Re: [RFC PATCH 4/5] arm: omap2: support port power on lan95xx devices

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On Tue, Dec 04, 2012 at 11:40:05AM +0800, Andy Green wrote:
> On 04/12/12 01:09, the mail apparently from Alan Stern included:
> >On Mon, 3 Dec 2012, Andy Green wrote:
> >
> >>Unless someone NAKs it for sure already (if you're already sure you're
> >>going to, please do so to avoid wasting time), I'll issue a try#2 of my
> >>code later which demonstrates what I mean.  At least I guess it's useful
> >>for comparative purposes.
> >
> >Before you go writing a whole lot more code, we should discuss the
> >basics a bit more clearly.  There are several unsettled issues here:
> 
> >      1. Should the LAN95xx stuff be associated with the ehci-omap.0's
> >	driver or with the hub port?  The port would be more flexible,
> >	offering the ability to turn the power off and on while the
> >	system is running without affecting anything else.  But the
> >	port code is currently in flux, which could cause this new
> >	addition to be delayed.
> 
> I think associating ULPI PHY reset and SMSC power and reset with the
> hub port power state is good.  Then, you could have the driver in a
> device with multiple onboard USB devices, and individually control
> whether they're eating power or not.  In the asset case, you'd
> associate mux assets with ehci-omap.0.
> 
> Yesterday I studied the hub port code and have a couple of patches,
> one normalizes the hub port device to have a stub driver.
> 
> The other then puts hub port power state signalling into runtime_pm
> handlers in the hub port device.  Until now, actually there's no
> code in hub.c to switch off a port.

Did you take a look at the most recent patches from Tianyu to add
support to power off a port if a device is suspended?

Start of the series:
http://marc.info/?l=linux-usb&m=135314427413307&w=2
Patch that adds power off on device suspend:
http://marc.info/?l=linux-usb&m=135314431913321&w=2

Tianyu also added some code to the xHCI host controller driver to call
into the ACPI methods to power off a port when the USB hub driver clears
the port power feature.

Sarah Sharp
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