[PATCH 0/2] gpio: Expose reset tolerance capability

[Andrew Jeffery <andrew@xxxxxxxx>]

Hello,

This short series enables GPIO state persistence across controller resets,
modifying gpiolib to expose control of the behaviour and providing an initial
implementation in the Aspeed GPIO controller.

This is a follow-up to the initial RFC series[1], which had some undesirable
features (and bugs).

>From the RFC, I've:

1. Dropped the idea of distinguishing between sleep and reset cases[2]
2. Changed the default behaviour from transitory to persistent (must explicitly
   request transitory behaviour for controllers supporting reset tolerance)[3]
3. Dropped the ability for userspace to configure whether or not the exported
   GPIO is persistent[4][5]

On point 2, whilst the patch modifying the sysfs interface ABI no-longer lives,
gpiolib-sysfs still requires modification to provide consistent behaviour with
the chardev interface in providing a default-persistent GPIO on export.

Regarding point 3, I figured this is something we can add later once there's
been some discussion on how much of a good idea it is.

As some of the capabilities in the RFC have been dropped, I've squashed the
gpiolib support into a single patch as it's not really that complex.

Hopefully that addresses the feedback on the RFC. Please review!

Andrew

[1] https://www.spinics.net/lists/devicetree/msg199559.html
[2] https://www.spinics.net/lists/devicetree/msg199566.html
[3] https://www.spinics.net/lists/devicetree/msg199574.html
[4] https://www.spinics.net/lists/devicetree/msg199568.html
[5] https://www.spinics.net/lists/devicetree/msg199569.html 

Andrew Jeffery (2):
  gpio: gpiolib: Expand sleep tolerance to include controller reset
  gpio: aspeed: Add support for reset tolerance

 drivers/gpio/gpio-aspeed.c              | 39 ++++++++++++++++++++--
 drivers/gpio/gpiolib-of.c               |  6 ++--
 drivers/gpio/gpiolib-sysfs.c            | 14 +++++---
 drivers/gpio/gpiolib.c                  | 58 ++++++++++++++++++++++++++++++---
 drivers/gpio/gpiolib.h                  |  2 +-
 include/dt-bindings/gpio/gpio.h         |  6 ++--
 include/linux/gpio/consumer.h           |  8 +++++
 include/linux/gpio/machine.h            |  4 +--
 include/linux/of_gpio.h                 |  2 +-
 include/linux/pinctrl/pinconf-generic.h |  2 ++
 10 files changed, 121 insertions(+), 20 deletions(-)

-- 
2.11.0

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