This patch adds support for the zynqmp modepin GPIO controller and
documented for the same. GPIO modepin driver set and get the value and
status of the PS_MODE pin, based on device-tree pin configuration.
These four-bits boot-mode pins are dedicated configurable as input/output.
After the stabilization of the system,these mode pins are sampled.

To access GPIO pins, added Xilinx ZynqMP firmware MDIO API support to
set and get PS_MODE pins value and status. These APIs are interface
APIs, between the mode pin controller driver and low-level API.

---
Changes in v2:
- Added Xilinx ZynqMP firmware MMIO API support to set and get pin
  value and status.
- DT Documentation- Addressed review comments: Update commit message
- Modepin driver- Addressed review comments:
  - Update APIs
  - Removed unwanted variables
  - Handle return path for probe function

Review Comments:
https://lore.kernel.org/linux-arm-kernel/20210624205055.GA1961487@robh.at.kernel.org/T/#u (local)
---

Piyush Mehta (3):
  firmware: zynqmp: Add MMIO read and write support for PS_MODE pin
  dt-bindings: gpio: zynqmp: Add binding documentation for modepin
  gpio: modepin: Add driver support for modepin GPIO controller

 .../bindings/gpio/xlnx,zynqmp-gpio-modepin.yaml    |  41 ++++++
 drivers/firmware/xilinx/zynqmp.c                   |  46 ++++++
 drivers/gpio/Kconfig                               |  12 ++
 drivers/gpio/Makefile                              |   1 +
 drivers/gpio/gpio-zynqmp-modepin.c                 | 158 +++++++++++++++++++++
 include/linux/firmware/xlnx-zynqmp.h               |  14 ++
 6 files changed, 272 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/gpio/xlnx,zynqmp-gpio-modepin.yaml
 create mode 100644 drivers/gpio/gpio-zynqmp-modepin.c

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2.7.4