This is the bulk of GPIO changes for the v4.1 development
cycle:
- A new GPIO hogging mechanism has been added. This can
be used on boards that want to drive some GPIO line high,
low, or set it as input on boot and then never touch it
again. For some embedded systems this is bliss and
simplifies things to a great extent.
- Some API cleanup and closure: gpiod_get_array() and
gpiod_put_array() has been added to get and put GPIOs
in bulk as was possible with the non-descriptor API.
- Encapsulate cross-calls to the pin control subsystem in
<linux/gpio/driver.h>. Now this should be the only header
any GPIO driver needs to include or something is wrong.
Cleanups restricting drivers to this include are welcomed
if tested.
- Sort the GPIO Kconfig and split it into submenus, as
it was becoming and unstructured, illogical and
unnavigatable mess. I hope this is easier to follow.
Menus that require a certain subsystem like I2C can
now be hidden nicely for example, still working on
others.
- New drivers:
- New driver for the Altera Soft GPIO.
- The F7188x driver now handles the F71869 and
F71869A variants.
- The MIPS Loongson driver has been moved to
drivers/gpio for consolidation and cleanup.
- Cleanups:
- The MAX732x is converted to use the GPIOLIB_IRQCHIP
infrastructure.
- The PCF857x is converted to use the GPIOLIB_IRQCHIP
infrastructure.
- Radical cleanup of the OMAP driver.
- Misc:
- Enable the DWAPB GPIO for all architectures. This is
a "hard IP" block from Synopsys which has started to
turn up in so diverse architectures as X86 Quark, ARC
and a slew of ARM systems. So even though it's not an
expander, it's generic enough to be available for all.
- We add a mock GPIO on Crystalcove PMIC after a long
discussion with Daniel Vetter et al, tracing back to
the shootout at the kernel summit where DRM drivers
and sub-componentization was discussed. In this case
a mock GPIO is assumed to be the best compromise
gaining some reuse of infrastructure without making
DRM drivers overly complex at the same time. Let's
see.