Re: [PATCH v2] phy: tegra: depend on COMMON_CLK to fix compile tests

[Krzysztof Kozlowski]

On Tue, 16 Mar 2021 at 16:47, Krzysztof Kozlowski
<krzysztof.kozlowski@xxxxxxxxxxxxx> wrote:
>
> On Tue, 16 Mar 2021 at 16:43, Dmitry Osipenko <digetx@xxxxxxxxx> wrote:
> >
> > 16.03.2021 10:55, Krzysztof Kozlowski пишет:
> > > From: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
> > >
> > > The Tegra USB PHY driver uses Common Clock Framework thus it cannot be
> > > built on platforms without it (e.g. compile test on MIPS with RALINK and
> > > SOC_RT305X):
> > >
> > >     /usr/bin/mips-linux-gnu-ld: drivers/usb/phy/phy-tegra-usb.o: in function `tegra_usb_phy_init':
> > >     phy-tegra-usb.c:(.text+0x1dd4): undefined reference to `clk_get_parent'
> > >
> > > Reported-by: kernel test robot <lkp@xxxxxxxxx>
> > > Signed-off-by: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
> > >
> > > ---
> > >
> > > Changes since v1:
> > > 1. Depend on COMMON_CLK always, not only for compile test.
> > > ---
> > >  drivers/usb/phy/Kconfig | 1 +
> > >  1 file changed, 1 insertion(+)
> > >
> > > diff --git a/drivers/usb/phy/Kconfig b/drivers/usb/phy/Kconfig
> > > index 52eebcb88c1f..7500e77a7d01 100644
> > > --- a/drivers/usb/phy/Kconfig
> > > +++ b/drivers/usb/phy/Kconfig
> > > @@ -163,6 +163,7 @@ config USB_MXS_PHY
> > >  config USB_TEGRA_PHY
> > >       tristate "NVIDIA Tegra USB PHY Driver"
> > >       depends on ARCH_TEGRA || COMPILE_TEST
> > > +     depends on COMMON_CLK
> > >       select USB_COMMON
> > >       select USB_PHY
> > >       select USB_ULPI
> > >
> >
> > But if COMMON_CLK is disabled, then include/linux/clk.h provides a stub
> > for clk_get_parent(), meaning that MIPS has its own COMMON_CLK, no?
>
> Hi,
>
> It depends on the platform. Not all of them implement every clk API,
> so you can have failures:
> https://lore.kernel.org/lkml/202102170017.MgPVy7aZ-lkp@xxxxxxxxx/

Ah, you mentioned the stub, so let me clarify more. The common clk
stubs are not used for cases like !COMMON_CLK && HAVE_LEGACY_CLK (or
HAVE_CLK, I don't remember). This is why you can have a MIPS platform
defining some of the clock operations thus not using COMMON_CLK at all
(and neither the stubs).

Best regards,
Krzysztof