linux_dsm_epyc7002/Documentation/devicetree/bindings/fsi/fsi-master-ast-cf.txt
Benjamin Herrenschmidt 2be5263c5d dt-bindings: fsi: Document binding for the fsi-master-ast-cf "device"
This isn't per-se a real device, it's a pseudo-device that
represents the use of the Aspeed built-in ColdFire to
implement the FSI protocol by bitbanging the GPIOs instead
of doing it from the ARM core.

Thus it's a drop-in replacement for the existing
fsi-master-gpio pseudo-device for use on systems based
on the Aspeed chips. It has most of the same properties,
plus some more needed to operate the coprocessor.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Rob Herring <robh@kernel.org>
2018-07-23 15:22:45 +10:00

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Device-tree bindings for ColdFire offloaded gpio-based FSI master driver
------------------------------------------------------------------------
Required properties:
- compatible =
"aspeed,ast2400-cf-fsi-master" for an AST2400 based system
or
"aspeed,ast2500-cf-fsi-master" for an AST2500 based system
- clock-gpios = <gpio-descriptor>; : GPIO for FSI clock
- data-gpios = <gpio-descriptor>; : GPIO for FSI data signal
- enable-gpios = <gpio-descriptor>; : GPIO for enable signal
- trans-gpios = <gpio-descriptor>; : GPIO for voltage translator enable
- mux-gpios = <gpio-descriptor>; : GPIO for pin multiplexing with other
functions (eg, external FSI masters)
- memory-region = <phandle>; : Reference to the reserved memory for
the ColdFire. Must be 2M aligned on
AST2400 and 1M aligned on AST2500
- aspeed,sram = <phandle>; : Reference to the SRAM node.
- aspeed,cvic = <phandle>; : Reference to the CVIC node.
Examples:
fsi-master {
compatible = "aspeed,ast2500-cf-fsi-master", "fsi-master";
clock-gpios = <&gpio 0>;
data-gpios = <&gpio 1>;
enable-gpios = <&gpio 2>;
trans-gpios = <&gpio 3>;
mux-gpios = <&gpio 4>;
memory-region = <&coldfire_memory>;
aspeed,sram = <&sram>;
aspeed,cvic = <&cvic>;
}