gpio: introduce a GPIO driver for SCMI

This basically abandons my earlier attempts and goes back to Takahiro Akashi's driver. Here is the link to Takahiro's patchset:

https://lore.kernel.org/all/[email protected]/

v6: Fix a build error when CONFIG_PINCONF is disabled
Fix the dt-binding subject and my email address Use pinconf_to_config_packed() instead of PIN_CONF_PACKED()

v5: Addresses Andy's cleanups to the driver.
Adrresses Krzysztof's comments about the dt spec file. And almost all the subsystem prefixes were wrong.

v4: Addressed Andy's comments about kernel-doc
Addressed Rob's comments on the spec file

v3: Forward ported Takahiro's patches and added some fixes ups to make
it work on current kernels.

AKASHI Takahiro (3):
pinctrl: introduce pinctrl_gpio_get_config()
gpio: dt-bindings: Add GPIO on top of generic pin control
gpio: gpio-by-pinctrl: add pinctrl based generic GPIO driver

Dan Carpenter (4):
pinctrl: scmi: Add SCMI_PIN_INPUT_VALUE
pinctrl: scmi: Delete PIN_CONFIG_OUTPUT_IMPEDANCE_OHMS support
pinctrl: scmi: ignore PIN_CONFIG_PERSIST_STATE
firmware: arm_scmi: Allow PINCTRL_REQUEST to return EOPNOTSUPP

 .../bindings/gpio/pin-control-gpio.yaml       |  59 ++++++++++
 drivers/firmware/arm_scmi/pinctrl.c           |   2 +
 drivers/gpio/Kconfig                          |  13 +++
 drivers/gpio/Makefile                         |   1 +
 drivers/gpio/gpio-by-pinctrl.c                | 101 ++++++++++++++++++
 drivers/pinctrl/core.c                        |  31 ++++++
 drivers/pinctrl/pinconf.h                     |   6 ++
 drivers/pinctrl/pinctrl-scmi.c                |  46 +++++---
 include/linux/pinctrl/consumer.h              |   9 ++
 9 files changed, 255 insertions(+), 13 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/gpio/pin-control-gpio.yaml
 create mode 100644 drivers/gpio/gpio-by-pinctrl.c

2.53.0