[PATCH 0/4] Allow ISA-style drivers on modern systems

[William Breathitt Gray]

Several modern devices, such as PC/104 cards, are expected to run on
modern systems via an ISA bus interface. Since ISA is a legacy interface
for most modern architectures, ISA support should remain disabled in
general. Support for ISA-style drivers should be enabled on a per driver
basis.

To allow ISA-style drivers on modern systems, this patchset introduces
the ISA_BUS_API and ISA_BUS Kconfig options. The X86 ISA bus driver will
now build conditionally on the ISA_BUS_API Kconfig option, which
defaults to the legacy ISA Kconfig option. The ISA_BUS Kconfig option
allows the ISA_BUS_API Kconfig option to be selected on architectures
which do not enable ISA (e.g. X86_64).

For now, the ISA_BUS Kconfig option is only be available on X86
architectures. Support for other architectures may be added as required.

An earlier attempt to allow the ISA bus driver to build for X86_64 took
an inappropriate approach resulting in legacy ISA drivers becoming
enabled unconditionally on untested and unsupported architectures.
Commit 51e68d055cba ("x86 isa: add back X86_32 dependency on
CONFIG_ISA"), added to restrict the ISA bus driver to only X86_32,
causes several drivers intended for X86_64 to be restricted to X86_32 as
well.

This patchset replaces the ISA Kconfig option dependency of several
drivers to ISA_BUS_API, so that they may build for X86_64 as intended.
The respective drivers are as follows:
    * ACCES 104-IDIO-16 GPIO driver
    * ACCES 104-IDI-48 GPIO driver
    * ACCES 104-DIO-48E GPIO driver
    * Apex Embedded Systems STX104 DAC driver
    * WinSystems EBC-C384 watchdog timer driver
    * WinSystems WS16C48 GPIO driver

William Breathitt Gray (4):
  isa: Allow ISA-style drivers on modern systems
  gpio: Allow PC/104 devices on X86_64
  iio: stx104: Allow build for X86_64
  watchdog: ebc-c384_wdt: Allow build for X86_64

 arch/x86/Kconfig         | 13 +++++++++++++
 drivers/base/Makefile    |  2 +-
 drivers/gpio/Kconfig     |  8 ++++----
 drivers/iio/dac/Kconfig  |  2 +-
 drivers/watchdog/Kconfig |  2 +-
 5 files changed, 20 insertions(+), 7 deletions(-)

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2.7.3