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

/*
 * I2C client/driver for the Linear Technology LTC2941 and LTC2943
 * 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/types.h>
#include <linux/errno.h>
#include <linux/swab.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/idr.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_THRESH_HIGH_MSB	= 0x04,
	LTC294X_REG_THRESH_HIGH_LSB	= 0x05,
	LTC294X_REG_THRESH_LOW_MSB	= 0x06,
	LTC294X_REG_THRESH_LOW_LSB	= 0x07,
	LTC294X_REG_VOLTAGE_MSB	= 0x08,
	LTC294X_REG_VOLTAGE_LSB	= 0x09,
	LTC294X_REG_CURRENT_MSB	= 0x0E,
	LTC294X_REG_CURRENT_LSB	= 0x0F,
	LTC294X_REG_TEMPERATURE_MSB	= 0x14,
	LTC294X_REG_TEMPERATURE_LSB	= 0x15,
};

#define LTC2943_REG_CONTROL_MODE_MASK (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 LTC2941_NUM_REGS	0x08
#define LTC2943_NUM_REGS	0x18

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 */
	int num_regs;	/* Number of registers (chip type) */
	int id;		/* Identifier of ltc294x chip */
	int charge;	/* Last charge register content */
	int r_sense;	/* mOhm */
	int Qlsb;	/* nAh */
};

static DEFINE_IDR(ltc294x_id);
static DEFINE_MUTEX(ltc294x_lock);

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 the 2943 into "monitor" mode, so it measures every 10 sec */
	if (info->num_regs == LTC2943_NUM_REGS)
		control |= LTC2943_REG_CONTROL_MODE_SCAN;

	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)
{
	int ret;
	u8 datar[2];

	ret = ltc294x_read_regs(info->client,
		LTC294X_REG_ACC_CHARGE_MSB, &datar[0], 2);
	if (ret < 0)
		return ret;
	return (datar[0] << 8) + datar[1];
}

static int ltc294x_get_charge_now(const struct ltc294x_info *info, int *val)
{
	int value = ltc294x_read_charge_register(info);

	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_get_charge_counter(
	const struct ltc294x_info *info, int *val)
{
	int value = ltc294x_read_charge_register(info);

	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];
	*val = ((value * 23600) / 0xFFFF) * 1000; /* in uV */
	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,
		LTC294X_REG_CURRENT_MSB, &datar[0], 2);
	value = (datar[0] << 8) | datar[1];
	value -= 0x7FFF;
	/* 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 * ((60000 * value) / (info->r_sense * 0x7FFF)); /* in uA */
	return ret;
}

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

	ret = ltc294x_read_regs(info->client,
		LTC294X_REG_TEMPERATURE_MSB, &datar[0], 2);
	value = (datar[0] << 8) | datar[1];
	/* Full-scale is 510 Kelvin, convert to centidegrees  */
	*val = (((51000 * value) / 0xFFFF) - 27215);
	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_NOW:
		return ltc294x_get_charge_now(info, &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_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_NOW:
		return 1;
	default:
		return 0;
	}
}

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

	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_NOW,
	POWER_SUPPLY_PROP_VOLTAGE_NOW,
	POWER_SUPPLY_PROP_CURRENT_NOW,
	POWER_SUPPLY_PROP_TEMP,
};

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);
	kfree(info->supply_desc.name);
	mutex_lock(&ltc294x_lock);
	idr_remove(&ltc294x_id, info->id);
	mutex_unlock(&ltc294x_lock);
	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;
	int ret;
	int num;
	u32 prescaler_exp;
	s32 r_sense;
	struct device_node *np;

	mutex_lock(&ltc294x_lock);
	ret = idr_alloc(&ltc294x_id, client, 0, 0, GFP_KERNEL);
	mutex_unlock(&ltc294x_lock);
	if (ret < 0)
		goto fail_id;

	num = ret;

	info = devm_kzalloc(&client->dev, sizeof(*info), GFP_KERNEL);
	if (info == NULL) {
		ret = -ENOMEM;
		goto fail_info;
	}

	i2c_set_clientdata(client, info);

	info->num_regs = id->driver_data;
	info->supply_desc.name = kasprintf(GFP_KERNEL, "%s-%d", client->name,
					   num);
	if (!info->supply_desc.name) {
		ret = -ENOMEM;
		goto fail_name;
	}

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

	/* 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");
		goto fail_name;
	}
	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->num_regs == LTC2943_NUM_REGS) {
		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));
	}

	info->client = client;
	info->id = num;
	info->supply_desc.type = POWER_SUPPLY_TYPE_BATTERY;
	info->supply_desc.properties = ltc294x_properties;
	if (info->num_regs >= LTC294X_REG_TEMPERATURE_LSB)
		info->supply_desc.num_properties =
			ARRAY_SIZE(ltc294x_properties);
	else if (info->num_regs >= LTC294X_REG_CURRENT_LSB)
		info->supply_desc.num_properties =
			ARRAY_SIZE(ltc294x_properties) - 1;
	else if (info->num_regs >= LTC294X_REG_VOLTAGE_LSB)
		info->supply_desc.num_properties =
			ARRAY_SIZE(ltc294x_properties) - 2;
	else
		info->supply_desc.num_properties =
			ARRAY_SIZE(ltc294x_properties) - 3;
	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");
		goto fail_comm;
	}

	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");
		ret = PTR_ERR(info->supply);
		goto fail_register;
	} else {
		schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
	}

	return 0;

fail_register:
	kfree(info->supply_desc.name);
fail_comm:
fail_name:
fail_info:
	mutex_lock(&ltc294x_lock);
	idr_remove(&ltc294x_id, num);
	mutex_unlock(&ltc294x_lock);
fail_id:
	return ret;
}

#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_NUM_REGS},
	{"ltc2943", LTC2943_NUM_REGS},
	{ },
};
MODULE_DEVICE_TABLE(i2c, ltc294x_i2c_id);

static struct i2c_driver ltc294x_driver = {
	.driver = {
		.name	= "LTC2941",
		.pm	= LTC294X_PM_OPS,
	},
	.probe		= ltc294x_i2c_probe,
	.remove		= ltc294x_i2c_remove,
	.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/LTC2943 Battery Gas Gauge IC driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
085bc24d ML	1	/*
	2	* I2C client/driver for the Linear Technology LTC2941 and LTC2943
	3	* Battery Gas Gauge IC
	4	*
	5	* Copyright (C) 2014 Topic Embedded Systems
	6	*
	7	* Author: Auryn Verwegen
	8	* Author: Mike Looijmans
	9	*/
	10	#include <linux/kernel.h>
	11	#include <linux/module.h>
	12	#include <linux/types.h>
	13	#include <linux/errno.h>
	14	#include <linux/swab.h>
	15	#include <linux/i2c.h>
	16	#include <linux/delay.h>
	17	#include <linux/idr.h>
	18	#include <linux/power_supply.h>
	19	#include <linux/slab.h>
	20
	21	#define I16_MSB(x) ((x >> 8) & 0xFF)
	22	#define I16_LSB(x) (x & 0xFF)
	23
	24	#define LTC294X_WORK_DELAY 10 /* Update delay in seconds */
	25
	26	#define LTC294X_MAX_VALUE 0xFFFF
	27	#define LTC294X_MID_SUPPLY 0x7FFF
	28
	29	#define LTC2941_MAX_PRESCALER_EXP 7
	30	#define LTC2943_MAX_PRESCALER_EXP 6
	31
	32	enum ltc294x_reg {
	33	LTC294X_REG_STATUS = 0x00,
	34	LTC294X_REG_CONTROL = 0x01,
	35	LTC294X_REG_ACC_CHARGE_MSB = 0x02,
	36	LTC294X_REG_ACC_CHARGE_LSB = 0x03,
	37	LTC294X_REG_THRESH_HIGH_MSB = 0x04,
	38	LTC294X_REG_THRESH_HIGH_LSB = 0x05,
	39	LTC294X_REG_THRESH_LOW_MSB = 0x06,
	40	LTC294X_REG_THRESH_LOW_LSB = 0x07,
	41	LTC294X_REG_VOLTAGE_MSB = 0x08,
	42	LTC294X_REG_VOLTAGE_LSB = 0x09,
	43	LTC294X_REG_CURRENT_MSB = 0x0E,
	44	LTC294X_REG_CURRENT_LSB = 0x0F,
	45	LTC294X_REG_TEMPERATURE_MSB = 0x14,
	46	LTC294X_REG_TEMPERATURE_LSB = 0x15,
	47	};
	48
	49	#define LTC2943_REG_CONTROL_MODE_MASK (BIT(7) \| BIT(6))
	50	#define LTC2943_REG_CONTROL_MODE_SCAN BIT(7)
	51	#define LTC294X_REG_CONTROL_PRESCALER_MASK (BIT(5) \| BIT(4) \| BIT(3))
	52	#define LTC294X_REG_CONTROL_SHUTDOWN_MASK (BIT(0))
	53	#define LTC294X_REG_CONTROL_PRESCALER_SET(x) \
	54	((x << 3) & LTC294X_REG_CONTROL_PRESCALER_MASK)
	55	#define LTC294X_REG_CONTROL_ALCC_CONFIG_DISABLED 0
	56
	57	#define LTC2941_NUM_REGS 0x08
	58	#define LTC2943_NUM_REGS 0x18
	59
	60	struct ltc294x_info {
	61	struct i2c_client client; / I2C Client pointer */
297d716f KK	62	struct power_supply supply; / Supply pointer */
297d716f KK	63	struct power_supply_desc supply_desc; /* Supply description */
085bc24d ML	64	struct delayed_work work; /* Work scheduler */
	65	int num_regs; /* Number of registers (chip type) */
	66	int id; /* Identifier of ltc294x chip */
	67	int charge; /* Last charge register content */
	68	int r_sense; /* mOhm */
	69	int Qlsb; /* nAh */
	70	};
	71
	72	static DEFINE_IDR(ltc294x_id);
	73	static DEFINE_MUTEX(ltc294x_lock);
	74
	75	static inline int convert_bin_to_uAh(
	76	const struct ltc294x_info *info, int Q)
	77	{
	78	return ((Q * (info->Qlsb / 10))) / 100;
	79	}
	80
	81	static inline int convert_uAh_to_bin(
	82	const struct ltc294x_info *info, int uAh)
	83	{
	84	int Q;
	85
	86	Q = (uAh * 100) / (info->Qlsb/10);
	87	return (Q < LTC294X_MAX_VALUE) ? Q : LTC294X_MAX_VALUE;
	88	}
	89
	90	static int ltc294x_read_regs(struct i2c_client *client,
	91	enum ltc294x_reg reg, u8 *buf, int num_regs)
	92	{
	93	int ret;
	94	struct i2c_msg msgs[2] = { };
	95	u8 reg_start = reg;
	96
	97	msgs[0].addr = client->addr;
	98	msgs[0].len = 1;
	99	msgs[0].buf = &reg_start;
	100
	101	msgs[1].addr = client->addr;
	102	msgs[1].len = num_regs;
	103	msgs[1].buf = buf;
	104	msgs[1].flags = I2C_M_RD;
	105
	106	ret = i2c_transfer(client->adapter, &msgs[0], 2);
	107	if (ret < 0) {
	108	dev_err(&client->dev, "ltc2941 read_reg failed!\n");
	109	return ret;
	110	}
	111
	112	dev_dbg(&client->dev, "%s (%#x, %d) -> %#x\n",
	113	__func__, reg, num_regs, *buf);
	114
	115	return 0;
	116	}
	117
	118	static int ltc294x_write_regs(struct i2c_client *client,
	119	enum ltc294x_reg reg, const u8 *buf, int num_regs)
	120	{
	121	int ret;
	122	u8 reg_start = reg;
	123
	124	ret = i2c_smbus_write_i2c_block_data(client, reg_start, num_regs, buf);
	125	if (ret < 0) {
	126	dev_err(&client->dev, "ltc2941 write_reg failed!\n");
	127	return ret;
128	}
129
130	dev_dbg(&client->dev, "%s (%#x, %d) -> %#x\n",
131	__func__, reg, num_regs, *buf);
132
133	return 0;
134	}
135
136	static int ltc294x_reset(const struct ltc294x_info *info, int prescaler_exp)
137	{
138	int ret;
139	u8 value;
140	u8 control;
141
142	/* Read status and control registers */
143	ret = ltc294x_read_regs(info->client, LTC294X_REG_CONTROL, &value, 1);
144	if (ret < 0) {
145	dev_err(&info->client->dev,
146	"Could not read registers from device\n");
147	goto error_exit;
148	}
149
150	control = LTC294X_REG_CONTROL_PRESCALER_SET(prescaler_exp) \|
151	LTC294X_REG_CONTROL_ALCC_CONFIG_DISABLED;
152	/* Put the 2943 into "monitor" mode, so it measures every 10 sec */
153	if (info->num_regs == LTC2943_NUM_REGS)
154	control \|= LTC2943_REG_CONTROL_MODE_SCAN;
155
156	if (value != control) {
157	ret = ltc294x_write_regs(info->client,
158	LTC294X_REG_CONTROL, &control, 1);
159	if (ret < 0) {
160	dev_err(&info->client->dev,
161	"Could not write register\n");
162	goto error_exit;
163	}
164	}
165
166	return 0;
167
168	error_exit:
169	return ret;
170	}
171
172	static int ltc294x_read_charge_register(const struct ltc294x_info *info)
173	{
174	int ret;
175	u8 datar[2];
176
177	ret = ltc294x_read_regs(info->client,
178	LTC294X_REG_ACC_CHARGE_MSB, &datar[0], 2);
179	if (ret < 0)
180	return ret;
181	return (datar[0] << 8) + datar[1];
182	}
183
184	static int ltc294x_get_charge_now(const struct ltc294x_info info, int val)
185	{
186	int value = ltc294x_read_charge_register(info);
187
188	if (value < 0)
189	return value;
190	/* When r_sense < 0, this counts up when the battery discharges */
191	if (info->Qlsb < 0)
192	value -= 0xFFFF;
193	*val = convert_bin_to_uAh(info, value);
194	return 0;
195	}
196
197	static int ltc294x_set_charge_now(const struct ltc294x_info *info, int val)
198	{
199	int ret;
200	u8 dataw[2];
201	u8 ctrl_reg;
202	s32 value;
203
204	value = convert_uAh_to_bin(info, val);
205	/* Direction depends on how sense+/- were connected */
206	if (info->Qlsb < 0)
207	value += 0xFFFF;
208	if ((value < 0) \|\| (value > 0xFFFF)) /* input validation */
209	return -EINVAL;
210
211	/* Read control register */
212	ret = ltc294x_read_regs(info->client,
213	LTC294X_REG_CONTROL, &ctrl_reg, 1);
214	if (ret < 0)
215	return ret;
216	/* Disable analog section */
217	ctrl_reg \|= LTC294X_REG_CONTROL_SHUTDOWN_MASK;
218	ret = ltc294x_write_regs(info->client,
219	LTC294X_REG_CONTROL, &ctrl_reg, 1);
220	if (ret < 0)
221	return ret;
222	/* Set new charge value */
223	dataw[0] = I16_MSB(value);
224	dataw[1] = I16_LSB(value);
225	ret = ltc294x_write_regs(info->client,
226	LTC294X_REG_ACC_CHARGE_MSB, &dataw[0], 2);
227	if (ret < 0)
228	goto error_exit;
229	/* Enable analog section */
230	error_exit:
231	ctrl_reg &= ~LTC294X_REG_CONTROL_SHUTDOWN_MASK;
232	ret = ltc294x_write_regs(info->client,
233	LTC294X_REG_CONTROL, &ctrl_reg, 1);
234
235	return ret < 0 ? ret : 0;
236	}
237
238	static int ltc294x_get_charge_counter(
239	const struct ltc294x_info info, int val)
240	{
241	int value = ltc294x_read_charge_register(info);
242
243	if (value < 0)
244	return value;
245	value -= LTC294X_MID_SUPPLY;
246	*val = convert_bin_to_uAh(info, value);
247	return 0;
248	}
249
250	static int ltc294x_get_voltage(const struct ltc294x_info info, int val)
251	{
252	int ret;
253	u8 datar[2];
254	u32 value;
255
256	ret = ltc294x_read_regs(info->client,
257	LTC294X_REG_VOLTAGE_MSB, &datar[0], 2);
258	value = (datar[0] << 8) \| datar[1];
259	val = ((value 23600) / 0xFFFF) * 1000; /* in uV */
260	return ret;
261	}
262
263	static int ltc294x_get_current(const struct ltc294x_info info, int val)
264	{
265	int ret;
266	u8 datar[2];
267	s32 value;
268
269	ret = ltc294x_read_regs(info->client,
270	LTC294X_REG_CURRENT_MSB, &datar[0], 2);
271	value = (datar[0] << 8) \| datar[1];
272	value -= 0x7FFF;
273	/* Value is in range -32k..+32k, r_sense is usually 10..50 mOhm,
274	* the formula below keeps everything in s32 range while preserving
275	* enough digits */
276	val = 1000 ((60000 * value) / (info->r_sense * 0x7FFF)); /* in uA */
277	return ret;
278	}
279
280	static int ltc294x_get_temperature(const struct ltc294x_info info, int val)
281	{
282	int ret;
283	u8 datar[2];
284	u32 value;
285
286	ret = ltc294x_read_regs(info->client,
287	LTC294X_REG_TEMPERATURE_MSB, &datar[0], 2);
288	value = (datar[0] << 8) \| datar[1];
289	/* Full-scale is 510 Kelvin, convert to centidegrees */
290	val = (((51000 value) / 0xFFFF) - 27215);
291	return ret;
292	}
293
294	static int ltc294x_get_property(struct power_supply *psy,
295	enum power_supply_property prop,
296	union power_supply_propval *val)
297	{
297d716f	298	struct ltc294x_info *info = power_supply_get_drvdata(psy);
085bc24d ML	299
	300	switch (prop) {
	301	case POWER_SUPPLY_PROP_CHARGE_NOW:
	302	return ltc294x_get_charge_now(info, &val->intval);
	303	case POWER_SUPPLY_PROP_CHARGE_COUNTER:
	304	return ltc294x_get_charge_counter(info, &val->intval);
	305	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
	306	return ltc294x_get_voltage(info, &val->intval);
	307	case POWER_SUPPLY_PROP_CURRENT_NOW:
	308	return ltc294x_get_current(info, &val->intval);
	309	case POWER_SUPPLY_PROP_TEMP:
	310	return ltc294x_get_temperature(info, &val->intval);
	311	default:
	312	return -EINVAL;
	313	}
	314	}
	315
	316	static int ltc294x_set_property(struct power_supply *psy,
	317	enum power_supply_property psp,
	318	const union power_supply_propval *val)
	319	{
297d716f	320	struct ltc294x_info *info = power_supply_get_drvdata(psy);
085bc24d ML	321
	322	switch (psp) {
	323	case POWER_SUPPLY_PROP_CHARGE_NOW:
	324	return ltc294x_set_charge_now(info, val->intval);
	325	default:
	326	return -EPERM;
	327	}
	328	}
	329
	330	static int ltc294x_property_is_writeable(
	331	struct power_supply *psy, enum power_supply_property psp)
	332	{
	333	switch (psp) {
	334	case POWER_SUPPLY_PROP_CHARGE_NOW:
	335	return 1;
	336	default:
	337	return 0;
	338	}
	339	}
	340
	341	static void ltc294x_update(struct ltc294x_info *info)
	342	{
	343	int charge = ltc294x_read_charge_register(info);
	344
	345	if (charge != info->charge) {
	346	info->charge = charge;
297d716f	347	power_supply_changed(info->supply);
085bc24d ML	348	}
	349	}
	350
	351	static void ltc294x_work(struct work_struct *work)
	352	{
	353	struct ltc294x_info *info;
	354
	355	info = container_of(work, struct ltc294x_info, work.work);
	356	ltc294x_update(info);
	357	schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
	358	}
	359
	360	static enum power_supply_property ltc294x_properties[] = {
	361	POWER_SUPPLY_PROP_CHARGE_COUNTER,
	362	POWER_SUPPLY_PROP_CHARGE_NOW,
	363	POWER_SUPPLY_PROP_VOLTAGE_NOW,
	364	POWER_SUPPLY_PROP_CURRENT_NOW,
	365	POWER_SUPPLY_PROP_TEMP,
	366	};
	367
	368	static int ltc294x_i2c_remove(struct i2c_client *client)
	369	{
	370	struct ltc294x_info *info = i2c_get_clientdata(client);
	371
	372	cancel_delayed_work(&info->work);
297d716f KK	373	power_supply_unregister(info->supply);
297d716f KK	374	kfree(info->supply_desc.name);
085bc24d ML	375	mutex_lock(&ltc294x_lock);
	376	idr_remove(&ltc294x_id, info->id);
	377	mutex_unlock(&ltc294x_lock);
	378	return 0;
	379	}
	380
	381	static int ltc294x_i2c_probe(struct i2c_client *client,
	382	const struct i2c_device_id *id)
	383	{
297d716f	384	struct power_supply_config psy_cfg = {};
085bc24d ML	385	struct ltc294x_info *info;
	386	int ret;
	387	int num;
	388	u32 prescaler_exp;
	389	s32 r_sense;
	390	struct device_node *np;
	391
	392	mutex_lock(&ltc294x_lock);
	393	ret = idr_alloc(&ltc294x_id, client, 0, 0, GFP_KERNEL);
	394	mutex_unlock(&ltc294x_lock);
	395	if (ret < 0)
	396	goto fail_id;
	397
	398	num = ret;
	399
	400	info = devm_kzalloc(&client->dev, sizeof(*info), GFP_KERNEL);
	401	if (info == NULL) {
	402	ret = -ENOMEM;
	403	goto fail_info;
	404	}
	405
	406	i2c_set_clientdata(client, info);
	407
	408	info->num_regs = id->driver_data;
297d716f KK	409	info->supply_desc.name = kasprintf(GFP_KERNEL, "%s-%d", client->name,
	410	num);
	411	if (!info->supply_desc.name) {
085bc24d ML	412	ret = -ENOMEM;
	413	goto fail_name;
	414	}
	415
	416	np = of_node_get(client->dev.of_node);
	417
	418	/* r_sense can be negative, when sense+ is connected to the battery
	419	* instead of the sense-. This results in reversed measurements. */
	420	ret = of_property_read_u32(np, "lltc,resistor-sense", &r_sense);
	421	if (ret < 0) {
	422	dev_err(&client->dev,
	423	"Could not find lltc,resistor-sense in devicetree\n");
	424	goto fail_name;
	425	}
	426	info->r_sense = r_sense;
	427
	428	ret = of_property_read_u32(np, "lltc,prescaler-exponent",
	429	&prescaler_exp);
	430	if (ret < 0) {
	431	dev_warn(&client->dev,
	432	"lltc,prescaler-exponent not in devicetree\n");
	433	prescaler_exp = LTC2941_MAX_PRESCALER_EXP;
	434	}
	435
	436	if (info->num_regs == LTC2943_NUM_REGS) {
	437	if (prescaler_exp > LTC2943_MAX_PRESCALER_EXP)
	438	prescaler_exp = LTC2943_MAX_PRESCALER_EXP;
	439	info->Qlsb = ((340 * 50000) / r_sense) /
	440	(4096 / (1 << (2*prescaler_exp)));
	441	} else {
	442	if (prescaler_exp > LTC2941_MAX_PRESCALER_EXP)
	443	prescaler_exp = LTC2941_MAX_PRESCALER_EXP;
4bf828cf	444	info->Qlsb = ((85 * 50000) / r_sense) /
085bc24d ML	445	(128 / (1 << prescaler_exp));
	446	}
	447
	448	info->client = client;
	449	info->id = num;
297d716f KK	450	info->supply_desc.type = POWER_SUPPLY_TYPE_BATTERY;
297d716f KK	451	info->supply_desc.properties = ltc294x_properties;
085bc24d	452	if (info->num_regs >= LTC294X_REG_TEMPERATURE_LSB)
297d716f	453	info->supply_desc.num_properties =
085bc24d ML	454	ARRAY_SIZE(ltc294x_properties);
085bc24d ML	455	else if (info->num_regs >= LTC294X_REG_CURRENT_LSB)
297d716f	456	info->supply_desc.num_properties =
085bc24d ML	457	ARRAY_SIZE(ltc294x_properties) - 1;
085bc24d ML	458	else if (info->num_regs >= LTC294X_REG_VOLTAGE_LSB)
297d716f	459	info->supply_desc.num_properties =
085bc24d ML	460	ARRAY_SIZE(ltc294x_properties) - 2;
085bc24d ML	461	else
297d716f	462	info->supply_desc.num_properties =
085bc24d	463	ARRAY_SIZE(ltc294x_properties) - 3;
297d716f KK	464	info->supply_desc.get_property = ltc294x_get_property;
	465	info->supply_desc.set_property = ltc294x_set_property;
	466	info->supply_desc.property_is_writeable = ltc294x_property_is_writeable;
	467	info->supply_desc.external_power_changed = NULL;
	468
	469	psy_cfg.drv_data = info;
085bc24d ML	470
	471	INIT_DELAYED_WORK(&info->work, ltc294x_work);
	472
	473	ret = ltc294x_reset(info, prescaler_exp);
	474	if (ret < 0) {
	475	dev_err(&client->dev, "Communication with chip failed\n");
	476	goto fail_comm;
	477	}
	478
297d716f KK	479	info->supply = power_supply_register(&client->dev, &info->supply_desc,
	480	&psy_cfg);
	481	if (IS_ERR(info->supply)) {
085bc24d	482	dev_err(&client->dev, "failed to register ltc2941\n");
297d716f	483	ret = PTR_ERR(info->supply);
085bc24d ML	484	goto fail_register;
	485	} else {
	486	schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
	487	}
	488
	489	return 0;
	490
	491	fail_register:
297d716f	492	kfree(info->supply_desc.name);
085bc24d ML	493	fail_comm:
	494	fail_name:
	495	fail_info:
	496	mutex_lock(&ltc294x_lock);
	497	idr_remove(&ltc294x_id, num);
	498	mutex_unlock(&ltc294x_lock);
	499	fail_id:
	500	return ret;
	501	}
	502
	503	#ifdef CONFIG_PM_SLEEP
	504
	505	static int ltc294x_suspend(struct device *dev)
	506	{
	507	struct i2c_client *client = to_i2c_client(dev);
	508	struct ltc294x_info *info = i2c_get_clientdata(client);
	509
	510	cancel_delayed_work(&info->work);
	511	return 0;
	512	}
	513
	514	static int ltc294x_resume(struct device *dev)
	515	{
	516	struct i2c_client *client = to_i2c_client(dev);
	517	struct ltc294x_info *info = i2c_get_clientdata(client);
	518
	519	schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
	520	return 0;
	521	}
	522
	523	static SIMPLE_DEV_PM_OPS(ltc294x_pm_ops, ltc294x_suspend, ltc294x_resume);
	524	#define LTC294X_PM_OPS (&ltc294x_pm_ops)
	525
	526	#else
	527	#define LTC294X_PM_OPS NULL
	528	#endif /* CONFIG_PM_SLEEP */
	529
	530
	531	static const struct i2c_device_id ltc294x_i2c_id[] = {
	532	{"ltc2941", LTC2941_NUM_REGS},
	533	{"ltc2943", LTC2943_NUM_REGS},
	534	{ },
	535	};
	536	MODULE_DEVICE_TABLE(i2c, ltc294x_i2c_id);
	537
	538	static struct i2c_driver ltc294x_driver = {
	539	.driver = {
	540	.name = "LTC2941",
	541	.pm = LTC294X_PM_OPS,
	542	},
	543	.probe = ltc294x_i2c_probe,
	544	.remove = ltc294x_i2c_remove,
	545	.id_table = ltc294x_i2c_id,
	546	};
	547	module_i2c_driver(ltc294x_driver);
	548
	549	MODULE_AUTHOR("Auryn Verwegen, Topic Embedded Systems");
	550	MODULE_AUTHOR("Mike Looijmans, Topic Embedded Products");
	551	MODULE_DESCRIPTION("LTC2941/LTC2943 Battery Gas Gauge IC driver");
	552	MODULE_LICENSE("GPL");