From: Roger Quadros <rogerq@ti.com>
To: Peter Chen <hzpeterchen@gmail.com>,
Alan Stern <stern@rowland.harvard.edu>
Cc: Felipe Balbi <balbi@kernel.org>, <gregkh@linuxfoundation.org>,
<peter.chen@freescale.com>, <dan.j.williams@intel.com>,
<jun.li@freescale.com>, <mathias.nyman@linux.intel.com>,
<tony@atomide.com>, <Joao.Pinto@synopsys.com>,
<abrestic@chromium.org>, <linux-usb@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <linux-omap@vger.kernel.org>
Subject: Re: [PATCH v6 01/12] usb: hcd: Initialize hcd->flags to 0
Date: Wed, 20 Apr 2016 11:15:30 +0300 [thread overview]
Message-ID: <57173AA2.5080204@ti.com> (raw)
In-Reply-To: <20160419015622.GH4477@shlinux2.ap.freescale.net>
On 19/04/16 04:56, Peter Chen wrote:
> On Mon, Apr 18, 2016 at 10:11:29AM -0400, Alan Stern wrote:
>> On Mon, 18 Apr 2016, Peter Chen wrote:
>>
>>> On Wed, Apr 06, 2016 at 09:32:22AM +0300, Roger Quadros wrote:
>>>> On 06/04/16 09:09, Felipe Balbi wrote:
>>>>>
>>>>> Hi,
>>>>>
>>>>> Roger Quadros <rogerq@ti.com> writes:
>>>>>> diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
>>>>>> index 2ca2cef..6b1930d 100644
>>>>>> --- a/drivers/usb/core/hcd.c
>>>>>> +++ b/drivers/usb/core/hcd.c
>>>>>> @@ -2706,6 +2706,7 @@ int usb_add_hcd(struct usb_hcd *hcd,
>>>>>> int retval;
>>>>>> struct usb_device *rhdev;
>>>>>>
>>>>>> + hcd->flags = 0;
>>>>>
>>>>> seems like this would make more sense in usb_del_hcd() instead.
>>>>>
>>>>
>>>> OK, I'll move it there.
>>>>
>>>
>>> It depends on Alan's comments, whether only usb_add_hcd/usb_del_hcd
>>> pair can be called repeat. If Alan acks it, I have no idea for it.
>>
>> Most of the host controller drivers were not written with this in mind,
>> but I think it would be a good thing to allow. It would speed up the
>> host/device role switches.
>>
>> This might mean we need to fix up several drivers to make them work
>> correctly in an OTG environment. It should be possible to do this. Is
>> there any particular reason why it would be difficult for Chipidea?
>>
>
> I just want to do clean remove at OTG environment, like rmmod, so I did
> this when I worked on chipidea OTG design.
> I am worried if there are some resources dedicated for host device, eg,
> clocks, gpio. etc.
>
> If OTG framework can know well hcd's add and remove, it is ok for chipidea
> just calling usb_add_hcd/usb_del_hcd currently, but I suggested roger
> adding platform hcd_ops as optional parameter in case the platform
> has special requirement for hcd_ops.
>
We have 2 users now, omap + dwc3 and sh + EHCI/OHCI and we didn't seem to
observe any issues with the usb_add/del_hcd approach.
Let's keep things minimal for now. In the future, if users need something more
we can always extend the framework.
cheers,
-roger
next prev parent reply other threads:[~2016-04-20 8:15 UTC|newest]
Thread overview: 100+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-05 14:05 [PATCH v6 00/12] USB OTG/dual-role framework Roger Quadros
2016-04-05 14:05 ` [PATCH v6 01/12] usb: hcd: Initialize hcd->flags to 0 Roger Quadros
2016-04-06 6:09 ` Felipe Balbi
2016-04-06 6:32 ` Roger Quadros
2016-04-07 9:42 ` Peter Chen
2016-04-07 10:40 ` Roger Quadros
2016-04-08 1:01 ` Peter Chen
2016-04-08 7:16 ` Roger Quadros
2016-04-08 7:45 ` Peter Chen
2016-04-18 2:29 ` Peter Chen
2016-04-18 14:11 ` Alan Stern
2016-04-19 1:56 ` Peter Chen
2016-04-20 8:15 ` Roger Quadros [this message]
2016-04-20 9:40 ` Peter Chen
2016-04-05 14:05 ` [PATCH v6 02/12] usb: hcd.h: Add OTG to HCD interface Roger Quadros
2016-04-18 7:41 ` Peter Chen
2016-04-05 14:05 ` [PATCH v6 03/12] usb: otg-fsm: use usb_otg wherever possible Roger Quadros
2016-04-18 7:42 ` Peter Chen
2016-04-05 14:05 ` [PATCH v6 04/12] usb: otg-fsm: move host controller operations into usb_otg->hcd_ops Roger Quadros
2016-04-18 8:00 ` Peter Chen
2016-04-05 14:05 ` [PATCH v6 05/12] usb: gadget.h: Add OTG to gadget interface Roger Quadros
2016-04-05 14:05 ` [PATCH v6 06/12] usb: otg: get rid of CONFIG_USB_OTG_FSM in favour of CONFIG_USB_OTG Roger Quadros
2016-04-18 8:05 ` Peter Chen
2016-04-20 8:12 ` Roger Quadros
2016-04-05 14:05 ` [PATCH v6 07/12] usb: otg: add OTG/dual-role core Roger Quadros
2016-04-07 8:52 ` Yoshihiro Shimoda
2016-04-07 11:45 ` Roger Quadros
2016-04-08 11:22 ` Yoshihiro Shimoda
2016-04-11 10:54 ` Roger Quadros
2016-04-14 8:36 ` Yoshihiro Shimoda
2016-04-14 10:59 ` Roger Quadros
2016-04-14 11:15 ` Yoshihiro Shimoda
2016-04-14 11:32 ` Roger Quadros
2016-04-15 9:59 ` Yoshihiro Shimoda
2016-04-15 10:57 ` Roger Quadros
2016-04-15 10:03 ` Yoshihiro Shimoda
2016-04-19 9:18 ` Peter Chen
2016-04-20 5:08 ` Yoshihiro Shimoda
2016-04-20 7:03 ` Roger Quadros
2016-04-22 6:05 ` Peter Chen
2016-04-22 1:26 ` Peter Chen
2016-04-22 3:34 ` Peter Chen
2016-04-22 5:57 ` Yoshihiro Shimoda
2016-04-15 9:25 ` Peter Chen
2016-04-15 11:00 ` Roger Quadros
2016-04-18 2:09 ` Peter Chen
2016-04-20 6:54 ` Roger Quadros
2016-04-20 9:26 ` Peter Chen
2016-04-19 8:06 ` Peter Chen
2016-04-20 7:02 ` Roger Quadros
2016-04-20 9:39 ` Peter Chen
2016-04-21 6:52 ` Peter Chen
2016-04-25 14:05 ` Roger Quadros
2016-04-26 2:07 ` Jun Li
2016-04-26 3:47 ` Peter Chen
2016-04-26 5:11 ` Jun Li
2016-04-26 6:28 ` Peter Chen
2016-04-26 7:00 ` Jun Li
2016-04-26 8:21 ` Peter Chen
2016-04-27 3:15 ` Peter Chen
2016-04-27 10:59 ` Roger Quadros
2016-04-28 1:54 ` Peter Chen
2016-04-28 8:01 ` Roger Quadros
2016-04-27 11:15 ` Roger Quadros
2016-04-05 14:05 ` [PATCH v6 08/12] usb: hcd: Adapt to OTG core Roger Quadros
2016-04-18 6:29 ` Peter Chen
2016-04-19 8:14 ` Peter Chen
2016-04-20 6:47 ` Roger Quadros
2016-04-20 6:46 ` Roger Quadros
2016-04-27 10:16 ` Jun Li
2016-04-27 11:00 ` Roger Quadros
2016-04-27 11:11 ` Roger Quadros
2016-04-27 12:49 ` Jun Li
2016-04-27 13:18 ` Jun Li
2016-04-05 14:05 ` [PATCH v6 09/12] usb: gadget: udc: adapt " Roger Quadros
2016-04-18 6:59 ` Peter Chen
2016-04-20 6:51 ` Roger Quadros
2016-04-21 6:38 ` Jun Li
2016-04-25 14:04 ` Roger Quadros
2016-04-26 0:07 ` Jun Li
2016-04-27 11:22 ` Roger Quadros
2016-04-28 9:54 ` Roger Quadros
2016-04-28 10:23 ` Jun Li
2016-04-28 12:22 ` Roger Quadros
2016-05-03 7:06 ` Jun Li
2016-05-03 15:44 ` Roger Quadros
2016-05-04 1:47 ` Peter Chen
2016-05-04 3:35 ` Peter Chen
2016-05-04 6:37 ` Roger Quadros
2016-05-04 7:53 ` Peter Chen
2016-05-04 8:03 ` Jun Li
2016-05-04 8:40 ` Roger Quadros
2016-05-04 8:39 ` Peter Chen
2016-04-05 14:05 ` [PATCH v6 10/12] usb: doc: dt-binding: Add otg-controller property Roger Quadros
2016-04-05 14:05 ` [PATCH v6 11/12] usb: core: hub: Notify OTG fsm when A device sets b_hnp_enable Roger Quadros
2016-04-18 7:08 ` Peter Chen
2016-04-27 14:35 ` Roger Quadros
2016-04-05 14:05 ` [PATCH v6 12/12] usb: host: xhci-plat: Add otg device to platform data Roger Quadros
2016-04-06 3:23 ` Yoshihiro Shimoda
2016-04-06 6:30 ` Roger Quadros
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