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SubjectRe: [PATCH v7 2/4] power: supply: Add support for the Qualcomm Battery Monitoring System
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On 16 September 2018 14:48:36 BST, Sebastian Reichel <sebastian.reichel@collabora.com> wrote:
>Hi,
>
>First of all thanks for the patch and big sorry for the long delay
>in reviewing this. I did not find enough time to do it properly
>until now :(
>
>On Thu, Jun 14, 2018 at 04:14:15PM +0100, Craig Tatlor wrote:
>> This patch adds a driver for the BMS (Battery Monitoring System)
>> block of the PM8941 PMIC, it uses a lookup table defined in the
>> device tree to generate a capacity from the BMS supplied OCV, it
>> then amends the coulomb counter to that to increase the accuracy
>> of the estimated capacity.
>>
>> Signed-off-by: Craig Tatlor <ctatlor97@gmail.com>
>> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
>> ---
>>
>> * Changes from v5:
>
>> Uses select for REGMAP_SPMI.
>
>>
>
>> * Changes from v4:
>
>> Cleaned up percentage interpolation function,
>
>> uses new fixp interpolation helper,
>
>> added some more error cases,
>
>> uses devm_power_supply_register(),
>
>> uses a DIV_ROUND_CLOSEST for division and
>
>> uses micro(volts / amp hours) instead of
>
>> milli (volts / amp hours).
>>
>> drivers/power/supply/Kconfig | 9 +
>> drivers/power/supply/Makefile | 1 +
>> drivers/power/supply/qcom_bms.c | 487
>++++++++++++++++++++++++++++++++
>> 3 files changed, 497 insertions(+)
>> create mode 100644 drivers/power/supply/qcom_bms.c
>>
>> diff --git a/drivers/power/supply/Kconfig
>b/drivers/power/supply/Kconfig
>> index 428b426842f4..75f2f375f992 100644
>> --- a/drivers/power/supply/Kconfig
>> +++ b/drivers/power/supply/Kconfig
>> @@ -82,6 +82,15 @@ config BATTERY_ACT8945A
>> Say Y here to enable support for power supply provided by
>> Active-semi ActivePath ACT8945A charger.
>>
>> +config BATTERY_BMS
>> + tristate "Qualcomm Battery Monitoring System driver"
>> + depends on MFD_SPMI_PMIC || COMPILE_TEST
>> + depends on OF
>> + select REGMAP_SPMI
>> + help
>> + Say Y to include support for the Battery Monitoring hardware
>> + found in some Qualcomm PM series PMICs.
>> +
>> config BATTERY_CPCAP
>> tristate "Motorola CPCAP PMIC battery driver"
>> depends on MFD_CPCAP && IIO
>> diff --git a/drivers/power/supply/Makefile
>b/drivers/power/supply/Makefile
>> index e83aa843bcc6..04204174b047 100644
>> --- a/drivers/power/supply/Makefile
>> +++ b/drivers/power/supply/Makefile
>> @@ -21,6 +21,7 @@ obj-$(CONFIG_BATTERY_88PM860X) +=
>88pm860x_battery.o
>> obj-$(CONFIG_BATTERY_ACT8945A) += act8945a_charger.o
>> obj-$(CONFIG_BATTERY_AXP20X) += axp20x_battery.o
>> obj-$(CONFIG_CHARGER_AXP20X) += axp20x_ac_power.o
>> +obj-$(CONFIG_BATTERY_BMS) += qcom_bms.o
>> obj-$(CONFIG_BATTERY_CPCAP) += cpcap-battery.o
>> obj-$(CONFIG_BATTERY_DS2760) += ds2760_battery.o
>> obj-$(CONFIG_BATTERY_DS2780) += ds2780_battery.o
>> diff --git a/drivers/power/supply/qcom_bms.c
>b/drivers/power/supply/qcom_bms.c
>> new file mode 100644
>> index 000000000000..718fd745c0f7
>> --- /dev/null
>> +++ b/drivers/power/supply/qcom_bms.c
>> @@ -0,0 +1,487 @@
>> +// SPDX-License-Identifier: GPL
>> +
>> +/*
>> + * Qualcomm Battery Monitoring System driver
>> + *
>> + * Copyright (C) 2018 Craig Tatlor <ctatlor97@gmail.com>
>> + */
>> +
>> +#include <linux/module.h>
>> +#include <linux/fixp-arith.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/power_supply.h>
>> +#include <linux/slab.h>
>> +#include <linux/bitops.h>
>> +#include <linux/of.h>
>> +#include <linux/of_platform.h>
>> +#include <linux/regmap.h>
>> +#include <linux/irq.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/iio/consumer.h>
>> +
>> +#define REG_BMS_OCV_FOR_SOC_DATA0 0x90
>> +#define REG_BMS_SHDW_CC_DATA0 0xA8
>> +#define REG_BMS_CC_DATA_CTL 0x42
>> +#define REG_BMS_CC_CLEAR_CTL 0x4
>> +
>> +#define BMS_HOLD_OREG_DATA BIT(0)
>> +#define BMS_CLEAR_SHDW_CC BIT(6)
>> +
>> +#define BMS_CC_READING_RESOLUTION_N 542535
>> +#define BMS_CC_READING_RESOLUTION_D 10000
>> +#define BMS_CC_READING_TICKS 56
>> +#define BMS_SLEEP_CLK_HZ 32764
>> +
>> +#define SECONDS_PER_HOUR 3600
>> +#define TEMPERATURE_COLS 5
>> +#define MAX_CAPACITY_ROWS 50
>> +
>> +/* lookup table for ocv -> capacity conversion */
>> +struct bms_ocv_lut {
>> + int rows;
>> + s8 temp_legend[TEMPERATURE_COLS];
>> + u8 capacity_legend[MAX_CAPACITY_ROWS];
>> + u32 lut[MAX_CAPACITY_ROWS][TEMPERATURE_COLS];
>> +};
>> +
>> +/* lookup table for battery temperature -> fcc conversion */
>> +struct bms_fcc_lut {
>> + s8 temp_legend[TEMPERATURE_COLS];
>> + u32 lut[TEMPERATURE_COLS];
>> +};
>> +
>> +struct bms_device_info {
>> + struct device *dev;
>> + struct regmap *regmap;
>> + struct bms_ocv_lut ocv_lut;
>> + struct power_supply_desc bat_desc;
>> + struct bms_fcc_lut fcc_lut;
>> + struct iio_channel *adc;
>> + struct mutex bms_output_lock;
>> + u32 base_addr;
>> +
>> + int ocv_thr_irq;
>> + u32 ocv;
>> +};
>> +
>> +static bool between(int left, int right, int val)
>> +{
>> + if (left <= val && val <= right)
>> + return true;
>> +
>> + if (left >= val && val >= right)
>> + return true;
>> +
>> + return false;
>> +}
>> +
>> +static int interpolate_capacity(int temp, u32 ocv,
>> + struct bms_ocv_lut *ocv_lut)
>> +{
>> + int pcj_minus_one = 0, pcj = 0, i2 = 0, i3 = 0, i, j;
>> +
>> + for (j = 0; j < TEMPERATURE_COLS; j++)
>> + if (temp <= ocv_lut->temp_legend[j])
>> + break;
>> +
>> + if (ocv >= ocv_lut->lut[0][j])
>> + return ocv_lut->capacity_legend[0];
>> +
>> + if (ocv <= ocv_lut->lut[ocv_lut->rows-1][j-1])
>> + return ocv_lut->capacity_legend[ocv_lut->rows-1];
>> +
>> + for (i = 0; i < ocv_lut->rows-1; i++) {
>> + if (between(ocv_lut->lut[i][j],
>> + ocv_lut->lut[i+1][j], ocv))
>> + i2 = i;
>> +
>> + if (between(ocv_lut->lut[i][j-1],
>> + ocv_lut->lut[i+1][j-1], ocv))
>> + i3 = i;
>> + }
>> +
>> + /* interpolate two capacities */
>> + pcj = fixp_linear_interpolate(ocv_lut->lut[i2][j],
>> + ocv_lut->capacity_legend[i2],
>> + ocv_lut->lut[i2+1][j],
>> + ocv_lut->capacity_legend[i2+1],
>> + ocv);
>> +
>> + pcj_minus_one = fixp_linear_interpolate(ocv_lut->lut[i3][j-1],
>> + ocv_lut->capacity_legend[i3],
>> + ocv_lut->lut[i3+1][j-1],
>> + ocv_lut->capacity_legend[i3+1],
>> + ocv);
>> +
>> + /* interpolate them with the battery temperature */
>> + return fixp_linear_interpolate(ocv_lut->temp_legend[j-1],
>> + pcj_minus_one,
>> + ocv_lut->temp_legend[j],
>> + pcj,
>> + temp);
>> +}
>> +
>> +static int interpolate_fcc(int temp, struct bms_fcc_lut *fcc_lut)
>> +{
>> + int i;
>> +
>> + for (i = 0; i < TEMPERATURE_COLS; i++)
>> + if (temp <= fcc_lut->temp_legend[i])
>> + break;
>> +
>> + return fixp_linear_interpolate(fcc_lut->temp_legend[i-1],
>> + fcc_lut->lut[i-1],
>> + fcc_lut->temp_legend[i],
>> + fcc_lut->lut[i],
>> + temp);
>> +}
>> +
>> +static int bms_lock_output_data(struct bms_device_info *di)
>> +{
>> + int ret;
>> +
>> + ret = regmap_update_bits(di->regmap, di->base_addr +
>> + REG_BMS_CC_DATA_CTL,
>> + BMS_HOLD_OREG_DATA, BMS_HOLD_OREG_DATA);
>> + if (ret) {
>> + dev_err(di->dev, "failed to lock bms output: %d", ret);
>> + return ret;
>> + }
>> +
>> + /*
>> + * Sleep for at least 100 microseconds here to make sure
>> + * there has been at least three cycles of the sleep clock
>> + * so that the registers are correctly locked.
>> + */
>> + usleep_range(100, 1000);
>> +
>> + return 0;
>> +}
>> +
>> +static int bms_unlock_output_data(struct bms_device_info *di)
>> +{
>> + int ret;
>> +
>> + ret = regmap_update_bits(di->regmap, di->base_addr +
>> + REG_BMS_CC_DATA_CTL,
>> + BMS_HOLD_OREG_DATA, 0);
>> + if (ret) {
>> + dev_err(di->dev, "failed to unlock bms output: %d", ret);
>> + return ret;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int bms_read_ocv(struct bms_device_info *di, u32 *ocv)
>> +{
>> + int ret;
>> + u16 read_ocv;
>> +
>> + mutex_lock(&di->bms_output_lock);
>> +
>> + ret = bms_lock_output_data(di);
>> + if (ret)
>> + goto err_lock;
>> +
>> + ret = regmap_bulk_read(di->regmap, di->base_addr+
>> + REG_BMS_OCV_FOR_SOC_DATA0, &read_ocv, 2);
>> + if (ret) {
>> + dev_err(di->dev, "open circuit voltage read failed: %d", ret);
>> + goto err_read;
>> + }
>> +
>> + dev_dbg(di->dev, "read open circuit voltage of: %d mv", read_ocv);
>> +
>> +
>
>one empty line is enough.
Will fix
>
>> + *ocv = read_ocv * 1000;
>> +
>> +err_read:
>> + bms_unlock_output_data(di);
>> +
>> +err_lock:
>> + mutex_unlock(&di->bms_output_lock);
>> +
>> + return ret;
>> +}
>> +
>> +static int bms_read_cc(struct bms_device_info *di, s64 *cc_uah)
>> +{
>> + int ret;
>> + s64 cc_raw_s36, cc_raw, cc_uv, cc_pvh;
>> +
>> + mutex_lock(&di->bms_output_lock);
>> +
>> + ret = bms_lock_output_data(di);
>> + if (ret)
>> + goto err_lock;
>> +
>> + ret = regmap_bulk_read(di->regmap, di->base_addr +
>> + REG_BMS_SHDW_CC_DATA0,
>> + &cc_raw_s36, 5);
>> + if (ret) {
>> + dev_err(di->dev, "coulomb counter read failed: %d", ret);
>> + goto err_read;
>> + }
>> +
>> + ret = bms_unlock_output_data(di);
>> + if (ret)
>> + goto err_lock;
>> +
>> + mutex_unlock(&di->bms_output_lock);
>> +
>> + cc_raw = sign_extend32(cc_raw_s36, 28);
>> +
>> + /* convert raw to uv */
>> + cc_uv = div_s64(cc_raw * BMS_CC_READING_RESOLUTION_N,
>> + BMS_CC_READING_RESOLUTION_D);
>> +
>> + /* convert uv to pvh */
>> + cc_pvh = div_s64(cc_uv * BMS_CC_READING_TICKS * 100000,
>> + BMS_SLEEP_CLK_HZ * SECONDS_PER_HOUR);
>> +
>> + /* divide by impedance */
>> + *cc_uah = div_s64(cc_pvh, 10000);
>> +
>> + dev_dbg(di->dev, "read coulomb counter value of: %lld uah",
>*cc_uah);
>> +
>> + return 0;
>> +
>> +err_read:
>> + bms_unlock_output_data(di);
>> +
>> +err_lock:
>> + mutex_unlock(&di->bms_output_lock);
>> +
>> + return ret;
>> +}
>> +
>> +static void bms_reset_cc(struct bms_device_info *di)
>> +{
>> + int ret;
>> +
>> + mutex_lock(&di->bms_output_lock);
>> +
>> + ret = regmap_update_bits(di->regmap, di->base_addr +
>> + REG_BMS_CC_CLEAR_CTL,
>> + BMS_CLEAR_SHDW_CC,
>> + BMS_CLEAR_SHDW_CC);
>> + if (ret) {
>> + dev_err(di->dev, "coulomb counter reset failed: %d", ret);
>> + goto err_lock;
>> + }
>> +
>> + /* wait at least three sleep cycles for cc to reset */
>> + usleep_range(100, 1000);
>> +
>> + ret = regmap_update_bits(di->regmap, di->base_addr +
>> + REG_BMS_CC_CLEAR_CTL,
>> + BMS_CLEAR_SHDW_CC, 0);
>> + if (ret)
>> + dev_err(di->dev, "coulomb counter re-enable failed: %d", ret);
>> +
>> +err_lock:
>> + mutex_unlock(&di->bms_output_lock);
>> +}
>> +
>> +static int bms_calculate_capacity(struct bms_device_info *di, int
>*capacity)
>> +{
>> + unsigned long fcc;
>> + int ret, temp, ocv_capacity, temp_degc;
>> + s64 cc = 0;
>> +
>> + ret = iio_read_channel_raw(di->adc, &temp);
>> + if (ret < 0) {
>> + dev_err(di->dev, "failed to read temperature: %d", ret);
>> + return ret;
>> + }
>> +
>> + temp_degc = DIV_ROUND_CLOSEST(temp, 1000);
>> +
>> + ret = bms_read_cc(di, &cc);
>> + if (ret < 0) {
>> + dev_err(di->dev, "failed to read coulomb counter: %d", ret);
>> + return ret;
>> + }
>> +
>> + /* interpolate capacity from open circuit voltage */
>> + ocv_capacity = interpolate_capacity(temp_degc, di->ocv,
>> + &di->ocv_lut);
>> +
>> + /* interpolate the full charge capacity from temperature */
>> + fcc = interpolate_fcc(temp_degc, &di->fcc_lut);
>> +
>> + /* append coloumb counter to capacity */
>> + *capacity = DIV_ROUND_CLOSEST(fcc * ocv_capacity, 100);
>> + *capacity = div_s64((*capacity - cc) * 100, fcc);
>> +
>> + return 0;
>> +}
>> +
>> +
>> +
>
>one empty line is enough.
Will fix
>
>> +/*
>> + * Return power_supply property
>> + */
>> +static int bms_get_property(struct power_supply *psy,
>> + enum power_supply_property psp,
>> + union power_supply_propval *val)
>> +{
>> + struct bms_device_info *di = power_supply_get_drvdata(psy);
>> + int ret;
>> +
>> + switch (psp) {
>> + case POWER_SUPPLY_PROP_CAPACITY:
>> + ret = bms_calculate_capacity(di, &val->intval);
>> + break;
>> + default:
>> + ret = -EINVAL;
>> + break;
>> + }
>> +
>> + if (val->intval == INT_MAX || val->intval == INT_MIN)
>> + ret = -EINVAL;
>> +
>> + return ret;
>> +}
>> +
>> +static enum power_supply_property bms_props[] = {
>> + POWER_SUPPLY_PROP_CAPACITY,
>> +};
>
>Why does the driver not expose the following battery information?
>
>temperature info via POWER_SUPPLY_PROP_TEMP
>ocv info via POWER_SUPPLY_PROP_VOLTAGE_OCV
>CC info via POWER_SUPPLY_PROP_CHARGE_COUNTER
>max current via POWER_SUPPLY_PROP_CURRENT_MAX

1. This is handled in the tsens driver iirc
2. Ocv is very inaccurate as it is only updated when device uses a very low amount of power (<10ma)
3. This isn't possible (unless you want to just give out the value anyway) due to the way the driver tracks the cc (resets on every ocv update)
4.this is done in the smbb driver, the BMS is only a fuelguage and not a fully blown charging ic
>
>> +static irqreturn_t bms_ocv_thr_irq_handler(int irq, void *dev_id)
>> +{
>> + struct bms_device_info *di = dev_id;
>> +
>> + if (bms_read_ocv(di, &di->ocv) < 0)
>> + return IRQ_HANDLED;
>> +
>> + bms_reset_cc(di);
>> + return IRQ_HANDLED;
>> +}
>
>You want to call power_supply_changed() here to notify userspace.
This doesn't mean battery is charged, just means ocv was updated (device used < 10ma of power)
>
>> +static int bms_probe(struct platform_device *pdev)
>> +{
>> + struct power_supply_config psy_cfg = {};
>> + struct bms_device_info *di;
>> + struct power_supply *bat;
>> + int ret;
>> +
>> + di = devm_kzalloc(&pdev->dev, sizeof(*di), GFP_KERNEL);
>> + if (!di)
>> + return -ENOMEM;
>> +
>> + di->dev = &pdev->dev;
>> +
>> + di->regmap = dev_get_regmap(pdev->dev.parent, NULL);
>> + if (!di->regmap) {
>> + dev_err(di->dev, "Unable to get regmap");
>> + return -EINVAL;
>> + }
>> +
>> + di->adc = devm_iio_channel_get(&pdev->dev, "temp");
>> + if (IS_ERR(di->adc))
>> + return PTR_ERR(di->adc);
>> +
>> + ret = of_property_read_u32(di->dev->of_node, "reg",
>&di->base_addr);
>> + if (ret < 0)
>> + return ret;
>> +
>> + ret = of_property_read_u8_array(di->dev->of_node,
>> + "qcom,ocv-temp-legend-celsius",
>> + (u8 *)di->ocv_lut.temp_legend,
>> + TEMPERATURE_COLS);
>> + if (ret < 0) {
>> + dev_err(di->dev, "no open circuit voltage temperature legend
>found");
>> + return ret;
>> + }
>> +
>> + di->ocv_lut.rows =
>of_property_read_variable_u8_array(di->dev->of_node,
>> + "qcom,ocv-capacity-legend",
>> + di->ocv_lut.capacity_legend, 0,
>> + MAX_CAPACITY_ROWS);
>> + if (di->ocv_lut.rows < 0) {
>> + dev_err(di->dev, "no open circuit voltage capacity legend found");
>> + return ret;
>> + }
>> +
>> + ret = of_property_read_variable_u32_array(di->dev->of_node,
>> + "qcom,ocv-lut-microvolt",
>> + (u32 *)di->ocv_lut.lut,
>> + TEMPERATURE_COLS,
>> + TEMPERATURE_COLS *
>> + MAX_CAPACITY_ROWS);
>> + if (ret < 0) {
>> + dev_err(di->dev, "no open circuit voltage lut array found");
>> + return ret;
>> + }
>> +
>> + ret = of_property_read_u8_array(di->dev->of_node,
>> + "qcom,fcc-temp-legend-celsius",
>> + (u8 *)di->fcc_lut.temp_legend,
>> + TEMPERATURE_COLS);
>> + if (ret < 0) {
>> + dev_err(di->dev, "no full charge capacity temperature legend
>found");
>> + return ret;
>> + }
>> +
>> + ret = of_property_read_u32_array(di->dev->of_node,
>> + "qcom,fcc-lut-microamp-hours",
>> + di->fcc_lut.lut,
>> + TEMPERATURE_COLS);
>> + if (ret < 0) {
>> + dev_err(di->dev, "no full charge capacity lut array found");
>> + return ret;
>> + }
>> +
>> + ret = bms_read_ocv(di, &di->ocv);
>> + if (ret < 0) {
>> + dev_err(di->dev, "failed to read initial open circuit voltage:
>%d",
>> + ret);
>> + return ret;
>> + }
>> +
>> + mutex_init(&di->bms_output_lock);
>> +
>> + di->ocv_thr_irq = platform_get_irq_byname(pdev, "ocv_thr");
>> +
>> + ret = devm_request_threaded_irq(di->dev, di->ocv_thr_irq, NULL,
>> + bms_ocv_thr_irq_handler,
>> + IRQF_TRIGGER_RISING | IRQF_ONESHOT,
>> + pdev->name, di);
>> + if (ret < 0) {
>> + dev_err(di->dev, "failed to request handler for open circuit
>voltage threshold IRQ");
>> + return ret;
>> + }
>> +
>> +
>
>one empty line is enough.
>
>> + di->bat_desc.name = "bms";
>> + di->bat_desc.type = POWER_SUPPLY_TYPE_BATTERY;
>> + di->bat_desc.properties = bms_props;
>> + di->bat_desc.num_properties = ARRAY_SIZE(bms_props);
>> + di->bat_desc.get_property = bms_get_property;
>> +
>> + psy_cfg.drv_data = di;
>
>psy_cfg.of_node = pdev->dev.of_node;
>
>> + bat = devm_power_supply_register(di->dev, &di->bat_desc, &psy_cfg);
>> +
>> + return PTR_ERR_OR_ZERO(bat);
>> +}
>> +
>> +static const struct of_device_id bms_of_match[] = {
>> + {.compatible = "qcom,pm8941-bms", },
>> + { },
>> +};
>> +MODULE_DEVICE_TABLE(of, bms_of_match);
>> +
>> +static struct platform_driver bms_driver = {
>> + .probe = bms_probe,
>> + .driver = {
>> + .name = "qcom-bms",
>> + .of_match_table = of_match_ptr(bms_of_match),
>> + },
>> +};
>> +module_platform_driver(bms_driver);
>> +
>> +MODULE_AUTHOR("Craig Tatlor <ctatlor97@gmail.com>");
>> +MODULE_DESCRIPTION("Qualcomm BMS driver");
>> +MODULE_LICENSE("GPL");
>
>Apart from the things above I would like to see the information
>about the battery cell itself being moved to 'struct
>power_supply_battery_info', see also my comment in the DT bindings.
Sure, will look into it
>
>-- Sebastian

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