1Battery Characteristics
2
3The devicetree battery node provides static battery characteristics.
4In smart batteries, these are typically stored in non-volatile memory
5on a fuel gauge chip. The battery node should be used where there is
6no appropriate non-volatile memory, or it is unprogrammed/incorrect.
7
8Upstream dts files should not include battery nodes, unless the battery
9represented cannot easily be replaced in the system by one of a
10different type. This prevents unpredictable, potentially harmful,
11behavior should a replacement that changes the battery type occur
12without a corresponding update to the dtb.
13
14Required Properties:
15 - compatible: Must be "simple-battery"
16
17Optional Properties:
18 - voltage-min-design-microvolt: drained battery voltage
19 - voltage-max-design-microvolt: fully charged battery voltage
20 - energy-full-design-microwatt-hours: battery design energy
21 - charge-full-design-microamp-hours: battery design capacity
22 - precharge-current-microamp: current for pre-charge phase
23 - charge-term-current-microamp: current for charge termination phase
24 - constant-charge-current-max-microamp: maximum constant input current
25 - constant-charge-voltage-max-microvolt: maximum constant input voltage
26 - factory-internal-resistance-micro-ohms: battery factory internal resistance
27 - ocv-capacity-table-0: An array providing the open circuit voltage (OCV)
28   of the battery and corresponding battery capacity percent, which is used
29   to look up battery capacity according to current OCV value. And the open
30   circuit voltage unit is microvolt.
31 - ocv-capacity-table-1: Same as ocv-capacity-table-0
32 ......
33 - ocv-capacity-table-n: Same as ocv-capacity-table-0
34 - ocv-capacity-celsius: An array containing the temperature in degree Celsius,
35   for each of the battery capacity lookup table. The first temperature value
36   specifies the OCV table 0, and the second temperature value specifies the
37   OCV table 1, and so on.
38
39Battery properties are named, where possible, for the corresponding
40elements in enum power_supply_property, defined in
41https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/linux/power_supply.h
42
43Batteries must be referenced by chargers and/or fuel-gauges
44using a phandle. The phandle's property should be named
45"monitored-battery".
46
47Example:
48
49	bat: battery {
50		compatible = "simple-battery";
51		voltage-min-design-microvolt = <3200000>;
52		voltage-max-design-microvolt = <4200000>;
53		energy-full-design-microwatt-hours = <5290000>;
54		charge-full-design-microamp-hours = <1430000>;
55		precharge-current-microamp = <256000>;
56		charge-term-current-microamp = <128000>;
57		constant-charge-current-max-microamp = <900000>;
58		constant-charge-voltage-max-microvolt = <4200000>;
59		factory-internal-resistance-micro-ohms = <250000>;
60		ocv-capacity-celsius = <(-10) 0 10>;
61		ocv-capacity-table-0 = <4185000 100>, <4113000 95>, <4066000 90>, ...;
62		ocv-capacity-table-1 = <4200000 100>, <4185000 95>, <4113000 90>, ...;
63		ocv-capacity-table-2 = <4250000 100>, <4200000 95>, <4185000 90>, ...;
64	};
65
66	charger: charger@11 {
67		....
68		monitored-battery = <&bat>;
69		...
70	};
71
72	fuel_gauge: fuel-gauge@22 {
73		....
74		monitored-battery = <&bat>;
75		...
76	};
77