On Fri, 2014-08-22 at 00:05 -0500, Mehresh Ramneek-B31383 wrote:
>
> -----Original Message-----
> From: Badola Nikhil-B46172
> Sent: Friday, August 22, 2014 10:18 AM
> To: Wood Scott-B07421
> Cc: linuxppc-dev@lists.ozlabs.org; devicet...@vger.kernel.org; Mehresh
> Ramneek-B31383
> Subject: RE: [PATCH] Documentation: dts: fsl-usb: Document USB node
> compatible string for IP version
>
> Adding Ramneek
>
> > -----Original Message-----
> > From: Wood Scott-B07421
> > Sent: Friday, August 22, 2014 3:53 AM
> > To: Badola Nikhil-B46172
> > Cc: linuxppc-dev@lists.ozlabs.org; devicet...@vger.kernel.org
> > Subject: Re: [PATCH] Documentation: dts: fsl-usb: Document USB node
> > compatible string for IP version
> >
> > On Thu, 2014-08-21 at 14:48 +0530, Nikhil Badola wrote:
> > > Document compatible string containing IP version in USB device tree
> > > node
> > >
> > > Signed-off-by: Nikhil Badola <nikhil.bad...@freescale.com>
> > > ---
> > > Documentation/devicetree/bindings/usb/fsl-usb.txt | 13
> > > ++++++++-----
> > > 1 file changed, 8 insertions(+), 5 deletions(-)
> >
> > Please CC devicet...@vger.kernel.org on all device tree patches (in
> > addition to linuxppc-dev).
> >
> > >
> > > diff --git a/Documentation/devicetree/bindings/usb/fsl-usb.txt
> > > b/Documentation/devicetree/bindings/usb/fsl-usb.txt
> > > index 4779c02..5a3a0a8 100644
> > > --- a/Documentation/devicetree/bindings/usb/fsl-usb.txt
> > > +++ b/Documentation/devicetree/bindings/usb/fsl-usb.txt
> > > @@ -10,7 +10,10 @@ Required properties :
> > > controllers, or "fsl-usb2-dr" for dual role USB controllers
> > > or "fsl,mpc5121-usb2-dr" for dual role USB controllers of MPC5121.
> > > Wherever applicable, the IP version of the USB controller should
> > > - also be mentioned (for eg. fsl-usb2-dr-v2.2 for bsc9132).
> > > + also be mentioned in another string.
> > > + For multi port host USB controller with IP version <IP_Ver>, it
> > > should be
> > > + "fsl-usb2-mph-<IP_Ver>". For dual role USB controller with IP version
> > > + <IP_Ver>, it should be "fsl-usb2-dr-<IP_Ver>".
> >
> > It was documented before -- this is just making it more explicit, right?
> >
> > FWIW, the version number can be read out of a USB register, so I'd
> > rather remove the suggestion to specify the version number and replace
> > it with a reference to the ID register.
> we have following two issues -
> (a) our USBIP version register doesn't have consistent "version field size"
> over
> multiple version(s). This is why we couldn't use it for reading version info
> across
> various IP versions
> (b) this register is not exposed in all SoC RMs (probably because of above
> reason)
:-(
If this is just a problem with older chips, we could have a new
compatible name that designates the family of USB block versions with a
sane version register.
> > > @@ -55,9 +58,9 @@ Example multi port host USB controller device node :
> > > port1;
> > > };
> > >
> > > -Example dual role USB controller device node :
> > > +Example dual role USB controller version 2.5 device node :
> > > usb@23000 {
> > > - compatible = "fsl-usb2-dr";
> > > + compatible = "fsl-usb2-dr-v2.5", "fsl-usb2-dr";
> > > reg = <23000 1000>;
> > > #address-cells = <1>;
> > > #size-cells = <0>;
> >
> > This example doesn't correspond to any device tree I see. Even after
> > your next patch that sets t2080's USB to v2.5, the addresses are different.
> >
> I reckon that the example emphasizes on showing how IP version information is
> to be stored in "compatible string". Is it necessary to make sure that we
> should
> always site actual values already used?
The more realistic the examples are, the better.
-Scott
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