220	{
	221	struct list_head *walk;
	222	struct list_head *tmp;
	223	struct ds1337_data *data;
	224
	225	list_for_each_safe(walk, tmp, &ds1337_clients) {
	226	data = list_entry(walk, struct ds1337_data, list);
	227	if (data->id == id)
	228	return ds1337_command(&data->client, cmd, arg);
	229	}
	230
	231	return -ENODEV;
	232	}
	233
	234	static int ds1337_attach_adapter(struct i2c_adapter *adapter)
	235	{
	236	return i2c_detect(adapter, &addr_data, ds1337_detect);
	237	}
	238
	239	/*
	240	* The following function does more than just detection. If detection
	241	* succeeds, it also registers the new chip.
	242	*/
	243	static int ds1337_detect(struct i2c_adapter *adapter, int address, int kind)
	244	{
	245	struct i2c_client *new_client;
	246	struct ds1337_data *data;
	247	int err = 0;
	248	const char *name = "";
	249
	250	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA \|
	251	I2C_FUNC_I2C))
	252	goto exit;
	253
	254	if (!(data = kmalloc(sizeof(struct ds1337_data), GFP_KERNEL))) {
	255	err = -ENOMEM;
	256	goto exit;
	257	}
	258	memset(data, 0, sizeof(struct ds1337_data));
	259	INIT_LIST_HEAD(&data->list);
	260
	261	/* The common I2C client data is placed right before the
	262	* DS1337-specific data.
	263	*/
	264	new_client = &data->client;
	265	i2c_set_clientdata(new_client, data);
266	new_client->addr = address;
267	new_client->adapter = adapter;
268	new_client->driver = &ds1337_driver;
269	new_client->flags = 0;
270
271	/*
272	* Now we do the remaining detection. A negative kind means that
273	* the driver was loaded with no force parameter (default), so we
274	* must both detect and identify the chip. A zero kind means that
275	* the driver was loaded with the force parameter, the detection
276	* step shall be skipped. A positive kind means that the driver
277	* was loaded with the force parameter and a given kind of chip is
278	* requested, so both the detection and the identification steps
279	* are skipped.
280	*
281	* For detection, we read registers that are most likely to cause
282	* detection failure, i.e. those that have more bits with fixed
283	* or reserved values.
284	*/
285
286	/* Default to an DS1337 if forced */
287	if (kind == 0)
288	kind = ds1337;
289
290	if (kind < 0) { /* detection and identification */
291	u8 data;
292
293	/* Check that status register bits 6-2 are zero */
294	if ((ds1337_read(new_client, DS1337_REG_STATUS, &data) < 0) \|\|
295	(data & 0x7c))
296	goto exit_free;
297
298	/* Check for a valid day register value */
299	if ((ds1337_read(new_client, DS1337_REG_DAY, &data) < 0) \|\|
300	(data == 0) \|\| (data & 0xf8))
301	goto exit_free;
302
303	/* Check for a valid date register value */
304	if ((ds1337_read(new_client, DS1337_REG_DATE, &data) < 0) \|\|
305	(data == 0) \|\| (data & 0xc0) \|\| ((data & 0x0f) > 9) \|\|
306	(data >= 0x32))
307	goto exit_free;
308
309	/* Check for a valid month register value */
310	if ((ds1337_read(new_client, DS1337_REG_MONTH, &data) < 0) \|\|
311	(data == 0) \|\| (data & 0x60) \|\| ((data & 0x0f) > 9) \|\|
312	((data >= 0x13) && (data <= 0x19)))
313	goto exit_free;
314
315	/* Check that control register bits 6-5 are zero */
316	if ((ds1337_read(new_client, DS1337_REG_CONTROL, &data) < 0) \|\|
317	(data & 0x60))
318	goto exit_free;
319
320	kind = ds1337;
321	}
322
323	if (kind == ds1337)
324	name = "ds1337";
325
326	/* We can fill in the remaining client fields */
327	strlcpy(new_client->name, name, I2C_NAME_SIZE);
328
329	/* Tell the I2C layer a new client has arrived */
330	if ((err = i2c_attach_client(new_client)))
331	goto exit_free;
332
333	/* Initialize the DS1337 chip */
334	ds1337_init_client(new_client);
335
336	/* Add client to local list */
337	data->id = ds1337_id++;
338	list_add(&data->list, &ds1337_clients);
339
340	return 0;
341
342	exit_free:
343	kfree(data);
344	exit:
345	return err;
346	}
347
348	static void ds1337_init_client(struct i2c_client *client)
349	{
350	s32 val;
351
352	/* Ensure that device is set in 24-hour mode */
353	val = i2c_smbus_read_byte_data(client, DS1337_REG_HOUR);
354	if ((val >= 0) && (val & (1 << 6)) == 0)
355	i2c_smbus_write_byte_data(client, DS1337_REG_HOUR,
356	val \| (1 << 6));
357	}
358
359	static int ds1337_detach_client(struct i2c_client *client)
360	{
361	int err;
362	struct ds1337_data *data = i2c_get_clientdata(client);
363
364	if ((err = i2c_detach_client(client))) {
365	dev_err(&client->dev, "Client deregistration failed, "
366	"client not detached.\n");
367	return err;
368	}
369
370	list_del(&data->list);
371	kfree(data);
372	return 0;
373	}
374
375	static int __init ds1337_init(void)
376	{
377	return i2c_add_driver(&ds1337_driver);
378	}
379
380	static void __exit ds1337_exit(void)
381	{
382	i2c_del_driver(&ds1337_driver);
383	}
384
385	MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
386	MODULE_DESCRIPTION("DS1337 RTC driver");
387	MODULE_LICENSE("GPL");
388
389	module_init(ds1337_init);
390	module_exit(ds1337_exit);