[deliverable/linux.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>

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