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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: Wed, 30 Oct 2019 01:15:16 +0000	[thread overview]
Message-ID: <20191030011505.GB26815@b29397-desktop> (raw)
In-Reply-To: <0c2c901c-a6f2-a81b-f5b1-e3f442d7c1ae@ti.com>

On 19-10-29 11:37:31, Roger Quadros wrote:
> 
> 
> On 29/10/2019 05:12, Peter Chen wrote:
> > 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.
> > 
> 
> Yes, user space needs to monitor /sys/class/usb_role/6000000.usb-role-switch/role
> 
> When it becomes "device" the UDC is available and it can prepare to configure
> the UDC.
> 
> Could you please give your Ack for this patch if it is OK? Thanks.
> 

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

-- 

Thanks,
Peter Chen

      parent reply	other threads:[~2019-10-30  1:15 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
2019-10-29  9:37         ` Roger Quadros
2019-10-29 10:33           ` Felipe Balbi
2019-10-30  1:15           ` Peter Chen [this message]

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