Messages in this thread | | | Date | Tue, 14 Jan 2020 12:15:48 -0300 | From | Paul Cercueil <> | Subject | Re: [PATCH] usb: common: usb-conn-gpio: Register charger |
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Hi Chunfeng,
Le jeu., janv. 9, 2020 at 10:27, Chunfeng Yun <chunfeng.yun@mediatek.com> a écrit : > Hi Paul, > > On Wed, 2020-01-08 at 14:26 -0300, Paul Cercueil wrote: >> Hi Greg, >> >> >> Le mer., janv. 8, 2020 at 17:53, Greg Kroah-Hartman >> <gregkh@linuxfoundation.org> a écrit : >> > On Tue, Jan 07, 2020 at 01:29:01AM +0100, Paul Cercueil wrote: >> >> Register a power supply charger, whose online state depends on >> >> whether >> >> the USB role is set to device or not. >> > >> > That says _what_ you are doing, but I have no idea _why_ you want >> to >> > do >> > this. >> > >> > What is this going to cause to have happen? What new userspace >> api is >> > going to result? What will a user do with this? >> >> This is useful when the USB role is the only way to know if the >> device >> is charging from USB. > There is no charger IC on your platform?
Correct.
> >> >> The API is the standard power supply charger API, you get a >> /sys/class/power_supply/xxx/online node which tells you the state of >> the charger. >> >> The sole purpose of this is to give userspace applications a way to >> know whether or not the charger is plugged. >> >> > Is this going to always show up, no matter if the role is not even >> > relevant for a power supply? >> >> I guess it'd always show up, yes. In which case would the role not >> be >> relevant for a power supply? > Do you also need it if the platform don't have battery?
I guess not. Would you prefer it to be disabled by default? If so, what would be the way to have it enabled? A flag in devicetree?
> >> Is gpio-b-connector not always used for >> OTG connectors? > It also supports device only mode, usually uses vBus pin to > enable/disable controller
Yes, that would work too. The problem would be a host-only gpio-b-connector.
-Paul
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