// SPDX-License-Identifier: GPL-2.0-only /* * axp288_fuel_gauge.c - Xpower AXP288 PMIC Fuel Gauge Driver * * Copyright (C) 2020-2021 Andrejus Basovas * Copyright (C) 2016-2021 Hans de Goede * Copyright (C) 2014 Intel Corporation * * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */ #include #include #include #include #include #include #include #include #include #include #include #include #include #define PS_STAT_VBUS_TRIGGER (1 << 0) #define PS_STAT_BAT_CHRG_DIR (1 << 2) #define PS_STAT_VBAT_ABOVE_VHOLD (1 << 3) #define PS_STAT_VBUS_VALID (1 << 4) #define PS_STAT_VBUS_PRESENT (1 << 5) #define CHRG_STAT_BAT_SAFE_MODE (1 << 3) #define CHRG_STAT_BAT_VALID (1 << 4) #define CHRG_STAT_BAT_PRESENT (1 << 5) #define CHRG_STAT_CHARGING (1 << 6) #define CHRG_STAT_PMIC_OTP (1 << 7) #define CHRG_CCCV_CC_MASK 0xf /* 4 bits */ #define CHRG_CCCV_CC_BIT_POS 0 #define CHRG_CCCV_CC_OFFSET 200 /* 200mA */ #define CHRG_CCCV_CC_LSB_RES 200 /* 200mA */ #define CHRG_CCCV_ITERM_20P (1 << 4) /* 20% of CC */ #define CHRG_CCCV_CV_MASK 0x60 /* 2 bits */ #define CHRG_CCCV_CV_BIT_POS 5 #define CHRG_CCCV_CV_4100MV 0x0 /* 4.10V */ #define CHRG_CCCV_CV_4150MV 0x1 /* 4.15V */ #define CHRG_CCCV_CV_4200MV 0x2 /* 4.20V */ #define CHRG_CCCV_CV_4350MV 0x3 /* 4.35V */ #define CHRG_CCCV_CHG_EN (1 << 7) #define FG_CNTL_OCV_ADJ_STAT (1 << 2) #define FG_CNTL_OCV_ADJ_EN (1 << 3) #define FG_CNTL_CAP_ADJ_STAT (1 << 4) #define FG_CNTL_CAP_ADJ_EN (1 << 5) #define FG_CNTL_CC_EN (1 << 6) #define FG_CNTL_GAUGE_EN (1 << 7) #define FG_15BIT_WORD_VALID (1 << 15) #define FG_15BIT_VAL_MASK 0x7fff #define FG_REP_CAP_VALID (1 << 7) #define FG_REP_CAP_VAL_MASK 0x7F #define FG_DES_CAP1_VALID (1 << 7) #define FG_DES_CAP_RES_LSB 1456 /* 1.456mAhr */ #define FG_DES_CC_RES_LSB 1456 /* 1.456mAhr */ #define FG_OCV_CAP_VALID (1 << 7) #define FG_OCV_CAP_VAL_MASK 0x7F #define FG_CC_CAP_VALID (1 << 7) #define FG_CC_CAP_VAL_MASK 0x7F #define FG_LOW_CAP_THR1_MASK 0xf0 /* 5% tp 20% */ #define FG_LOW_CAP_THR1_VAL 0xa0 /* 15 perc */ #define FG_LOW_CAP_THR2_MASK 0x0f /* 0% to 15% */ #define FG_LOW_CAP_WARN_THR 14 /* 14 perc */ #define FG_LOW_CAP_CRIT_THR 4 /* 4 perc */ #define FG_LOW_CAP_SHDN_THR 0 /* 0 perc */ #define DEV_NAME "axp288_fuel_gauge" /* 1.1mV per LSB expressed in uV */ #define VOLTAGE_FROM_ADC(a) ((a * 11) / 10) /* properties converted to uV, uA */ #define PROP_VOLT(a) ((a) * 1000) #define PROP_CURR(a) ((a) * 1000) #define AXP288_REG_UPDATE_INTERVAL (60 * HZ) #define AXP288_FG_INTR_NUM 6 enum { QWBTU_IRQ = 0, WBTU_IRQ, QWBTO_IRQ, WBTO_IRQ, WL2_IRQ, WL1_IRQ, }; enum { BAT_CHRG_CURR, BAT_D_CURR, BAT_VOLT, IIO_CHANNEL_NUM }; struct axp288_fg_info { struct device *dev; struct regmap *regmap; struct regmap_irq_chip_data *regmap_irqc; int irq[AXP288_FG_INTR_NUM]; struct iio_channel *iio_channel[IIO_CHANNEL_NUM]; struct power_supply *bat; struct mutex lock; int status; int max_volt; int pwr_op; int low_cap; struct dentry *debug_file; char valid; /* zero until following fields are valid */ unsigned long last_updated; /* in jiffies */ int pwr_stat; int fg_res; int bat_volt; int d_curr; int c_curr; int ocv; int fg_cc_mtr1; int fg_des_cap1; }; static enum power_supply_property fuel_gauge_props[] = { POWER_SUPPLY_PROP_STATUS, POWER_SUPPLY_PROP_PRESENT, POWER_SUPPLY_PROP_HEALTH, POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN, POWER_SUPPLY_PROP_VOLTAGE_NOW, POWER_SUPPLY_PROP_VOLTAGE_OCV, POWER_SUPPLY_PROP_CURRENT_NOW, POWER_SUPPLY_PROP_CAPACITY, POWER_SUPPLY_PROP_CAPACITY_ALERT_MIN, POWER_SUPPLY_PROP_TECHNOLOGY, POWER_SUPPLY_PROP_CHARGE_FULL, POWER_SUPPLY_PROP_CHARGE_NOW, }; static int fuel_gauge_reg_readb(struct axp288_fg_info *info, int reg) { unsigned int val; int ret; ret = regmap_read(info->regmap, reg, &val); if (ret < 0) { dev_err(info->dev, "Error reading reg 0x%02x err: %d\n", reg, ret); return ret; } return val; } static int fuel_gauge_reg_writeb(struct axp288_fg_info *info, int reg, u8 val) { int ret; ret = regmap_write(info->regmap, reg, (unsigned int)val); if (ret < 0) dev_err(info->dev, "Error writing reg 0x%02x err: %d\n", reg, ret); return ret; } static int fuel_gauge_read_15bit_word(struct axp288_fg_info *info, int reg) { unsigned char buf[2]; int ret; ret = regmap_bulk_read(info->regmap, reg, buf, 2); if (ret < 0) { dev_err(info->dev, "Error reading reg 0x%02x err: %d\n", reg, ret); return ret; } ret = get_unaligned_be16(buf); if (!(ret & FG_15BIT_WORD_VALID)) { dev_err(info->dev, "Error reg 0x%02x contents not valid\n", reg); return -ENXIO; } return ret & FG_15BIT_VAL_MASK; } static int fuel_gauge_read_12bit_word(struct axp288_fg_info *info, int reg) { unsigned char buf[2]; int ret; ret = regmap_bulk_read(info->regmap, reg, buf, 2); if (ret < 0) { dev_err(info->dev, "Error reading reg 0x%02x err: %d\n", reg, ret); return ret; } /* 12-bit data values have upper 8 bits in buf[0], lower 4 in buf[1] */ return (buf[0] << 4) | ((buf[1] >> 4) & 0x0f); } static int fuel_gauge_update_registers(struct axp288_fg_info *info) { int ret; if (info->valid && time_before(jiffies, info->last_updated + AXP288_REG_UPDATE_INTERVAL)) return 0; dev_dbg(info->dev, "Fuel Gauge updating register values...\n"); ret = iosf_mbi_block_punit_i2c_access(); if (ret < 0) return ret; ret = fuel_gauge_reg_readb(info, AXP20X_PWR_INPUT_STATUS); if (ret < 0) goto out; info->pwr_stat = ret; ret = fuel_gauge_reg_readb(info, AXP20X_FG_RES); if (ret < 0) goto out; info->fg_res = ret; ret = iio_read_channel_raw(info->iio_channel[BAT_VOLT], &info->bat_volt); if (ret < 0) goto out; if (info->pwr_stat & PS_STAT_BAT_CHRG_DIR) { info->d_curr = 0; ret = iio_read_channel_raw(info->iio_channel[BAT_CHRG_CURR], &info->c_curr); if (ret < 0) goto out; } else { info->c_curr = 0; ret = iio_read_channel_raw(info->iio_channel[BAT_D_CURR], &info->d_curr); if (ret < 0) goto out; } ret = fuel_gauge_read_12bit_word(info, AXP288_FG_OCVH_REG); if (ret < 0) goto out; info->ocv = ret; ret = fuel_gauge_read_15bit_word(info, AXP288_FG_CC_MTR1_REG); if (ret < 0) goto out; info->fg_cc_mtr1 = ret; ret = fuel_gauge_read_15bit_word(info, AXP288_FG_DES_CAP1_REG); if (ret < 0) goto out; info->fg_des_cap1 = ret; info->last_updated = jiffies; info->valid = 1; ret = 0; out: iosf_mbi_unblock_punit_i2c_access(); return ret; } static void fuel_gauge_get_status(struct axp288_fg_info *info) { int pwr_stat = info->pwr_stat; int fg_res = info->fg_res; int curr = info->d_curr; /* Report full if Vbus is valid and the reported capacity is 100% */ if (!(pwr_stat & PS_STAT_VBUS_VALID)) goto not_full; if (!(fg_res & FG_REP_CAP_VALID)) goto not_full; fg_res &= ~FG_REP_CAP_VALID; if (fg_res == 100) { info->status = POWER_SUPPLY_STATUS_FULL; return; } /* * Sometimes the charger turns itself off before fg-res reaches 100%. * When this happens the AXP288 reports a not-charging status and * 0 mA discharge current. */ if (fg_res < 90 || (pwr_stat & PS_STAT_BAT_CHRG_DIR)) goto not_full; if (curr == 0) { info->status = POWER_SUPPLY_STATUS_FULL; return; } not_full: if (pwr_stat & PS_STAT_BAT_CHRG_DIR) info->status = POWER_SUPPLY_STATUS_CHARGING; else info->status = POWER_SUPPLY_STATUS_DISCHARGING; } static int fuel_gauge_battery_health(struct axp288_fg_info *info) { int vocv = VOLTAGE_FROM_ADC(info->ocv); int health = POWER_SUPPLY_HEALTH_UNKNOWN; if (vocv > info->max_volt) health = POWER_SUPPLY_HEALTH_OVERVOLTAGE; else health = POWER_SUPPLY_HEALTH_GOOD; return health; } static int fuel_gauge_get_property(struct power_supply *ps, enum power_supply_property prop, union power_supply_propval *val) { struct axp288_fg_info *info = power_supply_get_drvdata(ps); int ret, value; mutex_lock(&info->lock); ret = fuel_gauge_update_registers(info); if (ret < 0) goto out; switch (prop) { case POWER_SUPPLY_PROP_STATUS: fuel_gauge_get_status(info); val->intval = info->status; break; case POWER_SUPPLY_PROP_HEALTH: val->intval = fuel_gauge_battery_health(info); break; case POWER_SUPPLY_PROP_VOLTAGE_NOW: value = VOLTAGE_FROM_ADC(info->bat_volt); val->intval = PROP_VOLT(value); break; case POWER_SUPPLY_PROP_VOLTAGE_OCV: value = VOLTAGE_FROM_ADC(info->ocv); val->intval = PROP_VOLT(value); break; case POWER_SUPPLY_PROP_CURRENT_NOW: if (info->d_curr > 0) value = -1 * info->d_curr; else value = info->c_curr; val->intval = PROP_CURR(value); break; case POWER_SUPPLY_PROP_PRESENT: if (info->pwr_op & CHRG_STAT_BAT_PRESENT) val->intval = 1; else val->intval = 0; break; case POWER_SUPPLY_PROP_CAPACITY: if (!(info->fg_res & FG_REP_CAP_VALID)) dev_err(info->dev, "capacity measurement not valid\n"); val->intval = (info->fg_res & FG_REP_CAP_VAL_MASK); break; case POWER_SUPPLY_PROP_CAPACITY_ALERT_MIN: val->intval = (info->low_cap & 0x0f); break; case POWER_SUPPLY_PROP_TECHNOLOGY: val->intval = POWER_SUPPLY_TECHNOLOGY_LION; break; case POWER_SUPPLY_PROP_CHARGE_NOW: val->intval = info->fg_cc_mtr1 * FG_DES_CAP_RES_LSB; break; case POWER_SUPPLY_PROP_CHARGE_FULL: val->intval = info->fg_des_cap1 * FG_DES_CAP_RES_LSB; break; case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN: val->intval = PROP_VOLT(info->max_volt); break; default: ret = -EINVAL; } out: mutex_unlock(&info->lock); return ret; } static int fuel_gauge_set_property(struct power_supply *ps, enum power_supply_property prop, const union power_supply_propval *val) { struct axp288_fg_info *info = power_supply_get_drvdata(ps); int new_low_cap, ret = 0; mutex_lock(&info->lock); switch (prop) { case POWER_SUPPLY_PROP_CAPACITY_ALERT_MIN: if ((val->intval < 0) || (val->intval > 15)) { ret = -EINVAL; break; } new_low_cap = info->low_cap; new_low_cap &= 0xf0; new_low_cap |= (val->intval & 0xf); ret = fuel_gauge_reg_writeb(info, AXP288_FG_LOW_CAP_REG, new_low_cap); if (ret == 0) info->low_cap = new_low_cap; break; default: ret = -EINVAL; break; } mutex_unlock(&info->lock); return ret; } static int fuel_gauge_property_is_writeable(struct power_supply *psy, enum power_supply_property psp) { int ret; switch (psp) { case POWER_SUPPLY_PROP_CAPACITY_ALERT_MIN: ret = 1; break; default: ret = 0; } return ret; } static irqreturn_t fuel_gauge_thread_handler(int irq, void *dev) { struct axp288_fg_info *info = dev; int i; for (i = 0; i < AXP288_FG_INTR_NUM; i++) { if (info->irq[i] == irq) break; } if (i >= AXP288_FG_INTR_NUM) { dev_warn(info->dev, "spurious interrupt!!\n"); return IRQ_NONE; } switch (i) { case QWBTU_IRQ: dev_info(info->dev, "Quit Battery under temperature in work mode IRQ (QWBTU)\n"); break; case WBTU_IRQ: dev_info(info->dev, "Battery under temperature in work mode IRQ (WBTU)\n"); break; case QWBTO_IRQ: dev_info(info->dev, "Quit Battery over temperature in work mode IRQ (QWBTO)\n"); break; case WBTO_IRQ: dev_info(info->dev, "Battery over temperature in work mode IRQ (WBTO)\n"); break; case WL2_IRQ: dev_info(info->dev, "Low Batt Warning(2) INTR\n"); break; case WL1_IRQ: dev_info(info->dev, "Low Batt Warning(1) INTR\n"); break; default: dev_warn(info->dev, "Spurious Interrupt!!!\n"); } info->valid = 0; /* Force updating of the cached registers */ power_supply_changed(info->bat); return IRQ_HANDLED; } static void fuel_gauge_external_power_changed(struct power_supply *psy) { struct axp288_fg_info *info = power_supply_get_drvdata(psy); info->valid = 0; /* Force updating of the cached registers */ power_supply_changed(info->bat); } static const struct power_supply_desc fuel_gauge_desc = { .name = DEV_NAME, .type = POWER_SUPPLY_TYPE_BATTERY, .properties = fuel_gauge_props, .num_properties = ARRAY_SIZE(fuel_gauge_props), .get_property = fuel_gauge_get_property, .set_property = fuel_gauge_set_property, .property_is_writeable = fuel_gauge_property_is_writeable, .external_power_changed = fuel_gauge_external_power_changed, }; static void fuel_gauge_init_irq(struct axp288_fg_info *info, struct platform_device *pdev) { int ret, i, pirq; for (i = 0; i < AXP288_FG_INTR_NUM; i++) { pirq = platform_get_irq(pdev, i); info->irq[i] = regmap_irq_get_virq(info->regmap_irqc, pirq); if (info->irq[i] < 0) { dev_warn(info->dev, "regmap_irq get virq failed for IRQ %d: %d\n", pirq, info->irq[i]); info->irq[i] = -1; goto intr_failed; } ret = request_threaded_irq(info->irq[i], NULL, fuel_gauge_thread_handler, IRQF_ONESHOT, DEV_NAME, info); if (ret) { dev_warn(info->dev, "request irq failed for IRQ %d: %d\n", pirq, info->irq[i]); info->irq[i] = -1; goto intr_failed; } } return; intr_failed: for (; i > 0; i--) { free_irq(info->irq[i - 1], info); info->irq[i - 1] = -1; } } /* * Some devices have no battery (HDMI sticks) and the axp288 battery's * detection reports one despite it not being there. * Please keep this listed sorted alphabetically. */ static const struct dmi_system_id axp288_no_battery_list[] = { { /* ACEPC T8 Cherry Trail Z8350 mini PC */ .matches = { DMI_EXACT_MATCH(DMI_BOARD_VENDOR, "To be filled by O.E.M."), DMI_EXACT_MATCH(DMI_BOARD_NAME, "Cherry Trail CR"), DMI_EXACT_MATCH(DMI_PRODUCT_SKU, "T8"), /* also match on somewhat unique bios-version */ DMI_EXACT_MATCH(DMI_BIOS_VERSION, "1.000"), }, }, { /* ACEPC T11 Cherry Trail Z8350 mini PC */ .matches = { DMI_EXACT_MATCH(DMI_BOARD_VENDOR, "To be filled by O.E.M."), DMI_EXACT_MATCH(DMI_BOARD_NAME, "Cherry Trail CR"), DMI_EXACT_MATCH(DMI_PRODUCT_SKU, "T11"), /* also match on somewhat unique bios-version */ DMI_EXACT_MATCH(DMI_BIOS_VERSION, "1.000"), }, }, { /* ECS EF20EA */ .matches = { DMI_MATCH(DMI_PRODUCT_NAME, "EF20EA"), }, }, { /* Intel Cherry Trail Compute Stick, Windows version */ .matches = { DMI_MATCH(DMI_SYS_VENDOR, "Intel"), DMI_MATCH(DMI_PRODUCT_NAME, "STK1AW32SC"), }, }, { /* Intel Cherry Trail Compute Stick, version without an OS */ .matches = { DMI_MATCH(DMI_SYS_VENDOR, "Intel"), DMI_MATCH(DMI_PRODUCT_NAME, "STK1A32SC"), }, }, { /* Meegopad T02 */ .matches = { DMI_MATCH(DMI_PRODUCT_NAME, "MEEGOPAD T02"), }, }, { /* Mele PCG03 Mini PC */ .matches = { DMI_EXACT_MATCH(DMI_BOARD_VENDOR, "Mini PC"), DMI_EXACT_MATCH(DMI_BOARD_NAME, "Mini PC"), }, }, { /* Minix Neo Z83-4 mini PC */ .matches = { DMI_MATCH(DMI_SYS_VENDOR, "MINIX"), DMI_MATCH(DMI_PRODUCT_NAME, "Z83-4"), } }, { /* Various Ace PC/Meegopad/MinisForum/Wintel Mini-PCs/HDMI-sticks */ .matches = { DMI_MATCH(DMI_BOARD_NAME, "T3 MRD"), DMI_MATCH(DMI_CHASSIS_TYPE, "3"), DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."), DMI_MATCH(DMI_BIOS_VERSION, "5.11"), }, }, {} }; static int axp288_fuel_gauge_probe(struct platform_device *pdev) { int i, ret = 0; struct axp288_fg_info *info; struct axp20x_dev *axp20x = dev_get_drvdata(pdev->dev.parent); struct power_supply_config psy_cfg = {}; static const char * const iio_chan_name[] = { [BAT_CHRG_CURR] = "axp288-chrg-curr", [BAT_D_CURR] = "axp288-chrg-d-curr", [BAT_VOLT] = "axp288-batt-volt", }; unsigned int val; if (dmi_check_system(axp288_no_battery_list)) return -ENODEV; info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL); if (!info) return -ENOMEM; info->dev = &pdev->dev; info->regmap = axp20x->regmap; info->regmap_irqc = axp20x->regmap_irqc; info->status = POWER_SUPPLY_STATUS_UNKNOWN; info->valid = 0; platform_set_drvdata(pdev, info); mutex_init(&info->lock); for (i = 0; i < IIO_CHANNEL_NUM; i++) { /* * Note cannot use devm_iio_channel_get because x86 systems * lack the device<->channel maps which iio_channel_get will * try to use when passed a non NULL device pointer. */ info->iio_channel[i] = iio_channel_get(NULL, iio_chan_name[i]); if (IS_ERR(info->iio_channel[i])) { ret = PTR_ERR(info->iio_channel[i]); dev_dbg(&pdev->dev, "error getting iiochan %s: %d\n", iio_chan_name[i], ret); /* Wait for axp288_adc to load */ if (ret == -ENODEV) ret = -EPROBE_DEFER; goto out_free_iio_chan; } } ret = iosf_mbi_block_punit_i2c_access(); if (ret < 0) goto out_free_iio_chan; /* * On some devices the fuelgauge and charger parts of the axp288 are * not used, check that the fuelgauge is enabled (CC_CTRL != 0). */ ret = regmap_read(axp20x->regmap, AXP20X_CC_CTRL, &val); if (ret < 0) goto unblock_punit_i2c_access; if (val == 0) { ret = -ENODEV; goto unblock_punit_i2c_access; } ret = fuel_gauge_reg_readb(info, AXP288_FG_DES_CAP1_REG); if (ret < 0) goto unblock_punit_i2c_access; if (!(ret & FG_DES_CAP1_VALID)) { dev_err(&pdev->dev, "axp288 not configured by firmware\n"); ret = -ENODEV; goto unblock_punit_i2c_access; } ret = fuel_gauge_reg_readb(info, AXP20X_CHRG_CTRL1); if (ret < 0) goto unblock_punit_i2c_access; switch ((ret & CHRG_CCCV_CV_MASK) >> CHRG_CCCV_CV_BIT_POS) { case CHRG_CCCV_CV_4100MV: info->max_volt = 4100; break; case CHRG_CCCV_CV_4150MV: info->max_volt = 4150; break; case CHRG_CCCV_CV_4200MV: info->max_volt = 4200; break; case CHRG_CCCV_CV_4350MV: info->max_volt = 4350; break; } ret = fuel_gauge_reg_readb(info, AXP20X_PWR_OP_MODE); if (ret < 0) goto unblock_punit_i2c_access; info->pwr_op = ret; ret = fuel_gauge_reg_readb(info, AXP288_FG_LOW_CAP_REG); if (ret < 0) goto unblock_punit_i2c_access; info->low_cap = ret; unblock_punit_i2c_access: iosf_mbi_unblock_punit_i2c_access(); /* In case we arrive here by goto because of a register access error */ if (ret < 0) goto out_free_iio_chan; psy_cfg.drv_data = info; info->bat = power_supply_register(&pdev->dev, &fuel_gauge_desc, &psy_cfg); if (IS_ERR(info->bat)) { ret = PTR_ERR(info->bat); dev_err(&pdev->dev, "failed to register battery: %d\n", ret); goto out_free_iio_chan; } fuel_gauge_init_irq(info, pdev); return 0; out_free_iio_chan: for (i = 0; i < IIO_CHANNEL_NUM; i++) if (!IS_ERR_OR_NULL(info->iio_channel[i])) iio_channel_release(info->iio_channel[i]); return ret; } static const struct platform_device_id axp288_fg_id_table[] = { { .name = DEV_NAME }, {}, }; MODULE_DEVICE_TABLE(platform, axp288_fg_id_table); static int axp288_fuel_gauge_remove(struct platform_device *pdev) { struct axp288_fg_info *info = platform_get_drvdata(pdev); int i; power_supply_unregister(info->bat); for (i = 0; i < AXP288_FG_INTR_NUM; i++) if (info->irq[i] >= 0) free_irq(info->irq[i], info); for (i = 0; i < IIO_CHANNEL_NUM; i++) iio_channel_release(info->iio_channel[i]); return 0; } static struct platform_driver axp288_fuel_gauge_driver = { .probe = axp288_fuel_gauge_probe, .remove = axp288_fuel_gauge_remove, .id_table = axp288_fg_id_table, .driver = { .name = DEV_NAME, }, }; module_platform_driver(axp288_fuel_gauge_driver); MODULE_AUTHOR("Ramakrishna Pallala "); MODULE_AUTHOR("Todd Brandt "); MODULE_DESCRIPTION("Xpower AXP288 Fuel Gauge Driver"); MODULE_LICENSE("GPL");