[deliverable/linux.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 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 =
		container_of(psy, struct ltc294x_info, supply);

	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 =
		container_of(psy, struct ltc294x_info, supply);

	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.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 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.name = kasprintf(GFP_KERNEL, "%s-%d", client->name, num);
	if (!info->supply.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 = ((58 * 50000) / r_sense) /
				(128 / (1 << prescaler_exp));
	}

	info->client = client;
	info->id = num;
	info->supply.type = POWER_SUPPLY_TYPE_BATTERY;
	info->supply.properties = ltc294x_properties;
	if (info->num_regs >= LTC294X_REG_TEMPERATURE_LSB)
		info->supply.num_properties =
			ARRAY_SIZE(ltc294x_properties);
	else if (info->num_regs >= LTC294X_REG_CURRENT_LSB)
		info->supply.num_properties =
			ARRAY_SIZE(ltc294x_properties) - 1;
	else if (info->num_regs >= LTC294X_REG_VOLTAGE_LSB)
		info->supply.num_properties =
			ARRAY_SIZE(ltc294x_properties) - 2;
	else
		info->supply.num_properties =
			ARRAY_SIZE(ltc294x_properties) - 3;
	info->supply.get_property = ltc294x_get_property;
	info->supply.set_property = ltc294x_set_property;
	info->supply.property_is_writeable = ltc294x_property_is_writeable;
	info->supply.external_power_changed	= NULL;

	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;
	}

	ret = power_supply_register(&client->dev, &info->supply);
	if (ret) {
		dev_err(&client->dev, "failed to register ltc2941\n");
		goto fail_register;
	} else {
		schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
	}

	return 0;

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