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NVIDIA Tegra124 and Tegra132 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,tegra124-car" or "nvidia,tegra132-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 the header files
<dt-bindings/clock/tegra124-car-common.h> (which covers IDs common
to Tegra124 and Tegra132) and <dt-bindings/clock/tegra124-car.h>
(for Tegra124-specific clocks).
- #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.
- nvidia,external-memory-controller : phandle of the EMC driver.
The node should contain a "emc-timings" subnode for each supported RAM type (see
field RAM_CODE in register PMC_STRAPPING_OPT_A).
Required properties for "emc-timings" nodes :
- nvidia,ram-code : Should contain the value of RAM_CODE this timing set
is used for.
Each "emc-timings" node should contain a "timing" subnode for every supported
EMC clock rate.
Required properties for "timing" nodes :
- clock-frequency : Should contain the memory clock rate to which this timing
relates.
- nvidia,parent-clock-frequency : Should contain the rate at which the current
parent of the EMC clock should be running at this timing.
- clocks : Must contain an entry for each entry in clock-names.
See ../clocks/clock-bindings.txt for details.
- clock-names : Must include the following entries:
- emc-parent : the clock that should be the parent of the EMC clock at this
timing.
Example SoC include file:
/ {
tegra_car: clock@60006000 {
compatible = "nvidia,tegra124-car";
reg = <0x60006000 0x1000>;
#clock-cells = <1>;
#reset-cells = <1>;
nvidia,external-memory-controller = <&emc>;
};
usb@c5004000 {
clocks = <&tegra_car TEGRA124_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 = <112400000>;
};
clk_32k: clock@1 {
compatible = "fixed-clock";
reg = <1>;
#clock-cells = <0>;
clock-frequency = <32768>;
};
};
&tegra_car {
clocks = <&clk_32k> <&osc>;
};
clock@60006000 {
emc-timings-3 {
nvidia,ram-code = <3>;
timing-12750000 {
clock-frequency = <12750000>;
nvidia,parent-clock-frequency = <408000000>;
clocks = <&tegra_car TEGRA124_CLK_PLL_P>;
clock-names = "emc-parent";
};
timing-20400000 {
clock-frequency = <20400000>;
nvidia,parent-clock-frequency = <408000000>;
clocks = <&tegra_car TEGRA124_CLK_PLL_P>;
clock-names = "emc-parent";
};
};
};
};
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