linux-kernel - Re: [PATCH 2/5] usb: xhci: plat: Create both HCDs before adding them

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Message-ID: <20150422134658.GB28007@lukather>
Date:	Wed, 22 Apr 2015 15:46:58 +0200
From:	Maxime Ripard <maxime.ripard@...e-electrons.com>
To:	Roger Quadros <rogerq@...com>
Cc:	Mathias Nyman <mathias.nyman@...ux.intel.com>,
	mathias.nyman@...el.com, gregkh@...uxfoundation.org,
	linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
	"Balbi, Felipe" <balbi@...com>, kishon@...comg
Subject: Re: [PATCH 2/5] usb: xhci: plat: Create both HCDs before adding them

On Tue, Apr 21, 2015 at 01:46:36PM +0300, Roger Quadros wrote:
> On 21/04/15 11:08, Maxime Ripard wrote:
> > On Tue, Apr 21, 2015 at 12:49:54PM +0300, Roger Quadros wrote:
> >> On 20/04/15 15:35, Mathias Nyman wrote:
> >>> Hi
> >>>
> >>> On 02.04.2015 15:23, Roger Quadros wrote:
> >>>> As xhci_hcd is now allocated by usb_create_hcd(), we don't
> >>>> need to add the primary HCD before creating the shared HCD.
> >>>>
> >>>> Creating the shared HCD before adding the primary HCD is particularly
> >>>> useful for the OTG use case so that we know at the OTG core if
> >>>> the HCD is in single configuration or dual (primary + shared)
> >>>> configuration.
> >>>>
> >>>
> >>> This doesn't apply as 
> >>>
> >>> commit 7b8ef22ea547b80475ac7feab06fb15e0fc143d8
> >>>     usb: xhci: plat: Add USB phy support
> >>>
> >>> changed xhci-plat.c since.
> >>>
> >>> I rebased it, and the changed version is sitting in the for-usb-next branch in:
> >>> git://git.kernel.org/pub/scm/linux/kernel/git/mnyman/xhci.git
> >>>
> >>> But it appeared to me that usb_add_hcd() and usb_remove_hcd() will also
> >>> call phy init and remove functions. As the order how hcds are created and added
> >>> would change I'd need some more eyes on this to see if it will cause regression.
> >>>
> >>> Or maybe in the best case we could get rid of the "Add USB phy support" patch as
> >>> we will call xhci_add_hcd() for the first hcd much later, and it could maybe init
> >>> the phy for us?
> >>
> >> I thought usb_phy_*() stuff would be deprecated and we should use
> >> phy framework instead i.e. phy_init() and friends.
> > 
> > Except that all drivers have not been converted yet... So it's not
> > really an option until then.
> > 
> >> In fact usb_add_hcd() is already handling the phy for us.
> > 
> > If it handles USB phy, then I don't really have an issue with it.
> 
> It handles usb_phy as well. It just expects hcd->usb_phy to be set.

Ok, perfect then.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

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