[PATCH v3 1/8] power: supply: core: Add resistance power supply property

[Fenglin Wu via B4 Relay <devnull+fenglin.wu.oss.qualcomm.com@kernel.org>]

From: Fenglin Wu <fenglin.wu@oss.qualcomm.com>

Some battery drivers provide the ability to export internal resistance
as a parameter. Add internal_resistance power supply property for that
purpose.

Signed-off-by: Fenglin Wu <fenglin.wu@oss.qualcomm.com>
---
 Documentation/ABI/testing/sysfs-class-power | 16 ++++++++++++++++
 drivers/power/supply/power_supply_sysfs.c   |  1 +
 include/linux/power_supply.h                |  1 +
 3 files changed, 18 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-class-power b/Documentation/ABI/testing/sysfs-class-power
index 560124cc31770cde03bcdbbba0d85a5bd78b15a0..cea1a38f5a8fb754d4e6323967ef6cf2e20a68ce 100644
--- a/Documentation/ABI/testing/sysfs-class-power
+++ b/Documentation/ABI/testing/sysfs-class-power
@@ -552,6 +552,22 @@ Description:
 			Integer > 0: representing full cycles
 			Integer = 0: cycle_count info is not available
 
+What:		/sys/class/power_supply/<supply_name>/internal_resistance
+Date:		August 2025
+Contact:	linux-arm-msm@vger.kernel.org
+Description:
+		Represent the battery's internal resistance, often referred
+		to as Equivalent Series Resistance (ESR). It is a dynamic
+		parameter that reflects the opposition to current flow within
+		the cell. It is not a fixed value but varies significantly
+		based on several operational conditions, including battery
+		state of charge (SoC), temperature, and whether the battery
+		is in a charging or discharging state.
+
+		Access: Read
+
+		Valid values: Represented in microohms
+
 **USB Properties**
 
 What:		/sys/class/power_supply/<supply_name>/input_current_limit
diff --git a/drivers/power/supply/power_supply_sysfs.c b/drivers/power/supply/power_supply_sysfs.c
index a438f7983d4f6a832e9d479184c7c35453e1757c..cfa8f90a88ebc8fc1c7447198f138e5d2e699e5a 100644
--- a/drivers/power/supply/power_supply_sysfs.c
+++ b/drivers/power/supply/power_supply_sysfs.c
@@ -220,6 +220,7 @@ static struct power_supply_attr power_supply_attrs[] __ro_after_init = {
 	POWER_SUPPLY_ATTR(MANUFACTURE_YEAR),
 	POWER_SUPPLY_ATTR(MANUFACTURE_MONTH),
 	POWER_SUPPLY_ATTR(MANUFACTURE_DAY),
+	POWER_SUPPLY_ATTR(INTERNAL_RESISTANCE),
 	/* Properties of type `const char *' */
 	POWER_SUPPLY_ATTR(MODEL_NAME),
 	POWER_SUPPLY_ATTR(MANUFACTURER),
diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
index c4cb854971f53a244ba7742a15ce7a5515da6199..8bc3b7a67eb5693a16db9b7d123e7881711c6bf4 100644
--- a/include/linux/power_supply.h
+++ b/include/linux/power_supply.h
@@ -174,6 +174,7 @@ enum power_supply_property {
 	POWER_SUPPLY_PROP_MANUFACTURE_YEAR,
 	POWER_SUPPLY_PROP_MANUFACTURE_MONTH,
 	POWER_SUPPLY_PROP_MANUFACTURE_DAY,
+	POWER_SUPPLY_PROP_INTERNAL_RESISTANCE,
 	/* Properties of type `const char *' */
 	POWER_SUPPLY_PROP_MODEL_NAME,
 	POWER_SUPPLY_PROP_MANUFACTURER,

-- 
2.34.1