summaryrefslogtreecommitdiffstats
path: root/drivers/power/supply/sc27xx_fuel_gauge.c
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--drivers/power/supply/sc27xx_fuel_gauge.c1350
1 files changed, 1350 insertions, 0 deletions
diff --git a/drivers/power/supply/sc27xx_fuel_gauge.c b/drivers/power/supply/sc27xx_fuel_gauge.c
new file mode 100644
index 000000000..bd23c4d9f
--- /dev/null
+++ b/drivers/power/supply/sc27xx_fuel_gauge.c
@@ -0,0 +1,1350 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Spreadtrum Communications Inc.
+
+#include <linux/gpio/consumer.h>
+#include <linux/iio/consumer.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/math64.h>
+#include <linux/module.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/power_supply.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+/* PMIC global control registers definition */
+#define SC27XX_MODULE_EN0 0xc08
+#define SC27XX_CLK_EN0 0xc18
+#define SC27XX_FGU_EN BIT(7)
+#define SC27XX_FGU_RTC_EN BIT(6)
+
+/* FGU registers definition */
+#define SC27XX_FGU_START 0x0
+#define SC27XX_FGU_CONFIG 0x4
+#define SC27XX_FGU_ADC_CONFIG 0x8
+#define SC27XX_FGU_STATUS 0xc
+#define SC27XX_FGU_INT_EN 0x10
+#define SC27XX_FGU_INT_CLR 0x14
+#define SC27XX_FGU_INT_STS 0x1c
+#define SC27XX_FGU_VOLTAGE 0x20
+#define SC27XX_FGU_OCV 0x24
+#define SC27XX_FGU_POCV 0x28
+#define SC27XX_FGU_CURRENT 0x2c
+#define SC27XX_FGU_LOW_OVERLOAD 0x34
+#define SC27XX_FGU_CLBCNT_SETH 0x50
+#define SC27XX_FGU_CLBCNT_SETL 0x54
+#define SC27XX_FGU_CLBCNT_DELTH 0x58
+#define SC27XX_FGU_CLBCNT_DELTL 0x5c
+#define SC27XX_FGU_CLBCNT_VALH 0x68
+#define SC27XX_FGU_CLBCNT_VALL 0x6c
+#define SC27XX_FGU_CLBCNT_QMAXL 0x74
+#define SC27XX_FGU_USER_AREA_SET 0xa0
+#define SC27XX_FGU_USER_AREA_CLEAR 0xa4
+#define SC27XX_FGU_USER_AREA_STATUS 0xa8
+#define SC27XX_FGU_VOLTAGE_BUF 0xd0
+#define SC27XX_FGU_CURRENT_BUF 0xf0
+
+#define SC27XX_WRITE_SELCLB_EN BIT(0)
+#define SC27XX_FGU_CLBCNT_MASK GENMASK(15, 0)
+#define SC27XX_FGU_CLBCNT_SHIFT 16
+#define SC27XX_FGU_LOW_OVERLOAD_MASK GENMASK(12, 0)
+
+#define SC27XX_FGU_INT_MASK GENMASK(9, 0)
+#define SC27XX_FGU_LOW_OVERLOAD_INT BIT(0)
+#define SC27XX_FGU_CLBCNT_DELTA_INT BIT(2)
+
+#define SC27XX_FGU_MODE_AREA_MASK GENMASK(15, 12)
+#define SC27XX_FGU_CAP_AREA_MASK GENMASK(11, 0)
+#define SC27XX_FGU_MODE_AREA_SHIFT 12
+
+#define SC27XX_FGU_FIRST_POWERTON GENMASK(3, 0)
+#define SC27XX_FGU_DEFAULT_CAP GENMASK(11, 0)
+#define SC27XX_FGU_NORMAIL_POWERTON 0x5
+
+#define SC27XX_FGU_CUR_BASIC_ADC 8192
+#define SC27XX_FGU_SAMPLE_HZ 2
+/* micro Ohms */
+#define SC27XX_FGU_IDEAL_RESISTANCE 20000
+
+/*
+ * struct sc27xx_fgu_data: describe the FGU device
+ * @regmap: regmap for register access
+ * @dev: platform device
+ * @battery: battery power supply
+ * @base: the base offset for the controller
+ * @lock: protect the structure
+ * @gpiod: GPIO for battery detection
+ * @channel: IIO channel to get battery temperature
+ * @charge_chan: IIO channel to get charge voltage
+ * @internal_resist: the battery internal resistance in mOhm
+ * @total_cap: the total capacity of the battery in mAh
+ * @init_cap: the initial capacity of the battery in mAh
+ * @alarm_cap: the alarm capacity
+ * @init_clbcnt: the initial coulomb counter
+ * @max_volt: the maximum constant input voltage in millivolt
+ * @min_volt: the minimum drained battery voltage in microvolt
+ * @boot_volt: the voltage measured during boot in microvolt
+ * @table_len: the capacity table length
+ * @resist_table_len: the resistance table length
+ * @cur_1000ma_adc: ADC value corresponding to 1000 mA
+ * @vol_1000mv_adc: ADC value corresponding to 1000 mV
+ * @calib_resist: the real resistance of coulomb counter chip in uOhm
+ * @cap_table: capacity table with corresponding ocv
+ * @resist_table: resistance percent table with corresponding temperature
+ */
+struct sc27xx_fgu_data {
+ struct regmap *regmap;
+ struct device *dev;
+ struct power_supply *battery;
+ u32 base;
+ struct mutex lock;
+ struct gpio_desc *gpiod;
+ struct iio_channel *channel;
+ struct iio_channel *charge_chan;
+ bool bat_present;
+ int internal_resist;
+ int total_cap;
+ int init_cap;
+ int alarm_cap;
+ int init_clbcnt;
+ int max_volt;
+ int min_volt;
+ int boot_volt;
+ int table_len;
+ int resist_table_len;
+ int cur_1000ma_adc;
+ int vol_1000mv_adc;
+ int calib_resist;
+ struct power_supply_battery_ocv_table *cap_table;
+ struct power_supply_resistance_temp_table *resist_table;
+};
+
+static int sc27xx_fgu_cap_to_clbcnt(struct sc27xx_fgu_data *data, int capacity);
+static void sc27xx_fgu_capacity_calibration(struct sc27xx_fgu_data *data,
+ int cap, bool int_mode);
+static void sc27xx_fgu_adjust_cap(struct sc27xx_fgu_data *data, int cap);
+static int sc27xx_fgu_get_temp(struct sc27xx_fgu_data *data, int *temp);
+
+static const char * const sc27xx_charger_supply_name[] = {
+ "sc2731_charger",
+ "sc2720_charger",
+ "sc2721_charger",
+ "sc2723_charger",
+};
+
+static int sc27xx_fgu_adc_to_current(struct sc27xx_fgu_data *data, s64 adc)
+{
+ return DIV_S64_ROUND_CLOSEST(adc * 1000, data->cur_1000ma_adc);
+}
+
+static int sc27xx_fgu_adc_to_voltage(struct sc27xx_fgu_data *data, s64 adc)
+{
+ return DIV_S64_ROUND_CLOSEST(adc * 1000, data->vol_1000mv_adc);
+}
+
+static int sc27xx_fgu_voltage_to_adc(struct sc27xx_fgu_data *data, int vol)
+{
+ return DIV_ROUND_CLOSEST(vol * data->vol_1000mv_adc, 1000);
+}
+
+static bool sc27xx_fgu_is_first_poweron(struct sc27xx_fgu_data *data)
+{
+ int ret, status, cap, mode;
+
+ ret = regmap_read(data->regmap,
+ data->base + SC27XX_FGU_USER_AREA_STATUS, &status);
+ if (ret)
+ return false;
+
+ /*
+ * We use low 4 bits to save the last battery capacity and high 12 bits
+ * to save the system boot mode.
+ */
+ mode = (status & SC27XX_FGU_MODE_AREA_MASK) >> SC27XX_FGU_MODE_AREA_SHIFT;
+ cap = status & SC27XX_FGU_CAP_AREA_MASK;
+
+ /*
+ * When FGU has been powered down, the user area registers became
+ * default value (0xffff), which can be used to valid if the system is
+ * first power on or not.
+ */
+ if (mode == SC27XX_FGU_FIRST_POWERTON || cap == SC27XX_FGU_DEFAULT_CAP)
+ return true;
+
+ return false;
+}
+
+static int sc27xx_fgu_save_boot_mode(struct sc27xx_fgu_data *data,
+ int boot_mode)
+{
+ int ret;
+
+ ret = regmap_update_bits(data->regmap,
+ data->base + SC27XX_FGU_USER_AREA_CLEAR,
+ SC27XX_FGU_MODE_AREA_MASK,
+ SC27XX_FGU_MODE_AREA_MASK);
+ if (ret)
+ return ret;
+
+ /*
+ * Since the user area registers are put on power always-on region,
+ * then these registers changing time will be a little long. Thus
+ * here we should delay 200us to wait until values are updated
+ * successfully according to the datasheet.
+ */
+ udelay(200);
+
+ ret = regmap_update_bits(data->regmap,
+ data->base + SC27XX_FGU_USER_AREA_SET,
+ SC27XX_FGU_MODE_AREA_MASK,
+ boot_mode << SC27XX_FGU_MODE_AREA_SHIFT);
+ if (ret)
+ return ret;
+
+ /*
+ * Since the user area registers are put on power always-on region,
+ * then these registers changing time will be a little long. Thus
+ * here we should delay 200us to wait until values are updated
+ * successfully according to the datasheet.
+ */
+ udelay(200);
+
+ /*
+ * According to the datasheet, we should set the USER_AREA_CLEAR to 0 to
+ * make the user area data available, otherwise we can not save the user
+ * area data.
+ */
+ return regmap_update_bits(data->regmap,
+ data->base + SC27XX_FGU_USER_AREA_CLEAR,
+ SC27XX_FGU_MODE_AREA_MASK, 0);
+}
+
+static int sc27xx_fgu_save_last_cap(struct sc27xx_fgu_data *data, int cap)
+{
+ int ret;
+
+ ret = regmap_update_bits(data->regmap,
+ data->base + SC27XX_FGU_USER_AREA_CLEAR,
+ SC27XX_FGU_CAP_AREA_MASK,
+ SC27XX_FGU_CAP_AREA_MASK);
+ if (ret)
+ return ret;
+
+ /*
+ * Since the user area registers are put on power always-on region,
+ * then these registers changing time will be a little long. Thus
+ * here we should delay 200us to wait until values are updated
+ * successfully according to the datasheet.
+ */
+ udelay(200);
+
+ ret = regmap_update_bits(data->regmap,
+ data->base + SC27XX_FGU_USER_AREA_SET,
+ SC27XX_FGU_CAP_AREA_MASK, cap);
+ if (ret)
+ return ret;
+
+ /*
+ * Since the user area registers are put on power always-on region,
+ * then these registers changing time will be a little long. Thus
+ * here we should delay 200us to wait until values are updated
+ * successfully according to the datasheet.
+ */
+ udelay(200);
+
+ /*
+ * According to the datasheet, we should set the USER_AREA_CLEAR to 0 to
+ * make the user area data available, otherwise we can not save the user
+ * area data.
+ */
+ return regmap_update_bits(data->regmap,
+ data->base + SC27XX_FGU_USER_AREA_CLEAR,
+ SC27XX_FGU_CAP_AREA_MASK, 0);
+}
+
+static int sc27xx_fgu_read_last_cap(struct sc27xx_fgu_data *data, int *cap)
+{
+ int ret, value;
+
+ ret = regmap_read(data->regmap,
+ data->base + SC27XX_FGU_USER_AREA_STATUS, &value);
+ if (ret)
+ return ret;
+
+ *cap = value & SC27XX_FGU_CAP_AREA_MASK;
+ return 0;
+}
+
+/*
+ * When system boots on, we can not read battery capacity from coulomb
+ * registers, since now the coulomb registers are invalid. So we should
+ * calculate the battery open circuit voltage, and get current battery
+ * capacity according to the capacity table.
+ */
+static int sc27xx_fgu_get_boot_capacity(struct sc27xx_fgu_data *data, int *cap)
+{
+ int volt, cur, oci, ocv, ret;
+ bool is_first_poweron = sc27xx_fgu_is_first_poweron(data);
+
+ /*
+ * If system is not the first power on, we should use the last saved
+ * battery capacity as the initial battery capacity. Otherwise we should
+ * re-calculate the initial battery capacity.
+ */
+ if (!is_first_poweron) {
+ ret = sc27xx_fgu_read_last_cap(data, cap);
+ if (ret)
+ return ret;
+
+ return sc27xx_fgu_save_boot_mode(data, SC27XX_FGU_NORMAIL_POWERTON);
+ }
+
+ /*
+ * After system booting on, the SC27XX_FGU_CLBCNT_QMAXL register saved
+ * the first sampled open circuit current.
+ */
+ ret = regmap_read(data->regmap, data->base + SC27XX_FGU_CLBCNT_QMAXL,
+ &cur);
+ if (ret)
+ return ret;
+
+ cur <<= 1;
+ oci = sc27xx_fgu_adc_to_current(data, cur - SC27XX_FGU_CUR_BASIC_ADC);
+
+ /*
+ * Should get the OCV from SC27XX_FGU_POCV register at the system
+ * beginning. It is ADC values reading from registers which need to
+ * convert the corresponding voltage.
+ */
+ ret = regmap_read(data->regmap, data->base + SC27XX_FGU_POCV, &volt);
+ if (ret)
+ return ret;
+
+ volt = sc27xx_fgu_adc_to_voltage(data, volt);
+ ocv = volt * 1000 - oci * data->internal_resist;
+ data->boot_volt = ocv;
+
+ /*
+ * Parse the capacity table to look up the correct capacity percent
+ * according to current battery's corresponding OCV values.
+ */
+ *cap = power_supply_ocv2cap_simple(data->cap_table, data->table_len,
+ ocv);
+
+ ret = sc27xx_fgu_save_last_cap(data, *cap);
+ if (ret)
+ return ret;
+
+ return sc27xx_fgu_save_boot_mode(data, SC27XX_FGU_NORMAIL_POWERTON);
+}
+
+static int sc27xx_fgu_set_clbcnt(struct sc27xx_fgu_data *data, int clbcnt)
+{
+ int ret;
+
+ ret = regmap_update_bits(data->regmap,
+ data->base + SC27XX_FGU_CLBCNT_SETL,
+ SC27XX_FGU_CLBCNT_MASK, clbcnt);
+ if (ret)
+ return ret;
+
+ ret = regmap_update_bits(data->regmap,
+ data->base + SC27XX_FGU_CLBCNT_SETH,
+ SC27XX_FGU_CLBCNT_MASK,
+ clbcnt >> SC27XX_FGU_CLBCNT_SHIFT);
+ if (ret)
+ return ret;
+
+ return regmap_update_bits(data->regmap, data->base + SC27XX_FGU_START,
+ SC27XX_WRITE_SELCLB_EN,
+ SC27XX_WRITE_SELCLB_EN);
+}
+
+static int sc27xx_fgu_get_clbcnt(struct sc27xx_fgu_data *data, int *clb_cnt)
+{
+ int ccl, cch, ret;
+
+ ret = regmap_read(data->regmap, data->base + SC27XX_FGU_CLBCNT_VALL,
+ &ccl);
+ if (ret)
+ return ret;
+
+ ret = regmap_read(data->regmap, data->base + SC27XX_FGU_CLBCNT_VALH,
+ &cch);
+ if (ret)
+ return ret;
+
+ *clb_cnt = ccl & SC27XX_FGU_CLBCNT_MASK;
+ *clb_cnt |= (cch & SC27XX_FGU_CLBCNT_MASK) << SC27XX_FGU_CLBCNT_SHIFT;
+
+ return 0;
+}
+
+static int sc27xx_fgu_get_vol_now(struct sc27xx_fgu_data *data, int *val)
+{
+ int ret;
+ u32 vol;
+
+ ret = regmap_read(data->regmap, data->base + SC27XX_FGU_VOLTAGE_BUF,
+ &vol);
+ if (ret)
+ return ret;
+
+ /*
+ * It is ADC values reading from registers which need to convert to
+ * corresponding voltage values.
+ */
+ *val = sc27xx_fgu_adc_to_voltage(data, vol);
+
+ return 0;
+}
+
+static int sc27xx_fgu_get_cur_now(struct sc27xx_fgu_data *data, int *val)
+{
+ int ret;
+ u32 cur;
+
+ ret = regmap_read(data->regmap, data->base + SC27XX_FGU_CURRENT_BUF,
+ &cur);
+ if (ret)
+ return ret;
+
+ /*
+ * It is ADC values reading from registers which need to convert to
+ * corresponding current values.
+ */
+ *val = sc27xx_fgu_adc_to_current(data, cur - SC27XX_FGU_CUR_BASIC_ADC);
+
+ return 0;
+}
+
+static int sc27xx_fgu_get_capacity(struct sc27xx_fgu_data *data, int *cap)
+{
+ int ret, cur_clbcnt, delta_clbcnt, delta_cap, temp;
+
+ /* Get current coulomb counters firstly */
+ ret = sc27xx_fgu_get_clbcnt(data, &cur_clbcnt);
+ if (ret)
+ return ret;
+
+ delta_clbcnt = cur_clbcnt - data->init_clbcnt;
+
+ /*
+ * Convert coulomb counter to delta capacity (mAh), and set multiplier
+ * as 10 to improve the precision.
+ */
+ temp = DIV_ROUND_CLOSEST(delta_clbcnt * 10, 36 * SC27XX_FGU_SAMPLE_HZ);
+ temp = sc27xx_fgu_adc_to_current(data, temp / 1000);
+
+ /*
+ * Convert to capacity percent of the battery total capacity,
+ * and multiplier is 100 too.
+ */
+ delta_cap = DIV_ROUND_CLOSEST(temp * 100, data->total_cap);
+ *cap = delta_cap + data->init_cap;
+
+ /* Calibrate the battery capacity in a normal range. */
+ sc27xx_fgu_capacity_calibration(data, *cap, false);
+
+ return 0;
+}
+
+static int sc27xx_fgu_get_vbat_vol(struct sc27xx_fgu_data *data, int *val)
+{
+ int ret, vol;
+
+ ret = regmap_read(data->regmap, data->base + SC27XX_FGU_VOLTAGE, &vol);
+ if (ret)
+ return ret;
+
+ /*
+ * It is ADC values reading from registers which need to convert to
+ * corresponding voltage values.
+ */
+ *val = sc27xx_fgu_adc_to_voltage(data, vol);
+
+ return 0;
+}
+
+static int sc27xx_fgu_get_current(struct sc27xx_fgu_data *data, int *val)
+{
+ int ret, cur;
+
+ ret = regmap_read(data->regmap, data->base + SC27XX_FGU_CURRENT, &cur);
+ if (ret)
+ return ret;
+
+ /*
+ * It is ADC values reading from registers which need to convert to
+ * corresponding current values.
+ */
+ *val = sc27xx_fgu_adc_to_current(data, cur - SC27XX_FGU_CUR_BASIC_ADC);
+
+ return 0;
+}
+
+static int sc27xx_fgu_get_vbat_ocv(struct sc27xx_fgu_data *data, int *val)
+{
+ int vol, cur, ret, temp, resistance;
+
+ ret = sc27xx_fgu_get_vbat_vol(data, &vol);
+ if (ret)
+ return ret;
+
+ ret = sc27xx_fgu_get_current(data, &cur);
+ if (ret)
+ return ret;
+
+ resistance = data->internal_resist;
+ if (data->resist_table_len > 0) {
+ ret = sc27xx_fgu_get_temp(data, &temp);
+ if (ret)
+ return ret;
+
+ resistance = power_supply_temp2resist_simple(data->resist_table,
+ data->resist_table_len, temp);
+ resistance = data->internal_resist * resistance / 100;
+ }
+
+ /* Return the battery OCV in micro volts. */
+ *val = vol * 1000 - cur * resistance;
+
+ return 0;
+}
+
+static int sc27xx_fgu_get_charge_vol(struct sc27xx_fgu_data *data, int *val)
+{
+ int ret, vol;
+
+ ret = iio_read_channel_processed(data->charge_chan, &vol);
+ if (ret < 0)
+ return ret;
+
+ *val = vol * 1000;
+ return 0;
+}
+
+static int sc27xx_fgu_get_temp(struct sc27xx_fgu_data *data, int *temp)
+{
+ return iio_read_channel_processed(data->channel, temp);
+}
+
+static int sc27xx_fgu_get_health(struct sc27xx_fgu_data *data, int *health)
+{
+ int ret, vol;
+
+ ret = sc27xx_fgu_get_vbat_vol(data, &vol);
+ if (ret)
+ return ret;
+
+ if (vol > data->max_volt)
+ *health = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
+ else
+ *health = POWER_SUPPLY_HEALTH_GOOD;
+
+ return 0;
+}
+
+static int sc27xx_fgu_get_status(struct sc27xx_fgu_data *data, int *status)
+{
+ union power_supply_propval val;
+ struct power_supply *psy;
+ int i, ret = -EINVAL;
+
+ for (i = 0; i < ARRAY_SIZE(sc27xx_charger_supply_name); i++) {
+ psy = power_supply_get_by_name(sc27xx_charger_supply_name[i]);
+ if (!psy)
+ continue;
+
+ ret = power_supply_get_property(psy, POWER_SUPPLY_PROP_STATUS,
+ &val);
+ power_supply_put(psy);
+ if (ret)
+ return ret;
+
+ *status = val.intval;
+ }
+
+ return ret;
+}
+
+static int sc27xx_fgu_get_property(struct power_supply *psy,
+ enum power_supply_property psp,
+ union power_supply_propval *val)
+{
+ struct sc27xx_fgu_data *data = power_supply_get_drvdata(psy);
+ int ret = 0;
+ int value;
+
+ mutex_lock(&data->lock);
+
+ switch (psp) {
+ case POWER_SUPPLY_PROP_STATUS:
+ ret = sc27xx_fgu_get_status(data, &value);
+ if (ret)
+ goto error;
+
+ val->intval = value;
+ break;
+
+ case POWER_SUPPLY_PROP_HEALTH:
+ ret = sc27xx_fgu_get_health(data, &value);
+ if (ret)
+ goto error;
+
+ val->intval = value;
+ break;
+
+ case POWER_SUPPLY_PROP_PRESENT:
+ val->intval = data->bat_present;
+ break;
+
+ case POWER_SUPPLY_PROP_TEMP:
+ ret = sc27xx_fgu_get_temp(data, &value);
+ if (ret)
+ goto error;
+
+ val->intval = value;
+ break;
+
+ case POWER_SUPPLY_PROP_TECHNOLOGY:
+ val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
+ break;
+
+ case POWER_SUPPLY_PROP_CAPACITY:
+ ret = sc27xx_fgu_get_capacity(data, &value);
+ if (ret)
+ goto error;
+
+ val->intval = value;
+ break;
+
+ case POWER_SUPPLY_PROP_VOLTAGE_AVG:
+ ret = sc27xx_fgu_get_vbat_vol(data, &value);
+ if (ret)
+ goto error;
+
+ val->intval = value * 1000;
+ break;
+
+ case POWER_SUPPLY_PROP_VOLTAGE_OCV:
+ ret = sc27xx_fgu_get_vbat_ocv(data, &value);
+ if (ret)
+ goto error;
+
+ val->intval = value;
+ break;
+
+ case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
+ ret = sc27xx_fgu_get_charge_vol(data, &value);
+ if (ret)
+ goto error;
+
+ val->intval = value;
+ break;
+
+ case POWER_SUPPLY_PROP_CURRENT_AVG:
+ ret = sc27xx_fgu_get_current(data, &value);
+ if (ret)
+ goto error;
+
+ val->intval = value * 1000;
+ break;
+
+ case POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN:
+ val->intval = data->total_cap * 1000;
+ break;
+
+ case POWER_SUPPLY_PROP_CHARGE_NOW:
+ ret = sc27xx_fgu_get_clbcnt(data, &value);
+ if (ret)
+ goto error;
+
+ value = DIV_ROUND_CLOSEST(value * 10,
+ 36 * SC27XX_FGU_SAMPLE_HZ);
+ val->intval = sc27xx_fgu_adc_to_current(data, value);
+
+ break;
+
+ case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+ ret = sc27xx_fgu_get_vol_now(data, &value);
+ if (ret)
+ goto error;
+
+ val->intval = value * 1000;
+ break;
+
+ case POWER_SUPPLY_PROP_CURRENT_NOW:
+ ret = sc27xx_fgu_get_cur_now(data, &value);
+ if (ret)
+ goto error;
+
+ val->intval = value * 1000;
+ break;
+
+ case POWER_SUPPLY_PROP_VOLTAGE_BOOT:
+ val->intval = data->boot_volt;
+ break;
+
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+error:
+ mutex_unlock(&data->lock);
+ return ret;
+}
+
+static int sc27xx_fgu_set_property(struct power_supply *psy,
+ enum power_supply_property psp,
+ const union power_supply_propval *val)
+{
+ struct sc27xx_fgu_data *data = power_supply_get_drvdata(psy);
+ int ret;
+
+ mutex_lock(&data->lock);
+
+ switch (psp) {
+ case POWER_SUPPLY_PROP_CAPACITY:
+ ret = sc27xx_fgu_save_last_cap(data, val->intval);
+ if (ret < 0)
+ dev_err(data->dev, "failed to save battery capacity\n");
+ break;
+
+ case POWER_SUPPLY_PROP_CALIBRATE:
+ sc27xx_fgu_adjust_cap(data, val->intval);
+ ret = 0;
+ break;
+
+ case POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN:
+ data->total_cap = val->intval / 1000;
+ ret = 0;
+ break;
+
+ default:
+ ret = -EINVAL;
+ }
+
+ mutex_unlock(&data->lock);
+
+ return ret;
+}
+
+static int sc27xx_fgu_property_is_writeable(struct power_supply *psy,
+ enum power_supply_property psp)
+{
+ return psp == POWER_SUPPLY_PROP_CAPACITY ||
+ psp == POWER_SUPPLY_PROP_CALIBRATE ||
+ psp == POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN;
+}
+
+static enum power_supply_property sc27xx_fgu_props[] = {
+ POWER_SUPPLY_PROP_STATUS,
+ POWER_SUPPLY_PROP_HEALTH,
+ POWER_SUPPLY_PROP_PRESENT,
+ POWER_SUPPLY_PROP_TEMP,
+ POWER_SUPPLY_PROP_TECHNOLOGY,
+ POWER_SUPPLY_PROP_CAPACITY,
+ POWER_SUPPLY_PROP_VOLTAGE_NOW,
+ POWER_SUPPLY_PROP_VOLTAGE_OCV,
+ POWER_SUPPLY_PROP_VOLTAGE_AVG,
+ POWER_SUPPLY_PROP_VOLTAGE_BOOT,
+ POWER_SUPPLY_PROP_CURRENT_NOW,
+ POWER_SUPPLY_PROP_CURRENT_AVG,
+ POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE,
+ POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN,
+ POWER_SUPPLY_PROP_CALIBRATE,
+ POWER_SUPPLY_PROP_CHARGE_NOW
+};
+
+static const struct power_supply_desc sc27xx_fgu_desc = {
+ .name = "sc27xx-fgu",
+ .type = POWER_SUPPLY_TYPE_BATTERY,
+ .properties = sc27xx_fgu_props,
+ .num_properties = ARRAY_SIZE(sc27xx_fgu_props),
+ .get_property = sc27xx_fgu_get_property,
+ .set_property = sc27xx_fgu_set_property,
+ .external_power_changed = power_supply_changed,
+ .property_is_writeable = sc27xx_fgu_property_is_writeable,
+ .no_thermal = true,
+};
+
+static void sc27xx_fgu_adjust_cap(struct sc27xx_fgu_data *data, int cap)
+{
+ int ret;
+
+ data->init_cap = cap;
+ ret = sc27xx_fgu_get_clbcnt(data, &data->init_clbcnt);
+ if (ret)
+ dev_err(data->dev, "failed to get init coulomb counter\n");
+}
+
+static void sc27xx_fgu_capacity_calibration(struct sc27xx_fgu_data *data,
+ int cap, bool int_mode)
+{
+ int ret, ocv, chg_sts, adc;
+
+ ret = sc27xx_fgu_get_vbat_ocv(data, &ocv);
+ if (ret) {
+ dev_err(data->dev, "get battery ocv error.\n");
+ return;
+ }
+
+ ret = sc27xx_fgu_get_status(data, &chg_sts);
+ if (ret) {
+ dev_err(data->dev, "get charger status error.\n");
+ return;
+ }
+
+ /*
+ * If we are in charging mode, then we do not need to calibrate the
+ * lower capacity.
+ */
+ if (chg_sts == POWER_SUPPLY_STATUS_CHARGING)
+ return;
+
+ if ((ocv > data->cap_table[0].ocv && cap < 100) || cap > 100) {
+ /*
+ * If current OCV value is larger than the max OCV value in
+ * OCV table, or the current capacity is larger than 100,
+ * we should force the inititial capacity to 100.
+ */
+ sc27xx_fgu_adjust_cap(data, 100);
+ } else if (ocv <= data->cap_table[data->table_len - 1].ocv) {
+ /*
+ * If current OCV value is leass than the minimum OCV value in
+ * OCV table, we should force the inititial capacity to 0.
+ */
+ sc27xx_fgu_adjust_cap(data, 0);
+ } else if ((ocv > data->cap_table[data->table_len - 1].ocv && cap <= 0) ||
+ (ocv > data->min_volt && cap <= data->alarm_cap)) {
+ /*
+ * If current OCV value is not matchable with current capacity,
+ * we should re-calculate current capacity by looking up the
+ * OCV table.
+ */
+ int cur_cap = power_supply_ocv2cap_simple(data->cap_table,
+ data->table_len, ocv);
+
+ sc27xx_fgu_adjust_cap(data, cur_cap);
+ } else if (ocv <= data->min_volt) {
+ /*
+ * If current OCV value is less than the low alarm voltage, but
+ * current capacity is larger than the alarm capacity, we should
+ * adjust the inititial capacity to alarm capacity.
+ */
+ if (cap > data->alarm_cap) {
+ sc27xx_fgu_adjust_cap(data, data->alarm_cap);
+ } else {
+ int cur_cap;
+
+ /*
+ * If current capacity is equal with 0 or less than 0
+ * (some error occurs), we should adjust inititial
+ * capacity to the capacity corresponding to current OCV
+ * value.
+ */
+ cur_cap = power_supply_ocv2cap_simple(data->cap_table,
+ data->table_len,
+ ocv);
+ sc27xx_fgu_adjust_cap(data, cur_cap);
+ }
+
+ if (!int_mode)
+ return;
+
+ /*
+ * After adjusting the battery capacity, we should set the
+ * lowest alarm voltage instead.
+ */
+ data->min_volt = data->cap_table[data->table_len - 1].ocv;
+ data->alarm_cap = power_supply_ocv2cap_simple(data->cap_table,
+ data->table_len,
+ data->min_volt);
+
+ adc = sc27xx_fgu_voltage_to_adc(data, data->min_volt / 1000);
+ regmap_update_bits(data->regmap,
+ data->base + SC27XX_FGU_LOW_OVERLOAD,
+ SC27XX_FGU_LOW_OVERLOAD_MASK, adc);
+ }
+}
+
+static irqreturn_t sc27xx_fgu_interrupt(int irq, void *dev_id)
+{
+ struct sc27xx_fgu_data *data = dev_id;
+ int ret, cap;
+ u32 status;
+
+ mutex_lock(&data->lock);
+
+ ret = regmap_read(data->regmap, data->base + SC27XX_FGU_INT_STS,
+ &status);
+ if (ret)
+ goto out;
+
+ ret = regmap_update_bits(data->regmap, data->base + SC27XX_FGU_INT_CLR,
+ status, status);
+ if (ret)
+ goto out;
+
+ /*
+ * When low overload voltage interrupt happens, we should calibrate the
+ * battery capacity in lower voltage stage.
+ */
+ if (!(status & SC27XX_FGU_LOW_OVERLOAD_INT))
+ goto out;
+
+ ret = sc27xx_fgu_get_capacity(data, &cap);
+ if (ret)
+ goto out;
+
+ sc27xx_fgu_capacity_calibration(data, cap, true);
+
+out:
+ mutex_unlock(&data->lock);
+
+ power_supply_changed(data->battery);
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t sc27xx_fgu_bat_detection(int irq, void *dev_id)
+{
+ struct sc27xx_fgu_data *data = dev_id;
+ int state;
+
+ mutex_lock(&data->lock);
+
+ state = gpiod_get_value_cansleep(data->gpiod);
+ if (state < 0) {
+ dev_err(data->dev, "failed to get gpio state\n");
+ mutex_unlock(&data->lock);
+ return IRQ_RETVAL(state);
+ }
+
+ data->bat_present = !!state;
+
+ mutex_unlock(&data->lock);
+
+ power_supply_changed(data->battery);
+ return IRQ_HANDLED;
+}
+
+static void sc27xx_fgu_disable(void *_data)
+{
+ struct sc27xx_fgu_data *data = _data;
+
+ regmap_update_bits(data->regmap, SC27XX_CLK_EN0, SC27XX_FGU_RTC_EN, 0);
+ regmap_update_bits(data->regmap, SC27XX_MODULE_EN0, SC27XX_FGU_EN, 0);
+}
+
+static int sc27xx_fgu_cap_to_clbcnt(struct sc27xx_fgu_data *data, int capacity)
+{
+ /*
+ * Get current capacity (mAh) = battery total capacity (mAh) *
+ * current capacity percent (capacity / 100).
+ */
+ int cur_cap = DIV_ROUND_CLOSEST(data->total_cap * capacity, 100);
+
+ /*
+ * Convert current capacity (mAh) to coulomb counter according to the
+ * formula: 1 mAh =3.6 coulomb.
+ */
+ return DIV_ROUND_CLOSEST(cur_cap * 36 * data->cur_1000ma_adc * SC27XX_FGU_SAMPLE_HZ, 10);
+}
+
+static int sc27xx_fgu_calibration(struct sc27xx_fgu_data *data)
+{
+ struct nvmem_cell *cell;
+ int calib_data, cal_4200mv;
+ void *buf;
+ size_t len;
+
+ cell = nvmem_cell_get(data->dev, "fgu_calib");
+ if (IS_ERR(cell))
+ return PTR_ERR(cell);
+
+ buf = nvmem_cell_read(cell, &len);
+ nvmem_cell_put(cell);
+
+ if (IS_ERR(buf))
+ return PTR_ERR(buf);
+
+ memcpy(&calib_data, buf, min(len, sizeof(u32)));
+
+ /*
+ * Get the ADC value corresponding to 4200 mV from eFuse controller
+ * according to below formula. Then convert to ADC values corresponding
+ * to 1000 mV and 1000 mA.
+ */
+ cal_4200mv = (calib_data & 0x1ff) + 6963 - 4096 - 256;
+ data->vol_1000mv_adc = DIV_ROUND_CLOSEST(cal_4200mv * 10, 42);
+ data->cur_1000ma_adc =
+ DIV_ROUND_CLOSEST(data->vol_1000mv_adc * 4 * data->calib_resist,
+ SC27XX_FGU_IDEAL_RESISTANCE);
+
+ kfree(buf);
+ return 0;
+}
+
+static int sc27xx_fgu_hw_init(struct sc27xx_fgu_data *data)
+{
+ struct power_supply_battery_info *info;
+ struct power_supply_battery_ocv_table *table;
+ int ret, delta_clbcnt, alarm_adc;
+
+ ret = power_supply_get_battery_info(data->battery, &info);
+ if (ret) {
+ dev_err(data->dev, "failed to get battery information\n");
+ return ret;
+ }
+
+ data->total_cap = info->charge_full_design_uah / 1000;
+ data->max_volt = info->constant_charge_voltage_max_uv / 1000;
+ data->internal_resist = info->factory_internal_resistance_uohm / 1000;
+ data->min_volt = info->voltage_min_design_uv;
+
+ /*
+ * For SC27XX fuel gauge device, we only use one ocv-capacity
+ * table in normal temperature 20 Celsius.
+ */
+ table = power_supply_find_ocv2cap_table(info, 20, &data->table_len);
+ if (!table)
+ return -EINVAL;
+
+ data->cap_table = devm_kmemdup(data->dev, table,
+ data->table_len * sizeof(*table),
+ GFP_KERNEL);
+ if (!data->cap_table) {
+ power_supply_put_battery_info(data->battery, info);
+ return -ENOMEM;
+ }
+
+ data->alarm_cap = power_supply_ocv2cap_simple(data->cap_table,
+ data->table_len,
+ data->min_volt);
+ if (!data->alarm_cap)
+ data->alarm_cap += 1;
+
+ data->resist_table_len = info->resist_table_size;
+ if (data->resist_table_len > 0) {
+ data->resist_table = devm_kmemdup(data->dev, info->resist_table,
+ data->resist_table_len *
+ sizeof(struct power_supply_resistance_temp_table),
+ GFP_KERNEL);
+ if (!data->resist_table) {
+ power_supply_put_battery_info(data->battery, info);
+ return -ENOMEM;
+ }
+ }
+
+ power_supply_put_battery_info(data->battery, info);
+
+ ret = sc27xx_fgu_calibration(data);
+ if (ret)
+ return ret;
+
+ /* Enable the FGU module */
+ ret = regmap_update_bits(data->regmap, SC27XX_MODULE_EN0,
+ SC27XX_FGU_EN, SC27XX_FGU_EN);
+ if (ret) {
+ dev_err(data->dev, "failed to enable fgu\n");
+ return ret;
+ }
+
+ /* Enable the FGU RTC clock to make it work */
+ ret = regmap_update_bits(data->regmap, SC27XX_CLK_EN0,
+ SC27XX_FGU_RTC_EN, SC27XX_FGU_RTC_EN);
+ if (ret) {
+ dev_err(data->dev, "failed to enable fgu RTC clock\n");
+ goto disable_fgu;
+ }
+
+ ret = regmap_update_bits(data->regmap, data->base + SC27XX_FGU_INT_CLR,
+ SC27XX_FGU_INT_MASK, SC27XX_FGU_INT_MASK);
+ if (ret) {
+ dev_err(data->dev, "failed to clear interrupt status\n");
+ goto disable_clk;
+ }
+
+ /*
+ * Set the voltage low overload threshold, which means when the battery
+ * voltage is lower than this threshold, the controller will generate
+ * one interrupt to notify.
+ */
+ alarm_adc = sc27xx_fgu_voltage_to_adc(data, data->min_volt / 1000);
+ ret = regmap_update_bits(data->regmap, data->base + SC27XX_FGU_LOW_OVERLOAD,
+ SC27XX_FGU_LOW_OVERLOAD_MASK, alarm_adc);
+ if (ret) {
+ dev_err(data->dev, "failed to set fgu low overload\n");
+ goto disable_clk;
+ }
+
+ /*
+ * Set the coulomb counter delta threshold, that means when the coulomb
+ * counter change is multiples of the delta threshold, the controller
+ * will generate one interrupt to notify the users to update the battery
+ * capacity. Now we set the delta threshold as a counter value of 1%
+ * capacity.
+ */
+ delta_clbcnt = sc27xx_fgu_cap_to_clbcnt(data, 1);
+
+ ret = regmap_update_bits(data->regmap, data->base + SC27XX_FGU_CLBCNT_DELTL,
+ SC27XX_FGU_CLBCNT_MASK, delta_clbcnt);
+ if (ret) {
+ dev_err(data->dev, "failed to set low delta coulomb counter\n");
+ goto disable_clk;
+ }
+
+ ret = regmap_update_bits(data->regmap, data->base + SC27XX_FGU_CLBCNT_DELTH,
+ SC27XX_FGU_CLBCNT_MASK,
+ delta_clbcnt >> SC27XX_FGU_CLBCNT_SHIFT);
+ if (ret) {
+ dev_err(data->dev, "failed to set high delta coulomb counter\n");
+ goto disable_clk;
+ }
+
+ /*
+ * Get the boot battery capacity when system powers on, which is used to
+ * initialize the coulomb counter. After that, we can read the coulomb
+ * counter to measure the battery capacity.
+ */
+ ret = sc27xx_fgu_get_boot_capacity(data, &data->init_cap);
+ if (ret) {
+ dev_err(data->dev, "failed to get boot capacity\n");
+ goto disable_clk;
+ }
+
+ /*
+ * Convert battery capacity to the corresponding initial coulomb counter
+ * and set into coulomb counter registers.
+ */
+ data->init_clbcnt = sc27xx_fgu_cap_to_clbcnt(data, data->init_cap);
+ ret = sc27xx_fgu_set_clbcnt(data, data->init_clbcnt);
+ if (ret) {
+ dev_err(data->dev, "failed to initialize coulomb counter\n");
+ goto disable_clk;
+ }
+
+ return 0;
+
+disable_clk:
+ regmap_update_bits(data->regmap, SC27XX_CLK_EN0, SC27XX_FGU_RTC_EN, 0);
+disable_fgu:
+ regmap_update_bits(data->regmap, SC27XX_MODULE_EN0, SC27XX_FGU_EN, 0);
+
+ return ret;
+}
+
+static int sc27xx_fgu_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
+ struct power_supply_config fgu_cfg = { };
+ struct sc27xx_fgu_data *data;
+ int ret, irq;
+
+ data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ data->regmap = dev_get_regmap(dev->parent, NULL);
+ if (!data->regmap) {
+ dev_err(dev, "failed to get regmap\n");
+ return -ENODEV;
+ }
+
+ ret = device_property_read_u32(dev, "reg", &data->base);
+ if (ret) {
+ dev_err(dev, "failed to get fgu address\n");
+ return ret;
+ }
+
+ ret = device_property_read_u32(&pdev->dev,
+ "sprd,calib-resistance-micro-ohms",
+ &data->calib_resist);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "failed to get fgu calibration resistance\n");
+ return ret;
+ }
+
+ data->channel = devm_iio_channel_get(dev, "bat-temp");
+ if (IS_ERR(data->channel)) {
+ dev_err(dev, "failed to get IIO channel\n");
+ return PTR_ERR(data->channel);
+ }
+
+ data->charge_chan = devm_iio_channel_get(dev, "charge-vol");
+ if (IS_ERR(data->charge_chan)) {
+ dev_err(dev, "failed to get charge IIO channel\n");
+ return PTR_ERR(data->charge_chan);
+ }
+
+ data->gpiod = devm_gpiod_get(dev, "bat-detect", GPIOD_IN);
+ if (IS_ERR(data->gpiod)) {
+ dev_err(dev, "failed to get battery detection GPIO\n");
+ return PTR_ERR(data->gpiod);
+ }
+
+ ret = gpiod_get_value_cansleep(data->gpiod);
+ if (ret < 0) {
+ dev_err(dev, "failed to get gpio state\n");
+ return ret;
+ }
+
+ data->bat_present = !!ret;
+ mutex_init(&data->lock);
+ data->dev = dev;
+ platform_set_drvdata(pdev, data);
+
+ fgu_cfg.drv_data = data;
+ fgu_cfg.of_node = np;
+ data->battery = devm_power_supply_register(dev, &sc27xx_fgu_desc,
+ &fgu_cfg);
+ if (IS_ERR(data->battery)) {
+ dev_err(dev, "failed to register power supply\n");
+ return PTR_ERR(data->battery);
+ }
+
+ ret = sc27xx_fgu_hw_init(data);
+ if (ret) {
+ dev_err(dev, "failed to initialize fgu hardware\n");
+ return ret;
+ }
+
+ ret = devm_add_action_or_reset(dev, sc27xx_fgu_disable, data);
+ if (ret) {
+ dev_err(dev, "failed to add fgu disable action\n");
+ return ret;
+ }
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0)
+ return irq;
+
+ ret = devm_request_threaded_irq(data->dev, irq, NULL,
+ sc27xx_fgu_interrupt,
+ IRQF_NO_SUSPEND | IRQF_ONESHOT,
+ pdev->name, data);
+ if (ret) {
+ dev_err(data->dev, "failed to request fgu IRQ\n");
+ return ret;
+ }
+
+ irq = gpiod_to_irq(data->gpiod);
+ if (irq < 0) {
+ dev_err(dev, "failed to translate GPIO to IRQ\n");
+ return irq;
+ }
+
+ ret = devm_request_threaded_irq(dev, irq, NULL,
+ sc27xx_fgu_bat_detection,
+ IRQF_ONESHOT | IRQF_TRIGGER_RISING |
+ IRQF_TRIGGER_FALLING,
+ pdev->name, data);
+ if (ret) {
+ dev_err(dev, "failed to request IRQ\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int sc27xx_fgu_resume(struct device *dev)
+{
+ struct sc27xx_fgu_data *data = dev_get_drvdata(dev);
+ int ret;
+
+ ret = regmap_update_bits(data->regmap, data->base + SC27XX_FGU_INT_EN,
+ SC27XX_FGU_LOW_OVERLOAD_INT |
+ SC27XX_FGU_CLBCNT_DELTA_INT, 0);
+ if (ret) {
+ dev_err(data->dev, "failed to disable fgu interrupts\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+static int sc27xx_fgu_suspend(struct device *dev)
+{
+ struct sc27xx_fgu_data *data = dev_get_drvdata(dev);
+ int ret, status, ocv;
+
+ ret = sc27xx_fgu_get_status(data, &status);
+ if (ret)
+ return ret;
+
+ /*
+ * If we are charging, then no need to enable the FGU interrupts to
+ * adjust the battery capacity.
+ */
+ if (status != POWER_SUPPLY_STATUS_NOT_CHARGING &&
+ status != POWER_SUPPLY_STATUS_DISCHARGING)
+ return 0;
+
+ ret = regmap_update_bits(data->regmap, data->base + SC27XX_FGU_INT_EN,
+ SC27XX_FGU_LOW_OVERLOAD_INT,
+ SC27XX_FGU_LOW_OVERLOAD_INT);
+ if (ret) {
+ dev_err(data->dev, "failed to enable low voltage interrupt\n");
+ return ret;
+ }
+
+ ret = sc27xx_fgu_get_vbat_ocv(data, &ocv);
+ if (ret)
+ goto disable_int;
+
+ /*
+ * If current OCV is less than the minimum voltage, we should enable the
+ * coulomb counter threshold interrupt to notify events to adjust the
+ * battery capacity.
+ */
+ if (ocv < data->min_volt) {
+ ret = regmap_update_bits(data->regmap,
+ data->base + SC27XX_FGU_INT_EN,
+ SC27XX_FGU_CLBCNT_DELTA_INT,
+ SC27XX_FGU_CLBCNT_DELTA_INT);
+ if (ret) {
+ dev_err(data->dev,
+ "failed to enable coulomb threshold int\n");
+ goto disable_int;
+ }
+ }
+
+ return 0;
+
+disable_int:
+ regmap_update_bits(data->regmap, data->base + SC27XX_FGU_INT_EN,
+ SC27XX_FGU_LOW_OVERLOAD_INT, 0);
+ return ret;
+}
+#endif
+
+static const struct dev_pm_ops sc27xx_fgu_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(sc27xx_fgu_suspend, sc27xx_fgu_resume)
+};
+
+static const struct of_device_id sc27xx_fgu_of_match[] = {
+ { .compatible = "sprd,sc2731-fgu", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, sc27xx_fgu_of_match);
+
+static struct platform_driver sc27xx_fgu_driver = {
+ .probe = sc27xx_fgu_probe,
+ .driver = {
+ .name = "sc27xx-fgu",
+ .of_match_table = sc27xx_fgu_of_match,
+ .pm = &sc27xx_fgu_pm_ops,
+ }
+};
+
+module_platform_driver(sc27xx_fgu_driver);
+
+MODULE_DESCRIPTION("Spreadtrum SC27XX PMICs Fual Gauge Unit Driver");
+MODULE_LICENSE("GPL v2");