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From:   Peter Chen <peter.chen@nxp.com>
To:     Roger Quadros <rogerq@ti.com>
CC:     Pawel Laszczak <pawell@cadence.com>,
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Subject: Re: [PATCH] usb: cdns3: gadget: Don't manage pullups
Thread-Topic: [PATCH] usb: cdns3: gadget: Don't manage pullups
Thread-Index: AQHViYCigHhLS+QXN0CJz1D+9q4PbKdn8nSAgAK+9ICAAHFQgIAF16UAgABrmoCAAQX0gA==
Date:   Wed, 30 Oct 2019 01:15:16 +0000
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On 19-10-29 11:37:31, Roger Quadros wrote:
>=20
>=20
> On 29/10/2019 05:12, Peter Chen wrote:
> > On 19-10-25 12:59:17, Roger Quadros wrote:
> > > Peter,
> > >=20
> > > On 25/10/2019 06:13, Peter Chen wrote:
> > > > On 19-10-23 09:17:45, Pawel Laszczak wrote:
> > > > > Hi,
> > > > >=20
> > > > > Reviewed-by: Pawel Laszczak <pawell@cadence.com>
> > > >=20
> > > > Hi Roger & Pawel,
> > > >=20
> > > > Assume gadget function has already enabled, if you switch host mode
> > > > to device mode, with your changes, where the device mode will be en=
abled
> > > > again?
> > >=20
> > > When it switches from device mode to host the UDC is removed. When we=
 switch
> > > back from host to device mode the UDC is added, so,
> > >=20
> > > usb_add_gadget_udc_release()-> check_pending_gadget_drivers()->
> > > udc_bind_to_driver()->usb_udc_connect_control()->usb_gadget_connect()=
->
> > > gadget->ops->pullup()
> >=20
> > Thanks. I have another question how you decide when to store UDC name
> > to /sys/kernel/config/usb_gadget/g1/UDC? Do you have a user daemon prog=
ram
> > to monitor VBUS or external connector? At host mode, the store operatio=
n
> > will fail due to there is NO UDC.
> >=20
>=20
> Yes, user space needs to monitor /sys/class/usb_role/6000000.usb-role-swi=
tch/role
>=20
> When it becomes "device" the UDC is available and it can prepare to confi=
gure
> the UDC.
>=20
> Could you please give your Ack for this patch if it is OK? Thanks.
>=20

Acked-by: Peter Chen <peter.chen@nxp.com>

--=20

Thanks,
Peter Chen=