# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/power/supply/battery.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#
title: Battery Characteristics
maintainers:
- Sebastian Reichel <sre@kernel.org>
description: |
The devicetree battery node provides static battery characteristics.
In smart batteries, these are typically stored in non-volatile memory
on a fuel gauge chip. The battery node should be used where there is
no appropriate non-volatile memory, or it is unprogrammed/incorrect.
Upstream dts files should not include battery nodes, unless the battery
represented cannot easily be replaced in the system by one of a
different type. This prevents unpredictable, potentially harmful,
behavior should a replacement that changes the battery type occur
without a corresponding update to the dtb.
Battery properties are named, where possible, for the corresponding elements
in enum power_supply_property, defined in include/linux/power_supply.h
Batteries must be referenced by chargers and/or fuel-gauges using a phandle.
The phandle's property should be named "monitored-battery".
properties:
compatible:
const: simple-battery
device-chemistry:
description: This describes the chemical technology of the battery.
oneOf:
- const: nickel-cadmium
- const: nickel-metal-hydride
- const: lithium-ion
description: This is a blanket type for all lithium-ion batteries,
including those below. If possible, a precise compatible string
from below should be used, but sometimes it is unknown which specific
lithium ion battery is employed and this wide compatible can be used.
- const: lithium-ion-polymer
- const: lithium-ion-iron-phosphate
- const: lithium-ion-manganese-oxide
over-voltage-threshold-microvolt:
description: battery over-voltage limit
re-charge-voltage-microvolt:
description: limit to automatically start charging again
voltage-min-design-microvolt:
description: drained battery voltage
voltage-max-design-microvolt:
description: fully charged battery voltage
energy-full-design-microwatt-hours:
description: battery design energy
charge-full-design-microamp-hours:
description: battery design capacity
trickle-charge-current-microamp:
description: current for trickle-charge phase
precharge-current-microamp:
description: current for pre-charge phase
precharge-upper-limit-microvolt:
description: limit when to change to constant charging
charge-term-current-microamp:
description: current for charge termination phase
constant-charge-current-max-microamp:
description: maximum constant input current
constant-charge-voltage-max-microvolt:
description: maximum constant input voltage
factory-internal-resistance-micro-ohms:
description: battery factory internal resistance
resistance-temp-table:
$ref: /schemas/types.yaml#/definitions/uint32-matrix
items:
items:
- description: the temperature in degree Celsius
- description: battery internal resistance percent
description: |
A table providing the temperature in degree Celsius
and corresponding battery internal resistance percent, which is used to
look up the resistance percent according to current temperature to get an
accurate batterty internal resistance in different temperatures.
ocv-capacity-celsius:
description: |
An array containing the temperature in degree Celsius,
for each of the battery capacity lookup table.
operating-range-celsius:
description: operating temperature range of a battery
items:
- description: minimum temperature at which battery can operate
- description: maximum temperature at which battery can operate
ambient-celsius:
description: safe range of ambient temperature
items:
- description: alert when ambient temperature is lower than this value
- description: alert when ambient temperature is higher than this value
alert-celsius:
description: safe range of battery temperature
items:
- description: alert when battery temperature is lower than this value
- description: alert when battery temperature is higher than this value
required:
- compatible
patternProperties:
'^ocv-capacity-table-[0-9]+$':
$ref: /schemas/types.yaml#/definitions/uint32-matrix
description: |
An array providing the open circuit voltage (OCV)
of the battery and corresponding battery capacity percent, which is used
to look up battery capacity according to current OCV value. And the open
circuit voltage unit is microvolt.
maxItems: 100
items:
items:
- description: open circuit voltage (OCV) in microvolts
- description: battery capacity percent
maximum: 100
additionalProperties: false
examples:
- |
power {
#address-cells = <1>;
#size-cells = <0>;
battery: battery {
compatible = "simple-battery";
over-voltage-threshold-microvolt = <4500000>;
re-charge-voltage-microvolt = <250000>;
voltage-min-design-microvolt = <3200000>;
voltage-max-design-microvolt = <4200000>;
energy-full-design-microwatt-hours = <5290000>;
charge-full-design-microamp-hours = <1430000>;
precharge-current-microamp = <256000>;
precharge-upper-limit-microvolt = <2500000>;
charge-term-current-microamp = <128000>;
constant-charge-current-max-microamp = <900000>;
constant-charge-voltage-max-microvolt = <4200000>;
factory-internal-resistance-micro-ohms = <250000>;
ocv-capacity-celsius = <(-10) 0 10>;
/* table for -10 degree Celsius */
ocv-capacity-table-0 = <4185000 100>, <4113000 95>, <4066000 90>;
/* table for 0 degree Celsius */
ocv-capacity-table-1 = <4200000 100>, <4185000 95>, <4113000 90>;
/* table for 10 degree Celsius */
ocv-capacity-table-2 = <4250000 100>, <4200000 95>, <4185000 90>;
resistance-temp-table = <20 100>, <10 90>, <0 80>, <(-10) 60>;
operating-range-celsius = <(-30) 50>;
ambient-celsius = <(-5) 50>;
alert-celsius = <0 40>;
};
charger@11 {
reg = <0x11>;
monitored-battery = <&battery>;
};
fuel-gauge@22 {
reg = <0x22>;
monitored-battery = <&battery>;
};
};