On 17/09/2023 12:33, Kieran Bingham wrote: > Quoting Krzysztof Kozlowski (2023-09-17 10:37:07) >> On 15/09/2023 18:59, Kieran Bingham wrote: >>> Add YAML device tree bindings for the ROHM BU64754 VCM Motor Driver for >>> Camera Autofocus. >>> >>> Signed-off-by: Kieran Bingham <kieran.bingham@xxxxxxxxxxxxxxxx> >>> --- >> >> ... >> >>> +properties: >>> + compatible: >>> + items: >>> + - enum: >>> + - rohm,bu64754 >>> + >>> + reg: >>> + maxItems: 1 >>> + >>> + vdd-supply: >> >> If the supply is not required, how the driver gets any power? > > It may not be controllable. It could be wired to be always on. That's different. You talk now about board, I am talking about device. Is the supply required for the device? If yes, then it should be required by the bindings. > > The device has a low power mode which is controllable by software, so it > could be always powered on and controlled via software only if desired. > The driver handles that already as if the regulator isn't specified the > power down register bits will be set to put it in low power mode. Best regards, Krzysztof