On Sat, Mar 07, 2026 at 04:25:44AM -0300, Val Packett wrote: > > On 3/3/26 3:13 AM, Jingyuan Liang wrote: > > Documentation describes the required and optional properties for > > implementing Device Tree for a Microsoft G6 Touch Digitizer that > > supports HID over SPI Protocol 1.0 specification. > > […] > > +properties: > > + compatible: > > + oneOf: > > + - items: > > + - enum: > > + - microsoft,g6-touch-digitizer > > + - const: hid-over-spi > > + - description: Just "hid-over-spi" alone is allowed, but not > > recommended. > > […] > > +required: > > + - compatible > > + - interrupts > > + - reset-gpios > > Why is reset required? Is it so implausible on some device implementing the > spec there wouldn't be a reset gpio?
No, because it is mandated by the spec: "HID SPI peripheral must provide a dedicated reset line, driven by the HOST, which, when toggled (pulled LOW for at least 10ms, normally HIGH), will have the effect of resetting the device. If a HID SPI peripheral is enumerated via ACPI, the device ASL configuration must expose an ACPI FLDR (_RST) method to control this line." The spec also states that the host must initiate reset during initialization of the device. > > > + - vdd-supply > Linux makes up a dummy regulator if DT doesn't provide one, so can > regulators even be required? There is still a supply line to the chip even if it is not exposed to the OS control. So as far as chip is concerned the supply is required. Thanks. -- Dmitry
