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

/*
 * Driver for TI BQ32000 RTC.
 *
 * Copyright (C) 2009 Semihalf.
 * Copyright (C) 2014 Pavel Machek <pavel@denx.de>
 *
 * 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.
 *
 * You can get hardware description at
 * http://www.ti.com/lit/ds/symlink/bq32000.pdf
 */

#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 */

#define BQ32K_CALIBRATION	0x07	/* CAL_CFG1, calibration and control */
#define BQ32K_TCH2		0x08	/* Trickle charge enable */
#define BQ32K_CFG2		0x09	/* Trickle charger control */

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;

	/*
	 * In case of oscillator failure, the register contents should be
	 * considered invalid. The flag is cleared the next time the RTC is set.
	 */
	if (regs.minutes & BQ32K_OF)
		return -EINVAL;

	tm->tm_sec = bcd2bin(regs.seconds & BQ32K_SECONDS_MASK);
	tm->tm_min = bcd2bin(regs.minutes & BQ32K_MINUTES_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 trickle_charger_of_init(struct device *dev, struct device_node *node)
{
	unsigned char reg;
	int error;
	u32 ohms = 0;

	if (of_property_read_u32(node, "trickle-resistor-ohms" , &ohms))
		return 0;

	switch (ohms) {
	case 180+940:
		/*
		 * TCHE[3:0] == 0x05, TCH2 == 1, TCFE == 0 (charging
		 * over diode and 940ohm resistor)
		 */

		if (of_property_read_bool(node, "trickle-diode-disable")) {
			dev_err(dev, "diode and resistor mismatch\n");
			return -EINVAL;
		}
		reg = 0x05;
		break;

	case 180+20000:
		/* diode disabled */

		if (!of_property_read_bool(node, "trickle-diode-disable")) {
			dev_err(dev, "bq32k: diode and resistor mismatch\n");
			return -EINVAL;
		}
		reg = 0x45;
		break;

	default:
		dev_err(dev, "invalid resistor value (%d)\n", ohms);
		return -EINVAL;
	}

	error = bq32k_write(dev, &reg, BQ32K_CFG2, 1);
	if (error)
		return error;

	reg = 0x20;
	error = bq32k_write(dev, &reg, BQ32K_TCH2, 1);
	if (error)
		return error;

	dev_info(dev, "Enabled trickle RTC battery charge.\n");
	return 0;
}

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)
		return error;
	if (reg & BQ32K_OF)
		dev_warn(dev, "Oscillator Failure. Check RTC battery.\n");

	if (client->dev.of_node)
		trickle_charger_of_init(dev, client->dev.of_node);

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

	i2c_set_clientdata(client, 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",
	},
	.probe		= bq32k_probe,
	.id_table	= bq32k_id,
};

module_i2c_driver(bq32k_driver);

MODULE_AUTHOR("Semihalf, Piotr Ziecik <kosmo@semihalf.com>");
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.
765a98a6	5	* Copyright (C) 2014 Pavel Machek <pavel@denx.de>
1ce7c83f PZ	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License version 2 as
	9	* published by the Free Software Foundation.
765a98a6 PM	10	*
	11	* You can get hardware description at
	12	* http://www.ti.com/lit/ds/symlink/bq32000.pdf
1ce7c83f PZ	13	*/
	14
	15	#include <linux/module.h>
	16	#include <linux/i2c.h>
	17	#include <linux/rtc.h>
	18	#include <linux/init.h>
	19	#include <linux/errno.h>
	20	#include <linux/bcd.h>
	21
	22	#define BQ32K_SECONDS 0x00 /* Seconds register address */
	23	#define BQ32K_SECONDS_MASK 0x7F /* Mask over seconds value */
	24	#define BQ32K_STOP 0x80 /* Oscillator Stop flat */
	25
	26	#define BQ32K_MINUTES 0x01 /* Minutes register address */
	27	#define BQ32K_MINUTES_MASK 0x7F /* Mask over minutes value */
	28	#define BQ32K_OF 0x80 /* Oscillator Failure flag */
	29
	30	#define BQ32K_HOURS_MASK 0x3F /* Mask over hours value */
	31	#define BQ32K_CENT 0x40 /* Century flag */
	32	#define BQ32K_CENT_EN 0x80 /* Century flag enable bit */
	33
765a98a6 PM	34	#define BQ32K_CALIBRATION 0x07 /* CAL_CFG1, calibration and control */
	35	#define BQ32K_TCH2 0x08 /* Trickle charge enable */
	36	#define BQ32K_CFG2 0x09 /* Trickle charger control */
	37
1ce7c83f PZ	38	struct bq32k_regs {
	39	uint8_t seconds;
	40	uint8_t minutes;
	41	uint8_t cent_hours;
	42	uint8_t day;
	43	uint8_t date;
	44	uint8_t month;
	45	uint8_t years;
	46	};
	47
	48	static struct i2c_driver bq32k_driver;
	49
	50	static int bq32k_read(struct device dev, void data, uint8_t off, uint8_t len)
	51	{
	52	struct i2c_client *client = to_i2c_client(dev);
	53	struct i2c_msg msgs[] = {
	54	{
	55	.addr = client->addr,
	56	.flags = 0,
	57	.len = 1,
	58	.buf = &off,
	59	}, {
	60	.addr = client->addr,
	61	.flags = I2C_M_RD,
	62	.len = len,
	63	.buf = data,
	64	}
	65	};
	66
	67	if (i2c_transfer(client->adapter, msgs, 2) == 2)
	68	return 0;
	69
	70	return -EIO;
	71	}
	72
	73	static int bq32k_write(struct device dev, void data, uint8_t off, uint8_t len)
	74	{
	75	struct i2c_client *client = to_i2c_client(dev);
	76	uint8_t buffer[len + 1];
	77
	78	buffer[0] = off;
	79	memcpy(&buffer[1], data, len);
	80
	81	if (i2c_master_send(client, buffer, len + 1) == len + 1)
	82	return 0;
	83
	84	return -EIO;
	85	}
	86
	87	static int bq32k_rtc_read_time(struct device dev, struct rtc_time tm)
	88	{
	89	struct bq32k_regs regs;
	90	int error;
	91
	92	error = bq32k_read(dev, &regs, 0, sizeof(regs));
	93	if (error)
	94	return error;
	95
421a5ba2 JÖ	96	/*
	97	* In case of oscillator failure, the register contents should be
	98	* considered invalid. The flag is cleared the next time the RTC is set.
	99	*/
	100	if (regs.minutes & BQ32K_OF)
	101	return -EINVAL;
	102
1ce7c83f	103	tm->tm_sec = bcd2bin(regs.seconds & BQ32K_SECONDS_MASK);
6ed1a51e	104	tm->tm_min = bcd2bin(regs.minutes & BQ32K_MINUTES_MASK);
1ce7c83f PZ	105	tm->tm_hour = bcd2bin(regs.cent_hours & BQ32K_HOURS_MASK);
	106	tm->tm_mday = bcd2bin(regs.date);
	107	tm->tm_wday = bcd2bin(regs.day) - 1;
	108	tm->tm_mon = bcd2bin(regs.month) - 1;
	109	tm->tm_year = bcd2bin(regs.years) +
	110	((regs.cent_hours & BQ32K_CENT) ? 100 : 0);
	111
	112	return rtc_valid_tm(tm);
	113	}
	114
	115	static int bq32k_rtc_set_time(struct device dev, struct rtc_time tm)
	116	{
	117	struct bq32k_regs regs;
	118
	119	regs.seconds = bin2bcd(tm->tm_sec);
	120	regs.minutes = bin2bcd(tm->tm_min);
	121	regs.cent_hours = bin2bcd(tm->tm_hour) \| BQ32K_CENT_EN;
	122	regs.day = bin2bcd(tm->tm_wday + 1);
	123	regs.date = bin2bcd(tm->tm_mday);
	124	regs.month = bin2bcd(tm->tm_mon + 1);
	125
	126	if (tm->tm_year >= 100) {
	127	regs.cent_hours \|= BQ32K_CENT;
	128	regs.years = bin2bcd(tm->tm_year - 100);
	129	} else
	130	regs.years = bin2bcd(tm->tm_year);
	131
	132	return bq32k_write(dev, &regs, 0, sizeof(regs));
	133	}
	134
	135	static const struct rtc_class_ops bq32k_rtc_ops = {
	136	.read_time = bq32k_rtc_read_time,
	137	.set_time = bq32k_rtc_set_time,
	138	};
	139
765a98a6 PM	140	static int trickle_charger_of_init(struct device dev, struct device_node node)
	141	{
	142	unsigned char reg;
	143	int error;
	144	u32 ohms = 0;
	145
	146	if (of_property_read_u32(node, "trickle-resistor-ohms" , &ohms))
	147	return 0;
	148
	149	switch (ohms) {
	150	case 180+940:
	151	/*
	152	* TCHE[3:0] == 0x05, TCH2 == 1, TCFE == 0 (charging
	153	* over diode and 940ohm resistor)
	154	*/
	155
	156	if (of_property_read_bool(node, "trickle-diode-disable")) {
	157	dev_err(dev, "diode and resistor mismatch\n");
	158	return -EINVAL;
	159	}
	160	reg = 0x05;
	161	break;
	162
	163	case 180+20000:
	164	/* diode disabled */
	165
	166	if (!of_property_read_bool(node, "trickle-diode-disable")) {
	167	dev_err(dev, "bq32k: diode and resistor mismatch\n");
	168	return -EINVAL;
	169	}
5a6e7599	170	reg = 0x45;
765a98a6 PM	171	break;
	172
	173	default:
	174	dev_err(dev, "invalid resistor value (%d)\n", ohms);
	175	return -EINVAL;
	176	}
	177
	178	error = bq32k_write(dev, &reg, BQ32K_CFG2, 1);
	179	if (error)
	180	return error;
	181
	182	reg = 0x20;
	183	error = bq32k_write(dev, &reg, BQ32K_TCH2, 1);
	184	if (error)
	185	return error;
	186
	187	dev_info(dev, "Enabled trickle RTC battery charge.\n");
	188	return 0;
	189	}
	190
1ce7c83f PZ	191	static int bq32k_probe(struct i2c_client *client,
	192	const struct i2c_device_id *id)
	193	{
	194	struct device *dev = &client->dev;
	195	struct rtc_device *rtc;
	196	uint8_t reg;
	197	int error;
	198
	199	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
	200	return -ENODEV;
	201
	202	/* Check Oscillator Stop flag */
	203	error = bq32k_read(dev, &reg, BQ32K_SECONDS, 1);
	204	if (!error && (reg & BQ32K_STOP)) {
	205	dev_warn(dev, "Oscillator was halted. Restarting...\n");
	206	reg &= ~BQ32K_STOP;
	207	error = bq32k_write(dev, &reg, BQ32K_SECONDS, 1);
	208	}
	209	if (error)
	210	return error;
	211
	212	/* Check Oscillator Failure flag */
	213	error = bq32k_read(dev, &reg, BQ32K_MINUTES, 1);
1ce7c83f PZ	214	if (error)
1ce7c83f PZ	215	return error;
421a5ba2 JÖ	216	if (reg & BQ32K_OF)
421a5ba2 JÖ	217	dev_warn(dev, "Oscillator Failure. Check RTC battery.\n");
1ce7c83f	218
617f6f7e	219	if (client->dev.of_node)
765a98a6 PM	220	trickle_charger_of_init(dev, client->dev.of_node);
765a98a6 PM	221
4e440681	222	rtc = devm_rtc_device_register(&client->dev, bq32k_driver.driver.name,
1ce7c83f PZ	223	&bq32k_rtc_ops, THIS_MODULE);
	224	if (IS_ERR(rtc))
	225	return PTR_ERR(rtc);
	226
	227	i2c_set_clientdata(client, rtc);
	228
	229	return 0;
	230	}
	231
1ce7c83f PZ	232	static const struct i2c_device_id bq32k_id[] = {
	233	{ "bq32000", 0 },
	234	{ }
	235	};
	236	MODULE_DEVICE_TABLE(i2c, bq32k_id);
	237
	238	static struct i2c_driver bq32k_driver = {
	239	.driver = {
	240	.name = "bq32k",
1ce7c83f PZ	241	},
1ce7c83f PZ	242	.probe = bq32k_probe,
1ce7c83f PZ	243	.id_table = bq32k_id,
	244	};
	245
0abc9201	246	module_i2c_driver(bq32k_driver);
1ce7c83f PZ	247
	248	MODULE_AUTHOR("Semihalf, Piotr Ziecik <kosmo@semihalf.com>");
	249	MODULE_DESCRIPTION("TI BQ32000 I2C RTC driver");
	250	MODULE_LICENSE("GPL");