Re: [PATCH v5 6/6] power: supply: Add Spreadtrum SC27XX fuel gauge unit driver

From: Baolin Wang
Date: Mon Oct 22 2018 - 06:49:24 EST

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On 22 October 2018 at 18:43, Sebastian Reichel <sre@xxxxxxxxxx> wrote:
> Hi,
>
> On Mon, Oct 22, 2018 at 01:54:50PM +0800, Baolin Wang wrote:
>> Hi Sebastian,
>>
>> On 22 October 2018 at 00:52, Sebastian Reichel <sre@xxxxxxxxxx> wrote:
>> > Hi,
>> >
>> > On Fri, Oct 19, 2018 at 06:53:15PM +0800, Baolin Wang wrote:
>> >> This patch adds the Spreadtrum SC27XX serial PMICs fuel gauge support,
>> >> which is used to calculate the battery capacity.
>> >>
>> >> Original-by: Yuanjiang Yu <yuanjiang.yu@xxxxxxxxxx>
>> >> Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx>
>> >> Acked-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
>> >> ---
>> >
>> > Looks mostly good. I have a few comments still. My plan is to merge
>> > this early after the merge window, if the final version is finished
>> > at this point.
>> >
>> >> Changes from v4:
>> >> - None.
>> >>
>> >> Changes from v3:
>> >> - None.
>> >>
>> >> Changes from v2:
>> >> - Use core helper functions to look up OCV capacity table.
>> >> - Use device_property_read_u32() instead of of_property_read_u32().
>> >> - Add acked tag from Linus.
>> >>
>> >> Changes from v1:
>> >> - Use battery standard properties to get internal resistance and ocv table.
>> >> - Change devm_gpiod_get_optional() to devm_gpiod_get().
>> >> - Add power_supply_changed() when detecting battery present change.
>> >> - Return micro volts for sc27xx_fgu_get_vbat_ocv().
>> >> ---
>> >> drivers/power/supply/Kconfig | 7 +
>> >> drivers/power/supply/Makefile | 1 +
>> >> drivers/power/supply/sc27xx_fuel_gauge.c | 661 ++++++++++++++++++++++++++++++
>> >> 3 files changed, 669 insertions(+)
>> >> create mode 100644 drivers/power/supply/sc27xx_fuel_gauge.c
>> >>
>> >> diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
>> >> index f27cf07..917f4b7 100644
>> >> --- a/drivers/power/supply/Kconfig
>> >> +++ b/drivers/power/supply/Kconfig
>> >> @@ -652,4 +652,11 @@ config CHARGER_SC2731
>> >> Say Y here to enable support for battery charging with SC2731
>> >> PMIC chips.
>> >>
>> >> +config FUEL_GAUGE_SC27XX
>> >> + tristate "Spreadtrum SC27XX fuel gauge driver"
>> >> + depends on MFD_SC27XX_PMIC || COMPILE_TEST
>> >> + help
>> >> + Say Y here to enable support for fuel gauge with SC27XX
>> >> + PMIC chips.
>> >> +
>> >> endif # POWER_SUPPLY
>> >> diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
>> >> index 767105b..b731c2a 100644
>> >> --- a/drivers/power/supply/Makefile
>> >> +++ b/drivers/power/supply/Makefile
>> >> @@ -86,3 +86,4 @@ obj-$(CONFIG_AXP288_FUEL_GAUGE) += axp288_fuel_gauge.o
>> >> obj-$(CONFIG_AXP288_CHARGER) += axp288_charger.o
>> >> obj-$(CONFIG_CHARGER_CROS_USBPD) += cros_usbpd-charger.o
>> >> obj-$(CONFIG_CHARGER_SC2731) += sc2731_charger.o
>> >> +obj-$(CONFIG_FUEL_GAUGE_SC27XX) += sc27xx_fuel_gauge.o
>> >> diff --git a/drivers/power/supply/sc27xx_fuel_gauge.c b/drivers/power/supply/sc27xx_fuel_gauge.c
>> >> new file mode 100644
>> >> index 0000000..1c0b856
>> >> --- /dev/null
>> >> +++ b/drivers/power/supply/sc27xx_fuel_gauge.c
>> >> @@ -0,0 +1,661 @@
>> >> +// 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/module.h>
>> >> +#include <linux/of.h>
>> >> +#include <linux/platform_device.h>
>> >> +#include <linux/power_supply.h>
>> >> +#include <linux/regmap.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_CLBCNT_SETH 0x50
>> >> +#define SC27XX_FGU_CLBCNT_SETL 0x54
>> >> +#define SC27XX_FGU_CLBCNT_VALH 0x68
>> >> +#define SC27XX_FGU_CLBCNT_VALL 0x6c
>> >> +#define SC27XX_FGU_CLBCNT_QMAXL 0x74
>> >> +
>> >> +#define SC27XX_WRITE_SELCLB_EN BIT(0)
>> >> +#define SC27XX_FGU_CLBCNT_MASK GENMASK(15, 0)
>> >> +#define SC27XX_FGU_CLBCNT_SHIFT 16
>> >> +
>> >> +#define SC27XX_FGU_1000MV_ADC 686
>> >> +#define SC27XX_FGU_1000MA_ADC 1372
>> >> +#define SC27XX_FGU_CUR_BASIC_ADC 8192
>> >> +#define SC27XX_FGU_SAMPLE_HZ 2
>> >> +
>> >> +/*
>> >> + * 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
>> >> + * @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
>> >> + * @init_clbcnt: the initial coulomb counter
>> >> + * @max_volt: the maximum constant input voltage in millivolt
>> >> + * @table_len: the capacity table length
>> >> + * @cap_table: capacity table with corresponding ocv
>> >> + */
>> >> +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;
>> >> + bool bat_present;
>> >> + int internal_resist;
>> >> + int total_cap;
>> >> + int init_cap;
>> >> + int init_clbcnt;
>> >> + int max_volt;
>> >> + int table_len;
>> >> + struct power_supply_battery_ocv_table *cap_table;
>> >> +};
>> >> +
>> >> +static const char * const sc27xx_charger_supply_name[] = {
>> >> + "sc2731_charger",
>> >> + "sc2720_charger",
>> >> + "sc2721_charger",
>> >> + "sc2723_charger",
>> >> +};
>> >> +
>> >> +static int sc27xx_fgu_adc_to_current(int adc)
>> >> +{
>> >> + return (adc * 1000) / SC27XX_FGU_1000MA_ADC;
>> >> +}
>> >> +
>> >> +static int sc27xx_fgu_adc_to_voltage(int adc)
>> >> +{
>> >> + return (adc * 1000) / SC27XX_FGU_1000MV_ADC;
>> >> +}
>> >> +
>> >> +/*
>> >> + * 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;
>> >> +
>> >> + /*
>> >> + * 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(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(volt);
>> >> + ocv = volt - (oci * data->internal_resist) / 1000;
>> >> +
>> >> + /*
>> >> + * 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);
>> >> +
>> >> + return 0;
>> >> +}
>> >> +
>> >> +static int sc27xx_fgu_set_clbcnt(struct sc27xx_fgu_data *data, int clbcnt)
>> >> +{
>> >> + int ret;
>> >> +
>> >> + clbcnt *= SC27XX_FGU_SAMPLE_HZ;
>> >> +
>> >> + 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;
>> >> + *clb_cnt /= SC27XX_FGU_SAMPLE_HZ;
>> >> +
>> >> + 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 100 to improve the precision.
>> >> + */
>> >> + temp = DIV_ROUND_CLOSEST(delta_clbcnt, 360);
>> >> + temp = sc27xx_fgu_adc_to_current(temp);
>> >> +
>> >> + /*
>> >> + * 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;
>> >> +
>> >> + 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(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(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;
>> >> +
>> >> + ret = sc27xx_fgu_get_vbat_vol(data, &vol);
>> >> + if (ret)
>> >> + return ret;
>> >> +
>> >> + ret = sc27xx_fgu_get_current(data, &cur);
>> >> + if (ret)
>> >> + return ret;
>> >> +
>> >> + /* Return the battery OCV in micro volts. */
>> >> + *val = vol * 1000 - cur * data->internal_resist;
>> >> +
>> >> + 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_NOW:
>> >> + 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_CURRENT_NOW:
>> >> + case POWER_SUPPLY_PROP_CURRENT_AVG:
>> >> + ret = sc27xx_fgu_get_current(data, &value);
>> >> + if (ret)
>> >> + goto error;
>> >> +
>> >> + val->intval = value * 1000;
>> >> + break;
>> >> +
>> >> + default:
>> >> + ret = -EINVAL;
>> >> + break;
>> >> + }
>> >> +
>> >> +error:
>> >> + mutex_unlock(&data->lock);
>> >> + return ret;
>> >> +}
>> >> +
>> >> +static void sc27xx_fgu_external_power_changed(struct power_supply *psy)
>> >> +{
>> >> + struct sc27xx_fgu_data *data = power_supply_get_drvdata(psy);
>> >> +
>> >> + power_supply_changed(data->battery);
>> >> +}
>> >> +
>> >> +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_CURRENT_NOW,
>> >> + POWER_SUPPLY_PROP_CURRENT_AVG,
>> >> +};
>> >> +
>> >> +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,
>> >> + .external_power_changed = sc27xx_fgu_external_power_changed,
>> >> +};
>> >> +
>> >> +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, 10);
>> >> +}
>> >> +
>> >> +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, i;
>> >> +
>> >> + 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;
>> >> +
>> >> + /*
>> >> + * 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_kzalloc(data->dev,
>> >> + data->table_len * sizeof(*table),
>> >> + GFP_KERNEL);
>> >> + if (!data->cap_table) {
>> >> + power_supply_put_battery_info(data->battery, &info);
>> >> + return -ENOMEM;
>> >> + }
>> >> +
>> >> + for (i = 0; i < data->table_len; i++) {
>> >> + data->cap_table[i].ocv = table[i].ocv / 1000;
>> >> + data->cap_table[i].capacity = table[i].capacity;
>> >> + }
>> >
>> > Don't divide the OCV by 1000. You feed this table into the
>> > generic power-supply function later, which should always
>> > get uV. Instead multiply the ocv parameter in your
>> > power_supply_ocv2cap_simple() call with 1000. This
>> > means you can just use devm_kmemdup() here.
>>
>> Good point. Will change it in next version.
>>
>> >
>> > Some ideas for later (I'm fine with merging the driver
>> > without these changes):
>> >
>> > * Store battery_info directly in private driver data
>> > instead of doing a copy of the temperature table.
>> > * Call power_supply_ocv2cap() with current battery
>> > temperature and let the power-supply core figure
>> > out which ocv-to-capacity curve should be used.
>>
>> I should keep my original method, since we have no temperature table
>> now and only use one room temperature (20 degree). Thanks for your
>> useful comments.
>
> Which should work perfectly fine with power_supply_ocv2cap(). It
> will use the nearest curve, which is always the 20ÂC one in your
> case. If you add a second temperature curve in the future (i.e.
> because of using the sc27xx fuel gauge with a different battery),
> it would just pick this up automatically. But I'm fine with doing
> this later.

Yes, it can work. But I'd like to do this fix when we need multiple
temperature values in future. Thanks for your understanding.

--
Baolin Wang
Best Regards

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