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

[Peter Chen]

Hi Pawel,

We are discussing if Cadence/TI/NXP could use the same USB PHY driver
(drivers/phy/cadence/phy-cadence-sierra.c), I find I can't get
Alan Douglas <adouglas at cadence.com>, would you please forward related
people? The question is like below, thanks.

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

> > >
> > > 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