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Date: Sun, 16 Sep 2018 15:48:36 +0200
From: Sebastian Reichel <sebastian.reichel@...labora.com>
To: Craig Tatlor <ctatlor97@...il.com>
Cc: linux-arm-msm@...r.kernel.org, Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Mauro Carvalho Chehab <mchehab+samsung@...nel.org>,
"David S. Miller" <davem@...emloft.net>,
Andrew Morton <akpm@...ux-foundation.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Linus Walleij <linus.walleij@...aro.org>,
Randy Dunlap <rdunlap@...radead.org>, linux-pm@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v7 2/4] power: supply: Add support for the Qualcomm
Battery Monitoring System
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@...il.com>
> Reviewed-by: Linus Walleij <linus.walleij@...aro.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@...il.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.
> + *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.
> +/*
> + * 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
> +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.
> +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@...il.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.
-- Sebastian
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