From: Roger Quadros <rogerq@ti.com>
To: Peter Chen <peter.chen@nxp.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 11:37:31 +0200 [thread overview]
Message-ID: <0c2c901c-a6f2-a81b-f5b1-e3f442d7c1ae@ti.com> (raw)
In-Reply-To: <20191029031223.GA26815@b29397-desktop>
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.
cheers,
-roger
--
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
next prev parent reply other threads:[~2019-10-29 9:37 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 [this message]
2019-10-29 10:33 ` Felipe Balbi
2019-10-30 1:15 ` Peter Chen
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