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From: Pawel Laszczak <pawell@cadence.com>
To: Pavel Machek <pavel@denx.de>,
	"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
Cc: "felipe.balbi@linux.intel.com" <felipe.balbi@linux.intel.com>,
	"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
	"rogerq@ti.com" <rogerq@ti.com>,
	"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>
Subject: RE: [PATCH v10 0/6] Introduced new Cadence USBSS DRD Driver.
Date: Mon, 22 Jul 2019 12:11:40 +0000	[thread overview]
Message-ID: <BYAPR07MB470924FB97951364BD3AB5B3DDC40@BYAPR07MB4709.namprd07.prod.outlook.com> (raw)
In-Reply-To: <20190722115644.GA12069@amd>

>
>Hi!
>
>> > >> This patch introduce new Cadence USBSS DRD driver to linux kernel.
>> > >>
>> > >> The Cadence USBSS DRD Controller is a highly configurable IP Core which
>> > >> can be instantiated as Dual-Role Device (DRD), Peripheral Only and
>> > >> Host Only (XHCI)configurations.
>> > >
>> > >I see you are using debugfs to select between DRD, peripheral-onlyh and XHCI...
>> > >
>> > >Is that good idea?
>> >
>> > Yes driver allows selecting dr_mode by debugfs. Controller also support such functionality
>> > so I don't understand why would it not be a good idea.
>> >
>> > I personally use this for testing but it can be used to limit controller functionality without
>> > recompiling kernel.
>>
>> debugfs is ONLY for debugging, never rely on it being enabled, or
>> mounted, on a system in order to have any normal operation happen.
>>
>> So for testing, yes, this is fine.  If this is going to be the normal
>> api/interface for how to control this driver, no, that is not acceptable
>> at all.
>
>It makes a lot of sense for end-user to toggle this... for example
>when he is lacking right cable for proper otg detection. As it is
>third driver offering this functionality, I believe we should stop
>treating it as debugging.
>

Exactly I use this for this purpose. Depending on my testing platform I have 
the adapter with Typ-c plugs or normal Type A plugs. In the second case, 
by means of this property I can force Device or Host mode from driver 
without changing adapter. 

Bu as I wrote I use it only for debugging purpose.  I believe  that device on 
the market should not work in this way. 

Cheers,
Pawel. 


  parent reply	other threads:[~2019-07-22 12:11 UTC|newest]

Thread overview: 59+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-21 18:32 [PATCH v10 0/6] Introduced new Cadence USBSS DRD Driver Pawel Laszczak
2019-07-21 18:32 ` [PATCH v10 1/6] dt-bindings: add binding for USBSS-DRD controller Pawel Laszczak
2019-07-21 18:32 ` [PATCH v10 2/6] usb:common Separated decoding functions from dwc3 driver Pawel Laszczak
2019-07-21 19:05   ` Joe Perches
2019-07-21 20:45     ` Alan Stern
2019-07-21 20:54       ` Joe Perches
2019-07-22 10:06     ` Pawel Laszczak
2019-07-22 11:49       ` gregkh
2019-07-21 18:32 ` [PATCH v10 3/6] usb:common Patch simplify usb_decode_set_clear_feature function Pawel Laszczak
2019-07-21 19:07   ` Joe Perches
2019-07-22 10:12     ` Pawel Laszczak
2019-07-21 18:32 ` [PATCH v10 4/6] usb:common Simplify usb_decode_get_set_descriptor function Pawel Laszczak
2019-07-21 18:32 ` [PATCH v10 5/6] usb:cdns3 Add Cadence USB3 DRD Driver Pawel Laszczak
2019-07-31  3:36   ` Pawel Laszczak
2019-08-07 12:08   ` Roger Quadros
2019-08-11 11:59     ` Pawel Laszczak
2019-08-12  8:45       ` Roger Quadros
2019-08-12  9:43         ` Pawel Laszczak
2019-08-12 10:31           ` Heikki Krogerus
2019-08-12 11:05             ` Roger Quadros
2019-08-12 12:46               ` Felipe Balbi
2019-08-12 13:04                 ` Roger Quadros
2019-08-13  5:15                   ` Felipe Balbi
2019-08-13  7:30                   ` Chunfeng Yun
2019-08-13  7:48                     ` Roger Quadros
2019-08-13  8:50                       ` Chunfeng Yun
2019-08-12 10:05       ` Roger Quadros
2019-08-12 11:10         ` Pawel Laszczak
2019-08-14 13:32   ` Roger Quadros
2019-08-15  6:10     ` Felipe Balbi
2019-08-19  8:20     ` Pawel Laszczak
2019-08-14 13:38   ` Roger Quadros
2019-08-14 14:30     ` Pawel Laszczak
2019-08-15 11:22   ` Roger Quadros
2019-08-19 10:30     ` Pawel Laszczak
2019-08-19 10:59       ` Roger Quadros
2019-08-23  8:53   ` Vignesh Raghavendra
2019-08-23  9:39     ` Pawel Laszczak
2019-08-26  2:16   ` Peter Chen
2019-08-26  7:53     ` Pawel Laszczak
2019-07-21 18:32 ` [PATCH v10 6/6] usb:cdns3 Fix for stuck packets in on-chip OUT buffer Pawel Laszczak
2019-07-21 19:03 ` [PATCH v10 0/6] Introduced new Cadence USBSS DRD Driver Pavel Machek
2019-07-22  9:58   ` Pawel Laszczak
2019-07-22 11:48     ` gregkh
2019-07-22 11:56       ` Pavel Machek
2019-07-22 12:11         ` gregkh
2019-07-22 12:11         ` Pawel Laszczak [this message]
2019-07-22 21:00         ` Pavel Machek
2019-07-23  4:32           ` Pawel Laszczak
2019-08-07 11:05             ` Roger Quadros
2019-08-08  4:12               ` Pawel Laszczak
2019-08-09 10:36                 ` Roger Quadros
2019-08-09 10:44                   ` Felipe Balbi
2019-08-13  8:22                 ` Pavel Machek
2019-08-15 12:12 ` Roger Quadros
2019-08-15 14:39   ` Alan Stern
2019-08-19 12:08     ` Roger Quadros
2019-08-19 14:19       ` Alan Stern
2019-08-21  9:54         ` Roger Quadros

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