xref: /freebsd-src/sys/contrib/device-tree/Bindings/clock/fixed-mmio-clock.txt (revision c66ec88fed842fbaad62c30d510644ceb7bd2d71)
1*c66ec88fSEmmanuel VadotBinding for simple memory mapped io fixed-rate clock sources.
2*c66ec88fSEmmanuel VadotThe driver reads a clock frequency value from a single 32-bit memory mapped
3*c66ec88fSEmmanuel VadotI/O register and registers it as a fixed rate clock.
4*c66ec88fSEmmanuel Vadot
5*c66ec88fSEmmanuel VadotIt was designed for test systems, like FPGA, not for complete, finished SoCs.
6*c66ec88fSEmmanuel Vadot
7*c66ec88fSEmmanuel VadotThis binding uses the common clock binding[1].
8*c66ec88fSEmmanuel Vadot
9*c66ec88fSEmmanuel Vadot[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
10*c66ec88fSEmmanuel Vadot
11*c66ec88fSEmmanuel VadotRequired properties:
12*c66ec88fSEmmanuel Vadot- compatible : shall be "fixed-mmio-clock".
13*c66ec88fSEmmanuel Vadot- #clock-cells : from common clock binding; shall be set to 0.
14*c66ec88fSEmmanuel Vadot- reg : Address and length of the clock value register set.
15*c66ec88fSEmmanuel Vadot
16*c66ec88fSEmmanuel VadotOptional properties:
17*c66ec88fSEmmanuel Vadot- clock-output-names : From common clock binding.
18*c66ec88fSEmmanuel Vadot
19*c66ec88fSEmmanuel VadotExample:
20*c66ec88fSEmmanuel Vadotsysclock: sysclock@fd020004 {
21*c66ec88fSEmmanuel Vadot	#clock-cells = <0>;
22*c66ec88fSEmmanuel Vadot	compatible = "fixed-mmio-clock";
23*c66ec88fSEmmanuel Vadot	reg = <0xfd020004 0x4>;
24*c66ec88fSEmmanuel Vadot};
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