[mirror_ubuntu-jammy-kernel.git] / drivers / rtc / rtc-bq32k.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Driver for TI BQ32000 RTC.
 *
 * Copyright (C) 2009 Semihalf.
 * Copyright (C) 2014 Pavel Machek <pavel@denx.de>
 *
 * You can get hardware description at
 * https://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 */
#define BQ32K_TCFE		BIT(6)	/* Trickle charge FET bypass */

#define MAX_LEN			10	/* Maximum number of consecutive
					 * register for this particular RTC.
					 */

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[MAX_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 0;
}

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 ssize_t bq32k_sysfs_show_tricklecharge_bypass(struct device *dev,
					       struct device_attribute *attr,
					       char *buf)
{
	int reg, error;

	error = bq32k_read(dev, &reg, BQ32K_CFG2, 1);
	if (error)
		return error;

	return sprintf(buf, "%d\n", (reg & BQ32K_TCFE) ? 1 : 0);
}

static ssize_t bq32k_sysfs_store_tricklecharge_bypass(struct device *dev,
						struct device_attribute *attr,
						const char *buf, size_t count)
{
	int reg, enable, error;

	if (kstrtoint(buf, 0, &enable))
		return -EINVAL;

	error = bq32k_read(dev, &reg, BQ32K_CFG2, 1);
	if (error)
		return error;

	if (enable) {
		reg |= BQ32K_TCFE;
		error = bq32k_write(dev, &reg, BQ32K_CFG2, 1);
		if (error)
			return error;

		dev_info(dev, "Enabled trickle charge FET bypass.\n");
	} else {
		reg &= ~BQ32K_TCFE;
		error = bq32k_write(dev, &reg, BQ32K_CFG2, 1);
		if (error)
			return error;

		dev_info(dev, "Disabled trickle charge FET bypass.\n");
	}

	return count;
}

static DEVICE_ATTR(trickle_charge_bypass, 0644,
		   bq32k_sysfs_show_tricklecharge_bypass,
		   bq32k_sysfs_store_tricklecharge_bypass);

static int bq32k_sysfs_register(struct device *dev)
{
	return device_create_file(dev, &dev_attr_trickle_charge_bypass);
}

static void bq32k_sysfs_unregister(struct device *dev)
{
	device_remove_file(dev, &dev_attr_trickle_charge_bypass);
}

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);

	error = bq32k_sysfs_register(&client->dev);
	if (error) {
		dev_err(&client->dev,
			"Unable to create sysfs entries for rtc bq32000\n");
		return error;
	}


	i2c_set_clientdata(client, rtc);

	return 0;
}

static int bq32k_remove(struct i2c_client *client)
{
	bq32k_sysfs_unregister(&client->dev);

	return 0;
}

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

static const __maybe_unused struct of_device_id bq32k_of_match[] = {
	{ .compatible = "ti,bq32000" },
	{ }
};
MODULE_DEVICE_TABLE(of, bq32k_of_match);

static struct i2c_driver bq32k_driver = {
	.driver = {
		.name	= "bq32k",
		.of_match_table = of_match_ptr(bq32k_of_match),
	},
	.probe		= bq32k_probe,
	.remove		= bq32k_remove,
	.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
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
1ce7c83f PZ	2	/*
	3	* Driver for TI BQ32000 RTC.
	4	*
	5	* Copyright (C) 2009 Semihalf.
765a98a6	6	* Copyright (C) 2014 Pavel Machek <pavel@denx.de>
1ce7c83f	7	*
765a98a6	8	* You can get hardware description at
3567d3d1	9	* https://www.ti.com/lit/ds/symlink/bq32000.pdf
1ce7c83f PZ	10	*/
	11
	12	#include <linux/module.h>
	13	#include <linux/i2c.h>
	14	#include <linux/rtc.h>
	15	#include <linux/init.h>
	16	#include <linux/errno.h>
	17	#include <linux/bcd.h>
	18
	19	#define BQ32K_SECONDS 0x00 /* Seconds register address */
	20	#define BQ32K_SECONDS_MASK 0x7F /* Mask over seconds value */
	21	#define BQ32K_STOP 0x80 /* Oscillator Stop flat */
	22
	23	#define BQ32K_MINUTES 0x01 /* Minutes register address */
	24	#define BQ32K_MINUTES_MASK 0x7F /* Mask over minutes value */
	25	#define BQ32K_OF 0x80 /* Oscillator Failure flag */
	26
	27	#define BQ32K_HOURS_MASK 0x3F /* Mask over hours value */
	28	#define BQ32K_CENT 0x40 /* Century flag */
	29	#define BQ32K_CENT_EN 0x80 /* Century flag enable bit */
	30
765a98a6 PM	31	#define BQ32K_CALIBRATION 0x07 /* CAL_CFG1, calibration and control */
	32	#define BQ32K_TCH2 0x08 /* Trickle charge enable */
	33	#define BQ32K_CFG2 0x09 /* Trickle charger control */
4c466872	34	#define BQ32K_TCFE BIT(6) /* Trickle charge FET bypass */
765a98a6	35
fed9b186 GS	36	#define MAX_LEN 10 /* Maximum number of consecutive
	37	* register for this particular RTC.
	38	*/
	39
1ce7c83f PZ	40	struct bq32k_regs {
	41	uint8_t seconds;
	42	uint8_t minutes;
	43	uint8_t cent_hours;
	44	uint8_t day;
	45	uint8_t date;
	46	uint8_t month;
	47	uint8_t years;
	48	};
	49
	50	static struct i2c_driver bq32k_driver;
	51
	52	static int bq32k_read(struct device dev, void data, uint8_t off, uint8_t len)
	53	{
	54	struct i2c_client *client = to_i2c_client(dev);
	55	struct i2c_msg msgs[] = {
	56	{
	57	.addr = client->addr,
	58	.flags = 0,
	59	.len = 1,
	60	.buf = &off,
	61	}, {
	62	.addr = client->addr,
	63	.flags = I2C_M_RD,
	64	.len = len,
	65	.buf = data,
	66	}
	67	};
	68
	69	if (i2c_transfer(client->adapter, msgs, 2) == 2)
	70	return 0;
	71
	72	return -EIO;
	73	}
	74
	75	static int bq32k_write(struct device dev, void data, uint8_t off, uint8_t len)
	76	{
	77	struct i2c_client *client = to_i2c_client(dev);
fed9b186	78	uint8_t buffer[MAX_LEN + 1];
1ce7c83f PZ	79
	80	buffer[0] = off;
	81	memcpy(&buffer[1], data, len);
	82
	83	if (i2c_master_send(client, buffer, len + 1) == len + 1)
	84	return 0;
	85
	86	return -EIO;
	87	}
	88
	89	static int bq32k_rtc_read_time(struct device dev, struct rtc_time tm)
	90	{
	91	struct bq32k_regs regs;
	92	int error;
	93
	94	error = bq32k_read(dev, &regs, 0, sizeof(regs));
	95	if (error)
	96	return error;
	97
421a5ba2 JÖ	98	/*
	99	* In case of oscillator failure, the register contents should be
	100	* considered invalid. The flag is cleared the next time the RTC is set.
	101	*/
	102	if (regs.minutes & BQ32K_OF)
	103	return -EINVAL;
	104
1ce7c83f	105	tm->tm_sec = bcd2bin(regs.seconds & BQ32K_SECONDS_MASK);
6ed1a51e	106	tm->tm_min = bcd2bin(regs.minutes & BQ32K_MINUTES_MASK);
1ce7c83f PZ	107	tm->tm_hour = bcd2bin(regs.cent_hours & BQ32K_HOURS_MASK);
	108	tm->tm_mday = bcd2bin(regs.date);
	109	tm->tm_wday = bcd2bin(regs.day) - 1;
	110	tm->tm_mon = bcd2bin(regs.month) - 1;
	111	tm->tm_year = bcd2bin(regs.years) +
	112	((regs.cent_hours & BQ32K_CENT) ? 100 : 0);
	113
22652ba7	114	return 0;
1ce7c83f PZ	115	}
	116
	117	static int bq32k_rtc_set_time(struct device dev, struct rtc_time tm)
	118	{
	119	struct bq32k_regs regs;
	120
	121	regs.seconds = bin2bcd(tm->tm_sec);
	122	regs.minutes = bin2bcd(tm->tm_min);
	123	regs.cent_hours = bin2bcd(tm->tm_hour) \| BQ32K_CENT_EN;
	124	regs.day = bin2bcd(tm->tm_wday + 1);
	125	regs.date = bin2bcd(tm->tm_mday);
	126	regs.month = bin2bcd(tm->tm_mon + 1);
	127
	128	if (tm->tm_year >= 100) {
	129	regs.cent_hours \|= BQ32K_CENT;
	130	regs.years = bin2bcd(tm->tm_year - 100);
	131	} else
	132	regs.years = bin2bcd(tm->tm_year);
	133
	134	return bq32k_write(dev, &regs, 0, sizeof(regs));
	135	}
	136
	137	static const struct rtc_class_ops bq32k_rtc_ops = {
	138	.read_time = bq32k_rtc_read_time,
	139	.set_time = bq32k_rtc_set_time,
	140	};
	141
765a98a6 PM	142	static int trickle_charger_of_init(struct device dev, struct device_node node)
	143	{
	144	unsigned char reg;
	145	int error;
	146	u32 ohms = 0;
	147
	148	if (of_property_read_u32(node, "trickle-resistor-ohms" , &ohms))
	149	return 0;
	150
	151	switch (ohms) {
	152	case 180+940:
	153	/*
	154	* TCHE[3:0] == 0x05, TCH2 == 1, TCFE == 0 (charging
	155	* over diode and 940ohm resistor)
	156	*/
	157
	158	if (of_property_read_bool(node, "trickle-diode-disable")) {
	159	dev_err(dev, "diode and resistor mismatch\n");
	160	return -EINVAL;
	161	}
	162	reg = 0x05;
	163	break;
	164
	165	case 180+20000:
	166	/* diode disabled */
	167
	168	if (!of_property_read_bool(node, "trickle-diode-disable")) {
	169	dev_err(dev, "bq32k: diode and resistor mismatch\n");
	170	return -EINVAL;
	171	}
5a6e7599	172	reg = 0x45;
765a98a6 PM	173	break;
	174
	175	default:
	176	dev_err(dev, "invalid resistor value (%d)\n", ohms);
	177	return -EINVAL;
	178	}
	179
	180	error = bq32k_write(dev, &reg, BQ32K_CFG2, 1);
	181	if (error)
	182	return error;
	183
	184	reg = 0x20;
	185	error = bq32k_write(dev, &reg, BQ32K_TCH2, 1);
	186	if (error)
	187	return error;
	188
	189	dev_info(dev, "Enabled trickle RTC battery charge.\n");
	190	return 0;
	191	}
	192
4c466872 EBS	193	static ssize_t bq32k_sysfs_show_tricklecharge_bypass(struct device *dev,
	194	struct device_attribute *attr,
	195	char *buf)
	196	{
	197	int reg, error;
	198
	199	error = bq32k_read(dev, &reg, BQ32K_CFG2, 1);
	200	if (error)
	201	return error;
	202
	203	return sprintf(buf, "%d\n", (reg & BQ32K_TCFE) ? 1 : 0);
	204	}
	205
	206	static ssize_t bq32k_sysfs_store_tricklecharge_bypass(struct device *dev,
	207	struct device_attribute *attr,
	208	const char *buf, size_t count)
	209	{
	210	int reg, enable, error;
	211
	212	if (kstrtoint(buf, 0, &enable))
	213	return -EINVAL;
	214
	215	error = bq32k_read(dev, &reg, BQ32K_CFG2, 1);
	216	if (error)
	217	return error;
	218
	219	if (enable) {
	220	reg \|= BQ32K_TCFE;
	221	error = bq32k_write(dev, &reg, BQ32K_CFG2, 1);
	222	if (error)
	223	return error;
	224
	225	dev_info(dev, "Enabled trickle charge FET bypass.\n");
	226	} else {
	227	reg &= ~BQ32K_TCFE;
	228	error = bq32k_write(dev, &reg, BQ32K_CFG2, 1);
	229	if (error)
	230	return error;
	231
	232	dev_info(dev, "Disabled trickle charge FET bypass.\n");
	233	}
	234
	235	return count;
	236	}
	237
	238	static DEVICE_ATTR(trickle_charge_bypass, 0644,
	239	bq32k_sysfs_show_tricklecharge_bypass,
	240	bq32k_sysfs_store_tricklecharge_bypass);
	241
	242	static int bq32k_sysfs_register(struct device *dev)
	243	{
	244	return device_create_file(dev, &dev_attr_trickle_charge_bypass);
	245	}
	246
	247	static void bq32k_sysfs_unregister(struct device *dev)
	248	{
	249	device_remove_file(dev, &dev_attr_trickle_charge_bypass);
	250	}
	251
1ce7c83f PZ	252	static int bq32k_probe(struct i2c_client *client,
	253	const struct i2c_device_id *id)
	254	{
	255	struct device *dev = &client->dev;
	256	struct rtc_device *rtc;
	257	uint8_t reg;
	258	int error;
	259
	260	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
	261	return -ENODEV;
	262
	263	/* Check Oscillator Stop flag */
	264	error = bq32k_read(dev, &reg, BQ32K_SECONDS, 1);
	265	if (!error && (reg & BQ32K_STOP)) {
	266	dev_warn(dev, "Oscillator was halted. Restarting...\n");
	267	reg &= ~BQ32K_STOP;
	268	error = bq32k_write(dev, &reg, BQ32K_SECONDS, 1);
	269	}
	270	if (error)
	271	return error;
	272
	273	/* Check Oscillator Failure flag */
	274	error = bq32k_read(dev, &reg, BQ32K_MINUTES, 1);
1ce7c83f PZ	275	if (error)
1ce7c83f PZ	276	return error;
421a5ba2 JÖ	277	if (reg & BQ32K_OF)
421a5ba2 JÖ	278	dev_warn(dev, "Oscillator Failure. Check RTC battery.\n");
1ce7c83f	279
617f6f7e	280	if (client->dev.of_node)
765a98a6 PM	281	trickle_charger_of_init(dev, client->dev.of_node);
765a98a6 PM	282
4e440681	283	rtc = devm_rtc_device_register(&client->dev, bq32k_driver.driver.name,
1ce7c83f PZ	284	&bq32k_rtc_ops, THIS_MODULE);
	285	if (IS_ERR(rtc))
	286	return PTR_ERR(rtc);
	287
4c466872 EBS	288	error = bq32k_sysfs_register(&client->dev);
	289	if (error) {
	290	dev_err(&client->dev,
	291	"Unable to create sysfs entries for rtc bq32000\n");
	292	return error;
	293	}
	294
	295
1ce7c83f PZ	296	i2c_set_clientdata(client, rtc);
	297
	298	return 0;
	299	}
	300
4c466872 EBS	301	static int bq32k_remove(struct i2c_client *client)
	302	{
	303	bq32k_sysfs_unregister(&client->dev);
	304
	305	return 0;
	306	}
	307
1ce7c83f PZ	308	static const struct i2c_device_id bq32k_id[] = {
	309	{ "bq32000", 0 },
	310	{ }
	311	};
	312	MODULE_DEVICE_TABLE(i2c, bq32k_id);
	313
b8ded817	314	static const __maybe_unused struct of_device_id bq32k_of_match[] = {
36138c70 JMC	315	{ .compatible = "ti,bq32000" },
	316	{ }
	317	};
	318	MODULE_DEVICE_TABLE(of, bq32k_of_match);
	319
1ce7c83f PZ	320	static struct i2c_driver bq32k_driver = {
	321	.driver = {
	322	.name = "bq32k",
36138c70	323	.of_match_table = of_match_ptr(bq32k_of_match),
1ce7c83f PZ	324	},
1ce7c83f PZ	325	.probe = bq32k_probe,
4c466872	326	.remove = bq32k_remove,
1ce7c83f PZ	327	.id_table = bq32k_id,
	328	};
	329
0abc9201	330	module_i2c_driver(bq32k_driver);
1ce7c83f PZ	331
	332	MODULE_AUTHOR("Semihalf, Piotr Ziecik <kosmo@semihalf.com>");
	333	MODULE_DESCRIPTION("TI BQ32000 I2C RTC driver");
	334	MODULE_LICENSE("GPL");