From: Roger Quadros <rogerq@ti.com>
To: Mark Rutland <mark.rutland@arm.com>
Cc: "tony@atomide.com" <tony@atomide.com>,
"b-cousson@ti.com" <b-cousson@ti.com>,
"balbi@ti.com" <balbi@ti.com>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"stern@rowland.harvard.edu" <stern@rowland.harvard.edu>,
"linux@arm.linux.org.uk" <linux@arm.linux.org.uk>,
"kishon@ti.com" <kishon@ti.com>,
"linux-omap@vger.kernel.org" <linux-omap@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 01/14] usb: phy: nop: Add device tree support and binding information
Date: Mon, 11 Feb 2013 17:14:26 +0200 [thread overview]
Message-ID: <51190AD2.3030006@ti.com> (raw)
In-Reply-To: <20130211114040.GA2726@e106331-lin.cambridge.arm.com>
On 02/11/2013 01:40 PM, Mark Rutland wrote:
> Hello,
>
> On Thu, Feb 07, 2013 at 04:02:41PM +0000, Roger Quadros wrote:
>> The PHY clock, clock rate, VCC regulator and RESET regulator
>> can now be provided via device tree.
>>
>> Signed-off-by: Roger Quadros <rogerq@ti.com>
>> Acked-by: Felipe Balbi <balbi@ti.com>
>> ---
>> .../devicetree/bindings/usb/usb-nop-xceiv.txt | 34 ++++++++++++++++++
>> drivers/usb/otg/nop-usb-xceiv.c | 36 +++++++++++++++----
>> 2 files changed, 62 insertions(+), 8 deletions(-)
>> create mode 100644 Documentation/devicetree/bindings/usb/usb-nop-xceiv.txt
>>
>> diff --git a/Documentation/devicetree/bindings/usb/usb-nop-xceiv.txt b/Documentation/devicetree/bindings/usb/usb-nop-xceiv.txt
>> new file mode 100644
>> index 0000000..d7e2726
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/usb/usb-nop-xceiv.txt
>> @@ -0,0 +1,34 @@
>> +USB NOP PHY
>> +
>> +Required properties:
>> +- compatible: should be usb-nop-xceiv
>
> This might be better as "linux,usb-no-xceiv", given this is a Linux-specific
> 'device'.
>
> Saying that, I'm not sure I understand why this device needs to be instantiated
> from devicetree. As I understand it from looking at the driver, it's purely a
> Linux implementation detail used in the case of autonomous PHYs, and not an
> actual piece of hardware or firmware system. I must admit to being unfamiliar
> with this area of hardware, have I misunderstood somethign here?
The PHY is a physical device and may need resources like power and clock to be functional.
The only reason that driver is named NOP is that many USB controllers know how to talk to
the standard PHYs and don't need any interface/management software.
The PHY driver you are looking at most likely doesn't have the recent changes I wrote to
manage the PHY clock/reset/power. i.e. patches 3, 4 and 5 in the series
https://lkml.org/lkml/2013/1/28/275
Before this, the ehci-omap driver was trying to manage the PHY power and reset, which was
wrong.
regards,
-roger
next prev parent reply other threads:[~2013-02-11 15:14 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-07 16:02 [PATCH v2 00/14] Device tree support for OMAP HS USB Host Roger Quadros
2013-02-07 16:02 ` [PATCH v2 01/14] usb: phy: nop: Add device tree support and binding information Roger Quadros
2013-02-11 11:40 ` Mark Rutland
2013-02-11 15:14 ` Roger Quadros [this message]
2013-02-11 15:31 ` Mark Rutland
2013-02-07 16:02 ` [PATCH v2 02/14] USB: phy: nop: Defer probe if device needs VCC/RESET Roger Quadros
2013-02-07 16:02 ` [PATCH v2 03/14] mfd: omap-usb-tll: move configuration code to omap_tll_init() Roger Quadros
2013-02-07 16:02 ` [PATCH v2 04/14] mfd: omap-usb-tll: Add device tree support Roger Quadros
2013-02-07 16:02 ` [PATCH v2 05/14] USB: ehci-omap: Get platform resources by index rather than by name Roger Quadros
2013-02-07 16:02 ` [PATCH v2 06/14] USB: ohci-omap3: " Roger Quadros
2013-02-07 16:02 ` [PATCH v2 07/14] USB: ohci-omap3: Add device tree support and binding information Roger Quadros
2013-02-11 11:46 ` Mark Rutland
2013-02-11 15:22 ` Roger Quadros
2013-02-11 15:32 ` Mark Rutland
2013-02-07 16:02 ` [PATCH v2 08/14] USB: ehci-omap: " Roger Quadros
2013-02-11 11:52 ` Mark Rutland
2013-02-07 16:02 ` [PATCH v2 09/14] mfd: omap-usb-host: " Roger Quadros
2013-02-11 12:00 ` Mark Rutland
2013-02-11 15:24 ` Roger Quadros
2013-02-07 16:02 ` [PATCH v2 10/14] ARM: dts: OMAP4: Add HS USB Host IP nodes Roger Quadros
2013-02-07 16:02 ` [PATCH v2 11/14] ARM: dts: omap4-panda: Add USB Host support Roger Quadros
2013-02-07 16:02 ` [PATCH v2 12/14] ARM: dts: OMAP3: Add HS USB Host IP nodes Roger Quadros
2013-02-07 16:02 ` [PATCH v2 13/14] ARM: dts: omap3-beagle: Add USB Host support Roger Quadros
2013-02-07 16:02 ` [PATCH v2 14/14] USB: ehci-omap: Fix autoloading of module Roger Quadros
2013-02-07 16:11 ` Alan Stern
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=51190AD2.3030006@ti.com \
--to=rogerq@ti.com \
--cc=b-cousson@ti.com \
--cc=balbi@ti.com \
--cc=gregkh@linuxfoundation.org \
--cc=kishon@ti.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-omap@vger.kernel.org \
--cc=linux@arm.linux.org.uk \
--cc=mark.rutland@arm.com \
--cc=stern@rowland.harvard.edu \
--cc=tony@atomide.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).