drivers/rtc/rtc-bq32k.c - third_party/linux - Git at Google

 // 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)
 {
 	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_new	= 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");
	// 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)
	{
	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_new = 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");