Thanks for the fast response! On Tue, Aug 13, 2019 at 12:02 AM Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > 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 :) Thanks, should be good now. > > > 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? Unfortunately this is for USB 2.0 ports, so it's not type-C. Is the type-C code still worth looking at? > > thanks, > > greg k-h
