Re: [PATCH 1/5] dt/bindings: Add binding for the DA8xx MUSB driver

Hello Rob,

is there any follow-up on this one?

Thanks
Petr

On 12.02.2016 18:24, Petr Kulhavy wrote:

On 12.02.2016 17:21, Rob Herring wrote:

quoted

On Thu, Feb 11, 2016 at 12:01:06PM +0100, Petr Kulhavy wrote:

quoted

+ - mentor,power : Specifies the maximum current in milliamperes the 
controller can
+     supply in host mode.

Still a no for me. Looks like this just sets hcd->power_budget. This
property may not be a regulator, but ultimately the value depends on
some regulator supplying Vbus. Also, given this has nothing to do with
MUSB h/w, however this is described should be generic.

I understand your point that the description should be generic.
However the USB 2.0 specification does not define any relation between 
the bMaxPower provided by the device and the actual power control.
As far as I understand the value just serves the purpose to raise a 
flag to the user if the attached device would draw too much power, and 
not to enable it at all.
Further, the value used by the protocol is not necessarily related to 
the real current that can be supported. The maximum current supported 
by the protocol is 510mA.

For instance on my development board the real maximum current is 
limited only by the mains power-supply used.
So it cannot even be modelled in the DT as a regulator because the 
power-supply is not part of the HW and
everybody can take a different one.

So defining a regulator just to store this arbitrary USB 2.0 value is 
a bit overkill for me.

Regards
Petr

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