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Message-ID: <20181022104333.uakqxng7naf65d6m@earth.universe>
Date: Mon, 22 Oct 2018 12:43:33 +0200
From: Sebastian Reichel <sre@...nel.org>
To: Baolin Wang <baolin.wang@...aro.org>
Cc: Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Linux PM list <linux-pm@...r.kernel.org>,
DTML <devicetree@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>, yuanjiang.yu@...soc.com,
Mark Brown <broonie@...nel.org>,
Craig Tatlor <ctatlor97@...il.com>,
Linus Walleij <linus.walleij@...aro.org>
Subject: Re: [PATCH v5 6/6] power: supply: Add Spreadtrum SC27XX fuel gauge
unit driver
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@...nel.org> 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@...soc.com>
> >> Signed-off-by: Baolin Wang <baolin.wang@...aro.org>
> >> Acked-by: Linus Walleij <linus.walleij@...aro.org>
> >> ---
> >
> > 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 20°C 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.
-- Sebastian
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