From: Peter Chen <peter.chen@nxp.com>
To: Roger Quadros <rogerq@ti.com>
Cc: Pawel Laszczak <pawell@cadence.com>,
"felipe.balbi@linux.intel.com" <felipe.balbi@linux.intel.com>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"nsekhar@ti.com" <nsekhar@ti.com>,
Rahul Kumar <kurahul@cadence.com>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] usb: cdns3: gadget: Don't manage pullups
Date: Tue, 29 Oct 2019 03:12:34 +0000 [thread overview]
Message-ID: <20191029031223.GA26815@b29397-desktop> (raw)
In-Reply-To: <83a1da01-19d6-65a9-aecd-2027fd62a272@ti.com>
On 19-10-25 12:59:17, Roger Quadros wrote:
> Peter,
>
> On 25/10/2019 06:13, Peter Chen wrote:
> > On 19-10-23 09:17:45, Pawel Laszczak wrote:
> > > Hi,
> > >
> > > Reviewed-by: Pawel Laszczak <pawell@cadence.com>
> >
> > Hi Roger & Pawel,
> >
> > Assume gadget function has already enabled, if you switch host mode
> > to device mode, with your changes, where the device mode will be enabled
> > again?
>
> 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,
>
> usb_add_gadget_udc_release()-> check_pending_gadget_drivers()->
> udc_bind_to_driver()->usb_udc_connect_control()->usb_gadget_connect()->
> gadget->ops->pullup()
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 program
to monitor VBUS or external connector? At host mode, the store operation
will fail due to there is NO UDC.
--
Thanks,
Peter Chen
next prev parent reply other threads:[~2019-10-29 3:12 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-23 9:02 [PATCH] usb: cdns3: gadget: Don't manage pullups Roger Quadros
2019-10-23 9:17 ` Pawel Laszczak
2019-10-25 3:13 ` Peter Chen
2019-10-25 9:59 ` Roger Quadros
2019-10-25 10:14 ` Felipe Balbi
2019-10-29 3:12 ` Peter Chen [this message]
2019-10-29 9:37 ` Roger Quadros
2019-10-29 10:33 ` Felipe Balbi
2019-10-30 1:15 ` Peter Chen
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