Hi Stephen, > -----Original Message----- > From: linux-usb-ow...@vger.kernel.org [mailto:linux-usb- > ow...@vger.kernel.org] On Behalf Of Peter Chen > Sent: Thursday, June 30, 2016 9:27 AM > To: Stephen Boyd <stephen.b...@linaro.org> > Cc: linux-...@vger.kernel.org; linux-arm-ker...@lists.infradead.org; > linux-kernel@vger.kernel.org; linux-arm-...@vger.kernel.org; Andy Gross > <andy.gr...@linaro.org>; Bjorn Andersson <bjorn.anders...@linaro.org>; > Neil Armstrong <narmstr...@baylibre.com>; Arnd Bergmann <a...@arndb.de>; > Felipe Balbi <ba...@kernel.org>; Peter Chen <peter.c...@nxp.com>; Greg > Kroah-Hartman <gre...@linuxfoundation.org> > Subject: Re: [PATCH 08/21] usb: chipidea: Kick OTG state machine for AVVIS > with vbus extcon > > On Wed, Jun 29, 2016 at 06:19:59PM -0700, Stephen Boyd wrote: > > Quoting Peter Chen (2016-06-28 20:09:13) > > > On Sun, Jun 26, 2016 at 12:28:25AM -0700, Stephen Boyd wrote: > > > > Force the OTG state machine to go forward when we're using an > > > > extcon for vbus detection. In this case, the controller may never > > > > raise an interrupt for AVVIS, so we need to simulate the event by > > > > toggling the appropriate OTG fsm bits and kicking the state > > > > machine again. > > > > > > > > > > Well, I think you may misunderstand the OTG FSM and dual-role. > > > From my and Felipe's point, there are seldom users for USB FSM, > > > there are only OTG FSM spec and related OTG certification. > > > > Probably yes. > > > > > > > > The OTG FSM needs related SoC support, the vbus will be off at > > > several states, and the SRP should be supported by SoC. > > > > > > By default, the dts needs below properties for disabling it if you > > > choose otg fsm support at kernel configuration. > > > > > > &usbotg1 { > > > vbus-supply = <®_usb_otg1_vbus>; > > > srp-disable; > > > hnp-disable; > > > adp-disable; > > > status = "okay"; > > > }; > > > > > > See Documentation/devicetree/bindings/usb/generic.txt. > > > > Does this mean we should be setting all those properties if we're > > using an extcon for vbus and id? > > It is not related to how we know vbus and id. If your controller is otg- > capable, and you don't want to enable OTG FSM (just want dual-role), you > should set them at dts since the zImage is multi-platforms, the > CONFIG_USB_OTG and CONFIG_USB_OTG_FSM may be chosen. > > > I have noticed that vbus is powered off after some time when no device > > is connected and we're in A_HOST state because the timeout for a B > > device connection happens. > > I think it is not you want, but it is OTG compliance.
For simple, if you don't want OTG(i.e HNP&SRP) at all, just needs dual role, you may disable CONFIG_USB_OTG and CONFIG_USB_OTG_FSM in your menuconfig, then you don't need touch all those properties. Li Jun > > -- > > Best Regards, > Peter Chen > -- > To unsubscribe from this list: send the line "unsubscribe linux-usb" in > the body of a message to majord...@vger.kernel.org More majordomo info at > http://vger.kernel.org/majordomo-info.html
