xref: /kernel/linux/linux-5.10/Documentation/devicetree/bindings/clock/nvidia,tegra30-car.txt

NVIDIA Tegra30 Clock And Reset Controller

This binding uses the common clock binding:
Documentation/devicetree/bindings/clock/clock-bindings.txt

The CAR (Clock And Reset) Controller on Tegra is the HW module responsible
for muxing and gating Tegra's clocks, and setting their rates.

Required properties :
- compatible : Should be "nvidia,tegra30-car"
- reg : Should contain CAR registers location and length
- clocks : Should contain phandle and clock specifiers for two clocks:
  the 32 KHz "32k_in", and the board-specific oscillator "osc".
- #clock-cells : Should be 1.
  In clock consumers, this cell represents the clock ID exposed by the
  CAR. The assignments may be found in header file
  <dt-bindings/clock/tegra30-car.h>.
- #reset-cells : Should be 1.
  In clock consumers, this cell represents the bit number in the CAR's
  array of CLK_RST_CONTROLLER_RST_DEVICES_* registers.

Example SoC include file:

/ {
	tegra_car: clock {
		compatible = "nvidia,tegra30-car";
		reg = <0x60006000 0x1000>;
		#clock-cells = <1>;
		#reset-cells = <1>;
	};

	usb@c5004000 {
		clocks = <&tegra_car TEGRA30_CLK_USB2>;
	};
};

Example board file:

/ {
	clocks {
		compatible = "simple-bus";
		#address-cells = <1>;
		#size-cells = <0>;

		osc: clock@0 {
			compatible = "fixed-clock";
			reg = <0>;
			#clock-cells = <0>;
			clock-frequency = <12000000>;
		};

		clk_32k: clock@1 {
			compatible = "fixed-clock";
			reg = <1>;
			#clock-cells = <0>;
			clock-frequency = <32768>;
		};
	};

	&tegra_car {
		clocks = <&clk_32k> <&osc>;
	};
};