From: Mathias Nyman <mathias.nyman@intel.com>
To: Yingjoe Chen <yingjoe.chen@mediatek.com>, balbi@ti.com
Cc: chunfeng.yun@mediatek.com, Mark Rutland <mark.rutland@arm.com>,
devicetree@vger.kernel.org, Sascha Hauer <s.hauer@pengutronix.de>,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
Rob Herring <robh+dt@kernel.org>,
linux-mediatek@lists.infradead.org,
Matthias Brugger <matthias.bgg@gmail.com>,
linux-arm-kernel@lists.infradead.org,
Maxime Ripard <maxime.ripard@free-electrons.com>,
Roger Quadros <rogerq@ti.com>
Subject: Re: [PATCH 3/6] xhci: probe phy before add usb_hcd
Date: Mon, 01 Jun 2015 18:17:04 +0300 [thread overview]
Message-ID: <556C7770.70506@intel.com> (raw)
In-Reply-To: <1433170337.12128.18.camel@mtksdaap41>
On 01.06.2015 17:52, Yingjoe Chen wrote:
> On Wed, 2015-05-27 at 07:18 -0500, Felipe Balbi wrote:
>> On Wed, May 27, 2015 at 07:48:00PM +0800, chunfeng.yun@mediatek.com wrote:
>>> From: Chunfeng Yun <chunfeng.yun@mediatek.com>
>>>
>>> find the phy driver before add primary usb_hcd to avoid acessing
>>> xHCI register which may hangup the system when the phy is not loaded
>>> yet and the related powers or clocks put in phy driver are not
>>> enabled.
>>
>> it seems like the same clock is needed by PHY and XHCI. This patch looks
>> incorrect.
>
>
> Hi,
>
> I agree that the driver should enable clock it used by itself and not
> depends on init order. This should be fixed.
>
> But in general, I think it make sense to only add hcd after all required
> resource are ready. At least it remove unnecessary calls to
> usb_add_hcd/usb_remove_hcd. Is it better if the commit message is
> changed to something like the below?
>
> Currently xhci_plat_probe() call usb_add_hcd before trying to init the
> phy. However if the phy is not ready at the moment, it have to remove
> the hcd and probe again later
>
> Change the init order so we only add hcd when all required resource are
> ready.
>
Hi
Rogers Quadros patchseries that changes how HCDs are created and added for
xhci-plat was just sent forward. It first creates both HCDs, then adds them.
Doesn't usb_add_hcd() as it's first task take care of the PHYs?
I'm hoping to remove that part completely from xhci-plat.c but haven't
looked into it properly yet.
-Mathias
next prev parent reply other threads:[~2015-06-01 15:14 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-27 11:47 [PATCH 0/6] Mediatek xHCI support chunfeng.yun
2015-05-27 11:47 ` [PATCH 1/6] dt-bindings: Add usb3.0 phy binding for MT65xx SoCs chunfeng.yun
2015-05-27 11:47 ` [PATCH 2/6] dt-bindings: Add a binding for Mediatek xHCI host controller chunfeng.yun
2015-05-27 11:48 ` [PATCH 3/6] xhci: probe phy before add usb_hcd chunfeng.yun
2015-05-27 12:18 ` Felipe Balbi
2015-06-01 14:52 ` Yingjoe Chen
2015-06-01 15:17 ` Mathias Nyman [this message]
2015-06-02 4:00 ` Roger Quadros
2015-05-27 11:48 ` [PATCH 4/6] usb: phy: add usb3.0 phy driver for mt65xx SoCs chunfeng.yun
2015-06-01 16:18 ` Felipe Balbi
2015-05-27 11:48 ` [PATCH 5/6] xhci: mediatek: support MTK xHCI host controller chunfeng.yun
2015-05-27 11:48 ` [PATCH 6/6] arm64: dts: mediatek: add xHCI & usb phy for mt8173 chunfeng.yun
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