Re: [PATCH v9 2/2] usb: dwc3: Add Google Tensor SoC DWC3 glue driver

[Thinh Nguyen <Thinh.Nguyen@synopsys.com>]

On Thu, Dec 04, 2025, Roy Luo wrote:
> On Thu, Dec 4, 2025 at 10:05 PM Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> >
> > On Fri, Dec 05, 2025 at 02:26:38AM +0000, Roy Luo wrote:
> > > +config USB_DWC3_GOOGLE
> > > +     tristate "Google Platform"
> > > +     depends on ARCH_GOOGLE || COMPILE_TEST
> >
> > There is no ARCH_GOOGLE in the tree now, so how is this supposed to
> > work?  Shouldn't tools that check for "invalid config options" trigger
> > on this?
> >
> > thanks,
> >
> > greg k-h
> 
> Hi Greg,
> 
> The menuconfig looks like the following and it doesn't complain:
> | Symbol: ARCH_GOOGLE [=ARCH_GOOGLE]
> | Type  : unknown
> |
> | Symbol: PHY_GOOGLE_USB [=y]
> | Type  : tristate
> | Defined at drivers/phy/Kconfig:104
> |     Prompt: Google Tensor SoC USB PHY driver
> |     Depends on: ARCH_GOOGLE || COMPILE_TEST [=y]
> 
> According to Kconfig documentation [1], the unknown symbol
> would simply be evaluated as an "n", which is what we want.
> "Convert the symbol into an expression. Boolean and tristate
> symbols are simply converted into the respective expression
> values. All other symbol types result in ‘n’."
> 
> In a different Kconfig documentation, an environment variable
> "KCONFIG_WARN_UNKNOWN_SYMBOLS" is there to detect
> undefined symbols in the "config input", but I can't find one that
> catches undefined symbols in the Kconfig tree itself.
> 
> That is, the tool seems to allow this.
> However, if this turns out to be a major problem. I think we
> can either:
> - Remove ARCH_GOOGLE and leave COMPILE_TEST as
>   the only dependency. Then add ARCH_GOOGLE back
>   later once it's in the tree.
> - Defer the whole patch series until ARCH_GOOGLE is
>   present (I hope not).
> 
> [1] https://urldefense.com/v3/__https://docs.kernel.org/kbuild/kconfig-language.html*menu-dependencies__;Iw!!A4F2R9G_pg!e-y2_BsSNhXF1v5K6tBJX-OabgKJM9WVdvwyKoB6tg9ooCLVg8WiQ4UrStOF2YZQ_Zs6tC6HVh7wCpqkEfU$ 
> [2] https://urldefense.com/v3/__https://www.kernel.org/doc/Documentation/kbuild/kconfig.rst__;!!A4F2R9G_pg!e-y2_BsSNhXF1v5K6tBJX-OabgKJM9WVdvwyKoB6tg9ooCLVg8WiQ4UrStOF2YZQ_Zs6tC6HVh7wHpoUlhY$ 
> 

Hi Greg, Roy,

Just checking, are we aligned here?

BR,
Thinh