[linux.git] / drivers / rtc / rtc-bq32k.c

/*
 * Driver for TI BQ32000 RTC.
 *
 * Copyright (C) 2009 Semihalf.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/rtc.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/bcd.h>

#define BQ32K_SECONDS		0x00	/* Seconds register address */
#define BQ32K_SECONDS_MASK	0x7F	/* Mask over seconds value */
#define BQ32K_STOP		0x80	/* Oscillator Stop flat */

#define BQ32K_MINUTES		0x01	/* Minutes register address */
#define BQ32K_MINUTES_MASK	0x7F	/* Mask over minutes value */
#define BQ32K_OF		0x80	/* Oscillator Failure flag */

#define BQ32K_HOURS_MASK	0x3F	/* Mask over hours value */
#define BQ32K_CENT		0x40	/* Century flag */
#define BQ32K_CENT_EN		0x80	/* Century flag enable bit */

struct bq32k_regs {
	uint8_t		seconds;
	uint8_t		minutes;
	uint8_t		cent_hours;
	uint8_t		day;
	uint8_t		date;
	uint8_t		month;
	uint8_t		years;
};

static struct i2c_driver bq32k_driver;

static int bq32k_read(struct device *dev, void *data, uint8_t off, uint8_t len)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct i2c_msg msgs[] = {
		{
			.addr = client->addr,
			.flags = 0,
			.len = 1,
			.buf = &off,
		}, {
			.addr = client->addr,
			.flags = I2C_M_RD,
			.len = len,
			.buf = data,
		}
	};

	if (i2c_transfer(client->adapter, msgs, 2) == 2)
		return 0;

	return -EIO;
}

static int bq32k_write(struct device *dev, void *data, uint8_t off, uint8_t len)
{
	struct i2c_client *client = to_i2c_client(dev);
	uint8_t buffer[len + 1];

	buffer[0] = off;
	memcpy(&buffer[1], data, len);

	if (i2c_master_send(client, buffer, len + 1) == len + 1)
		return 0;

	return -EIO;
}

static int bq32k_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
	struct bq32k_regs regs;
	int error;

	error = bq32k_read(dev, &regs, 0, sizeof(regs));
	if (error)
		return error;

	tm->tm_sec = bcd2bin(regs.seconds & BQ32K_SECONDS_MASK);
	tm->tm_min = bcd2bin(regs.minutes & BQ32K_SECONDS_MASK);
	tm->tm_hour = bcd2bin(regs.cent_hours & BQ32K_HOURS_MASK);
	tm->tm_mday = bcd2bin(regs.date);
	tm->tm_wday = bcd2bin(regs.day) - 1;
	tm->tm_mon = bcd2bin(regs.month) - 1;
	tm->tm_year = bcd2bin(regs.years) +
				((regs.cent_hours & BQ32K_CENT) ? 100 : 0);

	return rtc_valid_tm(tm);
}

static int bq32k_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
	struct bq32k_regs regs;

	regs.seconds = bin2bcd(tm->tm_sec);
	regs.minutes = bin2bcd(tm->tm_min);
	regs.cent_hours = bin2bcd(tm->tm_hour) | BQ32K_CENT_EN;
	regs.day = bin2bcd(tm->tm_wday + 1);
	regs.date = bin2bcd(tm->tm_mday);
	regs.month = bin2bcd(tm->tm_mon + 1);

	if (tm->tm_year >= 100) {
		regs.cent_hours |= BQ32K_CENT;
		regs.years = bin2bcd(tm->tm_year - 100);
	} else
		regs.years = bin2bcd(tm->tm_year);

	return bq32k_write(dev, &regs, 0, sizeof(regs));
}

static const struct rtc_class_ops bq32k_rtc_ops = {
	.read_time	= bq32k_rtc_read_time,
	.set_time	= bq32k_rtc_set_time,
};

static int bq32k_probe(struct i2c_client *client,
				const struct i2c_device_id *id)
{
	struct device *dev = &client->dev;
	struct rtc_device *rtc;
	uint8_t reg;
	int error;

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
		return -ENODEV;

	/* Check Oscillator Stop flag */
	error = bq32k_read(dev, &reg, BQ32K_SECONDS, 1);
	if (!error && (reg & BQ32K_STOP)) {
		dev_warn(dev, "Oscillator was halted. Restarting...\n");
		reg &= ~BQ32K_STOP;
		error = bq32k_write(dev, &reg, BQ32K_SECONDS, 1);
	}
	if (error)
		return error;

	/* Check Oscillator Failure flag */
	error = bq32k_read(dev, &reg, BQ32K_MINUTES, 1);
	if (!error && (reg & BQ32K_OF)) {
		dev_warn(dev, "Oscillator Failure. Check RTC battery.\n");
		reg &= ~BQ32K_OF;
		error = bq32k_write(dev, &reg, BQ32K_MINUTES, 1);
	}
	if (error)
		return error;

	rtc = rtc_device_register(bq32k_driver.driver.name, &client->dev,
						&bq32k_rtc_ops, THIS_MODULE);
	if (IS_ERR(rtc))
		return PTR_ERR(rtc);

	i2c_set_clientdata(client, rtc);

	return 0;
}

static int __devexit bq32k_remove(struct i2c_client *client)
{
	struct rtc_device *rtc = i2c_get_clientdata(client);

	rtc_device_unregister(rtc);
	return 0;
}

static const struct i2c_device_id bq32k_id[] = {
	{ "bq32000", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, bq32k_id);

static struct i2c_driver bq32k_driver = {
	.driver = {
		.name	= "bq32k",
		.owner	= THIS_MODULE,
	},
	.probe		= bq32k_probe,
	.remove		= __devexit_p(bq32k_remove),
	.id_table	= bq32k_id,
};

module_i2c_driver(bq32k_driver);

MODULE_AUTHOR("Semihalf, Piotr Ziecik <[email protected]>");
MODULE_DESCRIPTION("TI BQ32000 I2C RTC driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
1ce7c83f PZ	1	/*
	2	* Driver for TI BQ32000 RTC.
	3	*
	4	* Copyright (C) 2009 Semihalf.
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*/
	10
	11	#include <linux/module.h>
	12	#include <linux/i2c.h>
	13	#include <linux/rtc.h>
	14	#include <linux/init.h>
	15	#include <linux/errno.h>
	16	#include <linux/bcd.h>
	17
	18	#define BQ32K_SECONDS 0x00 /* Seconds register address */
	19	#define BQ32K_SECONDS_MASK 0x7F /* Mask over seconds value */
	20	#define BQ32K_STOP 0x80 /* Oscillator Stop flat */
	21
	22	#define BQ32K_MINUTES 0x01 /* Minutes register address */
	23	#define BQ32K_MINUTES_MASK 0x7F /* Mask over minutes value */
	24	#define BQ32K_OF 0x80 /* Oscillator Failure flag */
	25
	26	#define BQ32K_HOURS_MASK 0x3F /* Mask over hours value */
	27	#define BQ32K_CENT 0x40 /* Century flag */
	28	#define BQ32K_CENT_EN 0x80 /* Century flag enable bit */
	29
	30	struct bq32k_regs {
	31	uint8_t seconds;
	32	uint8_t minutes;
	33	uint8_t cent_hours;
	34	uint8_t day;
	35	uint8_t date;
	36	uint8_t month;
	37	uint8_t years;
	38	};
	39
	40	static struct i2c_driver bq32k_driver;
	41
	42	static int bq32k_read(struct device dev, void data, uint8_t off, uint8_t len)
	43	{
	44	struct i2c_client *client = to_i2c_client(dev);
	45	struct i2c_msg msgs[] = {
	46	{
	47	.addr = client->addr,
	48	.flags = 0,
	49	.len = 1,
	50	.buf = &off,
	51	}, {
	52	.addr = client->addr,
	53	.flags = I2C_M_RD,
	54	.len = len,
	55	.buf = data,
	56	}
	57	};
	58
	59	if (i2c_transfer(client->adapter, msgs, 2) == 2)
	60	return 0;
	61
	62	return -EIO;
	63	}
	64
65	static int bq32k_write(struct device dev, void data, uint8_t off, uint8_t len)
66	{
67	struct i2c_client *client = to_i2c_client(dev);
68	uint8_t buffer[len + 1];
69
70	buffer[0] = off;
71	memcpy(&buffer[1], data, len);
72
73	if (i2c_master_send(client, buffer, len + 1) == len + 1)
74	return 0;
75
76	return -EIO;
77	}
78
79	static int bq32k_rtc_read_time(struct device dev, struct rtc_time tm)
80	{
81	struct bq32k_regs regs;
82	int error;
83
84	error = bq32k_read(dev, &regs, 0, sizeof(regs));
85	if (error)
86	return error;
87
88	tm->tm_sec = bcd2bin(regs.seconds & BQ32K_SECONDS_MASK);
89	tm->tm_min = bcd2bin(regs.minutes & BQ32K_SECONDS_MASK);
90	tm->tm_hour = bcd2bin(regs.cent_hours & BQ32K_HOURS_MASK);
91	tm->tm_mday = bcd2bin(regs.date);
92	tm->tm_wday = bcd2bin(regs.day) - 1;
93	tm->tm_mon = bcd2bin(regs.month) - 1;
94	tm->tm_year = bcd2bin(regs.years) +
95	((regs.cent_hours & BQ32K_CENT) ? 100 : 0);
96
97	return rtc_valid_tm(tm);
98	}
99
100	static int bq32k_rtc_set_time(struct device dev, struct rtc_time tm)
101	{
102	struct bq32k_regs regs;
103
104	regs.seconds = bin2bcd(tm->tm_sec);
105	regs.minutes = bin2bcd(tm->tm_min);
106	regs.cent_hours = bin2bcd(tm->tm_hour) \| BQ32K_CENT_EN;
107	regs.day = bin2bcd(tm->tm_wday + 1);
108	regs.date = bin2bcd(tm->tm_mday);
109	regs.month = bin2bcd(tm->tm_mon + 1);
110
111	if (tm->tm_year >= 100) {
112	regs.cent_hours \|= BQ32K_CENT;
113	regs.years = bin2bcd(tm->tm_year - 100);
114	} else
115	regs.years = bin2bcd(tm->tm_year);
116
117	return bq32k_write(dev, &regs, 0, sizeof(regs));
118	}
119
120	static const struct rtc_class_ops bq32k_rtc_ops = {
121	.read_time = bq32k_rtc_read_time,
122	.set_time = bq32k_rtc_set_time,
123	};
124
125	static int bq32k_probe(struct i2c_client *client,
126	const struct i2c_device_id *id)
127	{
128	struct device *dev = &client->dev;
129	struct rtc_device *rtc;
130	uint8_t reg;
131	int error;
132
133	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
134	return -ENODEV;
135
136	/* Check Oscillator Stop flag */
137	error = bq32k_read(dev, &reg, BQ32K_SECONDS, 1);
138	if (!error && (reg & BQ32K_STOP)) {
139	dev_warn(dev, "Oscillator was halted. Restarting...\n");
140	reg &= ~BQ32K_STOP;
141	error = bq32k_write(dev, &reg, BQ32K_SECONDS, 1);
142	}
143	if (error)
144	return error;
145
146	/* Check Oscillator Failure flag */
147	error = bq32k_read(dev, &reg, BQ32K_MINUTES, 1);
148	if (!error && (reg & BQ32K_OF)) {
149	dev_warn(dev, "Oscillator Failure. Check RTC battery.\n");
150	reg &= ~BQ32K_OF;
151	error = bq32k_write(dev, &reg, BQ32K_MINUTES, 1);
152	}
153	if (error)
154	return error;
155
156	rtc = rtc_device_register(bq32k_driver.driver.name, &client->dev,
157	&bq32k_rtc_ops, THIS_MODULE);
158	if (IS_ERR(rtc))
159	return PTR_ERR(rtc);
160
161	i2c_set_clientdata(client, rtc);
162
163	return 0;
164	}
165
166	static int __devexit bq32k_remove(struct i2c_client *client)
167	{
168	struct rtc_device *rtc = i2c_get_clientdata(client);
169
170	rtc_device_unregister(rtc);
171	return 0;
172	}
173
174	static const struct i2c_device_id bq32k_id[] = {
175	{ "bq32000", 0 },
176	{ }
177	};
178	MODULE_DEVICE_TABLE(i2c, bq32k_id);
179
180	static struct i2c_driver bq32k_driver = {
181	.driver = {
182	.name = "bq32k",
183	.owner = THIS_MODULE,
184	},
185	.probe = bq32k_probe,
186	.remove = __devexit_p(bq32k_remove),
187	.id_table = bq32k_id,
188	};
189
0abc9201	190	module_i2c_driver(bq32k_driver);
1ce7c83f PZ	191
	192	MODULE_AUTHOR("Semihalf, Piotr Ziecik <[email protected]>");
	193	MODULE_DESCRIPTION("TI BQ32000 I2C RTC driver");
	194	MODULE_LICENSE("GPL");