Support the remote devices on the remote processor via the RPMSG bus on
i.MX platform.

Changes in v16:
  - Removed linux/mod_devicetable.h and an extra comma per Uwe's feedback.
  - Added the "packed" attribute to struct rpmsg_gpio_response and set
    "can_sleep = true", per Sashiko's review comments.
  - Removed the channel node from the rpmsg node in dts layout.

Changes in v15:
 - Update Kconfig description per AndrewD and Julian's feedback
 - Enable the GPIO driver even without a DT node per AndrewD's feedback
 - Update gpio-rpmsg.rst per Mathieu’s feedback
 - Code cleanup according the new gpio-rpmsg.rst and sashiko-bot's review
   feedback

Changes in v14:
 - Update gpio-rpmsg.rst per Mathieu’s feedback.
 - Align the rpmsg-gpio driver with the revised gpio-rpmsg.rst.
 - Modify rpmsg-core to enable prefix-based matching of RPMSG device IDs.

Changes in v13:
 - drop the support for legacy NXP firmware.
 - remove the fixed_up hooks from the rpmsg gpio driver.
 - code cleanup.

Changes in v12:
 - Fixed the "underline" warning reported by Randy.

Changes in v11:
 - Expand RPMSG for the first time per Shuah's review comment.

Changes in v10:
 - Update gpio-rpmsg.rst according to Daniel Baluta's review comments.
 - Add a kernel CONFIG for fixed up handlers and only enable it on
   i.MX products.
 - Fixed bugs reported by kernel test robot.

Changes in v9:
 - Reuse the gpio-virtio design for command and IRQ type definitions.
 - Remove msg_id, version, and vendor fields from the generic protocol.
 - Add fixed-up handlers to support legacy firmware.

Changes in v8:
 - Add "depends on REMOTEPROC" in Kconfig to fix the build error reported
   by the kernel test robot.
 - Move the .rst patch before the .yaml patch.
 - Handle the "ngpios" DT property based on Andrew's feedback.

Changes in v7:
 - Reworked the driver to use the rpmsg_driver framework instead of
   platform_driver, based on feedback from Bjorn and Arnaud.
 - Updated gpio-rpmsg.yaml and imx_rproc.yaml according to comments from
   Rob and Arnaud.
 - Further refinements to gpio-rpmsg.yaml per Arnaud's feedback.

Changes in v6:
 - make the driver more generic with the actions below:
     rename the driver file to gpio-rpmsg.c
     remove the imx related info in the function and variable names
     rename the imx_rpmsg.h to rpdev_info.h
     create a gpio-rpmsg.yaml and refer it in imx_rproc.yaml
 - update the gpio-rpmsg.rst according to the feedback from Andrew and
   move the source file to driver-api/gpio
 - fix the bug reported by Zhongqiu Han
 - remove the I2C related info

Changes in v5:
 - move the gpio-rpmsg.rst from admin-guide to staging directory after
   discussion with Randy Dunlap.
 - add include files with some code improvements per Bartosz's comments.

Changes in v4:
 - add a documentation to describe the transport protocol per Andrew's
   comments.
 - add a new handler to get the gpio direction.

Changes in v3:
 - fix various format issue and return value check per Peng 's review
   comments.
 - add the logic to also populate the subnodes which are not in the
   device map per Arnaud's request. (in imx_rproc.c)
 - update the yaml per Frank's review comments.

Changes in v2:
 - re-implemented the gpio driver per Linus Walleij's feedback by using
   GPIOLIB_IRQCHIP helper library.
 - fix various format issue per Mathieu/Peng 's review comments.
 - update the yaml doc per Rob's feedback

Shenwei Wang (5):
  docs: driver-api: gpio: rpmsg gpio driver over rpmsg bus
  dt-bindings: remoteproc: imx_rproc: Add "rpmsg" subnode support
  rpmsg: core: match rpmsg device IDs by prefix
  gpio: rpmsg: add generic rpmsg GPIO driver
  arm64: dts: imx8ulp: Add rpmsg node under imx_rproc

 .../devicetree/bindings/gpio/gpio-rpmsg.yaml  |  55 ++
 .../bindings/remoteproc/fsl,imx-rproc.yaml    |  46 ++
 Documentation/driver-api/gpio/gpio-rpmsg.rst  | 242 ++++++++
 Documentation/driver-api/gpio/index.rst       |   1 +
 arch/arm64/boot/dts/freescale/imx8ulp.dtsi    |  23 +
 drivers/gpio/Kconfig                          |  17 +
 drivers/gpio/Makefile                         |   1 +
 drivers/gpio/gpio-rpmsg.c                     | 585 ++++++++++++++++++
 drivers/rpmsg/rpmsg_core.c                    |   4 +-
 9 files changed, 973 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/gpio/gpio-rpmsg.yaml
 create mode 100644 Documentation/driver-api/gpio/gpio-rpmsg.rst
 create mode 100644 drivers/gpio/gpio-rpmsg.c

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2.43.0