This adds a gpio-driver which multiplexes existing GPIOs using latches.
Uwe asked [1] if that would be accectable as a new gpio driver, and here
is the result. For a better description what this is all about have a
look at the drawings in the patches.

The driver is pretty much straight forward. The only thing I wasn't sure
about is in which category in Kconfig the driver should be sorted in. I
decided for "Virtual GPIO drivers" which is not an exact match, but the
best I could find in the existing categories.

Sascha

[1] https://lore.kernel.org/all/CACRpkdaBO=JzokGUF6uXZc7ASVD7LjqBxTLGwX-FShM=A9gw9A@mail.gmail.com/t/ (local)

Sascha Hauer (2):
  gpio: Add gpio latch driver
  dt-bindings: gpio: Add gpio-latch binding document

 .../devicetree/bindings/gpio/gpio-latch.yaml  |  83 ++++++++
 drivers/gpio/Kconfig                          |   6 +
 drivers/gpio/Makefile                         |   1 +
 drivers/gpio/gpio-latch.c                     | 188 ++++++++++++++++++
 4 files changed, 278 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/gpio/gpio-latch.yaml
 create mode 100644 drivers/gpio/gpio-latch.c

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2.30.2