[linux-2.6-block.git] / drivers / power / supply / ltc2941-battery-gauge.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * I2C client/driver for the Linear Technology LTC2941, LTC2942, LTC2943
 * and LTC2944 Battery Gas Gauge IC
 *
 * Copyright (C) 2014 Topic Embedded Systems
 *
 * Author: Auryn Verwegen
 * Author: Mike Looijmans
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/swab.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/power_supply.h>
#include <linux/slab.h>

#define I16_MSB(x)			((x >> 8) & 0xFF)
#define I16_LSB(x)			(x & 0xFF)

#define LTC294X_WORK_DELAY		10	/* Update delay in seconds */

#define LTC294X_MAX_VALUE		0xFFFF
#define LTC294X_MID_SUPPLY		0x7FFF

#define LTC2941_MAX_PRESCALER_EXP	7
#define LTC2943_MAX_PRESCALER_EXP	6

enum ltc294x_reg {
	LTC294X_REG_STATUS		= 0x00,
	LTC294X_REG_CONTROL		= 0x01,
	LTC294X_REG_ACC_CHARGE_MSB	= 0x02,
	LTC294X_REG_ACC_CHARGE_LSB	= 0x03,
	LTC294X_REG_CHARGE_THR_HIGH_MSB	= 0x04,
	LTC294X_REG_CHARGE_THR_HIGH_LSB	= 0x05,
	LTC294X_REG_CHARGE_THR_LOW_MSB	= 0x06,
	LTC294X_REG_CHARGE_THR_LOW_LSB	= 0x07,
	LTC294X_REG_VOLTAGE_MSB		= 0x08,
	LTC294X_REG_VOLTAGE_LSB		= 0x09,
	LTC2942_REG_TEMPERATURE_MSB	= 0x0C,
	LTC2942_REG_TEMPERATURE_LSB	= 0x0D,
	LTC2943_REG_CURRENT_MSB		= 0x0E,
	LTC2943_REG_CURRENT_LSB		= 0x0F,
	LTC2943_REG_TEMPERATURE_MSB	= 0x14,
	LTC2943_REG_TEMPERATURE_LSB	= 0x15,
};

enum ltc294x_id {
	LTC2941_ID,
	LTC2942_ID,
	LTC2943_ID,
	LTC2944_ID,
};

#define LTC2941_REG_STATUS_CHIP_ID	BIT(7)

#define LTC2942_REG_CONTROL_MODE_SCAN	(BIT(7) | BIT(6))
#define LTC2943_REG_CONTROL_MODE_SCAN	BIT(7)
#define LTC294X_REG_CONTROL_PRESCALER_MASK	(BIT(5) | BIT(4) | BIT(3))
#define LTC294X_REG_CONTROL_SHUTDOWN_MASK	(BIT(0))
#define LTC294X_REG_CONTROL_PRESCALER_SET(x) \
	((x << 3) & LTC294X_REG_CONTROL_PRESCALER_MASK)
#define LTC294X_REG_CONTROL_ALCC_CONFIG_DISABLED	0
#define LTC294X_REG_CONTROL_ADC_DISABLE(x)	((x) & ~(BIT(7) | BIT(6)))

struct ltc294x_info {
	struct i2c_client *client;	/* I2C Client pointer */
	struct power_supply *supply;	/* Supply pointer */
	struct power_supply_desc supply_desc;	/* Supply description */
	struct delayed_work work;	/* Work scheduler */
	enum ltc294x_id id;		/* Chip type */
	int charge;	/* Last charge register content */
	int r_sense;	/* mOhm */
	int Qlsb;	/* nAh */
};

static inline int convert_bin_to_uAh(
	const struct ltc294x_info *info, int Q)
{
	return ((Q * (info->Qlsb / 10))) / 100;
}

static inline int convert_uAh_to_bin(
	const struct ltc294x_info *info, int uAh)
{
	int Q;

	Q = (uAh * 100) / (info->Qlsb/10);
	return (Q < LTC294X_MAX_VALUE) ? Q : LTC294X_MAX_VALUE;
}

static int ltc294x_read_regs(struct i2c_client *client,
	enum ltc294x_reg reg, u8 *buf, int num_regs)
{
	int ret;
	struct i2c_msg msgs[2] = { };
	u8 reg_start = reg;

	msgs[0].addr	= client->addr;
	msgs[0].len	= 1;
	msgs[0].buf	= &reg_start;

	msgs[1].addr	= client->addr;
	msgs[1].len	= num_regs;
	msgs[1].buf	= buf;
	msgs[1].flags	= I2C_M_RD;

	ret = i2c_transfer(client->adapter, &msgs[0], 2);
	if (ret < 0) {
		dev_err(&client->dev, "ltc2941 read_reg failed!\n");
		return ret;
	}

	dev_dbg(&client->dev, "%s (%#x, %d) -> %#x\n",
		__func__, reg, num_regs, *buf);

	return 0;
}

static int ltc294x_write_regs(struct i2c_client *client,
	enum ltc294x_reg reg, const u8 *buf, int num_regs)
{
	int ret;
	u8 reg_start = reg;

	ret = i2c_smbus_write_i2c_block_data(client, reg_start, num_regs, buf);
	if (ret < 0) {
		dev_err(&client->dev, "ltc2941 write_reg failed!\n");
		return ret;
	}

	dev_dbg(&client->dev, "%s (%#x, %d) -> %#x\n",
		__func__, reg, num_regs, *buf);

	return 0;
}

static int ltc294x_reset(const struct ltc294x_info *info, int prescaler_exp)
{
	int ret;
	u8 value;
	u8 control;

	/* Read status and control registers */
	ret = ltc294x_read_regs(info->client, LTC294X_REG_CONTROL, &value, 1);
	if (ret < 0) {
		dev_err(&info->client->dev,
			"Could not read registers from device\n");
		goto error_exit;
	}

	control = LTC294X_REG_CONTROL_PRESCALER_SET(prescaler_exp) |
				LTC294X_REG_CONTROL_ALCC_CONFIG_DISABLED;
	/* Put device into "monitor" mode */
	switch (info->id) {
	case LTC2942_ID:	/* 2942 measures every 2 sec */
		control |= LTC2942_REG_CONTROL_MODE_SCAN;
		break;
	case LTC2943_ID:
	case LTC2944_ID:	/* 2943 and 2944 measure every 10 sec */
		control |= LTC2943_REG_CONTROL_MODE_SCAN;
		break;
	default:
		break;
	}

	if (value != control) {
		ret = ltc294x_write_regs(info->client,
			LTC294X_REG_CONTROL, &control, 1);
		if (ret < 0) {
			dev_err(&info->client->dev,
				"Could not write register\n");
			goto error_exit;
		}
	}

	return 0;

error_exit:
	return ret;
}

static int ltc294x_read_charge_register(const struct ltc294x_info *info,
					enum ltc294x_reg reg)
 {
	int ret;
	u8 datar[2];

	ret = ltc294x_read_regs(info->client, reg, &datar[0], 2);
	if (ret < 0)
		return ret;
	return (datar[0] << 8) + datar[1];
}

static int ltc294x_get_charge(const struct ltc294x_info *info,
				enum ltc294x_reg reg, int *val)
{
	int value = ltc294x_read_charge_register(info, reg);

	if (value < 0)
		return value;
	/* When r_sense < 0, this counts up when the battery discharges */
	if (info->Qlsb < 0)
		value -= 0xFFFF;
	*val = convert_bin_to_uAh(info, value);
	return 0;
}

static int ltc294x_set_charge_now(const struct ltc294x_info *info, int val)
{
	int ret;
	u8 dataw[2];
	u8 ctrl_reg;
	s32 value;

	value = convert_uAh_to_bin(info, val);
	/* Direction depends on how sense+/- were connected */
	if (info->Qlsb < 0)
		value += 0xFFFF;
	if ((value < 0) || (value > 0xFFFF)) /* input validation */
		return -EINVAL;

	/* Read control register */
	ret = ltc294x_read_regs(info->client,
		LTC294X_REG_CONTROL, &ctrl_reg, 1);
	if (ret < 0)
		return ret;
	/* Disable analog section */
	ctrl_reg |= LTC294X_REG_CONTROL_SHUTDOWN_MASK;
	ret = ltc294x_write_regs(info->client,
		LTC294X_REG_CONTROL, &ctrl_reg, 1);
	if (ret < 0)
		return ret;
	/* Set new charge value */
	dataw[0] = I16_MSB(value);
	dataw[1] = I16_LSB(value);
	ret = ltc294x_write_regs(info->client,
		LTC294X_REG_ACC_CHARGE_MSB, &dataw[0], 2);
	if (ret < 0)
		goto error_exit;
	/* Enable analog section */
error_exit:
	ctrl_reg &= ~LTC294X_REG_CONTROL_SHUTDOWN_MASK;
	ret = ltc294x_write_regs(info->client,
		LTC294X_REG_CONTROL, &ctrl_reg, 1);

	return ret < 0 ? ret : 0;
}

static int ltc294x_set_charge_thr(const struct ltc294x_info *info,
					enum ltc294x_reg reg, int val)
{
	u8 dataw[2];
	s32 value;

	value = convert_uAh_to_bin(info, val);
	/* Direction depends on how sense+/- were connected */
	if (info->Qlsb < 0)
		value += 0xFFFF;
	if ((value < 0) || (value > 0xFFFF)) /* input validation */
		return -EINVAL;

	/* Set new charge value */
	dataw[0] = I16_MSB(value);
	dataw[1] = I16_LSB(value);
	return ltc294x_write_regs(info->client, reg, &dataw[0], 2);
}

static int ltc294x_get_charge_counter(
	const struct ltc294x_info *info, int *val)
{
	int value = ltc294x_read_charge_register(info, LTC294X_REG_ACC_CHARGE_MSB);

	if (value < 0)
		return value;
	value -= LTC294X_MID_SUPPLY;
	*val = convert_bin_to_uAh(info, value);
	return 0;
}

static int ltc294x_get_voltage(const struct ltc294x_info *info, int *val)
{
	int ret;
	u8 datar[2];
	u32 value;

	ret = ltc294x_read_regs(info->client,
		LTC294X_REG_VOLTAGE_MSB, &datar[0], 2);
	value = (datar[0] << 8) | datar[1];
	switch (info->id) {
	case LTC2943_ID:
		value *= 23600 * 2;
		value /= 0xFFFF;
		value *= 1000 / 2;
		break;
	case LTC2944_ID:
		value *= 70800 / 5*4;
		value /= 0xFFFF;
		value *= 1000 * 5/4;
		break;
	default:
		value *= 6000 * 10;
		value /= 0xFFFF;
		value *= 1000 / 10;
		break;
	}
	*val = value;
	return ret;
}

static int ltc294x_get_current(const struct ltc294x_info *info, int *val)
{
	int ret;
	u8 datar[2];
	s32 value;

	ret = ltc294x_read_regs(info->client,
		LTC2943_REG_CURRENT_MSB, &datar[0], 2);
	value = (datar[0] << 8) | datar[1];
	value -= 0x7FFF;
	if (info->id == LTC2944_ID)
		value *= 64000;
	else
		value *= 60000;
	/* Value is in range -32k..+32k, r_sense is usually 10..50 mOhm,
	 * the formula below keeps everything in s32 range while preserving
	 * enough digits */
	*val = 1000 * (value / (info->r_sense * 0x7FFF)); /* in uA */
	return ret;
}

static int ltc294x_get_temperature(const struct ltc294x_info *info, int *val)
{
	enum ltc294x_reg reg;
	int ret;
	u8 datar[2];
	u32 value;

	if (info->id == LTC2942_ID) {
		reg = LTC2942_REG_TEMPERATURE_MSB;
		value = 6000;	/* Full-scale is 600 Kelvin */
	} else {
		reg = LTC2943_REG_TEMPERATURE_MSB;
		value = 5100;	/* Full-scale is 510 Kelvin */
	}
	ret = ltc294x_read_regs(info->client, reg, &datar[0], 2);
	value *= (datar[0] << 8) | datar[1];
	/* Convert to tenths of degree Celsius */
	*val = value / 0xFFFF - 2722;
	return ret;
}

static int ltc294x_get_property(struct power_supply *psy,
				enum power_supply_property prop,
				union power_supply_propval *val)
{
	struct ltc294x_info *info = power_supply_get_drvdata(psy);

	switch (prop) {
	case POWER_SUPPLY_PROP_CHARGE_FULL:
		return ltc294x_get_charge(info, LTC294X_REG_CHARGE_THR_HIGH_MSB,
						&val->intval);
	case POWER_SUPPLY_PROP_CHARGE_EMPTY:
		return ltc294x_get_charge(info, LTC294X_REG_CHARGE_THR_LOW_MSB,
						&val->intval);
	case POWER_SUPPLY_PROP_CHARGE_NOW:
		return ltc294x_get_charge(info, LTC294X_REG_ACC_CHARGE_MSB,
						&val->intval);
	case POWER_SUPPLY_PROP_CHARGE_COUNTER:
		return ltc294x_get_charge_counter(info, &val->intval);
	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
		return ltc294x_get_voltage(info, &val->intval);
	case POWER_SUPPLY_PROP_CURRENT_NOW:
		return ltc294x_get_current(info, &val->intval);
	case POWER_SUPPLY_PROP_TEMP:
		return ltc294x_get_temperature(info, &val->intval);
	default:
		return -EINVAL;
	}
}

static int ltc294x_set_property(struct power_supply *psy,
	enum power_supply_property psp,
	const union power_supply_propval *val)
{
	struct ltc294x_info *info = power_supply_get_drvdata(psy);

	switch (psp) {
	case POWER_SUPPLY_PROP_CHARGE_FULL:
		return ltc294x_set_charge_thr(info,
			LTC294X_REG_CHARGE_THR_HIGH_MSB, val->intval);
	case POWER_SUPPLY_PROP_CHARGE_EMPTY:
		return ltc294x_set_charge_thr(info,
			LTC294X_REG_CHARGE_THR_LOW_MSB, val->intval);
	case POWER_SUPPLY_PROP_CHARGE_NOW:
		return ltc294x_set_charge_now(info, val->intval);
	default:
		return -EPERM;
	}
}

static int ltc294x_property_is_writeable(
	struct power_supply *psy, enum power_supply_property psp)
{
	switch (psp) {
	case POWER_SUPPLY_PROP_CHARGE_FULL:
	case POWER_SUPPLY_PROP_CHARGE_EMPTY:
	case POWER_SUPPLY_PROP_CHARGE_NOW:
		return 1;
	default:
		return 0;
	}
}

static void ltc294x_update(struct ltc294x_info *info)
{
	int charge = ltc294x_read_charge_register(info, LTC294X_REG_ACC_CHARGE_MSB);

	if (charge != info->charge) {
		info->charge = charge;
		power_supply_changed(info->supply);
	}
}

static void ltc294x_work(struct work_struct *work)
{
	struct ltc294x_info *info;

	info = container_of(work, struct ltc294x_info, work.work);
	ltc294x_update(info);
	schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
}

static enum power_supply_property ltc294x_properties[] = {
	POWER_SUPPLY_PROP_CHARGE_COUNTER,
	POWER_SUPPLY_PROP_CHARGE_FULL,
	POWER_SUPPLY_PROP_CHARGE_EMPTY,
	POWER_SUPPLY_PROP_CHARGE_NOW,
	POWER_SUPPLY_PROP_VOLTAGE_NOW,
	POWER_SUPPLY_PROP_TEMP,
	POWER_SUPPLY_PROP_CURRENT_NOW,
};

static int ltc294x_i2c_remove(struct i2c_client *client)
{
	struct ltc294x_info *info = i2c_get_clientdata(client);

	cancel_delayed_work(&info->work);
	power_supply_unregister(info->supply);
	return 0;
}

static int ltc294x_i2c_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
{
	struct power_supply_config psy_cfg = {};
	struct ltc294x_info *info;
	struct device_node *np;
	int ret;
	u32 prescaler_exp;
	s32 r_sense;
	u8 status;

	info = devm_kzalloc(&client->dev, sizeof(*info), GFP_KERNEL);
	if (info == NULL)
		return -ENOMEM;

	i2c_set_clientdata(client, info);

	np = of_node_get(client->dev.of_node);

	info->id = (enum ltc294x_id)of_device_get_match_data(&client->dev);
	info->supply_desc.name = np->name;

	/* r_sense can be negative, when sense+ is connected to the battery
	 * instead of the sense-. This results in reversed measurements. */
	ret = of_property_read_u32(np, "lltc,resistor-sense", &r_sense);
	if (ret < 0) {
		dev_err(&client->dev,
			"Could not find lltc,resistor-sense in devicetree\n");
		return ret;
	}
	info->r_sense = r_sense;

	ret = of_property_read_u32(np, "lltc,prescaler-exponent",
		&prescaler_exp);
	if (ret < 0) {
		dev_warn(&client->dev,
			"lltc,prescaler-exponent not in devicetree\n");
		prescaler_exp = LTC2941_MAX_PRESCALER_EXP;
	}

	if (info->id == LTC2943_ID) {
		if (prescaler_exp > LTC2943_MAX_PRESCALER_EXP)
			prescaler_exp = LTC2943_MAX_PRESCALER_EXP;
		info->Qlsb = ((340 * 50000) / r_sense) /
				(4096 / (1 << (2*prescaler_exp)));
	} else {
		if (prescaler_exp > LTC2941_MAX_PRESCALER_EXP)
			prescaler_exp = LTC2941_MAX_PRESCALER_EXP;
		info->Qlsb = ((85 * 50000) / r_sense) /
				(128 / (1 << prescaler_exp));
	}

	/* Read status register to check for LTC2942 */
	if (info->id == LTC2941_ID || info->id == LTC2942_ID) {
		ret = ltc294x_read_regs(client, LTC294X_REG_STATUS, &status, 1);
		if (ret < 0) {
			dev_err(&client->dev,
				"Could not read status register\n");
			return ret;
		}
		if (status & LTC2941_REG_STATUS_CHIP_ID)
			info->id = LTC2941_ID;
		else
			info->id = LTC2942_ID;
	}

	info->client = client;
	info->supply_desc.type = POWER_SUPPLY_TYPE_BATTERY;
	info->supply_desc.properties = ltc294x_properties;
	switch (info->id) {
	case LTC2944_ID:
	case LTC2943_ID:
		info->supply_desc.num_properties =
			ARRAY_SIZE(ltc294x_properties);
		break;
	case LTC2942_ID:
		info->supply_desc.num_properties =
			ARRAY_SIZE(ltc294x_properties) - 1;
		break;
	case LTC2941_ID:
	default:
		info->supply_desc.num_properties =
			ARRAY_SIZE(ltc294x_properties) - 3;
		break;
	}
	info->supply_desc.get_property = ltc294x_get_property;
	info->supply_desc.set_property = ltc294x_set_property;
	info->supply_desc.property_is_writeable = ltc294x_property_is_writeable;
	info->supply_desc.external_power_changed	= NULL;

	psy_cfg.drv_data = info;

	INIT_DELAYED_WORK(&info->work, ltc294x_work);

	ret = ltc294x_reset(info, prescaler_exp);
	if (ret < 0) {
		dev_err(&client->dev, "Communication with chip failed\n");
		return ret;
	}

	info->supply = power_supply_register(&client->dev, &info->supply_desc,
					     &psy_cfg);
	if (IS_ERR(info->supply)) {
		dev_err(&client->dev, "failed to register ltc2941\n");
		return PTR_ERR(info->supply);
	} else {
		schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
	}

	return 0;
}

static void ltc294x_i2c_shutdown(struct i2c_client *client)
{
	struct ltc294x_info *info = i2c_get_clientdata(client);
	int ret;
	u8 value;
	u8 control;

	/* The LTC2941 does not need any special handling */
	if (info->id == LTC2941_ID)
		return;

	/* Read control register */
	ret = ltc294x_read_regs(info->client, LTC294X_REG_CONTROL, &value, 1);
	if (ret < 0)
		return;

	/* Disable continuous ADC conversion as this drains the battery */
	control = LTC294X_REG_CONTROL_ADC_DISABLE(value);
	if (control != value)
		ltc294x_write_regs(info->client, LTC294X_REG_CONTROL,
			&control, 1);
}

#ifdef CONFIG_PM_SLEEP

static int ltc294x_suspend(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct ltc294x_info *info = i2c_get_clientdata(client);

	cancel_delayed_work(&info->work);
	return 0;
}

static int ltc294x_resume(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct ltc294x_info *info = i2c_get_clientdata(client);

	schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
	return 0;
}

static SIMPLE_DEV_PM_OPS(ltc294x_pm_ops, ltc294x_suspend, ltc294x_resume);
#define LTC294X_PM_OPS (&ltc294x_pm_ops)

#else
#define LTC294X_PM_OPS NULL
#endif /* CONFIG_PM_SLEEP */


static const struct i2c_device_id ltc294x_i2c_id[] = {
	{ "ltc2941", LTC2941_ID, },
	{ "ltc2942", LTC2942_ID, },
	{ "ltc2943", LTC2943_ID, },
	{ "ltc2944", LTC2944_ID, },
	{ },
};
MODULE_DEVICE_TABLE(i2c, ltc294x_i2c_id);

static const struct of_device_id ltc294x_i2c_of_match[] = {
	{
		.compatible = "lltc,ltc2941",
		.data = (void *)LTC2941_ID,
	},
	{
		.compatible = "lltc,ltc2942",
		.data = (void *)LTC2942_ID,
	},
	{
		.compatible = "lltc,ltc2943",
		.data = (void *)LTC2943_ID,
	},
	{
		.compatible = "lltc,ltc2944",
		.data = (void *)LTC2944_ID,
	},
	{ },
};
MODULE_DEVICE_TABLE(of, ltc294x_i2c_of_match);

static struct i2c_driver ltc294x_driver = {
	.driver = {
		.name	= "LTC2941",
		.of_match_table = ltc294x_i2c_of_match,
		.pm	= LTC294X_PM_OPS,
	},
	.probe		= ltc294x_i2c_probe,
	.remove		= ltc294x_i2c_remove,
	.shutdown	= ltc294x_i2c_shutdown,
	.id_table	= ltc294x_i2c_id,
};
module_i2c_driver(ltc294x_driver);

MODULE_AUTHOR("Auryn Verwegen, Topic Embedded Systems");
MODULE_AUTHOR("Mike Looijmans, Topic Embedded Products");
MODULE_DESCRIPTION("LTC2941/LTC2942/LTC2943/LTC2944 Battery Gas Gauge IC driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
09c434b8	1	// SPDX-License-Identifier: GPL-2.0-only
085bc24d	2	/*
17825ff6 DB	3	* I2C client/driver for the Linear Technology LTC2941, LTC2942, LTC2943
17825ff6 DB	4	* and LTC2944 Battery Gas Gauge IC
085bc24d ML	5	*
	6	* Copyright (C) 2014 Topic Embedded Systems
	7	*
	8	* Author: Auryn Verwegen
	9	* Author: Mike Looijmans
	10	*/
	11	#include <linux/kernel.h>
	12	#include <linux/module.h>
9697277e	13	#include <linux/of_device.h>
085bc24d ML	14	#include <linux/types.h>
	15	#include <linux/errno.h>
	16	#include <linux/swab.h>
	17	#include <linux/i2c.h>
	18	#include <linux/delay.h>
085bc24d ML	19	#include <linux/power_supply.h>
	20	#include <linux/slab.h>
	21
	22	#define I16_MSB(x) ((x >> 8) & 0xFF)
	23	#define I16_LSB(x) (x & 0xFF)
	24
	25	#define LTC294X_WORK_DELAY 10 /* Update delay in seconds */
	26
	27	#define LTC294X_MAX_VALUE 0xFFFF
	28	#define LTC294X_MID_SUPPLY 0x7FFF
	29
	30	#define LTC2941_MAX_PRESCALER_EXP 7
	31	#define LTC2943_MAX_PRESCALER_EXP 6
	32
	33	enum ltc294x_reg {
	34	LTC294X_REG_STATUS = 0x00,
	35	LTC294X_REG_CONTROL = 0x01,
	36	LTC294X_REG_ACC_CHARGE_MSB = 0x02,
	37	LTC294X_REG_ACC_CHARGE_LSB = 0x03,
3bf4e03d LM	38	LTC294X_REG_CHARGE_THR_HIGH_MSB = 0x04,
	39	LTC294X_REG_CHARGE_THR_HIGH_LSB = 0x05,
	40	LTC294X_REG_CHARGE_THR_LOW_MSB = 0x06,
	41	LTC294X_REG_CHARGE_THR_LOW_LSB = 0x07,
63e67c57 LM	42	LTC294X_REG_VOLTAGE_MSB = 0x08,
	43	LTC294X_REG_VOLTAGE_LSB = 0x09,
	44	LTC2942_REG_TEMPERATURE_MSB = 0x0C,
	45	LTC2942_REG_TEMPERATURE_LSB = 0x0D,
	46	LTC2943_REG_CURRENT_MSB = 0x0E,
	47	LTC2943_REG_CURRENT_LSB = 0x0F,
	48	LTC2943_REG_TEMPERATURE_MSB = 0x14,
	49	LTC2943_REG_TEMPERATURE_LSB = 0x15,
	50	};
	51
	52	enum ltc294x_id {
	53	LTC2941_ID,
a65df832	54	LTC2942_ID,
63e67c57	55	LTC2943_ID,
17825ff6	56	LTC2944_ID,
085bc24d ML	57	};
085bc24d ML	58
a65df832 LM	59	#define LTC2941_REG_STATUS_CHIP_ID BIT(7)
	60
	61	#define LTC2942_REG_CONTROL_MODE_SCAN (BIT(7) \| BIT(6))
	62	#define LTC2943_REG_CONTROL_MODE_SCAN BIT(7)
085bc24d ML	63	#define LTC294X_REG_CONTROL_PRESCALER_MASK (BIT(5) \| BIT(4) \| BIT(3))
	64	#define LTC294X_REG_CONTROL_SHUTDOWN_MASK (BIT(0))
	65	#define LTC294X_REG_CONTROL_PRESCALER_SET(x) \
	66	((x << 3) & LTC294X_REG_CONTROL_PRESCALER_MASK)
	67	#define LTC294X_REG_CONTROL_ALCC_CONFIG_DISABLED 0
5f2f0d61	68	#define LTC294X_REG_CONTROL_ADC_DISABLE(x) ((x) & ~(BIT(7) \| BIT(6)))
085bc24d	69
085bc24d ML	70	struct ltc294x_info {
085bc24d ML	71	struct i2c_client client; / I2C Client pointer */
297d716f KK	72	struct power_supply supply; / Supply pointer */
297d716f KK	73	struct power_supply_desc supply_desc; /* Supply description */
085bc24d	74	struct delayed_work work; /* Work scheduler */
63e67c57	75	enum ltc294x_id id; /* Chip type */
085bc24d ML	76	int charge; /* Last charge register content */
	77	int r_sense; /* mOhm */
	78	int Qlsb; /* nAh */
	79	};
	80
085bc24d ML	81	static inline int convert_bin_to_uAh(
	82	const struct ltc294x_info *info, int Q)
	83	{
	84	return ((Q * (info->Qlsb / 10))) / 100;
	85	}
	86
	87	static inline int convert_uAh_to_bin(
	88	const struct ltc294x_info *info, int uAh)
	89	{
	90	int Q;
	91
	92	Q = (uAh * 100) / (info->Qlsb/10);
	93	return (Q < LTC294X_MAX_VALUE) ? Q : LTC294X_MAX_VALUE;
	94	}
	95
	96	static int ltc294x_read_regs(struct i2c_client *client,
	97	enum ltc294x_reg reg, u8 *buf, int num_regs)
	98	{
	99	int ret;
	100	struct i2c_msg msgs[2] = { };
	101	u8 reg_start = reg;
	102
	103	msgs[0].addr = client->addr;
	104	msgs[0].len = 1;
	105	msgs[0].buf = &reg_start;
	106
	107	msgs[1].addr = client->addr;
	108	msgs[1].len = num_regs;
	109	msgs[1].buf = buf;
	110	msgs[1].flags = I2C_M_RD;
	111
	112	ret = i2c_transfer(client->adapter, &msgs[0], 2);
	113	if (ret < 0) {
	114	dev_err(&client->dev, "ltc2941 read_reg failed!\n");
	115	return ret;
	116	}
	117
	118	dev_dbg(&client->dev, "%s (%#x, %d) -> %#x\n",
	119	__func__, reg, num_regs, *buf);
	120
	121	return 0;
	122	}
	123
	124	static int ltc294x_write_regs(struct i2c_client *client,
	125	enum ltc294x_reg reg, const u8 *buf, int num_regs)
	126	{
	127	int ret;
	128	u8 reg_start = reg;
	129
	130	ret = i2c_smbus_write_i2c_block_data(client, reg_start, num_regs, buf);
	131	if (ret < 0) {
	132	dev_err(&client->dev, "ltc2941 write_reg failed!\n");
	133	return ret;
	134	}
	135
	136	dev_dbg(&client->dev, "%s (%#x, %d) -> %#x\n",
	137	__func__, reg, num_regs, *buf);
	138
	139	return 0;
	140	}
	141
	142	static int ltc294x_reset(const struct ltc294x_info *info, int prescaler_exp)
	143	{
	144	int ret;
145	u8 value;
146	u8 control;
147
148	/* Read status and control registers */
149	ret = ltc294x_read_regs(info->client, LTC294X_REG_CONTROL, &value, 1);
150	if (ret < 0) {
151	dev_err(&info->client->dev,
152	"Could not read registers from device\n");
153	goto error_exit;
154	}
155
156	control = LTC294X_REG_CONTROL_PRESCALER_SET(prescaler_exp) \|
157	LTC294X_REG_CONTROL_ALCC_CONFIG_DISABLED;
a65df832 LM	158	/* Put device into "monitor" mode */
	159	switch (info->id) {
	160	case LTC2942_ID: /* 2942 measures every 2 sec */
	161	control \|= LTC2942_REG_CONTROL_MODE_SCAN;
	162	break;
17825ff6 DB	163	case LTC2943_ID:
17825ff6 DB	164	case LTC2944_ID: /* 2943 and 2944 measure every 10 sec */
085bc24d	165	control \|= LTC2943_REG_CONTROL_MODE_SCAN;
a65df832 LM	166	break;
	167	default:
	168	break;
	169	}
085bc24d ML	170
	171	if (value != control) {
	172	ret = ltc294x_write_regs(info->client,
	173	LTC294X_REG_CONTROL, &control, 1);
	174	if (ret < 0) {
	175	dev_err(&info->client->dev,
	176	"Could not write register\n");
	177	goto error_exit;
	178	}
	179	}
	180
	181	return 0;
	182
	183	error_exit:
	184	return ret;
	185	}
	186
3bf4e03d LM	187	static int ltc294x_read_charge_register(const struct ltc294x_info *info,
	188	enum ltc294x_reg reg)
	189	{
085bc24d ML	190	int ret;
	191	u8 datar[2];
	192
3bf4e03d	193	ret = ltc294x_read_regs(info->client, reg, &datar[0], 2);
085bc24d ML	194	if (ret < 0)
	195	return ret;
	196	return (datar[0] << 8) + datar[1];
	197	}
	198
3bf4e03d LM	199	static int ltc294x_get_charge(const struct ltc294x_info *info,
3bf4e03d LM	200	enum ltc294x_reg reg, int *val)
085bc24d	201	{
3bf4e03d	202	int value = ltc294x_read_charge_register(info, reg);
085bc24d ML	203
	204	if (value < 0)
	205	return value;
	206	/* When r_sense < 0, this counts up when the battery discharges */
	207	if (info->Qlsb < 0)
	208	value -= 0xFFFF;
	209	*val = convert_bin_to_uAh(info, value);
	210	return 0;
	211	}
	212
	213	static int ltc294x_set_charge_now(const struct ltc294x_info *info, int val)
	214	{
	215	int ret;
	216	u8 dataw[2];
	217	u8 ctrl_reg;
	218	s32 value;
	219
	220	value = convert_uAh_to_bin(info, val);
	221	/* Direction depends on how sense+/- were connected */
	222	if (info->Qlsb < 0)
	223	value += 0xFFFF;
	224	if ((value < 0) \|\| (value > 0xFFFF)) /* input validation */
	225	return -EINVAL;
	226
	227	/* Read control register */
	228	ret = ltc294x_read_regs(info->client,
	229	LTC294X_REG_CONTROL, &ctrl_reg, 1);
	230	if (ret < 0)
	231	return ret;
	232	/* Disable analog section */
	233	ctrl_reg \|= LTC294X_REG_CONTROL_SHUTDOWN_MASK;
	234	ret = ltc294x_write_regs(info->client,
	235	LTC294X_REG_CONTROL, &ctrl_reg, 1);
	236	if (ret < 0)
	237	return ret;
	238	/* Set new charge value */
	239	dataw[0] = I16_MSB(value);
	240	dataw[1] = I16_LSB(value);
	241	ret = ltc294x_write_regs(info->client,
	242	LTC294X_REG_ACC_CHARGE_MSB, &dataw[0], 2);
	243	if (ret < 0)
	244	goto error_exit;
	245	/* Enable analog section */
	246	error_exit:
	247	ctrl_reg &= ~LTC294X_REG_CONTROL_SHUTDOWN_MASK;
	248	ret = ltc294x_write_regs(info->client,
	249	LTC294X_REG_CONTROL, &ctrl_reg, 1);
	250
	251	return ret < 0 ? ret : 0;
	252	}
	253
3bf4e03d LM	254	static int ltc294x_set_charge_thr(const struct ltc294x_info *info,
	255	enum ltc294x_reg reg, int val)
	256	{
	257	u8 dataw[2];
	258	s32 value;
	259
	260	value = convert_uAh_to_bin(info, val);
	261	/* Direction depends on how sense+/- were connected */
	262	if (info->Qlsb < 0)
	263	value += 0xFFFF;
	264	if ((value < 0) \|\| (value > 0xFFFF)) /* input validation */
	265	return -EINVAL;
	266
	267	/* Set new charge value */
	268	dataw[0] = I16_MSB(value);
	269	dataw[1] = I16_LSB(value);
	270	return ltc294x_write_regs(info->client, reg, &dataw[0], 2);
	271	}
	272
085bc24d ML	273	static int ltc294x_get_charge_counter(
	274	const struct ltc294x_info info, int val)
	275	{
3bf4e03d	276	int value = ltc294x_read_charge_register(info, LTC294X_REG_ACC_CHARGE_MSB);
085bc24d ML	277
	278	if (value < 0)
	279	return value;
	280	value -= LTC294X_MID_SUPPLY;
	281	*val = convert_bin_to_uAh(info, value);
	282	return 0;
	283	}
	284
	285	static int ltc294x_get_voltage(const struct ltc294x_info info, int val)
	286	{
	287	int ret;
	288	u8 datar[2];
	289	u32 value;
	290
	291	ret = ltc294x_read_regs(info->client,
	292	LTC294X_REG_VOLTAGE_MSB, &datar[0], 2);
	293	value = (datar[0] << 8) \| datar[1];
a65df832 LM	294	switch (info->id) {
	295	case LTC2943_ID:
	296	value = 23600 2;
	297	value /= 0xFFFF;
	298	value *= 1000 / 2;
	299	break;
17825ff6 DB	300	case LTC2944_ID:
	301	value = 70800 / 54;
	302	value /= 0xFFFF;
	303	value = 1000 5/4;
	304	break;
a65df832 LM	305	default:
	306	value = 6000 10;
	307	value /= 0xFFFF;
	308	value *= 1000 / 10;
	309	break;
	310	}
	311	*val = value;
085bc24d ML	312	return ret;
	313	}
	314
	315	static int ltc294x_get_current(const struct ltc294x_info info, int val)
	316	{
	317	int ret;
	318	u8 datar[2];
	319	s32 value;
	320
	321	ret = ltc294x_read_regs(info->client,
63e67c57	322	LTC2943_REG_CURRENT_MSB, &datar[0], 2);
085bc24d ML	323	value = (datar[0] << 8) \| datar[1];
085bc24d ML	324	value -= 0x7FFF;
17825ff6 DB	325	if (info->id == LTC2944_ID)
	326	value *= 64000;
	327	else
	328	value *= 60000;
085bc24d ML	329	/* Value is in range -32k..+32k, r_sense is usually 10..50 mOhm,
	330	* the formula below keeps everything in s32 range while preserving
	331	* enough digits */
17825ff6	332	val = 1000 (value / (info->r_sense * 0x7FFF)); /* in uA */
085bc24d ML	333	return ret;
	334	}
	335
	336	static int ltc294x_get_temperature(const struct ltc294x_info info, int val)
	337	{
a65df832	338	enum ltc294x_reg reg;
085bc24d ML	339	int ret;
	340	u8 datar[2];
	341	u32 value;
	342
a65df832 LM	343	if (info->id == LTC2942_ID) {
a65df832 LM	344	reg = LTC2942_REG_TEMPERATURE_MSB;
dde5953f	345	value = 6000; /* Full-scale is 600 Kelvin */
a65df832 LM	346	} else {
a65df832 LM	347	reg = LTC2943_REG_TEMPERATURE_MSB;
dde5953f	348	value = 5100; /* Full-scale is 510 Kelvin */
a65df832 LM	349	}
	350	ret = ltc294x_read_regs(info->client, reg, &datar[0], 2);
	351	value *= (datar[0] << 8) \| datar[1];
dde5953f LM	352	/* Convert to tenths of degree Celsius */
dde5953f LM	353	*val = value / 0xFFFF - 2722;
085bc24d ML	354	return ret;
	355	}
	356
	357	static int ltc294x_get_property(struct power_supply *psy,
	358	enum power_supply_property prop,
	359	union power_supply_propval *val)
	360	{
297d716f	361	struct ltc294x_info *info = power_supply_get_drvdata(psy);
085bc24d ML	362
085bc24d ML	363	switch (prop) {
3bf4e03d LM	364	case POWER_SUPPLY_PROP_CHARGE_FULL:
	365	return ltc294x_get_charge(info, LTC294X_REG_CHARGE_THR_HIGH_MSB,
	366	&val->intval);
	367	case POWER_SUPPLY_PROP_CHARGE_EMPTY:
	368	return ltc294x_get_charge(info, LTC294X_REG_CHARGE_THR_LOW_MSB,
	369	&val->intval);
085bc24d	370	case POWER_SUPPLY_PROP_CHARGE_NOW:
3bf4e03d LM	371	return ltc294x_get_charge(info, LTC294X_REG_ACC_CHARGE_MSB,
3bf4e03d LM	372	&val->intval);
085bc24d ML	373	case POWER_SUPPLY_PROP_CHARGE_COUNTER:
	374	return ltc294x_get_charge_counter(info, &val->intval);
	375	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
	376	return ltc294x_get_voltage(info, &val->intval);
	377	case POWER_SUPPLY_PROP_CURRENT_NOW:
	378	return ltc294x_get_current(info, &val->intval);
	379	case POWER_SUPPLY_PROP_TEMP:
	380	return ltc294x_get_temperature(info, &val->intval);
	381	default:
	382	return -EINVAL;
	383	}
	384	}
	385
	386	static int ltc294x_set_property(struct power_supply *psy,
	387	enum power_supply_property psp,
	388	const union power_supply_propval *val)
	389	{
297d716f	390	struct ltc294x_info *info = power_supply_get_drvdata(psy);
085bc24d ML	391
085bc24d ML	392	switch (psp) {
3bf4e03d LM	393	case POWER_SUPPLY_PROP_CHARGE_FULL:
	394	return ltc294x_set_charge_thr(info,
	395	LTC294X_REG_CHARGE_THR_HIGH_MSB, val->intval);
	396	case POWER_SUPPLY_PROP_CHARGE_EMPTY:
	397	return ltc294x_set_charge_thr(info,
	398	LTC294X_REG_CHARGE_THR_LOW_MSB, val->intval);
085bc24d ML	399	case POWER_SUPPLY_PROP_CHARGE_NOW:
	400	return ltc294x_set_charge_now(info, val->intval);
	401	default:
	402	return -EPERM;
	403	}
	404	}
	405
	406	static int ltc294x_property_is_writeable(
	407	struct power_supply *psy, enum power_supply_property psp)
	408	{
	409	switch (psp) {
3bf4e03d LM	410	case POWER_SUPPLY_PROP_CHARGE_FULL:
3bf4e03d LM	411	case POWER_SUPPLY_PROP_CHARGE_EMPTY:
085bc24d ML	412	case POWER_SUPPLY_PROP_CHARGE_NOW:
	413	return 1;
	414	default:
	415	return 0;
	416	}
	417	}
	418
	419	static void ltc294x_update(struct ltc294x_info *info)
	420	{
3bf4e03d	421	int charge = ltc294x_read_charge_register(info, LTC294X_REG_ACC_CHARGE_MSB);
085bc24d ML	422
	423	if (charge != info->charge) {
	424	info->charge = charge;
297d716f	425	power_supply_changed(info->supply);
085bc24d ML	426	}
	427	}
	428
	429	static void ltc294x_work(struct work_struct *work)
	430	{
	431	struct ltc294x_info *info;
	432
	433	info = container_of(work, struct ltc294x_info, work.work);
	434	ltc294x_update(info);
	435	schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
	436	}
	437
	438	static enum power_supply_property ltc294x_properties[] = {
	439	POWER_SUPPLY_PROP_CHARGE_COUNTER,
3bf4e03d LM	440	POWER_SUPPLY_PROP_CHARGE_FULL,
3bf4e03d LM	441	POWER_SUPPLY_PROP_CHARGE_EMPTY,
085bc24d ML	442	POWER_SUPPLY_PROP_CHARGE_NOW,
085bc24d ML	443	POWER_SUPPLY_PROP_VOLTAGE_NOW,
085bc24d	444	POWER_SUPPLY_PROP_TEMP,
63e67c57	445	POWER_SUPPLY_PROP_CURRENT_NOW,
085bc24d ML	446	};
	447
	448	static int ltc294x_i2c_remove(struct i2c_client *client)
	449	{
	450	struct ltc294x_info *info = i2c_get_clientdata(client);
	451
	452	cancel_delayed_work(&info->work);
297d716f	453	power_supply_unregister(info->supply);
085bc24d ML	454	return 0;
	455	}
	456
	457	static int ltc294x_i2c_probe(struct i2c_client *client,
	458	const struct i2c_device_id *id)
	459	{
297d716f	460	struct power_supply_config psy_cfg = {};
085bc24d	461	struct ltc294x_info *info;
a65df832	462	struct device_node *np;
085bc24d	463	int ret;
085bc24d ML	464	u32 prescaler_exp;
085bc24d ML	465	s32 r_sense;
a65df832	466	u8 status;
085bc24d	467
085bc24d	468	info = devm_kzalloc(&client->dev, sizeof(*info), GFP_KERNEL);
377b641a ML	469	if (info == NULL)
377b641a ML	470	return -ENOMEM;
085bc24d ML	471
	472	i2c_set_clientdata(client, info);
	473
085bc24d ML	474	np = of_node_get(client->dev.of_node);
085bc24d ML	475
63e67c57	476	info->id = (enum ltc294x_id)of_device_get_match_data(&client->dev);
377b641a ML	477	info->supply_desc.name = np->name;
377b641a ML	478
085bc24d ML	479	/* r_sense can be negative, when sense+ is connected to the battery
	480	* instead of the sense-. This results in reversed measurements. */
	481	ret = of_property_read_u32(np, "lltc,resistor-sense", &r_sense);
	482	if (ret < 0) {
	483	dev_err(&client->dev,
	484	"Could not find lltc,resistor-sense in devicetree\n");
377b641a	485	return ret;
085bc24d ML	486	}
	487	info->r_sense = r_sense;
	488
	489	ret = of_property_read_u32(np, "lltc,prescaler-exponent",
	490	&prescaler_exp);
	491	if (ret < 0) {
	492	dev_warn(&client->dev,
	493	"lltc,prescaler-exponent not in devicetree\n");
	494	prescaler_exp = LTC2941_MAX_PRESCALER_EXP;
	495	}
	496
63e67c57	497	if (info->id == LTC2943_ID) {
085bc24d ML	498	if (prescaler_exp > LTC2943_MAX_PRESCALER_EXP)
	499	prescaler_exp = LTC2943_MAX_PRESCALER_EXP;
	500	info->Qlsb = ((340 * 50000) / r_sense) /
	501	(4096 / (1 << (2*prescaler_exp)));
	502	} else {
	503	if (prescaler_exp > LTC2941_MAX_PRESCALER_EXP)
	504	prescaler_exp = LTC2941_MAX_PRESCALER_EXP;
4bf828cf	505	info->Qlsb = ((85 * 50000) / r_sense) /
085bc24d ML	506	(128 / (1 << prescaler_exp));
	507	}
	508
a65df832 LM	509	/* Read status register to check for LTC2942 */
	510	if (info->id == LTC2941_ID \|\| info->id == LTC2942_ID) {
	511	ret = ltc294x_read_regs(client, LTC294X_REG_STATUS, &status, 1);
	512	if (ret < 0) {
	513	dev_err(&client->dev,
	514	"Could not read status register\n");
	515	return ret;
	516	}
	517	if (status & LTC2941_REG_STATUS_CHIP_ID)
	518	info->id = LTC2941_ID;
	519	else
	520	info->id = LTC2942_ID;
	521	}
	522
085bc24d	523	info->client = client;
297d716f KK	524	info->supply_desc.type = POWER_SUPPLY_TYPE_BATTERY;
297d716f KK	525	info->supply_desc.properties = ltc294x_properties;
63e67c57	526	switch (info->id) {
17825ff6	527	case LTC2944_ID:
63e67c57	528	case LTC2943_ID:
297d716f	529	info->supply_desc.num_properties =
085bc24d	530	ARRAY_SIZE(ltc294x_properties);
63e67c57	531	break;
a65df832 LM	532	case LTC2942_ID:
	533	info->supply_desc.num_properties =
	534	ARRAY_SIZE(ltc294x_properties) - 1;
	535	break;
63e67c57 LM	536	case LTC2941_ID:
63e67c57 LM	537	default:
297d716f	538	info->supply_desc.num_properties =
085bc24d	539	ARRAY_SIZE(ltc294x_properties) - 3;
63e67c57 LM	540	break;
63e67c57 LM	541	}
297d716f KK	542	info->supply_desc.get_property = ltc294x_get_property;
	543	info->supply_desc.set_property = ltc294x_set_property;
	544	info->supply_desc.property_is_writeable = ltc294x_property_is_writeable;
	545	info->supply_desc.external_power_changed = NULL;
	546
	547	psy_cfg.drv_data = info;
085bc24d ML	548
	549	INIT_DELAYED_WORK(&info->work, ltc294x_work);
	550
	551	ret = ltc294x_reset(info, prescaler_exp);
	552	if (ret < 0) {
	553	dev_err(&client->dev, "Communication with chip failed\n");
377b641a	554	return ret;
085bc24d ML	555	}
085bc24d ML	556
297d716f KK	557	info->supply = power_supply_register(&client->dev, &info->supply_desc,
	558	&psy_cfg);
	559	if (IS_ERR(info->supply)) {
085bc24d	560	dev_err(&client->dev, "failed to register ltc2941\n");
377b641a	561	return PTR_ERR(info->supply);
085bc24d ML	562	} else {
	563	schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
	564	}
	565
	566	return 0;
085bc24d ML	567	}
085bc24d ML	568
5f2f0d61 ML	569	static void ltc294x_i2c_shutdown(struct i2c_client *client)
	570	{
	571	struct ltc294x_info *info = i2c_get_clientdata(client);
	572	int ret;
	573	u8 value;
	574	u8 control;
	575
	576	/* The LTC2941 does not need any special handling */
	577	if (info->id == LTC2941_ID)
	578	return;
	579
	580	/* Read control register */
	581	ret = ltc294x_read_regs(info->client, LTC294X_REG_CONTROL, &value, 1);
	582	if (ret < 0)
	583	return;
	584
	585	/* Disable continuous ADC conversion as this drains the battery */
	586	control = LTC294X_REG_CONTROL_ADC_DISABLE(value);
	587	if (control != value)
	588	ltc294x_write_regs(info->client, LTC294X_REG_CONTROL,
	589	&control, 1);
	590	}
	591
085bc24d ML	592	#ifdef CONFIG_PM_SLEEP
	593
	594	static int ltc294x_suspend(struct device *dev)
	595	{
	596	struct i2c_client *client = to_i2c_client(dev);
	597	struct ltc294x_info *info = i2c_get_clientdata(client);
	598
	599	cancel_delayed_work(&info->work);
	600	return 0;
	601	}
	602
	603	static int ltc294x_resume(struct device *dev)
	604	{
	605	struct i2c_client *client = to_i2c_client(dev);
	606	struct ltc294x_info *info = i2c_get_clientdata(client);
	607
	608	schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
	609	return 0;
	610	}
	611
	612	static SIMPLE_DEV_PM_OPS(ltc294x_pm_ops, ltc294x_suspend, ltc294x_resume);
	613	#define LTC294X_PM_OPS (&ltc294x_pm_ops)
	614
	615	#else
	616	#define LTC294X_PM_OPS NULL
	617	#endif /* CONFIG_PM_SLEEP */
	618
	619
	620	static const struct i2c_device_id ltc294x_i2c_id[] = {
63e67c57	621	{ "ltc2941", LTC2941_ID, },
a65df832	622	{ "ltc2942", LTC2942_ID, },
63e67c57	623	{ "ltc2943", LTC2943_ID, },
17825ff6	624	{ "ltc2944", LTC2944_ID, },
085bc24d ML	625	{ },
	626	};
	627	MODULE_DEVICE_TABLE(i2c, ltc294x_i2c_id);
	628
9697277e JMC	629	static const struct of_device_id ltc294x_i2c_of_match[] = {
	630	{
	631	.compatible = "lltc,ltc2941",
63e67c57	632	.data = (void *)LTC2941_ID,
9697277e	633	},
a65df832 LM	634	{
	635	.compatible = "lltc,ltc2942",
	636	.data = (void *)LTC2942_ID,
	637	},
9697277e JMC	638	{
9697277e JMC	639	.compatible = "lltc,ltc2943",
63e67c57	640	.data = (void *)LTC2943_ID,
9697277e	641	},
17825ff6 DB	642	{
	643	.compatible = "lltc,ltc2944",
	644	.data = (void *)LTC2944_ID,
	645	},
9697277e JMC	646	{ },
	647	};
	648	MODULE_DEVICE_TABLE(of, ltc294x_i2c_of_match);
	649
085bc24d ML	650	static struct i2c_driver ltc294x_driver = {
	651	.driver = {
	652	.name = "LTC2941",
9697277e	653	.of_match_table = ltc294x_i2c_of_match,
085bc24d ML	654	.pm = LTC294X_PM_OPS,
	655	},
	656	.probe = ltc294x_i2c_probe,
	657	.remove = ltc294x_i2c_remove,
5f2f0d61	658	.shutdown = ltc294x_i2c_shutdown,
085bc24d ML	659	.id_table = ltc294x_i2c_id,
	660	};
	661	module_i2c_driver(ltc294x_driver);
	662
	663	MODULE_AUTHOR("Auryn Verwegen, Topic Embedded Systems");
	664	MODULE_AUTHOR("Mike Looijmans, Topic Embedded Products");
17825ff6	665	MODULE_DESCRIPTION("LTC2941/LTC2942/LTC2943/LTC2944 Battery Gas Gauge IC driver");
085bc24d	666	MODULE_LICENSE("GPL");