On Mon, Aug 12, 2019 at 06:08:43PM -0600, Nick Crews wrote: > Hi Greg! Hi! First off, please fix your email client to not send html so that vger does not reject your messages :) > I am working on a Chrome OS device that supports a policy called "USB Power > Share," which allows users to turn the laptop into a charge pack for their > phone. When the policy is enabled, power will be supplied to the USB ports > even when the system is in low power states such as S3 and S5. When > disabled, then no power will be supplied in S3 and S5. I wrote a driver > <https://lore.kernel.org/patchwork/patch/1062995/> for this already as part > of drivers/platform/chrome/, but Enric Balletbo i Serra, the maintainer, > had the reasonable suggestion of trying to move this into the USB subsystem. Correct suggestion. > Has anything like this been done before? Do you have any preliminary > thoughts on this before I start writing code? A few things that I haven't > figured out yet: > - How to make this feature only available on certain devices. Using device > tree? Kconfig? Making a separate driver just for this device that plugs > into the USB core? > - The feature is only supported on some USB ports, so we need a way of > filtering on a per-port basis. Look at the drivers/usb/typec/ code, I think that should do everything you need here as this is a typec standard functionality, right? thanks, greg k-h
