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

Changes in v4:
 - add a documentation to describe the tranport 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

Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Arnaud POULIQUEN <arnaud.pouliquen@foss.st.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: linux-gpio@vger.kernel.org

Shenwei Wang (5):
  dt-bindings: remoteproc: imx_rproc: Add "rpmsg" subnode support
  remoteproc: imx_rproc: Populate devices under "rpmsg" subnode
  docs: admin-guide: gpio: rpmsg: gpio over rpmsg bus
  gpio: imx-rpmsg: add imx-rpmsg GPIO driver
  arm64: dts: imx8ulp: Add rpmsg node under imx_rproc

 Documentation/admin-guide/gpio/gpio-rpmsg.rst | 202 ++++++++
 Documentation/admin-guide/gpio/index.rst      |   1 +
 .../bindings/remoteproc/fsl,imx-rproc.yaml    | 123 +++++
 arch/arm64/boot/dts/freescale/imx8ulp.dtsi    |  27 +
 drivers/gpio/Kconfig                          |  17 +
 drivers/gpio/Makefile                         |   1 +
 drivers/gpio/gpio-imx-rpmsg.c                 | 467 ++++++++++++++++++
 drivers/remoteproc/imx_rproc.c                | 146 ++++++
 include/linux/rpmsg/imx_rpmsg.h               |  48 ++
 9 files changed, 1032 insertions(+)
 create mode 100644 Documentation/admin-guide/gpio/gpio-rpmsg.rst
 create mode 100644 drivers/gpio/gpio-imx-rpmsg.c
 create mode 100644 include/linux/rpmsg/imx_rpmsg.h

--
2.43.0