From: Tuomas Tynkkynen <ttynkkynen@xxxxxxxxxx>
The DFLL is the main clocksource for the fast CPU cluster on Tegra124
and also provides automatic CPU rail voltage scaling as well. The DFLL
is a separate IP block from the usual Tegra124 clock-and-reset
controller, so it gets its own node in the device tree.
Signed-off-by: Tuomas Tynkkynen <ttynkkynen@xxxxxxxxxx>
Signed-off-by: Mikko Perttunen <mikko.perttunen@xxxxxxxx>
Cc: devicetree@xxxxxxxxxxxxxxx
---
v8:
- Changed dfll@ -> clock@
- Changed compatibility string to "nvidia,tegra124-dfll"
- Clarified how the vdd-cpu-supply property is used
- Marked nvidia,cg-scale as optional since it is a boolean property
- Expanded the 'FS mode' term to 'full speed mode'
- Added dvco reset control
.../bindings/clock/nvidia,tegra124-dfll.txt | 79 ++++++++++++++++++++++
1 file changed, 79 insertions(+)
create mode 100644 Documentation/devicetree/bindings/clock/nvidia,tegra124-dfll.txt
diff --git a/Documentation/devicetree/bindings/clock/nvidia,tegra124-dfll.txt b/Documentation/devicetree/bindings/clock/nvidia,tegra124-dfll.txt
new file mode 100644
index 0000000..ee7e5fd
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/nvidia,tegra124-dfll.txt
@@ -0,0 +1,79 @@
+NVIDIA Tegra124 DFLL FCPU clocksource
+
+This binding uses the common clock binding:
+Documentation/devicetree/bindings/clock/clock-bindings.txt
+
+The DFLL IP block on Tegra is a root clocksource designed for clocking
+the fast CPU cluster. It consists of a free-running voltage controlled
+oscillator connected to the CPU voltage rail (VDD_CPU), and a closed loop
+control module that will automatically adjust the VDD_CPU voltage by
+communicating with an off-chip PMIC either via an I2C bus or via PWM signals.
+Currently only the I2C mode is supported by these bindings.
+
+Required properties:
+- compatible : should be "nvidia,tegra124-dfll"
+- reg : Defines the following set of registers, in the order listed:
+ - registers for the DFLL control logic.
+ - registers for the I2C output logic.
+ - registers for the integrated I2C master controller.
+ - look-up table RAM for voltage register values.
+- interrupts: Should contain the DFLL block interrupt.
+- clocks: Must contain an entry for each entry in clock-names.
+ See clock-bindings.txt for details.
+- clock-names: Must include the following entries:
+ - soc: Clock source for the DFLL control logic.
+ - ref: The closed loop reference clock
+ - i2c: Clock source for the integrated I2C master.
+- resets: Must contain an entry for each entry in reset-names.
+ See ../reset/reset.txt for details.
+- reset-names: Must include the following entries:
+ - dvco: Reset control for the DFLL DVCO.
+- #clock-cells: Must be 0.
+- clock-output-names: Name of the clock output.
+- vdd-cpu-supply: Regulator for the CPU voltage rail that the DFLL
+ hardware will start controlling. The regulator will be queried for
+ the I2C register, control values and supported voltages.
+
+Required properties for the control loop parameters:
+- nvidia,sample-rate: Sample rate of the DFLL control loop.
+- nvidia,droop-ctrl: See the register CL_DVFS_DROOP_CTRL in the TRM.
+- nvidia,force-mode: See the field DFLL_PARAMS_FORCE_MODE in the TRM.
+- nvidia,cf: Numeric value, see the field DFLL_PARAMS_CF_PARAM in the TRM.
+- nvidia,ci: Numeric value, see the field DFLL_PARAMS_CI_PARAM in the TRM.
+- nvidia,cg: Numeric value, see the field DFLL_PARAMS_CG_PARAM in the TRM.
+
+Optional properties for the control loop parameters:
+- nvidia,cg-scale: Boolean value, see the field DFLL_PARAMS_CG_SCALE in the TRM.
+
+Required properties for I2C mode:
+- nvidia,i2c-fs-rate: I2C transfer rate, if using full speed mode.
+
+Example:
+
+clock@0,70110000 {
+ compatible = "nvidia,tegra124-dfll";
+ reg = <0 0x70110000 0 0x100>, /* DFLL control */
+ <0 0x70110000 0 0x100>, /* I2C output control */
+ <0 0x70110100 0 0x100>, /* Integrated I2C controller */
+ <0 0x70110200 0 0x100>; /* Look-up table RAM */
+ interrupts = <GIC_SPI 62 IRQ_TYPE_LEVEL_HIGH>;
+ clocks = <&tegra_car TEGRA124_CLK_DFLL_SOC>,
+ <&tegra_car TEGRA124_CLK_DFLL_REF>,
+ <&tegra_car TEGRA124_CLK_I2C5>;
+ clock-names = "soc", "ref", "i2c";
+ resets = <&tegra_car TEGRA124_RST_DFLL_DVCO>;
+ reset-names = "dvco";
+ #clock-cells = <0>;
+ clock-output-names = "dfllCPU_out";
+ vdd-cpu-supply = <&vdd_cpu>;
+ status = "okay";
+
+ nvidia,sample-rate = <12500>;
+ nvidia,droop-ctrl = <0x00000f00>;
+ nvidia,force-mode = <1>;
+ nvidia,cf = <10>;
+ nvidia,ci = <0>;
+ nvidia,cg = <2>;
+
+ nvidia,i2c-fs-rate = <400000>;
+};
--
2.3.0
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