From 83a86e27c34d06ec2dc117fb293e80f78402df49 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Andr=C3=A9=20Draszik?= Date: Mon, 2 Mar 2026 13:32:09 +0000 Subject: [PATCH] power: supply: max17042: consider task period (max77759) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Several (register) values reported by the fuel gauge depend on its internal task period and it needs to be taken into account when calculating results. All relevant example formulas in the data sheet assume the default task period (of 5760) and final results need to be adjusted based on the task period in effect. Update the code as and where necessary. Reviewed-by: Peter Griffin Signed-off-by: André Draszik Link: https://patch.msgid.link/20260302-max77759-fg-v3-10-3c5f01dbda23@linaro.org Signed-off-by: Sebastian Reichel --- drivers/power/supply/max17042_battery.c | 20 ++++++++++++++++++++ include/linux/power/max17042_battery.h | 1 + 2 files changed, 21 insertions(+) diff --git a/drivers/power/supply/max17042_battery.c b/drivers/power/supply/max17042_battery.c index b9a21cef2cc6..bafbf8706055 100644 --- a/drivers/power/supply/max17042_battery.c +++ b/drivers/power/supply/max17042_battery.c @@ -61,6 +61,7 @@ struct max17042_chip { struct work_struct work; int init_complete; int irq; + int task_period; }; static enum power_supply_property max17042_battery_props[] = { @@ -331,6 +332,8 @@ static int max17042_get_property(struct power_supply *psy, return ret; data64 = data * 5000000ll; + data64 *= chip->task_period; + do_div(data64, MAX17042_DEFAULT_TASK_PERIOD); do_div(data64, chip->pdata->r_sns); val->intval = data64; break; @@ -340,6 +343,8 @@ static int max17042_get_property(struct power_supply *psy, return ret; data64 = data * 5000000ll; + data64 *= chip->task_period; + do_div(data64, MAX17042_DEFAULT_TASK_PERIOD); do_div(data64, chip->pdata->r_sns); val->intval = data64; break; @@ -349,6 +354,8 @@ static int max17042_get_property(struct power_supply *psy, return ret; data64 = data * 5000000ll; + data64 *= chip->task_period; + do_div(data64, MAX17042_DEFAULT_TASK_PERIOD); do_div(data64, chip->pdata->r_sns); val->intval = data64; break; @@ -358,6 +365,8 @@ static int max17042_get_property(struct power_supply *psy, return ret; data64 = sign_extend64(data, 15) * 5000000ll; + data64 *= chip->task_period; + data64 = div_s64(data64, MAX17042_DEFAULT_TASK_PERIOD); val->intval = div_s64(data64, chip->pdata->r_sns); break; case POWER_SUPPLY_PROP_TEMP: @@ -1142,6 +1151,17 @@ static int max17042_probe(struct i2c_client *client, struct device *dev, int irq regmap_write(chip->regmap, MAX17042_LearnCFG, 0x0007); } + chip->task_period = MAX17042_DEFAULT_TASK_PERIOD; + if (chip->chip_type == MAXIM_DEVICE_TYPE_MAX77759) { + ret = regmap_read(chip->regmap, MAX17042_TaskPeriod, &val); + if (ret) + return dev_err_probe(dev, ret, + "failed to read task period\n"); + chip->task_period = val; + } + dev_dbg(dev, "task period: %#.4x (%d)\n", chip->task_period, + chip->task_period); + chip->battery = devm_power_supply_register(dev, max17042_desc, &psy_cfg); if (IS_ERR(chip->battery)) diff --git a/include/linux/power/max17042_battery.h b/include/linux/power/max17042_battery.h index 05097f08ea36..d5b08313cf11 100644 --- a/include/linux/power/max17042_battery.h +++ b/include/linux/power/max17042_battery.h @@ -17,6 +17,7 @@ #define MAX17042_DEFAULT_VMAX (4500) /* LiHV cell max */ #define MAX17042_DEFAULT_TEMP_MIN (0) /* For sys without temp sensor */ #define MAX17042_DEFAULT_TEMP_MAX (700) /* 70 degrees Celcius */ +#define MAX17042_DEFAULT_TASK_PERIOD (5760) /* Consider RepCap which is less then 10 units below FullCAP full */ #define MAX17042_FULL_THRESHOLD 10