[net-next-2.6.git] / drivers / rtc / rtc-ds1374.c

/*
 * RTC client/driver for the Maxim/Dallas DS1374 Real-Time Clock over I2C
 *
 * Based on code by Randy Vinson <rvinson@mvista.com>,
 * which was based on the m41t00.c by Mark Greer <mgreer@mvista.com>.
 *
 * Copyright (C) 2006-2007 Freescale Semiconductor
 *
 * 2005 (c) MontaVista Software, Inc. This file is licensed under
 * the terms of the GNU General Public License version 2. This program
 * is licensed "as is" without any warranty of any kind, whether express
 * or implied.
 */
/*
 * It would be more efficient to use i2c msgs/i2c_transfer directly but, as
 * recommened in .../Documentation/i2c/writing-clients section
 * "Sending and receiving", using SMBus level communication is preferred.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/i2c.h>
#include <linux/rtc.h>
#include <linux/bcd.h>
#include <linux/workqueue.h>
#include <linux/slab.h>

#define DS1374_REG_TOD0		0x00 /* Time of Day */
#define DS1374_REG_TOD1		0x01
#define DS1374_REG_TOD2		0x02
#define DS1374_REG_TOD3		0x03
#define DS1374_REG_WDALM0	0x04 /* Watchdog/Alarm */
#define DS1374_REG_WDALM1	0x05
#define DS1374_REG_WDALM2	0x06
#define DS1374_REG_CR		0x07 /* Control */
#define DS1374_REG_CR_AIE	0x01 /* Alarm Int. Enable */
#define DS1374_REG_CR_WDALM	0x20 /* 1=Watchdog, 0=Alarm */
#define DS1374_REG_CR_WACE	0x40 /* WD/Alarm counter enable */
#define DS1374_REG_SR		0x08 /* Status */
#define DS1374_REG_SR_OSF	0x80 /* Oscillator Stop Flag */
#define DS1374_REG_SR_AF	0x01 /* Alarm Flag */
#define DS1374_REG_TCR		0x09 /* Trickle Charge */

static const struct i2c_device_id ds1374_id[] = {
	{ "ds1374", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, ds1374_id);

struct ds1374 {
	struct i2c_client *client;
	struct rtc_device *rtc;
	struct work_struct work;

	/* The mutex protects alarm operations, and prevents a race
	 * between the enable_irq() in the workqueue and the free_irq()
	 * in the remove function.
	 */
	struct mutex mutex;
	int exiting;
};

static struct i2c_driver ds1374_driver;

static int ds1374_read_rtc(struct i2c_client *client, u32 *time,
                           int reg, int nbytes)
{
	u8 buf[4];
	int ret;
	int i;

	if (nbytes > 4) {
		WARN_ON(1);
		return -EINVAL;
	}

	ret = i2c_smbus_read_i2c_block_data(client, reg, nbytes, buf);

	if (ret < 0)
		return ret;
	if (ret < nbytes)
		return -EIO;

	for (i = nbytes - 1, *time = 0; i >= 0; i--)
		*time = (*time << 8) | buf[i];

	return 0;
}

static int ds1374_write_rtc(struct i2c_client *client, u32 time,
                            int reg, int nbytes)
{
	u8 buf[4];
	int i;

	if (nbytes > 4) {
		WARN_ON(1);
		return -EINVAL;
	}

	for (i = 0; i < nbytes; i++) {
		buf[i] = time & 0xff;
		time >>= 8;
	}

	return i2c_smbus_write_i2c_block_data(client, reg, nbytes, buf);
}

static int ds1374_check_rtc_status(struct i2c_client *client)
{
	int ret = 0;
	int control, stat;

	stat = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
	if (stat < 0)
		return stat;

	if (stat & DS1374_REG_SR_OSF)
		dev_warn(&client->dev,
		         "oscillator discontinuity flagged, "
		         "time unreliable\n");

	stat &= ~(DS1374_REG_SR_OSF | DS1374_REG_SR_AF);

	ret = i2c_smbus_write_byte_data(client, DS1374_REG_SR, stat);
	if (ret < 0)
		return ret;

	/* If the alarm is pending, clear it before requesting
	 * the interrupt, so an interrupt event isn't reported
	 * before everything is initialized.
	 */

	control = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
	if (control < 0)
		return control;

	control &= ~(DS1374_REG_CR_WACE | DS1374_REG_CR_AIE);
	return i2c_smbus_write_byte_data(client, DS1374_REG_CR, control);
}

static int ds1374_read_time(struct device *dev, struct rtc_time *time)
{
	struct i2c_client *client = to_i2c_client(dev);
	u32 itime;
	int ret;

	ret = ds1374_read_rtc(client, &itime, DS1374_REG_TOD0, 4);
	if (!ret)
		rtc_time_to_tm(itime, time);

	return ret;
}

static int ds1374_set_time(struct device *dev, struct rtc_time *time)
{
	struct i2c_client *client = to_i2c_client(dev);
	unsigned long itime;

	rtc_tm_to_time(time, &itime);
	return ds1374_write_rtc(client, itime, DS1374_REG_TOD0, 4);
}

/* The ds1374 has a decrementer for an alarm, rather than a comparator.
 * If the time of day is changed, then the alarm will need to be
 * reset.
 */
static int ds1374_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct ds1374 *ds1374 = i2c_get_clientdata(client);
	u32 now, cur_alarm;
	int cr, sr;
	int ret = 0;

	if (client->irq <= 0)
		return -EINVAL;

	mutex_lock(&ds1374->mutex);

	cr = ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
	if (ret < 0)
		goto out;

	sr = ret = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
	if (ret < 0)
		goto out;

	ret = ds1374_read_rtc(client, &now, DS1374_REG_TOD0, 4);
	if (ret)
		goto out;

	ret = ds1374_read_rtc(client, &cur_alarm, DS1374_REG_WDALM0, 3);
	if (ret)
		goto out;

	rtc_time_to_tm(now + cur_alarm, &alarm->time);
	alarm->enabled = !!(cr & DS1374_REG_CR_WACE);
	alarm->pending = !!(sr & DS1374_REG_SR_AF);

out:
	mutex_unlock(&ds1374->mutex);
	return ret;
}

static int ds1374_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct ds1374 *ds1374 = i2c_get_clientdata(client);
	struct rtc_time now;
	unsigned long new_alarm, itime;
	int cr;
	int ret = 0;

	if (client->irq <= 0)
		return -EINVAL;

	ret = ds1374_read_time(dev, &now);
	if (ret < 0)
		return ret;

	rtc_tm_to_time(&alarm->time, &new_alarm);
	rtc_tm_to_time(&now, &itime);

	/* This can happen due to races, in addition to dates that are
	 * truly in the past.  To avoid requiring the caller to check for
	 * races, dates in the past are assumed to be in the recent past
	 * (i.e. not something that we'd rather the caller know about via
	 * an error), and the alarm is set to go off as soon as possible.
	 */
	if (time_before_eq(new_alarm, itime))
		new_alarm = 1;
	else
		new_alarm -= itime;

	mutex_lock(&ds1374->mutex);

	ret = cr = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
	if (ret < 0)
		goto out;

	/* Disable any existing alarm before setting the new one
	 * (or lack thereof). */
	cr &= ~DS1374_REG_CR_WACE;

	ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
	if (ret < 0)
		goto out;

	ret = ds1374_write_rtc(client, new_alarm, DS1374_REG_WDALM0, 3);
	if (ret)
		goto out;

	if (alarm->enabled) {
		cr |= DS1374_REG_CR_WACE | DS1374_REG_CR_AIE;
		cr &= ~DS1374_REG_CR_WDALM;

		ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
	}

out:
	mutex_unlock(&ds1374->mutex);
	return ret;
}

static irqreturn_t ds1374_irq(int irq, void *dev_id)
{
	struct i2c_client *client = dev_id;
	struct ds1374 *ds1374 = i2c_get_clientdata(client);

	disable_irq_nosync(irq);
	schedule_work(&ds1374->work);
	return IRQ_HANDLED;
}

static void ds1374_work(struct work_struct *work)
{
	struct ds1374 *ds1374 = container_of(work, struct ds1374, work);
	struct i2c_client *client = ds1374->client;
	int stat, control;

	mutex_lock(&ds1374->mutex);

	stat = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
	if (stat < 0)
		goto unlock;

	if (stat & DS1374_REG_SR_AF) {
		stat &= ~DS1374_REG_SR_AF;
		i2c_smbus_write_byte_data(client, DS1374_REG_SR, stat);

		control = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
		if (control < 0)
			goto out;

		control &= ~(DS1374_REG_CR_WACE | DS1374_REG_CR_AIE);
		i2c_smbus_write_byte_data(client, DS1374_REG_CR, control);

		rtc_update_irq(ds1374->rtc, 1, RTC_AF | RTC_IRQF);
	}

out:
	if (!ds1374->exiting)
		enable_irq(client->irq);
unlock:
	mutex_unlock(&ds1374->mutex);
}

static int ds1374_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct ds1374 *ds1374 = i2c_get_clientdata(client);
	int ret = -ENOIOCTLCMD;

	mutex_lock(&ds1374->mutex);

	switch (cmd) {
	case RTC_AIE_OFF:
		ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
		if (ret < 0)
			goto out;

		ret &= ~DS1374_REG_CR_WACE;

		ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, ret);
		if (ret < 0)
			goto out;

		break;

	case RTC_AIE_ON:
		ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
		if (ret < 0)
			goto out;

		ret |= DS1374_REG_CR_WACE | DS1374_REG_CR_AIE;
		ret &= ~DS1374_REG_CR_WDALM;

		ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, ret);
		if (ret < 0)
			goto out;

		break;
	}

out:
	mutex_unlock(&ds1374->mutex);
	return ret;
}

static const struct rtc_class_ops ds1374_rtc_ops = {
	.read_time = ds1374_read_time,
	.set_time = ds1374_set_time,
	.read_alarm = ds1374_read_alarm,
	.set_alarm = ds1374_set_alarm,
	.ioctl = ds1374_ioctl,
};

static int ds1374_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	struct ds1374 *ds1374;
	int ret;

	ds1374 = kzalloc(sizeof(struct ds1374), GFP_KERNEL);
	if (!ds1374)
		return -ENOMEM;

	ds1374->client = client;
	i2c_set_clientdata(client, ds1374);

	INIT_WORK(&ds1374->work, ds1374_work);
	mutex_init(&ds1374->mutex);

	ret = ds1374_check_rtc_status(client);
	if (ret)
		goto out_free;

	if (client->irq > 0) {
		ret = request_irq(client->irq, ds1374_irq, 0,
		                  "ds1374", client);
		if (ret) {
			dev_err(&client->dev, "unable to request IRQ\n");
			goto out_free;
		}

		device_set_wakeup_capable(&client->dev, 1);
	}

	ds1374->rtc = rtc_device_register(client->name, &client->dev,
	                                  &ds1374_rtc_ops, THIS_MODULE);
	if (IS_ERR(ds1374->rtc)) {
		ret = PTR_ERR(ds1374->rtc);
		dev_err(&client->dev, "unable to register the class device\n");
		goto out_irq;
	}

	return 0;

out_irq:
	if (client->irq > 0)
		free_irq(client->irq, client);

out_free:
	kfree(ds1374);
	return ret;
}

static int __devexit ds1374_remove(struct i2c_client *client)
{
	struct ds1374 *ds1374 = i2c_get_clientdata(client);

	if (client->irq > 0) {
		mutex_lock(&ds1374->mutex);
		ds1374->exiting = 1;
		mutex_unlock(&ds1374->mutex);

		free_irq(client->irq, client);
		flush_scheduled_work();
	}

	rtc_device_unregister(ds1374->rtc);
	kfree(ds1374);
	return 0;
}

#ifdef CONFIG_PM
static int ds1374_suspend(struct i2c_client *client, pm_message_t state)
{
	if (client->irq >= 0 && device_may_wakeup(&client->dev))
		enable_irq_wake(client->irq);
	return 0;
}

static int ds1374_resume(struct i2c_client *client)
{
	if (client->irq >= 0 && device_may_wakeup(&client->dev))
		disable_irq_wake(client->irq);
	return 0;
}
#else
#define ds1374_suspend	NULL
#define ds1374_resume	NULL
#endif

static struct i2c_driver ds1374_driver = {
	.driver = {
		.name = "rtc-ds1374",
		.owner = THIS_MODULE,
	},
	.probe = ds1374_probe,
	.suspend = ds1374_suspend,
	.resume = ds1374_resume,
	.remove = __devexit_p(ds1374_remove),
	.id_table = ds1374_id,
};

static int __init ds1374_init(void)
{
	return i2c_add_driver(&ds1374_driver);
}

static void __exit ds1374_exit(void)
{
	i2c_del_driver(&ds1374_driver);
}

module_init(ds1374_init);
module_exit(ds1374_exit);

MODULE_AUTHOR("Scott Wood <scottwood@freescale.com>");
MODULE_DESCRIPTION("Maxim/Dallas DS1374 RTC Driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
bf4994d7 SW	1	/*
	2	* RTC client/driver for the Maxim/Dallas DS1374 Real-Time Clock over I2C
	3	*
	4	* Based on code by Randy Vinson <rvinson@mvista.com>,
	5	* which was based on the m41t00.c by Mark Greer <mgreer@mvista.com>.
	6	*
	7	* Copyright (C) 2006-2007 Freescale Semiconductor
	8	*
	9	* 2005 (c) MontaVista Software, Inc. This file is licensed under
	10	* the terms of the GNU General Public License version 2. This program
	11	* is licensed "as is" without any warranty of any kind, whether express
	12	* or implied.
	13	*/
	14	/*
	15	* It would be more efficient to use i2c msgs/i2c_transfer directly but, as
	16	* recommened in .../Documentation/i2c/writing-clients section
	17	* "Sending and receiving", using SMBus level communication is preferred.
	18	*/
	19
	20	#include <linux/kernel.h>
	21	#include <linux/module.h>
	22	#include <linux/interrupt.h>
	23	#include <linux/i2c.h>
	24	#include <linux/rtc.h>
	25	#include <linux/bcd.h>
	26	#include <linux/workqueue.h>
5a0e3ad6	27	#include <linux/slab.h>
bf4994d7 SW	28
	29	#define DS1374_REG_TOD0 0x00 /* Time of Day */
	30	#define DS1374_REG_TOD1 0x01
	31	#define DS1374_REG_TOD2 0x02
	32	#define DS1374_REG_TOD3 0x03
	33	#define DS1374_REG_WDALM0 0x04 /* Watchdog/Alarm */
	34	#define DS1374_REG_WDALM1 0x05
	35	#define DS1374_REG_WDALM2 0x06
	36	#define DS1374_REG_CR 0x07 /* Control */
	37	#define DS1374_REG_CR_AIE 0x01 /* Alarm Int. Enable */
	38	#define DS1374_REG_CR_WDALM 0x20 /* 1=Watchdog, 0=Alarm */
	39	#define DS1374_REG_CR_WACE 0x40 /* WD/Alarm counter enable */
	40	#define DS1374_REG_SR 0x08 /* Status */
	41	#define DS1374_REG_SR_OSF 0x80 /* Oscillator Stop Flag */
	42	#define DS1374_REG_SR_AF 0x01 /* Alarm Flag */
	43	#define DS1374_REG_TCR 0x09 /* Trickle Charge */
	44
3760f736	45	static const struct i2c_device_id ds1374_id[] = {
f2eb4327	46	{ "ds1374", 0 },
3760f736 JD	47	{ }
	48	};
	49	MODULE_DEVICE_TABLE(i2c, ds1374_id);
	50
bf4994d7 SW	51	struct ds1374 {
	52	struct i2c_client *client;
	53	struct rtc_device *rtc;
	54	struct work_struct work;
	55
	56	/* The mutex protects alarm operations, and prevents a race
	57	* between the enable_irq() in the workqueue and the free_irq()
	58	* in the remove function.
	59	*/
	60	struct mutex mutex;
	61	int exiting;
	62	};
	63
	64	static struct i2c_driver ds1374_driver;
	65
	66	static int ds1374_read_rtc(struct i2c_client client, u32 time,
	67	int reg, int nbytes)
	68	{
	69	u8 buf[4];
	70	int ret;
	71	int i;
	72
	73	if (nbytes > 4) {
	74	WARN_ON(1);
	75	return -EINVAL;
	76	}
	77
	78	ret = i2c_smbus_read_i2c_block_data(client, reg, nbytes, buf);
	79
	80	if (ret < 0)
	81	return ret;
	82	if (ret < nbytes)
	83	return -EIO;
	84
	85	for (i = nbytes - 1, *time = 0; i >= 0; i--)
	86	time = (time << 8) \| buf[i];
	87
	88	return 0;
	89	}
	90
	91	static int ds1374_write_rtc(struct i2c_client *client, u32 time,
	92	int reg, int nbytes)
	93	{
	94	u8 buf[4];
	95	int i;
	96
	97	if (nbytes > 4) {
	98	WARN_ON(1);
	99	return -EINVAL;
	100	}
	101
	102	for (i = 0; i < nbytes; i++) {
	103	buf[i] = time & 0xff;
	104	time >>= 8;
	105	}
	106
	107	return i2c_smbus_write_i2c_block_data(client, reg, nbytes, buf);
	108	}
	109
	110	static int ds1374_check_rtc_status(struct i2c_client *client)
	111	{
	112	int ret = 0;
	113	int control, stat;
	114
115	stat = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
116	if (stat < 0)
117	return stat;
118
119	if (stat & DS1374_REG_SR_OSF)
120	dev_warn(&client->dev,
121	"oscillator discontinuity flagged, "
122	"time unreliable\n");
123
124	stat &= ~(DS1374_REG_SR_OSF \| DS1374_REG_SR_AF);
125
126	ret = i2c_smbus_write_byte_data(client, DS1374_REG_SR, stat);
127	if (ret < 0)
128	return ret;
129
130	/* If the alarm is pending, clear it before requesting
131	* the interrupt, so an interrupt event isn't reported
132	* before everything is initialized.
133	*/
134
135	control = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
136	if (control < 0)
137	return control;
138
139	control &= ~(DS1374_REG_CR_WACE \| DS1374_REG_CR_AIE);
140	return i2c_smbus_write_byte_data(client, DS1374_REG_CR, control);
141	}
142
143	static int ds1374_read_time(struct device dev, struct rtc_time time)
144	{
145	struct i2c_client *client = to_i2c_client(dev);
146	u32 itime;
147	int ret;
148
149	ret = ds1374_read_rtc(client, &itime, DS1374_REG_TOD0, 4);
150	if (!ret)
151	rtc_time_to_tm(itime, time);
152
153	return ret;
154	}
155
156	static int ds1374_set_time(struct device dev, struct rtc_time time)
157	{
158	struct i2c_client *client = to_i2c_client(dev);
159	unsigned long itime;
160
161	rtc_tm_to_time(time, &itime);
162	return ds1374_write_rtc(client, itime, DS1374_REG_TOD0, 4);
163	}
164
165	/* The ds1374 has a decrementer for an alarm, rather than a comparator.
166	* If the time of day is changed, then the alarm will need to be
167	* reset.
168	*/
169	static int ds1374_read_alarm(struct device dev, struct rtc_wkalrm alarm)
170	{
171	struct i2c_client *client = to_i2c_client(dev);
172	struct ds1374 *ds1374 = i2c_get_clientdata(client);
173	u32 now, cur_alarm;
174	int cr, sr;
175	int ret = 0;
176
b42f9317	177	if (client->irq <= 0)
bf4994d7 SW	178	return -EINVAL;
	179
	180	mutex_lock(&ds1374->mutex);
	181
	182	cr = ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
	183	if (ret < 0)
	184	goto out;
	185
	186	sr = ret = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
	187	if (ret < 0)
	188	goto out;
	189
	190	ret = ds1374_read_rtc(client, &now, DS1374_REG_TOD0, 4);
	191	if (ret)
	192	goto out;
	193
	194	ret = ds1374_read_rtc(client, &cur_alarm, DS1374_REG_WDALM0, 3);
	195	if (ret)
	196	goto out;
	197
	198	rtc_time_to_tm(now + cur_alarm, &alarm->time);
	199	alarm->enabled = !!(cr & DS1374_REG_CR_WACE);
	200	alarm->pending = !!(sr & DS1374_REG_SR_AF);
	201
	202	out:
	203	mutex_unlock(&ds1374->mutex);
	204	return ret;
	205	}
	206
	207	static int ds1374_set_alarm(struct device dev, struct rtc_wkalrm alarm)
	208	{
	209	struct i2c_client *client = to_i2c_client(dev);
	210	struct ds1374 *ds1374 = i2c_get_clientdata(client);
	211	struct rtc_time now;
	212	unsigned long new_alarm, itime;
	213	int cr;
	214	int ret = 0;
	215
b42f9317	216	if (client->irq <= 0)
bf4994d7 SW	217	return -EINVAL;
	218
	219	ret = ds1374_read_time(dev, &now);
	220	if (ret < 0)
	221	return ret;
	222
	223	rtc_tm_to_time(&alarm->time, &new_alarm);
	224	rtc_tm_to_time(&now, &itime);
	225
bf4994d7 SW	226	/* This can happen due to races, in addition to dates that are
	227	* truly in the past. To avoid requiring the caller to check for
	228	* races, dates in the past are assumed to be in the recent past
	229	* (i.e. not something that we'd rather the caller know about via
	230	* an error), and the alarm is set to go off as soon as possible.
	231	*/
fa7af8b1	232	if (time_before_eq(new_alarm, itime))
bf4994d7	233	new_alarm = 1;
fa7af8b1 RK	234	else
fa7af8b1 RK	235	new_alarm -= itime;
bf4994d7 SW	236
	237	mutex_lock(&ds1374->mutex);
	238
	239	ret = cr = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
	240	if (ret < 0)
	241	goto out;
	242
	243	/* Disable any existing alarm before setting the new one
	244	* (or lack thereof). */
	245	cr &= ~DS1374_REG_CR_WACE;
	246
	247	ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
	248	if (ret < 0)
	249	goto out;
	250
	251	ret = ds1374_write_rtc(client, new_alarm, DS1374_REG_WDALM0, 3);
	252	if (ret)
	253	goto out;
	254
	255	if (alarm->enabled) {
	256	cr \|= DS1374_REG_CR_WACE \| DS1374_REG_CR_AIE;
	257	cr &= ~DS1374_REG_CR_WDALM;
	258
	259	ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
	260	}
	261
	262	out:
	263	mutex_unlock(&ds1374->mutex);
	264	return ret;
	265	}
	266
	267	static irqreturn_t ds1374_irq(int irq, void *dev_id)
	268	{
	269	struct i2c_client *client = dev_id;
	270	struct ds1374 *ds1374 = i2c_get_clientdata(client);
	271
	272	disable_irq_nosync(irq);
	273	schedule_work(&ds1374->work);
	274	return IRQ_HANDLED;
	275	}
	276
	277	static void ds1374_work(struct work_struct *work)
	278	{
	279	struct ds1374 *ds1374 = container_of(work, struct ds1374, work);
	280	struct i2c_client *client = ds1374->client;
	281	int stat, control;
	282
	283	mutex_lock(&ds1374->mutex);
	284
	285	stat = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
	286	if (stat < 0)
28df30e6	287	goto unlock;
bf4994d7 SW	288
	289	if (stat & DS1374_REG_SR_AF) {
	290	stat &= ~DS1374_REG_SR_AF;
	291	i2c_smbus_write_byte_data(client, DS1374_REG_SR, stat);
	292
	293	control = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
	294	if (control < 0)
	295	goto out;
	296
	297	control &= ~(DS1374_REG_CR_WACE \| DS1374_REG_CR_AIE);
	298	i2c_smbus_write_byte_data(client, DS1374_REG_CR, control);
	299
bf4994d7	300	rtc_update_irq(ds1374->rtc, 1, RTC_AF \| RTC_IRQF);
bf4994d7 SW	301	}
	302
	303	out:
	304	if (!ds1374->exiting)
	305	enable_irq(client->irq);
28df30e6	306	unlock:
bf4994d7 SW	307	mutex_unlock(&ds1374->mutex);
	308	}
	309
	310	static int ds1374_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
	311	{
	312	struct i2c_client *client = to_i2c_client(dev);
	313	struct ds1374 *ds1374 = i2c_get_clientdata(client);
	314	int ret = -ENOIOCTLCMD;
	315
	316	mutex_lock(&ds1374->mutex);
	317
	318	switch (cmd) {
	319	case RTC_AIE_OFF:
	320	ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
	321	if (ret < 0)
	322	goto out;
	323
	324	ret &= ~DS1374_REG_CR_WACE;
	325
	326	ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, ret);
	327	if (ret < 0)
	328	goto out;
	329
	330	break;
	331
	332	case RTC_AIE_ON:
	333	ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
	334	if (ret < 0)
	335	goto out;
	336
	337	ret \|= DS1374_REG_CR_WACE \| DS1374_REG_CR_AIE;
	338	ret &= ~DS1374_REG_CR_WDALM;
	339
	340	ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, ret);
	341	if (ret < 0)
	342	goto out;
	343
	344	break;
	345	}
	346
	347	out:
	348	mutex_unlock(&ds1374->mutex);
	349	return ret;
	350	}
	351
	352	static const struct rtc_class_ops ds1374_rtc_ops = {
	353	.read_time = ds1374_read_time,
	354	.set_time = ds1374_set_time,
	355	.read_alarm = ds1374_read_alarm,
	356	.set_alarm = ds1374_set_alarm,
	357	.ioctl = ds1374_ioctl,
	358	};
	359
d2653e92 JD	360	static int ds1374_probe(struct i2c_client *client,
d2653e92 JD	361	const struct i2c_device_id *id)
bf4994d7 SW	362	{
	363	struct ds1374 *ds1374;
	364	int ret;
	365
	366	ds1374 = kzalloc(sizeof(struct ds1374), GFP_KERNEL);
	367	if (!ds1374)
	368	return -ENOMEM;
	369
	370	ds1374->client = client;
	371	i2c_set_clientdata(client, ds1374);
	372
	373	INIT_WORK(&ds1374->work, ds1374_work);
	374	mutex_init(&ds1374->mutex);
	375
	376	ret = ds1374_check_rtc_status(client);
	377	if (ret)
	378	goto out_free;
	379
b42f9317	380	if (client->irq > 0) {
bf4994d7 SW	381	ret = request_irq(client->irq, ds1374_irq, 0,
	382	"ds1374", client);
	383	if (ret) {
	384	dev_err(&client->dev, "unable to request IRQ\n");
	385	goto out_free;
	386	}
26b3c01f AV	387
26b3c01f AV	388	device_set_wakeup_capable(&client->dev, 1);
bf4994d7 SW	389	}
	390
	391	ds1374->rtc = rtc_device_register(client->name, &client->dev,
	392	&ds1374_rtc_ops, THIS_MODULE);
	393	if (IS_ERR(ds1374->rtc)) {
	394	ret = PTR_ERR(ds1374->rtc);
	395	dev_err(&client->dev, "unable to register the class device\n");
	396	goto out_irq;
	397	}
	398
	399	return 0;
	400
	401	out_irq:
b42f9317	402	if (client->irq > 0)
bf4994d7 SW	403	free_irq(client->irq, client);
	404
	405	out_free:
bf4994d7 SW	406	kfree(ds1374);
	407	return ret;
	408	}
	409
	410	static int __devexit ds1374_remove(struct i2c_client *client)
	411	{
	412	struct ds1374 *ds1374 = i2c_get_clientdata(client);
	413
b42f9317	414	if (client->irq > 0) {
bf4994d7 SW	415	mutex_lock(&ds1374->mutex);
	416	ds1374->exiting = 1;
	417	mutex_unlock(&ds1374->mutex);
	418
	419	free_irq(client->irq, client);
	420	flush_scheduled_work();
	421	}
	422
	423	rtc_device_unregister(ds1374->rtc);
bf4994d7 SW	424	kfree(ds1374);
	425	return 0;
	426	}
	427
986e36a5 MP	428	#ifdef CONFIG_PM
	429	static int ds1374_suspend(struct i2c_client *client, pm_message_t state)
	430	{
	431	if (client->irq >= 0 && device_may_wakeup(&client->dev))
	432	enable_irq_wake(client->irq);
	433	return 0;
	434	}
	435
	436	static int ds1374_resume(struct i2c_client *client)
	437	{
	438	if (client->irq >= 0 && device_may_wakeup(&client->dev))
	439	disable_irq_wake(client->irq);
	440	return 0;
	441	}
	442	#else
	443	#define ds1374_suspend NULL
	444	#define ds1374_resume NULL
	445	#endif
	446
bf4994d7 SW	447	static struct i2c_driver ds1374_driver = {
	448	.driver = {
	449	.name = "rtc-ds1374",
	450	.owner = THIS_MODULE,
	451	},
	452	.probe = ds1374_probe,
986e36a5 MP	453	.suspend = ds1374_suspend,
986e36a5 MP	454	.resume = ds1374_resume,
bf4994d7	455	.remove = __devexit_p(ds1374_remove),
3760f736	456	.id_table = ds1374_id,
bf4994d7 SW	457	};
	458
	459	static int __init ds1374_init(void)
	460	{
	461	return i2c_add_driver(&ds1374_driver);
	462	}
	463
	464	static void __exit ds1374_exit(void)
	465	{
	466	i2c_del_driver(&ds1374_driver);
	467	}
	468
	469	module_init(ds1374_init);
	470	module_exit(ds1374_exit);
	471
	472	MODULE_AUTHOR("Scott Wood <scottwood@freescale.com>");
	473	MODULE_DESCRIPTION("Maxim/Dallas DS1374 RTC Driver");
	474	MODULE_LICENSE("GPL");