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-rw-r--r--drivers/power/supply/ltc2941-battery-gauge.c648
1 files changed, 648 insertions, 0 deletions
diff --git a/drivers/power/supply/ltc2941-battery-gauge.c b/drivers/power/supply/ltc2941-battery-gauge.c
new file mode 100644
index 000000000..657305214
--- /dev/null
+++ b/drivers/power/supply/ltc2941-battery-gauge.c
@@ -0,0 +1,648 @@
+// 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/devm-helpers.h>
+#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(0x%x[%d]) failed: %pe\n",
+ reg, num_regs, ERR_PTR(ret));
+ 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(0x%x[%d]) failed: %pe\n",
+ reg, num_regs, ERR_PTR(ret));
+ 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)
+ return ret;
+
+ 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)
+ return ret;
+ }
+
+ return 0;
+}
+
+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_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) (uintptr_t) 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)
+ return dev_err_probe(&client->dev, ret,
+ "Could not find lltc,resistor-sense in devicetree\n");
+ 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) >>
+ (12 - 2*prescaler_exp);
+ } else {
+ if (prescaler_exp > LTC2941_MAX_PRESCALER_EXP)
+ prescaler_exp = LTC2941_MAX_PRESCALER_EXP;
+ info->Qlsb = ((85 * 50000) / r_sense) >>
+ (7 - 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)
+ return dev_err_probe(&client->dev, ret,
+ "Could not read status register\n");
+ 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;
+
+ ret = devm_delayed_work_autocancel(&client->dev, &info->work,
+ ltc294x_work);
+ if (ret)
+ return ret;
+
+ ret = ltc294x_reset(info, prescaler_exp);
+ if (ret < 0)
+ return dev_err_probe(&client->dev, ret,
+ "Communication with chip failed\n");
+
+ info->supply = devm_power_supply_register(&client->dev,
+ &info->supply_desc, &psy_cfg);
+ if (IS_ERR(info->supply))
+ return dev_err_probe(&client->dev, PTR_ERR(info->supply),
+ "failed to register ltc2941\n");
+
+ 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,
+ .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");