[U-Boot] [PATCH v5 6/7] phy: Add USB PHY driver for the cadence USB3

Peter Chen peter.chen at nxp.com
Thu Aug 29 03:16:30 UTC 2019


  
> >
> > This is indeed a different driver. IMO it would be better to keep the
> > driver closer to its linux version. The reason for that  is that it is
> > quite new and will be adapted when platforms starts supporting it. If
> > we start with something too far from the original, it will hard to update.
> > Already I see that the registers initialized are not all the same as
> > in the linux driver and not all the values are the same either, nor
> > are the register names
> >
> > TI's J7 platforms is using this PHY driver for USB3/PCIe support, and
> > the linux driver has already seen quite a few modifications to get it
> > to work
> (https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.ti.
> > com%2Fti-linux-kernel%2Fti-linux-kernel%2Fblobs%2Fhistory%2Fti-linux-
> > 4.19.y%2Fdrivers%2Fphy%2Fcadence%2Fphy-cadence-
> > sierra.c&data=02%7C01%7Csherry.sun%40nxp.com%7C84f9122d7eb64
> > 9820bae08d72b997681%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0
> > %7C637025810458595586&sdata=6JpD7VcFudhzXSVP0WaGVEp7Fwrue
> > A%2B4V6eeOfif19w%3D&reserved=0)
> > Adding support for it on top of this current version will be rather difficult.
> >
> 
> Thanks for your advice.
> Actually I am not familiar with this phy driver in linux, so also +peter, who worked on
> this USB driver under linux, maybe he can give some suggestions.
> 

Add Alan from Cadence

Alan, we find the suggested value at this driver (drivers/phy/cadence/phy-cadence-sierra.c)
is so different with "USB 3.0 PHY User Guide for 28FDSOI" CH 3.1.1 Bring-up Sequence.
Does this driver support this 28nm PHY? If it supports, why the initialized value is so different?
The UG suggested value can be used at NXP platform.

Peter


More information about the U-Boot mailing list