Merge series "spi: Add support for Realtek RTL838x/RTL839x SoC SPI" from Bert Vermeul...

Merge series "spi: Add support for Realtek RTL838x/RTL839x SoC SPI" from Bert Vermeulen <bert@biot.com>:

v5:
- Changed SoC compatible to list exact models

v4:
- Added SoC series-specific compatible matches.

v3:
- Added cpu_relax() to busy loop.
- Dropped .remove callback from driver struct.
- Use (variations of) realtek-rtl as prefix.
- Dropped Kconfig entry, and use MACH_REALTEK_RTL setting to build the
  driver, since there's no point booting without the SPI-connected flash.

v2:
- Rewrote from spi-nor driver to regular spi driver, implementing only
  set_cs() and transfer_one(). (Thanks Chuanhong Guo!)

Bert Vermeulen (2):
  dt-bindings: spi: Realtek RTL838x/RTL839x SPI controller
  spi: realtek-rtl: Add support for Realtek RTL838x/RTL839x SPI
    controllers

 .../bindings/spi/realtek,rtl-spi.yaml         |  41 ++++
 drivers/spi/Makefile                          |   1 +
 drivers/spi/spi-realtek-rtl.c                 | 209 ++++++++++++++++++
 3 files changed, 251 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/spi/realtek,rtl-spi.yaml
 create mode 100644 drivers/spi/spi-realtek-rtl.c

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2.25.1