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

From: Baolin Wang
Date: Mon Oct 22 2018 - 01:55:00 EST

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.

--
Baolin Wang
Best Regards