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From: Arun Ramamurthy <>
To: Arnd Bergmann <>,
	Alan Stern <>
Cc: Mark Rutland <>, <>,
	"Scott Branden" <>,
	Pawel Moll <>,
	"Ian Campbell" <>,
	Ray Jui <>, <>,
	Kishon Vijay Abraham I <>,
	Jonathan Richardson <>,
	Rob Herring <>,
	"Dmitry Torokhov" <>,
	Kumar Gala <>,
	"Anatol Pomazau" <>
Subject: Re: [PATCH 1/2] phy: usbphy: Add dt documentation for Broadcom Cygnus USB PHY driver
Date: Wed, 25 Feb 2015 16:24:06 -0800	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

Hello Alan and Arnd

I wanted to follow up on this patch and ascertain what I would have to 
change. Please see below for my questions

On 15-02-18 04:46 PM, Arun Ramamurthy wrote:
> On 15-02-18 07:15 AM, Arnd Bergmann wrote:
>> On Tuesday 17 February 2015 13:05:50 Arun Ramamurthy wrote:
>>> On 15-02-17 12:53 PM, Arnd Bergmann wrote:
>>>> On Tuesday 17 February 2015 12:00:49 Arun Ramamurthy wrote:
>>>>> Arnd, I patched the ehci and ohci driver to accept multiple phys so
>>>>> they
>>>>> require different names and cannot both be "usb". That patch was
>>>>> accepted by Alen Stern but I did not update the bindings
>>>>> documentation.
>>>>> I will send out another patch for that. Could we go with the naming
>>>>> scheme of "usb" + "p" + port number or do you have other suggestions?
>>>> I don't have a good idea, but I think it would be best if the first
>>>> phy could remain named "usb" for compatibility with the existing
>>>> binding.
>>> The patch was written in a way that all the existing and new drivers can
>>> continue to use "usb" if they are using only one phy so that we remain
>>> compatible. The names need to be different only if more than one phy is
>>> specified. In such cases i don't think the first phy should be "usb" as
>>> it would be confusing to have
>>>          phy-names = "usb","usbp1"
>> I see your patch now, as 7e7a0e67f2c ("usb: ehci-platform: add support
>> for
>> multiple phys per controller"), and I'm not too happy about the way you
>> did this.
>> We already concluded that there should have been a binding change
>> to go along with this, and that would have caught the fact that you
>> circumvent the API here by reading the phy names manually. That
>> part should never have made it into the kernel.
>> I think we can do this either by defining specific names for the
>> phy, or by changing the generic PHY binding to allow anonymous
>> phy references (leaving out "phy-names" entirely), and adding a
>> proper API for that.
> Thanks Arnd, I will wait for Alan's comments before proceeding. I am
> happy to patch the ehci-platform driver to use a new api instead of
> devm_phy_get if that is the best option.
>>> Should I run this by Alan Stern?
>> I've added him to Cc here. He clearly didn't know the background about
>> the DT binding change, and should not need to, but he may have an opinion
>> on what names we should use.
Arnd, should I re patch the ehci-platform driver to avoid phy-names 
entirely? Alan, if not do you have an opinion on what the usb phy names 
should be? The current patch uses "usbp" + port number such as "usbp0" , 
"usbp1" etc

>>>> What is the reason for having two phys in your case? Are these
>>>> identical phy devices connected to a single controller or do they
>>>> server different purposes?
>>> Yes, we have three identical phys connected to a single host controller
>>> and one of the phys is also connected to the device controller
>> Ok, no problem with that, let's just make sure we come up with a
>> good binding for it.
Arnd do you have any other comments on the phy driver itself? Thank you
>>     Arnd

  reply	other threads:[~2015-02-26  0:22 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-17 19:20 [PATCH 0/2] USB PHY driver for Broadcom's Cygnus chipset Arun Ramamurthy
2015-02-17 19:20 ` [PATCH 1/2] phy: usbphy: Add dt documentation for Broadcom Cygnus USB PHY driver Arun Ramamurthy
2015-02-17 19:41   ` Arnd Bergmann
2015-02-17 20:00     ` Arun Ramamurthy
2015-02-17 20:53       ` Arnd Bergmann
2015-02-17 21:05         ` Arun Ramamurthy
2015-02-18 15:15           ` Arnd Bergmann
2015-02-19  0:46             ` Arun Ramamurthy
2015-02-26  0:24               ` Arun Ramamurthy [this message]
2015-03-10 20:27                 ` Arnd Bergmann
2015-03-11 21:37                   ` Arun Ramamurthy
2015-03-11 21:47                     ` Arnd Bergmann
2015-02-17 19:20 ` [PATCH 2/2] phy: usbphy: Add " Arun Ramamurthy
2015-02-18  6:10   ` Kishon Vijay Abraham I
2015-03-05 22:33   ` Dmitry Torokhov

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