Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1373266

Re: [PATCH v6 01/12] usb: hcd: Initialize hcd->flags to 0

From Roger Quadros <rogerq@ti.com>
Newsgroups linux.kernel
Subject Re: [PATCH v6 01/12] usb: hcd: Initialize hcd->flags to 0
Date 2016-04-07 12:50 +0200
Message-ID <rlfFE-2v3-7@gated-at.bofh.it> (permalink)
References <rkzQ5-4UX-1@gated-at.bofh.it> <rkzQ8-4UX-55@gated-at.bofh.it> <rkOYO-880-9@gated-at.bofh.it> <rkPia-8gZ-9@gated-at.bofh.it> <rleJA-1Ne-7@gated-at.bofh.it>
Organization linux.* mail to news gateway

Show all headers | View raw

On 07/04/16 12:42, 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;
>>>
> 
> I am not sure if this usb_add(remove)_hcd pair is safe and clean enough
> for start/stop host role. From my point, we may need to do like
> .probe/.remove host platform driver interface. In that case, we can make

probe and remove are meant to be called from bus layer.
I do not see a way how OTG framework can call probe/remove of HCD driver.
Some HCDs may be platform devices, some PCI, so different entities are calling
the HCD .probe hook.

> sure the clocks and regulators are off, and hcd will be zero-initialized

why can't we make that sure that is taken care of within the hcd_ops?
Why should some driver keep its regulators and clocks enabled when hcd is stopped?
It doesn't need to. If it is doing so now, it needs to be fixed.

> next time. Assume we are at gadget mode, we may not hope the vbus regulator
> is still on which is for host only. So, this part may need to implement
> by each user.
> 

Yes, correctness of this has to be taken care by each driver.

cheers,
-roger

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH v6 00/12] USB OTG/dual-role framework Roger Quadros <rogerq@ti.com> - 2016-04-05 16:10 +0200
  [PATCH v6 10/12] usb: doc: dt-binding: Add otg-controller property Roger Quadros <rogerq@ti.com> - 2016-04-05 16:10 +0200
  [PATCH v6 09/12] usb: gadget: udc: adapt to OTG core Roger Quadros <rogerq@ti.com> - 2016-04-05 16:10 +0200
  [PATCH v6 12/12] usb: host: xhci-plat: Add otg device to platform data Roger Quadros <rogerq@ti.com> - 2016-04-05 16:10 +0200
    RE: [PATCH v6 12/12] usb: host: xhci-plat: Add otg device to platform  data Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> - 2016-04-06 05:30 +0200
      Re: [PATCH v6 12/12] usb: host: xhci-plat: Add otg device to platform  data Roger Quadros <rogerq@ti.com> - 2016-04-06 08:40 +0200
  [PATCH v6 06/12] usb: otg: get rid of CONFIG_USB_OTG_FSM in favour of CONFIG_USB_OTG Roger Quadros <rogerq@ti.com> - 2016-04-05 16:10 +0200
  [PATCH v6 07/12] usb: otg: add OTG/dual-role core Roger Quadros <rogerq@ti.com> - 2016-04-05 16:10 +0200
    RE: [PATCH v6 07/12] usb: otg: add OTG/dual-role core Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> - 2016-04-07 11:00 +0200
      Re: [PATCH v6 07/12] usb: otg: add OTG/dual-role core Roger Quadros <rogerq@ti.com> - 2016-04-07 13:50 +0200
        RE: [PATCH v6 07/12] usb: otg: add OTG/dual-role core Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> - 2016-04-08 13:30 +0200
          Re: [PATCH v6 07/12] usb: otg: add OTG/dual-role core Roger Quadros <rogerq@ti.com> - 2016-04-11 13:00 +0200
            RE: [PATCH v6 07/12] usb: otg: add OTG/dual-role core Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> - 2016-04-14 10:40 +0200
              Re: [PATCH v6 07/12] usb: otg: add OTG/dual-role core Roger Quadros <rogerq@ti.com> - 2016-04-14 13:10 +0200
                RE: [PATCH v6 07/12] usb: otg: add OTG/dual-role core Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> - 2016-04-14 13:20 +0200
                Re: [PATCH v6 07/12] usb: otg: add OTG/dual-role core Roger Quadros <rogerq@ti.com> - 2016-04-14 13:40 +0200
                RE: [PATCH v6 07/12] usb: otg: add OTG/dual-role core Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> - 2016-04-15 12:00 +0200
                Re: [PATCH v6 07/12] usb: otg: add OTG/dual-role core Roger Quadros <rogerq@ti.com> - 2016-04-15 13:00 +0200
                RE: [PATCH v6 07/12] usb: otg: add OTG/dual-role core Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> - 2016-04-15 12:10 +0200
    Re: [PATCH v6 07/12] usb: otg: add OTG/dual-role core Peter Chen <hzpeterchen@gmail.com> - 2016-04-15 11:40 +0200
      Re: [PATCH v6 07/12] usb: otg: add OTG/dual-role core Roger Quadros <rogerq@ti.com> - 2016-04-15 13:10 +0200
  [PATCH v6 05/12] usb: gadget.h: Add OTG to gadget interface Roger Quadros <rogerq@ti.com> - 2016-04-05 16:10 +0200
  [PATCH v6 02/12] usb: hcd.h: Add OTG to HCD interface Roger Quadros <rogerq@ti.com> - 2016-04-05 16:10 +0200
  [PATCH v6 04/12] usb: otg-fsm: move host controller operations into usb_otg->hcd_ops Roger Quadros <rogerq@ti.com> - 2016-04-05 16:10 +0200
  [PATCH v6 11/12] usb: core: hub: Notify OTG fsm when A device sets b_hnp_enable Roger Quadros <rogerq@ti.com> - 2016-04-05 16:10 +0200
  [PATCH v6 01/12] usb: hcd: Initialize hcd->flags to 0 Roger Quadros <rogerq@ti.com> - 2016-04-05 16:10 +0200
    Re: [PATCH v6 01/12] usb: hcd: Initialize hcd->flags to 0 Felipe Balbi <balbi@kernel.org> - 2016-04-06 08:20 +0200
      Re: [PATCH v6 01/12] usb: hcd: Initialize hcd->flags to 0 Roger Quadros <rogerq@ti.com> - 2016-04-06 08:40 +0200
        Re: [PATCH v6 01/12] usb: hcd: Initialize hcd->flags to 0 Peter Chen <hzpeterchen@gmail.com> - 2016-04-07 11:50 +0200
          Re: [PATCH v6 01/12] usb: hcd: Initialize hcd->flags to 0 Roger Quadros <rogerq@ti.com> - 2016-04-07 12:50 +0200
            Re: [PATCH v6 01/12] usb: hcd: Initialize hcd->flags to 0 Peter Chen <hzpeterchen@gmail.com> - 2016-04-08 03:10 +0200
              Re: [PATCH v6 01/12] usb: hcd: Initialize hcd->flags to 0 Roger Quadros <rogerq@ti.com> - 2016-04-08 09:20 +0200
                Re: [PATCH v6 01/12] usb: hcd: Initialize hcd->flags to 0 Peter Chen <hzpeterchen@gmail.com> - 2016-04-08 10:00 +0200
  [PATCH v6 08/12] usb: hcd: Adapt to OTG core Roger Quadros <rogerq@ti.com> - 2016-04-05 16:20 +0200

csiph-web