linux_dsm_epyc7002/Documentation/devicetree/bindings/mfd/syscon.txt
Baolin Wang 3bafc09e77
mfd: syscon: Add hardware spinlock support
Some system control registers need hardware spinlock to synchronize
between the multiple subsystems, so we should add hardware spinlock
support for syscon.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
2018-01-12 18:32:55 +00:00

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* System Controller Registers R/W driver
System controller node represents a register region containing a set
of miscellaneous registers. The registers are not cohesive enough to
represent as any specific type of device. The typical use-case is for
some other node's driver, or platform-specific code, to acquire a
reference to the syscon node (e.g. by phandle, node path, or search
using a specific compatible value), interrogate the node (or associated
OS driver) to determine the location of the registers, and access the
registers directly.
Required properties:
- compatible: Should contain "syscon".
- reg: the register region can be accessed from syscon
Optional property:
- reg-io-width: the size (in bytes) of the IO accesses that should be
performed on the device.
- hwlocks: reference to a phandle of a hardware spinlock provider node.
Examples:
gpr: iomuxc-gpr@20e0000 {
compatible = "fsl,imx6q-iomuxc-gpr", "syscon";
reg = <0x020e0000 0x38>;
hwlocks = <&hwlock1 1>;
};
hwlock1: hwspinlock@40500000 {
...
reg = <0x40500000 0x1000>;
#hwlock-cells = <1>;
};