Documentation/devicetree/bindings/power/supply/rohm,bd99954.yaml

   1 # SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
   2 %YAML 1.2
   3 ---
   4 $id: http://devicetree.org/schemas/power/supply/rohm,bd99954.yaml#
   5 $schema: http://devicetree.org/meta-schemas/core.yaml#
   6
   7 title: ROHM BD99954 Battery charger
   8
   9 maintainers:
  10   - Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
  11   - Markus Laine <markus.laine@fi.rohmeurope.com>
  12   - Mikko Mutanen <mikko.mutanen@fi.rohmeurope.com>
  13
  14 description: |
  15   The ROHM BD99954 is a Battery Management LSI for 1-4 cell Lithium-Ion
  16   secondary battery intended to be used in space-constraint equipment such
  17   as Low profile Notebook PC, Tablets and other applications. BD99954
  18   provides a Dual-source Battery Charger, two port BC1.2 detection and a
  19   Battery Monitor.
  20
  21
  22 properties:
  23   compatible:
  24     const: rohm,bd99954
  25 #
  26 #    The battery charging profile of BD99954.
  27 #
  28 #    Curve (1) represents charging current.
  29 #    Curve (2) represents battery voltage.
  30 #
  31 #    The BD99954 data sheet divides charging to three phases.
  32 #    a) Trickle-charge with constant current (8).
  33 #    b) pre-charge with constant current (6)
  34 #    c) fast-charge with:
  35 #       First a constant current (5) phase (CC)
  36 #       Then constant voltage (CV) phase (after the battery voltage has reached
  37 #       target level - until charging current has dropped to termination
  38 #       level (7)
  39 #
  40 #     V ^                                                        ^ I
  41 #       .                                                        .
  42 #       .                                                        .
  43 # (4)- -.- - - - - - - - - - - - - -  +++++++++++++++++++++++++++.
  44 #       .                            /                           .
  45 #       .                     ++++++/++ - - - - - - - - - - - - -.- - (5)
  46 #       .                     +    /  +                          .
  47 #       .                     +   -   --                         .
  48 #       .                     +  -     +                         .
  49 #       .                     +.-      -:                        .
  50 #       .                    .+         +`                       .
  51 #       .                  .- +       | `/                       .
  52 #       .               .."   +          .:                      .
  53 #       .             -"      +           --                     .
  54 #       .    (2)  ..."        +       |    :-                    .
  55 #       .    ...""            +             -:                   .
  56 # (3)- -.-.""- - - - -+++++++++ - - - - - - -.:- - - - - - - - - .- - (6)
  57 #       .             +                       `:.                .
  58 #       .             +               |         -:               .
  59 #       .             +                           -:             .
  60 #       .             +                             ..           .
  61 #       .   (1)       +               |               "+++- - - -.- - (7)
  62 #       -++++++++++++++- - - - - - - - - - - - - - - - - + - - - .- - (8)
  63 #       .                                                +       -
  64 #       -------------------------------------------------+++++++++-->
  65 #       |             |       |   CC   |      CV         |
  66 #       | --trickle-- | -pre- | ---------fast----------- |
  67 #
  68 #   The charger uses the following battery properties
  69 # - trickle-charge-current-microamp:
  70 #     Current used at trickle-charge phase (8 in above chart)
  71 #     minimum: 64000
  72 #     maximum: 1024000
  73 #     multipleOf: 64000
  74 # - precharge-current-microamp:
  75 #     Current used at pre-charge phase (6 in above chart)
  76 #     minimum: 64000
  77 #     maximum: 1024000
  78 #     multipleOf: 64000
  79 # - constant-charge-current-max-microamp
  80 #     Current used at fast charge constant current phase (5 in above chart)
  81 #     minimum: 64000
  82 #     maximum: 1024000
  83 #     multipleOf: 64000
  84 # - constant-charge-voltage-max-microvolt
  85 #     The constant voltage used in fast charging phase (4 in above chart)
  86 #     minimum: 2560000
  87 #     maximum: 19200000
  88 #     multipleOf: 16000
  89 # - precharge-upper-limit-microvolt
  90 #     charging mode is changed from trickle charging to pre-charging
  91 #     when battery voltage exceeds this limit voltage (3 in above chart)
  92 #     minimum: 2048000
  93 #     maximum: 19200000
  94 #     multipleOf: 64000
  95 # - re-charge-voltage-microvolt
  96 #     minimum: 2560000
  97 #     maximum: 19200000
  98 #     multipleOf: 16000
  99 #     re-charging is automatically started when battry has been discharging
 100 #     to the point where the battery voltage drops below this limit
 101 # - over-voltage-threshold-microvolt
 102 #     battery is expected to be faulty if battery voltage exceeds this limit.
 103 #     Charger will then enter to a "battery faulty" -state
 104 #     minimum: 2560000
 105 #     maximum: 19200000
 106 #     multipleOf: 16000
 107 # - charge-term-current-microamp
 108 #     minimum: 0
 109 #     maximum: 1024000
 110 #     multipleOf: 64000
 111 #     a charge cycle terminates when the battery voltage is above recharge
 112 #     threshold, and the current is below this setting (7 in above chart)
 113 #   See also Documentation/devicetree/bindings/power/supply/battery.yaml
 114
 115   reg:
 116     maxItems: 1
 117
 118   interrupts:
 119     maxItems: 1
 120
 121   monitored-battery:
 122     description:
 123       phandle of battery characteristics devicetree node
 124
 125   rohm,vsys-regulation-microvolt:
 126     description: system specific lower limit for system voltage.
 127     minimum: 2560000
 128     maximum: 19200000
 129     multipleOf: 64000
 130
 131   rohm,vbus-input-current-limit-microamp:
 132     description: system specific VBUS input current limit (in microamps).
 133     minimum: 32000
 134     maximum: 16352000
 135     multipleOf: 32000
 136
 137   rohm,vcc-input-current-limit-microamp:
 138     description: system specific VCC/VACP input current limit (in microamps).
 139     minimum: 32000
 140     maximum: 16352000
 141     multipleOf: 32000
 142
 143 required:
 144   - compatible
 145
 146 additionalProperties: false
 147
 148 examples:
 149   - |
 150     i2c {
 151         #address-cells = <1>;
 152         #size-cells = <0>;
 153         charger@9 {
 154             compatible = "rohm,bd99954";
 155             monitored-battery = <&battery>;
 156             reg = <0x9>;
 157             interrupt-parent = <&gpio1>;
 158             interrupts = <29 8>;
 159             rohm,vsys-regulation-microvolt = <8960000>;
 160             rohm,vbus-input-current-limit-microamp = <1472000>;
 161             rohm,vcc-input-current-limit-microamp = <1472000>;
 162         };
 163     };