On Mon, Feb 14, 2022 at 8:16 PM Maciej W. Rozycki <macro@xxxxxxxxxxx> wrote: > > Nowadays PC-style parallel ports come in the form of PCI and PCIe option > cards and there are some combined parallel/serial option cards as well > that we handle in the parport subsystem. There is nothing in particular > that would prevent them from being used in any system equipped with PCI > or PCIe connectivity, except that we do not permit the PARPORT_PC config > option to be selected for platforms for which ARCH_MIGHT_HAVE_PC_PARPORT > has not been set for. > > The only PCI platforms that actually can't make use of PC-style parallel > port hardware are those newer PCIe systems that have no support for I/O > cycles in the host bridge, required by such parallel ports. Notably, > this includes the s390 arch, which has port I/O accessors that cause > compilation warnings (promoted to errors with `-Werror'), and there are > other cases such as the POWER9 PHB4 device, though this one has variable > port I/O accessors that depend on the particular system. Also it is not > clear whether the serial port side of devices enabled by PARPORT_SERIAL > uses port I/O or MMIO. Finally Super I/O solutions are always either > ISA or platform devices. > > Make the PARPORT_PC option selectable also for PCI systems then, except > for the s390 arch, however limit the availability of PARPORT_PC_SUPERIO > to platforms that enable ARCH_MIGHT_HAVE_PC_PARPORT. Update platforms > accordingly for the required <asm/parport.h> header. > > Signed-off-by: Maciej W. Rozycki <macro@xxxxxxxxxxx> Acked-by: Sudip Mukherjee <sudipm.mukherjee@xxxxxxxxx> Usually parport patches goes via Greg's tree. Adding Greg. -- Regards Sudip
