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remarkable-linux/drivers/power/ltc2941-battery-gauge.c
Mike Looijmans 377b641ac8 power/ltc2941-battery-gauge.c: Use the devicetree node name as supply name 
Make it possible to set the name of the supply from the devicetree.
Like other power supply drivers just use the node name. This makes
the code smaller as well, as it doesn't need to allocate memory to
hold the name and allocate a unique ID.

Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
2015-07-24 16:52:24 +02:00

515 lines
13 KiB
C
Raw Blame History

/*
* 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/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 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 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);
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;
u32 prescaler_exp;
s32 r_sense;
struct device_node *np;
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->num_regs = id->driver_data;
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->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->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");
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;
}
#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");
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