From 16056396b7709b0ee33d88329e9a41166bc8d6a0 Mon Sep 17 00:00:00 2001 From: Matti Vaittinen Date: Mon, 15 Dec 2025 15:18:11 +0200 Subject: [PATCH] dt-bindings: battery: Voltage drop properties ROHM has developed a so called "zero-correction" -algorithm to improve the fuel-gauging accuracy close to the point where battery is depleted. This relies on battery specific "VDR" (voltage drop rate) tables, which are measured from the battery, and which describe the voltage drop rate. More thorough explanation about the "zero correction" and "VDR" parameters is here: https://lore.kernel.org/all/676253b9-ff69-7891-1f26-a8b5bb5a421b@fi.rohmeurope.com/ Document the VDR zero-correction specific battery properties used by the BD71815, BD71828, BD72720 and some other ROHM chargers. (Note, charger drivers aren't upstream yet). Signed-off-by: Matti Vaittinen Reviewed-by: Rob Herring (Arm) Reviewed-by: Linus Walleij Link: https://patch.msgid.link/461f2840a03e0189ecd4f1a7c261014342ddee91.1765804226.git.mazziesaccount@gmail.com Signed-off-by: Lee Jones --- .../bindings/power/supply/battery.yaml | 22 +++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/Documentation/devicetree/bindings/power/supply/battery.yaml b/Documentation/devicetree/bindings/power/supply/battery.yaml index d1a2080557a00..8ebf05d9497c4 100644 --- a/Documentation/devicetree/bindings/power/supply/battery.yaml +++ b/Documentation/devicetree/bindings/power/supply/battery.yaml @@ -128,6 +128,21 @@ properties: - description: alert when battery temperature is lower than this value - description: alert when battery temperature is higher than this value + # The volt-drop* -properties describe voltage-drop for a battery, described + # as VDROP in: + # https://patentimages.storage.googleapis.com/6c/f5/17/c1d901c220f6a9/US20150032394A1.pdf + volt-drop-thresh-microvolt: + description: Threshold for starting the VDR correction + maximum: 48000000 + + volt-drop-soc-bp: + description: Table of capacity values matching the values in VDR tables. + The value should be given as basis points, 1/100 of a percent. + + volt-drop-temperatures-millicelsius: + description: An array containing the temperature in milli celsius, for each + of the VDR lookup table. + required: - compatible @@ -146,6 +161,13 @@ patternProperties: - description: battery capacity percent maximum: 100 + '^volt-drop-[0-9]-microvolt': + description: Table of the voltage drop rate (VDR) values. Each entry in the + table should match a capacity value in the volt-drop-soc table. + Furthermore, the values should be obtained for the temperature given in + volt-drop-temperatures-millicelsius table at index matching the + number in this table's name. + additionalProperties: false examples: -- 2.47.3