Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH v10 5/6] usb:cdns3 Add Cadence USB3 DRD Driver
To:     Felipe Balbi <felipe.balbi@linux.intel.com>,
        Heikki Krogerus <heikki.krogerus@linux.intel.com>,
        Pawel Laszczak <pawell@cadence.com>
CC:     "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
        "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "jbergsagel@ti.com" <jbergsagel@ti.com>,
        "nsekhar@ti.com" <nsekhar@ti.com>, "nm@ti.com" <nm@ti.com>,
        Suresh Punnoose <sureshp@cadence.com>,
        Jayshri Dajiram Pawar <jpawar@cadence.com>,
        Rahul Kumar <kurahul@cadence.com>,
        Anil Joy Varughese <aniljoy@cadence.com>
References: <1563733939-21214-1-git-send-email-pawell@cadence.com>
 <1563733939-21214-6-git-send-email-pawell@cadence.com>
 <88742d5b-ee10-cf4e-6724-58e7bdd19cb9@ti.com>
 <BYAPR07MB47090BCA728600F0C2F4E129DDD00@BYAPR07MB4709.namprd07.prod.outlook.com>
 <1e557bcf-2d50-f600-0e81-1f9fba5499a1@ti.com>
 <BYAPR07MB4709F306EC472B7AABEB7D4CDDD30@BYAPR07MB4709.namprd07.prod.outlook.com>
 <20190812103147.GA4691@kuha.fi.intel.com>
 <d3bba104-9a85-df8d-c62d-6acb8913c3fe@ti.com> <874l2mtuu6.fsf@gmail.com>
From:   Roger Quadros <rogerq@ti.com>
Message-ID: <679b82bc-9f33-91ad-4acf-bf6a29e51bc1@ti.com>
Date:   Mon, 12 Aug 2019 16:04:52 +0300
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101
 Thunderbird/60.8.0
MIME-Version: 1.0
In-Reply-To: <874l2mtuu6.fsf@gmail.com>
Content-Type: text/plain; charset="utf-8"
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk


On 12/08/2019 15:46, Felipe Balbi wrote:
> 
> Hi,
> 
> Roger Quadros <rogerq@ti.com> writes:
>>> The sysfs file we expose from the class for the role switches is
>>> primarily meant for supporting proprietary protocols that require us
>>> to basically override the connector USB data role. The default role
>>> should always be selected in the drivers.
>>
>> OK. Let's take this example
>> - Port is dual-role port micro AB.
>> - microAB to type-A adapter is connected which pulls ID low. port transitions
>> to "host" role by the controller driver.
>> - proprietary protocol want to switch role to device role so writes "device" to
>> mode switch sysfs. port transitions to "device" role.
>>
>> Now, how does controller driver know to fall back to HW based role switching?
> 
> Use a 'disconnect' or 'suspend' event to go reset it? But that should,
> probably, be done at kernel space, no?
> 

Yes that could be one option.
So after a disconnect, sysfs role should reflect actual hardware role. correct?

cheers,
-roger
-- 
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki