This is the bulk of GPIO changes for the v3.17 development
cycle, and this time we got a lot of action going on and
it will continue:
- The core GPIO library implementation has been split up in
three different files:
- gpiolib.c for the latest and greatest and shiny GPIO
library code using GPIO descriptors only
- gpiolib-legacy.c for the old integer number space API
that we are phasing out gradually
- gpiolib-sysfs.c for the sysfs interface that we are
not entirely happy with, but has to live on for
ABI compatibility
- Add a flags argument to *gpiod_get* functions, with some
backward-compatibility macros to ease transitions. We
should have had the flags there from the beginning it
seems, now we need to clean up the mess. There is a plan
on how to move forward here devised by Alexandre Courbot
and Mark Brown.
- Split off a special <linux/gpio/machine.h> header for the
board gpio table registration, as per example from the
regulator subsystem.
- Start to kill off the return value from gpiochip_remove()
by removing the __must_check attribute and removing all
checks inside the drivers/gpio directory. The rationale
is: well what were we supposed to do if there is an error
code? Not much: print an error message. And gpiolib already
does that. So make this function return void eventually.
- Some cleanups of hairy gpiolib code, make some functions
not to be used outside the library private and make sure
they are not exported, remove gpiod_lock/unlock_as_irq()
as the existing function is for driver-internal use and
fine as it is, delete gpio_ensure_requested() as it is
not meaningful anymore.
- Support the GPIOF_ACTIVE_LOW flag from gpio_request_one()
function calls, which is logical since this is already
supported when referencing GPIOs from e.g. device trees.
- Switch STMPE, intel-mid, lynxpoint and ACPI (!) to use
the gpiolib irqchip helpers cutting down on GPIO irqchip
boilerplate a bit more.
- New driver for the Zynq GPIO block.
- The usual incremental improvements around a bunch of
drivers.
- Janitorial syntactic and semantic cleanups by Jingoo Han,
and Rickard Strandqvist especially.