[PATCH v2 0/2] gpio: add new SET_CONFIG ioctl() to gpio chardev

[Kent Gibson <warthog618@xxxxxxxxx>]

Changes from v1:
 Address v1 review comments, specifically refactoring line handle flag 
 validation out of linehandle_create in a separate patch, and refactoring  
 the set_config itself to improve readability and minimize changes to 
 existing code.

Add the GPIOHANDLE_SET_CONFIG_IOCTL to the gpio chardev.
The ioctl allows some of the configuration of a requested handle to be
changed without having to release the line.
The primary use case is the changing of direction for bi-directional 
lines.

The patch series is against Bart's gpio/for-next branch[1] with v4 of 
my bias patch series "gpio: expose line bias flags to userspace" applied.
This is necessary to support setting of the bias flags introduced 
there.

The patch has been successfully tested against gpio-mockup using the 
feature/pud_set_config branch of my Go gpiod library[2], as libgpiod has 
not yet been updated with the uAPI change.

Kent Gibson (2):
  gpiolib: move validation of line handle flags into helper function
  gpio: add new SET_CONFIG ioctl() to gpio chardev

 drivers/gpio/gpiolib.c    | 162 ++++++++++++++++++++++++++++----------
 include/uapi/linux/gpio.h |  18 +++++
 2 files changed, 138 insertions(+), 42 deletions(-)

-- 
2.23.0

[1] git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux.git
[2] https://github.com/warthog618/gpiod.git