Re: [PATCH 4/5] PCI: mt7621: Add missing 'MODULE_LICENSE()' definition

[Arnd Bergmann]

On Mon, Nov 15, 2021 at 1:44 PM Krzysztof Wilczyński <kw@xxxxxxxxx> wrote:
> > MT7620 PCIe host controller driver can be built as a module but there is no
> > 'MODULE_LICENSE()' specified in code, causing a build error due to missing
> > license information.
> >
> > ERROR: modpost: missing MODULE_LICENSE() in drivers/pci/controller/pcie-mt7621.o
> >
> > Fix this by adding 'MODULE_LICENSE()' to the driver.
> >
> > Fixes: 2bdd5238e756 ("PCI: mt7621: Add MediaTek MT7621 PCIe host controller driver")
> > Signed-off-by: Yanteng Si <siyanteng@xxxxxxxxxxx>
> > Signed-off-by: Sergio Paracuellos <sergio.paracuellos@xxxxxxxxx>
> > ---
> >  drivers/pci/controller/pcie-mt7621.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/pci/controller/pcie-mt7621.c b/drivers/pci/controller/pcie-mt7621.c
> > index 9cf541f5de9c..a120a61ede07 100644
> > --- a/drivers/pci/controller/pcie-mt7621.c
> > +++ b/drivers/pci/controller/pcie-mt7621.c
> > @@ -561,3 +561,5 @@ static struct platform_driver mt7621_pci_driver = {
> >       },
> >  };
> >  builtin_platform_driver(mt7621_pci_driver);
> > +
> > +MODULE_LICENSE("GPL v2");
>
> A question here about the builtin_platform_driver() use in this driver,
> especially since it's set as tristate in Kconfig, thus I am not sure if
> using builtin_platform_driver() over module_platform_driver() is correct?
>
> Unless this is more because you need to reply on device_initcall() for the
> driver to properly initialise?

builtin_platform_driver() does the right thing for loadable modules that
have no module-unload and are not intended to be removable.

This is often use for PCI drivers, but after Rob reworked this code a while
back, it should actually be possible to reliably remove and reload PCI
host bridge drivers, and it would be good to eventually lift the restriction
here as well.

        Arnd