diff options
Diffstat (limited to 'Documentation/devicetree/bindings/clock/nvidia,tegra124-dfll.txt')
| -rw-r--r-- | Documentation/devicetree/bindings/clock/nvidia,tegra124-dfll.txt | 155 |
1 files changed, 155 insertions, 0 deletions
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 000000000..958e0ad78 --- /dev/null +++ b/Documentation/devicetree/bindings/clock/nvidia,tegra124-dfll.txt @@ -0,0 +1,155 @@ +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. + +Required properties: +- compatible : should be one of: + - "nvidia,tegra124-dfll": for Tegra124 + - "nvidia,tegra210-dfll": for Tegra210 +- 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. + +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. + +Required properties for PWM mode: +- nvidia,pwm-period-nanoseconds: period of PWM square wave in nanoseconds. +- 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"; + 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>; + + 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>; +}; + +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-nanoseconds = <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>; + }; + }; +}; |