On Fri, May 3, 2024 at 10:47 AM Johan Hovold <johan@xxxxxxxxxx> wrote: > > If the above holds true, the driver can then just check for the open drain flag > > in the reset-gpios phandle, and if that is set, conclude that it should not > > actively drive the line low in the poweroff state. > > That is an alternative I considered but rejected as just knowing that > the gpio is open-drain is not necessarily sufficient, for example, if > the reset line is pulled to always-on rail while power to the device can > be cut. > > Perhaps no one would ever construct hardware like that, but it does not > seem like the hardware property I'm trying to encode necessarily follows > from having an open-drain reset line. > > And then the OS should probably not make assumptions like that either, > especially since getting it wrong can potentially lead to damaged > hardware. OK it's a fair point. I was worried about over-specification of behaviour, as that always leads to contradictions. + no-reset-on-power-off: + type: boolean + description: + Reset line is wired so that it can be left deasserted when the power + supply is off. To be nitpicky: *should* be left deasserted rather than *can* be left deasserted, right? If the behaviour is desirable but not strictly required. Yours, Linus Walleij
