Re: [PATCH v2 1/2] dt-bindings: power: supply: maxim,max8903: add DC and USB input current-limit controls

[Rob Herring (Arm)]

On Fri, 05 Jun 2026 11:18:12 +0200, Herman van Hazendonk wrote:
> Add three optional properties to the MAX8903 charger binding to
> describe board-level GPIO control of the DC and USB input current
> limits:
> 
> DC input (TA / DOK pin):
>   - dc-current-limit-gpios (1..4 GPIOs): mux control lines feeding
>     the MAX8903 IDC resistor mux;
>   - dc-current-limit-mapping (uint32-matrix of {microamps,
>     gpio_bit_pattern} pairs): the available current levels and the
>     GPIO bit pattern that selects each level.
> 
> USB input (USB / UOK pin):
>   - usb-current-limit-gpios: a single GPIO driving the IUSB pin.
>     The IUSB pin is silicon-fixed by the MAX8903 datasheet (Pin
>     Description): low selects 100 mA, high selects 500 mA. Only
>     the GPIO mapping is board-specific; the current values are
>     not exposed in DT.
> 
> A dependentRequired block ties dc-current-limit-gpios and
> dc-current-limit-mapping together so an incomplete DT cannot pass
> validation with only one half of the pair.
> 
> These let userspace clamp the input draw via the standard
> POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT power_supply attribute. The HP
> TouchPad uses both: two TLMM lines select between 0.5 A, 1.0 A,
> 1.5 A and 2.0 A DC input current limits behind the MAX8903B
> charger, and a third TLMM line picks the IUSB 100 mA / 500 mA
> limit.
> 
> These are purely additive; existing platforms remain unaffected.
> 
> Signed-off-by: Herman van Hazendonk <github.com@xxxxxxxxxx>
> ---
>  .../bindings/power/supply/maxim,max8903.yaml       | 53 ++++++++++++++++++++++
>  1 file changed, 53 insertions(+)
> 

Reviewed-by: Rob Herring (Arm) <robh@xxxxxxxxxx>