@@ -8,7 +8,6 @@ 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"
@@ -45,10 +44,31 @@ Required properties for the control loop parameters:
Optional properties for the control loop parameters:
- nvidia,cg-scale: Boolean value, see the field DFLL_PARAMS_CG_SCALE in the TRM.
+Optional properties for mode selection:
+- nvidia,pwm-to-pmic: Use PWM to control regulator rather then I2C.
+
Required properties for I2C mode:
- nvidia,i2c-fs-rate: I2C transfer rate, if using full speed mode.
-Example:
+Required properties for PWM mode:
+- nvidia,pwm-period: period of PWM square wave in microseconds.
+- nvidia,pwm-tristate-microvolts: Regulator voltage in micro volts when PWM
+ control is disabled and the PWM output is tristated. Note that this voltage is
+ configured in hardware, typically via a resistor divider.
+- nvidia,pwm-min-microvolts: Regulator voltage in micro volts when PWM control
+ is enabled and PWM output is low. Hence, this is the minimum output voltage
+ that the regulator supports when PWM control is enabled.
+- nvidia,pwm-voltage-step-microvolts: Voltage increase in micro volts
+ corresponding to a 1/33th increase in duty cycle. Eg the voltage for 2/33th
+ duty cycle would be: nvidia,pwm-min-microvolts +
+ nvidia,pwm-voltage-step-microvolts * 2.
+- pinctrl-0: I/O pad configuration when PWM control is enabled.
+- pinctrl-1: I/O pad configuration when PWM control is disabled.
+- pinctrl-names: must include the following entries:
+ - dvfs_pwm_enable: I/O pad configuration when PWM control is enabled.
+ - dvfs_pwm_disable: I/O pad configuration when PWM control is disabled.
+
+Example for I2C:
clock@70110000 {
compatible = "nvidia,tegra124-dfll";
@@ -76,3 +96,58 @@ clock@70110000 {
nvidia,i2c-fs-rate = <400000>;
};
+
+Example for PWM:
+
+clock@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 TEGRA210_CLK_DFLL_SOC>,
+ <&tegra_car TEGRA210_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";
+
+ nvidia,sample-rate = <25000>;
+ nvidia,droop-ctrl = <0x00000f00>;
+ nvidia,force-mode = <1>;
+ nvidia,cf = <6>;
+ nvidia,ci = <0>;
+ nvidia,cg = <2>;
+
+ nvidia,pwm-min-microvolts = <708000>; /* 708mV */
+ nvidia,pwm-period = <2500>; /* 2.5us */
+ nvidia,pwm-to-pmic;
+ nvidia,pwm-tristate-microvolts = <1000000>;
+ nvidia,pwm-voltage-step-microvolts = <19200>; /* 19.2mV */
+
+ pinctrl-names = "dvfs_pwm_enable", "dvfs_pwm_disable";
+ pinctrl-0 = <&dvfs_pwm_active_state>;
+ pinctrl-1 = <&dvfs_pwm_inactive_state>;
+};
+
+/* pinmux nodes added for completeness. Binding doc can be found in:
+ * Documentation/devicetree/bindings/pinctrl/nvidia,tegra210-pinmux.txt
+ */
+
+pinmux: pinmux@700008d4 {
+ dvfs_pwm_active_state: dvfs_pwm_active {
+ dvfs_pwm_pbb1 {
+ nvidia,pins = "dvfs_pwm_pbb1";
+ nvidia,tristate = <TEGRA_PIN_DISABLE>;
+ };
+ };
+ dvfs_pwm_inactive_state: dvfs_pwm_inactive {
+ dvfs_pwm_pbb1 {
+ nvidia,pins = "dvfs_pwm_pbb1";
+ nvidia,tristate = <TEGRA_PIN_ENABLE>;
+ };
+ };
+};