[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>
#include <linux/slab.h>
#include <linux/pm.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_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct ds1374 *ds1374 = i2c_get_clientdata(client);
	int ret;

	mutex_lock(&ds1374->mutex);

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

	if (enabled) {
		ret |= DS1374_REG_CR_WACE | DS1374_REG_CR_AIE;
		ret &= ~DS1374_REG_CR_WDALM;
	} else {
		ret &= ~DS1374_REG_CR_WACE;
	}
	ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, ret);

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,
	.alarm_irq_enable = ds1374_alarm_irq_enable,
};

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

	ds1374 = devm_kzalloc(&client->dev, 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)
		return ret;

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

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

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

	return 0;
}

static int 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);

		devm_free_irq(&client->dev, client->irq, client);
		cancel_work_sync(&ds1374->work);
	}

	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int ds1374_suspend(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);

	if (client->irq >= 0 && device_may_wakeup(&client->dev))
		enable_irq_wake(client->irq);
	return 0;
}

static int ds1374_resume(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);

	if (client->irq >= 0 && device_may_wakeup(&client->dev))
		disable_irq_wake(client->irq);
	return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(ds1374_pm, ds1374_suspend, ds1374_resume);

static struct i2c_driver ds1374_driver = {
	.driver = {
		.name = "rtc-ds1374",
		.owner = THIS_MODULE,
		.pm = &ds1374_pm,
	},
	.probe = ds1374_probe,
	.remove = ds1374_remove,
	.id_table = ds1374_id,
};

module_i2c_driver(ds1374_driver);

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>
bc96ba74	28	#include <linux/pm.h>
bf4994d7 SW	29
	30	#define DS1374_REG_TOD0 0x00 /* Time of Day */
	31	#define DS1374_REG_TOD1 0x01
	32	#define DS1374_REG_TOD2 0x02
	33	#define DS1374_REG_TOD3 0x03
	34	#define DS1374_REG_WDALM0 0x04 /* Watchdog/Alarm */
	35	#define DS1374_REG_WDALM1 0x05
	36	#define DS1374_REG_WDALM2 0x06
	37	#define DS1374_REG_CR 0x07 /* Control */
	38	#define DS1374_REG_CR_AIE 0x01 /* Alarm Int. Enable */
	39	#define DS1374_REG_CR_WDALM 0x20 /* 1=Watchdog, 0=Alarm */
	40	#define DS1374_REG_CR_WACE 0x40 /* WD/Alarm counter enable */
	41	#define DS1374_REG_SR 0x08 /* Status */
	42	#define DS1374_REG_SR_OSF 0x80 /* Oscillator Stop Flag */
	43	#define DS1374_REG_SR_AF 0x01 /* Alarm Flag */
	44	#define DS1374_REG_TCR 0x09 /* Trickle Charge */
	45
3760f736	46	static const struct i2c_device_id ds1374_id[] = {
f2eb4327	47	{ "ds1374", 0 },
3760f736 JD	48	{ }
	49	};
	50	MODULE_DEVICE_TABLE(i2c, ds1374_id);
	51
bf4994d7 SW	52	struct ds1374 {
	53	struct i2c_client *client;
	54	struct rtc_device *rtc;
	55	struct work_struct work;
	56
	57	/* The mutex protects alarm operations, and prevents a race
	58	* between the enable_irq() in the workqueue and the free_irq()
	59	* in the remove function.
	60	*/
	61	struct mutex mutex;
	62	int exiting;
	63	};
	64
	65	static struct i2c_driver ds1374_driver;
	66
	67	static int ds1374_read_rtc(struct i2c_client client, u32 time,
adc7b9b6	68	int reg, int nbytes)
bf4994d7 SW	69	{
	70	u8 buf[4];
	71	int ret;
	72	int i;
	73
	74	if (nbytes > 4) {
	75	WARN_ON(1);
	76	return -EINVAL;
	77	}
	78
	79	ret = i2c_smbus_read_i2c_block_data(client, reg, nbytes, buf);
	80
	81	if (ret < 0)
	82	return ret;
	83	if (ret < nbytes)
	84	return -EIO;
	85
	86	for (i = nbytes - 1, *time = 0; i >= 0; i--)
	87	time = (time << 8) \| buf[i];
	88
	89	return 0;
	90	}
	91
	92	static int ds1374_write_rtc(struct i2c_client *client, u32 time,
adc7b9b6	93	int reg, int nbytes)
bf4994d7 SW	94	{
	95	u8 buf[4];
	96	int i;
	97
	98	if (nbytes > 4) {
	99	WARN_ON(1);
	100	return -EINVAL;
	101	}
	102
	103	for (i = 0; i < nbytes; i++) {
	104	buf[i] = time & 0xff;
	105	time >>= 8;
	106	}
	107
	108	return i2c_smbus_write_i2c_block_data(client, reg, nbytes, buf);
	109	}
	110
	111	static int ds1374_check_rtc_status(struct i2c_client *client)
	112	{
	113	int ret = 0;
	114	int control, stat;
	115
	116	stat = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
	117	if (stat < 0)
	118	return stat;
	119
	120	if (stat & DS1374_REG_SR_OSF)
	121	dev_warn(&client->dev,
adc7b9b6	122	"oscillator discontinuity flagged, time unreliable\n");
bf4994d7 SW	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
16380c15	310	static int ds1374_alarm_irq_enable(struct device *dev, unsigned int enabled)
bf4994d7 SW	311	{
	312	struct i2c_client *client = to_i2c_client(dev);
	313	struct ds1374 *ds1374 = i2c_get_clientdata(client);
16380c15	314	int ret;
bf4994d7 SW	315
	316	mutex_lock(&ds1374->mutex);
	317
16380c15 JS	318	ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
	319	if (ret < 0)
	320	goto out;
bf4994d7	321
16380c15	322	if (enabled) {
bf4994d7 SW	323	ret \|= DS1374_REG_CR_WACE \| DS1374_REG_CR_AIE;
bf4994d7 SW	324	ret &= ~DS1374_REG_CR_WDALM;
16380c15 JS	325	} else {
16380c15 JS	326	ret &= ~DS1374_REG_CR_WACE;
bf4994d7	327	}
16380c15	328	ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, ret);
bf4994d7 SW	329
	330	out:
	331	mutex_unlock(&ds1374->mutex);
	332	return ret;
	333	}
	334
	335	static const struct rtc_class_ops ds1374_rtc_ops = {
	336	.read_time = ds1374_read_time,
	337	.set_time = ds1374_set_time,
	338	.read_alarm = ds1374_read_alarm,
	339	.set_alarm = ds1374_set_alarm,
16380c15	340	.alarm_irq_enable = ds1374_alarm_irq_enable,
bf4994d7 SW	341	};
bf4994d7 SW	342
d2653e92 JD	343	static int ds1374_probe(struct i2c_client *client,
d2653e92 JD	344	const struct i2c_device_id *id)
bf4994d7 SW	345	{
	346	struct ds1374 *ds1374;
	347	int ret;
	348
d1a96639	349	ds1374 = devm_kzalloc(&client->dev, sizeof(struct ds1374), GFP_KERNEL);
bf4994d7 SW	350	if (!ds1374)
	351	return -ENOMEM;
	352
	353	ds1374->client = client;
	354	i2c_set_clientdata(client, ds1374);
	355
	356	INIT_WORK(&ds1374->work, ds1374_work);
	357	mutex_init(&ds1374->mutex);
	358
	359	ret = ds1374_check_rtc_status(client);
	360	if (ret)
d1a96639	361	return ret;
bf4994d7	362
b42f9317	363	if (client->irq > 0) {
d1a96639	364	ret = devm_request_irq(&client->dev, client->irq, ds1374_irq, 0,
adc7b9b6	365	"ds1374", client);
bf4994d7 SW	366	if (ret) {
bf4994d7 SW	367	dev_err(&client->dev, "unable to request IRQ\n");
d1a96639	368	return ret;
bf4994d7	369	}
26b3c01f AV	370
26b3c01f AV	371	device_set_wakeup_capable(&client->dev, 1);
bf4994d7 SW	372	}
bf4994d7 SW	373
d1a96639	374	ds1374->rtc = devm_rtc_device_register(&client->dev, client->name,
adc7b9b6	375	&ds1374_rtc_ops, THIS_MODULE);
bf4994d7	376	if (IS_ERR(ds1374->rtc)) {
bf4994d7	377	dev_err(&client->dev, "unable to register the class device\n");
d1a96639	378	return PTR_ERR(ds1374->rtc);
bf4994d7 SW	379	}
	380
	381	return 0;
bf4994d7 SW	382	}
bf4994d7 SW	383
5a167f45	384	static int ds1374_remove(struct i2c_client *client)
bf4994d7 SW	385	{
	386	struct ds1374 *ds1374 = i2c_get_clientdata(client);
	387
b42f9317	388	if (client->irq > 0) {
bf4994d7 SW	389	mutex_lock(&ds1374->mutex);
	390	ds1374->exiting = 1;
	391	mutex_unlock(&ds1374->mutex);
	392
d1a96639	393	devm_free_irq(&client->dev, client->irq, client);
9db8995b	394	cancel_work_sync(&ds1374->work);
bf4994d7 SW	395	}
bf4994d7 SW	396
bf4994d7 SW	397	return 0;
	398	}
	399
8b80ef64	400	#ifdef CONFIG_PM_SLEEP
bc96ba74	401	static int ds1374_suspend(struct device *dev)
986e36a5	402	{
bc96ba74 MB	403	struct i2c_client *client = to_i2c_client(dev);
bc96ba74 MB	404
986e36a5 MP	405	if (client->irq >= 0 && device_may_wakeup(&client->dev))
	406	enable_irq_wake(client->irq);
	407	return 0;
	408	}
	409
bc96ba74	410	static int ds1374_resume(struct device *dev)
986e36a5	411	{
bc96ba74 MB	412	struct i2c_client *client = to_i2c_client(dev);
bc96ba74 MB	413
986e36a5 MP	414	if (client->irq >= 0 && device_may_wakeup(&client->dev))
	415	disable_irq_wake(client->irq);
	416	return 0;
	417	}
8b80ef64	418	#endif
bc96ba74 MB	419
	420	static SIMPLE_DEV_PM_OPS(ds1374_pm, ds1374_suspend, ds1374_resume);
	421
bf4994d7 SW	422	static struct i2c_driver ds1374_driver = {
	423	.driver = {
	424	.name = "rtc-ds1374",
	425	.owner = THIS_MODULE,
8b80ef64	426	.pm = &ds1374_pm,
bf4994d7 SW	427	},
bf4994d7 SW	428	.probe = ds1374_probe,
5a167f45	429	.remove = ds1374_remove,
3760f736	430	.id_table = ds1374_id,
bf4994d7 SW	431	};
bf4994d7 SW	432
0abc9201	433	module_i2c_driver(ds1374_driver);
bf4994d7 SW	434
	435	MODULE_AUTHOR("Scott Wood <scottwood@freescale.com>");
	436	MODULE_DESCRIPTION("Maxim/Dallas DS1374 RTC Driver");
	437	MODULE_LICENSE("GPL");