[linux.git] / drivers / rtc / rtc-ds3232.c

/*
 * RTC client/driver for the Maxim/Dallas DS3232 Real-Time Clock over I2C
 *
 * Copyright (C) 2009-2011 Freescale Semiconductor.
 * Author: Jack Lan <[email protected]>
 *
 * This program is free software; you can redistribute  it and/or modify it
 * under  the terms of  the GNU General  Public License as published by the
 * Free Software Foundation;  either version 2 of the  License, or (at your
 * option) any later version.
 */
/*
 * 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 DS3232_REG_SECONDS	0x00
#define DS3232_REG_MINUTES	0x01
#define DS3232_REG_HOURS	0x02
#define DS3232_REG_AMPM		0x02
#define DS3232_REG_DAY		0x03
#define DS3232_REG_DATE		0x04
#define DS3232_REG_MONTH	0x05
#define DS3232_REG_CENTURY	0x05
#define DS3232_REG_YEAR		0x06
#define DS3232_REG_ALARM1         0x07	/* Alarm 1 BASE */
#define DS3232_REG_ALARM2         0x0B	/* Alarm 2 BASE */
#define DS3232_REG_CR		0x0E	/* Control register */
#	define DS3232_REG_CR_nEOSC        0x80
#       define DS3232_REG_CR_INTCN        0x04
#       define DS3232_REG_CR_A2IE        0x02
#       define DS3232_REG_CR_A1IE        0x01

#define DS3232_REG_SR	0x0F	/* control/status register */
#	define DS3232_REG_SR_OSF   0x80
#       define DS3232_REG_SR_BSY   0x04
#       define DS3232_REG_SR_A2F   0x02
#       define DS3232_REG_SR_A1F   0x01

struct ds3232 {
	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 ds3232_driver;

static int ds3232_check_rtc_status(struct i2c_client *client)
{
	int ret = 0;
	int control, stat;

	stat = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
	if (stat < 0)
		return stat;

	if (stat & DS3232_REG_SR_OSF)
		dev_warn(&client->dev,
				"oscillator discontinuity flagged, "
				"time unreliable\n");

	stat &= ~(DS3232_REG_SR_OSF | DS3232_REG_SR_A1F | DS3232_REG_SR_A2F);

	ret = i2c_smbus_write_byte_data(client, DS3232_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, DS3232_REG_CR);
	if (control < 0)
		return control;

	control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE);
	control |= DS3232_REG_CR_INTCN;

	return i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
}

static int ds3232_read_time(struct device *dev, struct rtc_time *time)
{
	struct i2c_client *client = to_i2c_client(dev);
	int ret;
	u8 buf[7];
	unsigned int year, month, day, hour, minute, second;
	unsigned int week, twelve_hr, am_pm;
	unsigned int century, add_century = 0;

	ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_SECONDS, 7, buf);

	if (ret < 0)
		return ret;
	if (ret < 7)
		return -EIO;

	second = buf[0];
	minute = buf[1];
	hour = buf[2];
	week = buf[3];
	day = buf[4];
	month = buf[5];
	year = buf[6];

	/* Extract additional information for AM/PM and century */

	twelve_hr = hour & 0x40;
	am_pm = hour & 0x20;
	century = month & 0x80;

	/* Write to rtc_time structure */

	time->tm_sec = bcd2bin(second);
	time->tm_min = bcd2bin(minute);
	if (twelve_hr) {
		/* Convert to 24 hr */
		if (am_pm)
			time->tm_hour = bcd2bin(hour & 0x1F) + 12;
		else
			time->tm_hour = bcd2bin(hour & 0x1F);
	} else {
		time->tm_hour = bcd2bin(hour);
	}

	/* Day of the week in linux range is 0~6 while 1~7 in RTC chip */
	time->tm_wday = bcd2bin(week) - 1;
	time->tm_mday = bcd2bin(day);
	/* linux tm_mon range:0~11, while month range is 1~12 in RTC chip */
	time->tm_mon = bcd2bin(month & 0x7F) - 1;
	if (century)
		add_century = 100;

	time->tm_year = bcd2bin(year) + add_century;

	return rtc_valid_tm(time);
}

static int ds3232_set_time(struct device *dev, struct rtc_time *time)
{
	struct i2c_client *client = to_i2c_client(dev);
	u8 buf[7];

	/* Extract time from rtc_time and load into ds3232*/

	buf[0] = bin2bcd(time->tm_sec);
	buf[1] = bin2bcd(time->tm_min);
	buf[2] = bin2bcd(time->tm_hour);
	/* Day of the week in linux range is 0~6 while 1~7 in RTC chip */
	buf[3] = bin2bcd(time->tm_wday + 1);
	buf[4] = bin2bcd(time->tm_mday); /* Date */
	/* linux tm_mon range:0~11, while month range is 1~12 in RTC chip */
	buf[5] = bin2bcd(time->tm_mon + 1);
	if (time->tm_year >= 100) {
		buf[5] |= 0x80;
		buf[6] = bin2bcd(time->tm_year - 100);
	} else {
		buf[6] = bin2bcd(time->tm_year);
	}

	return i2c_smbus_write_i2c_block_data(client,
					      DS3232_REG_SECONDS, 7, buf);
}

/*
 * DS3232 has two alarm, we only use alarm1
 * According to linux specification, only support one-shot alarm
 * no periodic alarm mode
 */
static int ds3232_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct ds3232 *ds3232 = i2c_get_clientdata(client);
	int control, stat;
	int ret;
	u8 buf[4];

	mutex_lock(&ds3232->mutex);

	ret = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
	if (ret < 0)
		goto out;
	stat = ret;
	ret = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
	if (ret < 0)
		goto out;
	control = ret;
	ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf);
	if (ret < 0)
		goto out;

	alarm->time.tm_sec = bcd2bin(buf[0] & 0x7F);
	alarm->time.tm_min = bcd2bin(buf[1] & 0x7F);
	alarm->time.tm_hour = bcd2bin(buf[2] & 0x7F);
	alarm->time.tm_mday = bcd2bin(buf[3] & 0x7F);

	alarm->time.tm_mon = -1;
	alarm->time.tm_year = -1;
	alarm->time.tm_wday = -1;
	alarm->time.tm_yday = -1;
	alarm->time.tm_isdst = -1;

	alarm->enabled = !!(control & DS3232_REG_CR_A1IE);
	alarm->pending = !!(stat & DS3232_REG_SR_A1F);

	ret = 0;
out:
	mutex_unlock(&ds3232->mutex);
	return ret;
}

/*
 * linux rtc-module does not support wday alarm
 * and only 24h time mode supported indeed
 */
static int ds3232_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct ds3232 *ds3232 = i2c_get_clientdata(client);
	int control, stat;
	int ret;
	u8 buf[4];

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

	mutex_lock(&ds3232->mutex);

	buf[0] = bin2bcd(alarm->time.tm_sec);
	buf[1] = bin2bcd(alarm->time.tm_min);
	buf[2] = bin2bcd(alarm->time.tm_hour);
	buf[3] = bin2bcd(alarm->time.tm_mday);

	/* clear alarm interrupt enable bit */
	ret = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
	if (ret < 0)
		goto out;
	control = ret;
	control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE);
	ret = i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
	if (ret < 0)
		goto out;

	/* clear any pending alarm flag */
	ret = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
	if (ret < 0)
		goto out;
	stat = ret;
	stat &= ~(DS3232_REG_SR_A1F | DS3232_REG_SR_A2F);
	ret = i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat);
	if (ret < 0)
		goto out;

	ret = i2c_smbus_write_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf);

	if (alarm->enabled) {
		control |= DS3232_REG_CR_A1IE;
		ret = i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
	}
out:
	mutex_unlock(&ds3232->mutex);
	return ret;
}

static void ds3232_update_alarm(struct i2c_client *client)
{
	struct ds3232 *ds3232 = i2c_get_clientdata(client);
	int control;
	int ret;
	u8 buf[4];

	mutex_lock(&ds3232->mutex);

	ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf);
	if (ret < 0)
		goto unlock;

	buf[0] = bcd2bin(buf[0]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ?
								0x80 : buf[0];
	buf[1] = bcd2bin(buf[1]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ?
								0x80 : buf[1];
	buf[2] = bcd2bin(buf[2]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ?
								0x80 : buf[2];
	buf[3] = bcd2bin(buf[3]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ?
								0x80 : buf[3];

	ret = i2c_smbus_write_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf);
	if (ret < 0)
		goto unlock;

	control = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
	if (control < 0)
		goto unlock;

	if (ds3232->rtc->irq_data & (RTC_AF | RTC_UF))
		/* enable alarm1 interrupt */
		control |= DS3232_REG_CR_A1IE;
	else
		/* disable alarm1 interrupt */
		control &= ~(DS3232_REG_CR_A1IE);
	i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);

unlock:
	mutex_unlock(&ds3232->mutex);
}

static int ds3232_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct ds3232 *ds3232 = i2c_get_clientdata(client);

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

	if (enabled)
		ds3232->rtc->irq_data |= RTC_AF;
	else
		ds3232->rtc->irq_data &= ~RTC_AF;

	ds3232_update_alarm(client);
	return 0;
}

static irqreturn_t ds3232_irq(int irq, void *dev_id)
{
	struct i2c_client *client = dev_id;
	struct ds3232 *ds3232 = i2c_get_clientdata(client);

	disable_irq_nosync(irq);
	schedule_work(&ds3232->work);
	return IRQ_HANDLED;
}

static void ds3232_work(struct work_struct *work)
{
	struct ds3232 *ds3232 = container_of(work, struct ds3232, work);
	struct i2c_client *client = ds3232->client;
	int stat, control;

	mutex_lock(&ds3232->mutex);

	stat = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
	if (stat < 0)
		goto unlock;

	if (stat & DS3232_REG_SR_A1F) {
		control = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
		if (control < 0)
			goto out;
		/* disable alarm1 interrupt */
		control &= ~(DS3232_REG_CR_A1IE);
		i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);

		/* clear the alarm pend flag */
		stat &= ~DS3232_REG_SR_A1F;
		i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat);

		rtc_update_irq(ds3232->rtc, 1, RTC_AF | RTC_IRQF);
	}

out:
	if (!ds3232->exiting)
		enable_irq(client->irq);
unlock:
	mutex_unlock(&ds3232->mutex);
}

static const struct rtc_class_ops ds3232_rtc_ops = {
	.read_time = ds3232_read_time,
	.set_time = ds3232_set_time,
	.read_alarm = ds3232_read_alarm,
	.set_alarm = ds3232_set_alarm,
	.alarm_irq_enable = ds3232_alarm_irq_enable,
};

static int ds3232_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	struct ds3232 *ds3232;
	int ret;

	ds3232 = devm_kzalloc(&client->dev, sizeof(struct ds3232), GFP_KERNEL);
	if (!ds3232)
		return -ENOMEM;

	ds3232->client = client;
	i2c_set_clientdata(client, ds3232);

	INIT_WORK(&ds3232->work, ds3232_work);
	mutex_init(&ds3232->mutex);

	ret = ds3232_check_rtc_status(client);
	if (ret)
		return ret;

	ds3232->rtc = devm_rtc_device_register(&client->dev, client->name,
					  &ds3232_rtc_ops, THIS_MODULE);
	if (IS_ERR(ds3232->rtc)) {
		return PTR_ERR(ds3232->rtc);
	}

	if (client->irq >= 0) {
		ret = devm_request_irq(&client->dev, client->irq, ds3232_irq,
				       IRQF_SHARED, "ds3232", client);
		if (ret) {
			dev_err(&client->dev, "unable to request IRQ\n");
		}
	}

	return 0;
}

static int ds3232_remove(struct i2c_client *client)
{
	struct ds3232 *ds3232 = i2c_get_clientdata(client);

	if (client->irq >= 0) {
		mutex_lock(&ds3232->mutex);
		ds3232->exiting = 1;
		mutex_unlock(&ds3232->mutex);

		devm_free_irq(&client->dev, client->irq, client);
		cancel_work_sync(&ds3232->work);
	}

	return 0;
}

static const struct i2c_device_id ds3232_id[] = {
	{ "ds3232", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, ds3232_id);

static struct i2c_driver ds3232_driver = {
	.driver = {
		.name = "rtc-ds3232",
		.owner = THIS_MODULE,
	},
	.probe = ds3232_probe,
	.remove = ds3232_remove,
	.id_table = ds3232_id,
};

module_i2c_driver(ds3232_driver);

MODULE_AUTHOR("Srikanth Srinivasan <[email protected]>");
MODULE_DESCRIPTION("Maxim/Dallas DS3232 RTC Driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
c03675f0 RZ	1	/*
	2	* RTC client/driver for the Maxim/Dallas DS3232 Real-Time Clock over I2C
	3	*
a2d6d2fa	4	* Copyright (C) 2009-2011 Freescale Semiconductor.
f46418c5	5	* Author: Jack Lan <[email protected]>
c03675f0 RZ	6	*
	7	* This program is free software; you can redistribute it and/or modify it
	8	* under the terms of the GNU General Public License as published by the
	9	* Free Software Foundation; either version 2 of the License, or (at your
	10	* option) any later version.
	11	*/
	12	/*
	13	* It would be more efficient to use i2c msgs/i2c_transfer directly but, as
	14	* recommened in .../Documentation/i2c/writing-clients section
	15	* "Sending and receiving", using SMBus level communication is preferred.
	16	*/
	17
	18	#include <linux/kernel.h>
	19	#include <linux/module.h>
	20	#include <linux/interrupt.h>
	21	#include <linux/i2c.h>
	22	#include <linux/rtc.h>
	23	#include <linux/bcd.h>
	24	#include <linux/workqueue.h>
	25	#include <linux/slab.h>
	26
	27	#define DS3232_REG_SECONDS 0x00
	28	#define DS3232_REG_MINUTES 0x01
	29	#define DS3232_REG_HOURS 0x02
	30	#define DS3232_REG_AMPM 0x02
	31	#define DS3232_REG_DAY 0x03
	32	#define DS3232_REG_DATE 0x04
	33	#define DS3232_REG_MONTH 0x05
	34	#define DS3232_REG_CENTURY 0x05
	35	#define DS3232_REG_YEAR 0x06
	36	#define DS3232_REG_ALARM1 0x07 /* Alarm 1 BASE */
	37	#define DS3232_REG_ALARM2 0x0B /* Alarm 2 BASE */
	38	#define DS3232_REG_CR 0x0E /* Control register */
	39	# define DS3232_REG_CR_nEOSC 0x80
	40	# define DS3232_REG_CR_INTCN 0x04
	41	# define DS3232_REG_CR_A2IE 0x02
	42	# define DS3232_REG_CR_A1IE 0x01
	43
	44	#define DS3232_REG_SR 0x0F /* control/status register */
	45	# define DS3232_REG_SR_OSF 0x80
	46	# define DS3232_REG_SR_BSY 0x04
	47	# define DS3232_REG_SR_A2F 0x02
	48	# define DS3232_REG_SR_A1F 0x01
	49
	50	struct ds3232 {
	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 ds3232_driver;
	64
	65	static int ds3232_check_rtc_status(struct i2c_client *client)
	66	{
	67	int ret = 0;
	68	int control, stat;
	69
70	stat = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
71	if (stat < 0)
72	return stat;
73
74	if (stat & DS3232_REG_SR_OSF)
75	dev_warn(&client->dev,
76	"oscillator discontinuity flagged, "
77	"time unreliable\n");
78
79	stat &= ~(DS3232_REG_SR_OSF \| DS3232_REG_SR_A1F \| DS3232_REG_SR_A2F);
80
81	ret = i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat);
82	if (ret < 0)
83	return ret;
84
85	/* If the alarm is pending, clear it before requesting
86	* the interrupt, so an interrupt event isn't reported
87	* before everything is initialized.
88	*/
89
90	control = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
91	if (control < 0)
92	return control;
93
94	control &= ~(DS3232_REG_CR_A1IE \| DS3232_REG_CR_A2IE);
95	control \|= DS3232_REG_CR_INTCN;
96
97	return i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
98	}
99
100	static int ds3232_read_time(struct device dev, struct rtc_time time)
101	{
102	struct i2c_client *client = to_i2c_client(dev);
103	int ret;
104	u8 buf[7];
105	unsigned int year, month, day, hour, minute, second;
106	unsigned int week, twelve_hr, am_pm;
107	unsigned int century, add_century = 0;
108
109	ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_SECONDS, 7, buf);
110
111	if (ret < 0)
112	return ret;
113	if (ret < 7)
114	return -EIO;
115
116	second = buf[0];
117	minute = buf[1];
118	hour = buf[2];
119	week = buf[3];
120	day = buf[4];
121	month = buf[5];
122	year = buf[6];
123
124	/* Extract additional information for AM/PM and century */
125
126	twelve_hr = hour & 0x40;
127	am_pm = hour & 0x20;
128	century = month & 0x80;
129
130	/* Write to rtc_time structure */
131
132	time->tm_sec = bcd2bin(second);
133	time->tm_min = bcd2bin(minute);
134	if (twelve_hr) {
135	/* Convert to 24 hr */
136	if (am_pm)
137	time->tm_hour = bcd2bin(hour & 0x1F) + 12;
138	else
139	time->tm_hour = bcd2bin(hour & 0x1F);
140	} else {
141	time->tm_hour = bcd2bin(hour);
142	}
143
a2d6d2fa LX	144	/* Day of the week in linux range is 0~6 while 1~7 in RTC chip */
a2d6d2fa LX	145	time->tm_wday = bcd2bin(week) - 1;
c03675f0	146	time->tm_mday = bcd2bin(day);
a2d6d2fa LX	147	/* linux tm_mon range:0~11, while month range is 1~12 in RTC chip */
a2d6d2fa LX	148	time->tm_mon = bcd2bin(month & 0x7F) - 1;
c03675f0 RZ	149	if (century)
	150	add_century = 100;
	151
	152	time->tm_year = bcd2bin(year) + add_century;
	153
	154	return rtc_valid_tm(time);
	155	}
	156
	157	static int ds3232_set_time(struct device dev, struct rtc_time time)
	158	{
	159	struct i2c_client *client = to_i2c_client(dev);
	160	u8 buf[7];
	161
	162	/* Extract time from rtc_time and load into ds3232*/
	163
	164	buf[0] = bin2bcd(time->tm_sec);
	165	buf[1] = bin2bcd(time->tm_min);
	166	buf[2] = bin2bcd(time->tm_hour);
a2d6d2fa LX	167	/* Day of the week in linux range is 0~6 while 1~7 in RTC chip */
a2d6d2fa LX	168	buf[3] = bin2bcd(time->tm_wday + 1);
c03675f0	169	buf[4] = bin2bcd(time->tm_mday); /* Date */
a2d6d2fa LX	170	/* linux tm_mon range:0~11, while month range is 1~12 in RTC chip */
a2d6d2fa LX	171	buf[5] = bin2bcd(time->tm_mon + 1);
c03675f0 RZ	172	if (time->tm_year >= 100) {
	173	buf[5] \|= 0x80;
	174	buf[6] = bin2bcd(time->tm_year - 100);
	175	} else {
	176	buf[6] = bin2bcd(time->tm_year);
	177	}
	178
	179	return i2c_smbus_write_i2c_block_data(client,
	180	DS3232_REG_SECONDS, 7, buf);
	181	}
	182
f46418c5 LCB	183	/*
	184	* DS3232 has two alarm, we only use alarm1
	185	* According to linux specification, only support one-shot alarm
	186	* no periodic alarm mode
	187	*/
	188	static int ds3232_read_alarm(struct device dev, struct rtc_wkalrm alarm)
	189	{
	190	struct i2c_client *client = to_i2c_client(dev);
	191	struct ds3232 *ds3232 = i2c_get_clientdata(client);
	192	int control, stat;
	193	int ret;
	194	u8 buf[4];
	195
	196	mutex_lock(&ds3232->mutex);
	197
	198	ret = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
	199	if (ret < 0)
	200	goto out;
	201	stat = ret;
	202	ret = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
	203	if (ret < 0)
	204	goto out;
	205	control = ret;
	206	ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf);
	207	if (ret < 0)
	208	goto out;
	209
	210	alarm->time.tm_sec = bcd2bin(buf[0] & 0x7F);
	211	alarm->time.tm_min = bcd2bin(buf[1] & 0x7F);
	212	alarm->time.tm_hour = bcd2bin(buf[2] & 0x7F);
	213	alarm->time.tm_mday = bcd2bin(buf[3] & 0x7F);
	214
	215	alarm->time.tm_mon = -1;
	216	alarm->time.tm_year = -1;
	217	alarm->time.tm_wday = -1;
	218	alarm->time.tm_yday = -1;
	219	alarm->time.tm_isdst = -1;
	220
	221	alarm->enabled = !!(control & DS3232_REG_CR_A1IE);
	222	alarm->pending = !!(stat & DS3232_REG_SR_A1F);
	223
	224	ret = 0;
	225	out:
	226	mutex_unlock(&ds3232->mutex);
	227	return ret;
	228	}
	229
	230	/*
	231	* linux rtc-module does not support wday alarm
	232	* and only 24h time mode supported indeed
	233	*/
	234	static int ds3232_set_alarm(struct device dev, struct rtc_wkalrm alarm)
	235	{
	236	struct i2c_client *client = to_i2c_client(dev);
	237	struct ds3232 *ds3232 = i2c_get_clientdata(client);
	238	int control, stat;
	239	int ret;
	240	u8 buf[4];
	241
	242	if (client->irq <= 0)
	243	return -EINVAL;
	244
	245	mutex_lock(&ds3232->mutex);
	246
247	buf[0] = bin2bcd(alarm->time.tm_sec);
248	buf[1] = bin2bcd(alarm->time.tm_min);
249	buf[2] = bin2bcd(alarm->time.tm_hour);
250	buf[3] = bin2bcd(alarm->time.tm_mday);
251
252	/* clear alarm interrupt enable bit */
253	ret = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
254	if (ret < 0)
255	goto out;
256	control = ret;
257	control &= ~(DS3232_REG_CR_A1IE \| DS3232_REG_CR_A2IE);
258	ret = i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
259	if (ret < 0)
260	goto out;
261
262	/* clear any pending alarm flag */
263	ret = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
264	if (ret < 0)
265	goto out;
266	stat = ret;
267	stat &= ~(DS3232_REG_SR_A1F \| DS3232_REG_SR_A2F);
268	ret = i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat);
269	if (ret < 0)
270	goto out;
271
272	ret = i2c_smbus_write_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf);
273
274	if (alarm->enabled) {
275	control \|= DS3232_REG_CR_A1IE;
276	ret = i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
277	}
278	out:
279	mutex_unlock(&ds3232->mutex);
280	return ret;
281	}
282
283	static void ds3232_update_alarm(struct i2c_client *client)
284	{
285	struct ds3232 *ds3232 = i2c_get_clientdata(client);
286	int control;
287	int ret;
288	u8 buf[4];
289
290	mutex_lock(&ds3232->mutex);
291
292	ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf);
293	if (ret < 0)
294	goto unlock;
295
296	buf[0] = bcd2bin(buf[0]) < 0 \|\| (ds3232->rtc->irq_data & RTC_UF) ?
297	0x80 : buf[0];
298	buf[1] = bcd2bin(buf[1]) < 0 \|\| (ds3232->rtc->irq_data & RTC_UF) ?
299	0x80 : buf[1];
300	buf[2] = bcd2bin(buf[2]) < 0 \|\| (ds3232->rtc->irq_data & RTC_UF) ?
301	0x80 : buf[2];
302	buf[3] = bcd2bin(buf[3]) < 0 \|\| (ds3232->rtc->irq_data & RTC_UF) ?
303	0x80 : buf[3];
304
305	ret = i2c_smbus_write_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf);
306	if (ret < 0)
307	goto unlock;
308
309	control = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
310	if (control < 0)
311	goto unlock;
312
313	if (ds3232->rtc->irq_data & (RTC_AF \| RTC_UF))
314	/* enable alarm1 interrupt */
315	control \|= DS3232_REG_CR_A1IE;
316	else
317	/* disable alarm1 interrupt */
318	control &= ~(DS3232_REG_CR_A1IE);
319	i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
320
321	unlock:
322	mutex_unlock(&ds3232->mutex);
323	}
324
325	static int ds3232_alarm_irq_enable(struct device *dev, unsigned int enabled)
326	{
327	struct i2c_client *client = to_i2c_client(dev);
328	struct ds3232 *ds3232 = i2c_get_clientdata(client);
329
330	if (client->irq <= 0)
331	return -EINVAL;
332
333	if (enabled)
334	ds3232->rtc->irq_data \|= RTC_AF;
335	else
336	ds3232->rtc->irq_data &= ~RTC_AF;
337
338	ds3232_update_alarm(client);
339	return 0;
340	}
341
c03675f0 RZ	342	static irqreturn_t ds3232_irq(int irq, void *dev_id)
	343	{
	344	struct i2c_client *client = dev_id;
	345	struct ds3232 *ds3232 = i2c_get_clientdata(client);
	346
	347	disable_irq_nosync(irq);
	348	schedule_work(&ds3232->work);
	349	return IRQ_HANDLED;
	350	}
	351
	352	static void ds3232_work(struct work_struct *work)
	353	{
	354	struct ds3232 *ds3232 = container_of(work, struct ds3232, work);
	355	struct i2c_client *client = ds3232->client;
	356	int stat, control;
	357
	358	mutex_lock(&ds3232->mutex);
	359
	360	stat = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
	361	if (stat < 0)
	362	goto unlock;
	363
	364	if (stat & DS3232_REG_SR_A1F) {
	365	control = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
	366	if (control < 0)
	367	goto out;
	368	/* disable alarm1 interrupt */
	369	control &= ~(DS3232_REG_CR_A1IE);
	370	i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
	371
	372	/* clear the alarm pend flag */
	373	stat &= ~DS3232_REG_SR_A1F;
	374	i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat);
	375
	376	rtc_update_irq(ds3232->rtc, 1, RTC_AF \| RTC_IRQF);
	377	}
	378
	379	out:
	380	if (!ds3232->exiting)
	381	enable_irq(client->irq);
	382	unlock:
	383	mutex_unlock(&ds3232->mutex);
	384	}
	385
	386	static const struct rtc_class_ops ds3232_rtc_ops = {
	387	.read_time = ds3232_read_time,
	388	.set_time = ds3232_set_time,
f46418c5 LCB	389	.read_alarm = ds3232_read_alarm,
	390	.set_alarm = ds3232_set_alarm,
	391	.alarm_irq_enable = ds3232_alarm_irq_enable,
c03675f0 RZ	392	};
c03675f0 RZ	393
5a167f45 GKH	394	static int ds3232_probe(struct i2c_client *client,
5a167f45 GKH	395	const struct i2c_device_id *id)
c03675f0 RZ	396	{
	397	struct ds3232 *ds3232;
	398	int ret;
	399
66714612	400	ds3232 = devm_kzalloc(&client->dev, sizeof(struct ds3232), GFP_KERNEL);
c03675f0 RZ	401	if (!ds3232)
	402	return -ENOMEM;
	403
	404	ds3232->client = client;
	405	i2c_set_clientdata(client, ds3232);
	406
	407	INIT_WORK(&ds3232->work, ds3232_work);
	408	mutex_init(&ds3232->mutex);
	409
	410	ret = ds3232_check_rtc_status(client);
	411	if (ret)
66714612	412	return ret;
c03675f0	413
66714612	414	ds3232->rtc = devm_rtc_device_register(&client->dev, client->name,
c03675f0 RZ	415	&ds3232_rtc_ops, THIS_MODULE);
c03675f0 RZ	416	if (IS_ERR(ds3232->rtc)) {
66714612	417	return PTR_ERR(ds3232->rtc);
c03675f0 RZ	418	}
	419
	420	if (client->irq >= 0) {
a8a15eb1 BB	421	ret = devm_request_irq(&client->dev, client->irq, ds3232_irq,
a8a15eb1 BB	422	IRQF_SHARED, "ds3232", client);
c03675f0 RZ	423	if (ret) {
c03675f0 RZ	424	dev_err(&client->dev, "unable to request IRQ\n");
c03675f0 RZ	425	}
	426	}
	427
	428	return 0;
c03675f0 RZ	429	}
c03675f0 RZ	430
5a167f45	431	static int ds3232_remove(struct i2c_client *client)
c03675f0 RZ	432	{
	433	struct ds3232 *ds3232 = i2c_get_clientdata(client);
	434
	435	if (client->irq >= 0) {
	436	mutex_lock(&ds3232->mutex);
	437	ds3232->exiting = 1;
	438	mutex_unlock(&ds3232->mutex);
	439
66714612	440	devm_free_irq(&client->dev, client->irq, client);
9db8995b	441	cancel_work_sync(&ds3232->work);
c03675f0 RZ	442	}
c03675f0 RZ	443
c03675f0 RZ	444	return 0;
	445	}
	446
	447	static const struct i2c_device_id ds3232_id[] = {
	448	{ "ds3232", 0 },
	449	{ }
	450	};
	451	MODULE_DEVICE_TABLE(i2c, ds3232_id);
	452
	453	static struct i2c_driver ds3232_driver = {
	454	.driver = {
	455	.name = "rtc-ds3232",
	456	.owner = THIS_MODULE,
	457	},
	458	.probe = ds3232_probe,
5a167f45	459	.remove = ds3232_remove,
c03675f0 RZ	460	.id_table = ds3232_id,
	461	};
	462
0abc9201	463	module_i2c_driver(ds3232_driver);
c03675f0 RZ	464
	465	MODULE_AUTHOR("Srikanth Srinivasan <[email protected]>");
	466	MODULE_DESCRIPTION("Maxim/Dallas DS3232 RTC Driver");
	467	MODULE_LICENSE("GPL");