linux/Documentation/devicetree/bindings/hwmon/npcm750-pwm-fan.txt

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Nuvoton NPCM7xx PWM and Fan Tacho controller device
The Nuvoton BMC NPCM7XX supports 8 Pulse-width modulation (PWM)
controller outputs and 16 Fan tachometer controller inputs.
Required properties for pwm-fan node
- #address-cells : should be 1.
- #size-cells : should be 0.
- compatible : "nuvoton,npcm750-pwm-fan" for Poleg NPCM7XX.
- reg : specifies physical base address and size of the registers.
- reg-names : must contain:
* "pwm" for the PWM registers.
* "fan" for the Fan registers.
- clocks : phandle of reference clocks.
- clock-names : must contain
* "pwm" for PWM controller operating clock.
* "fan" for Fan controller operating clock.
- interrupts : contain the Fan interrupts with flags for falling edge.
- pinctrl-names : a pinctrl state named "default" must be defined.
- pinctrl-0 : phandle referencing pin configuration of the PWM and Fan
controller ports.
fan subnode format:
===================
Under fan subnode can be upto 8 child nodes, each child node representing a fan.
Each fan subnode must have one PWM channel and atleast one Fan tach channel.
For PWM channel can be configured cooling-levels to create cooling device.
Cooling device could be bound to a thermal zone for the thermal control.
Required properties for each child node:
- reg : specify the PWM output channel.
integer value in the range 0 through 7, that represent
the PWM channel number that used.
- fan-tach-ch : specify the Fan tach input channel.
integer value in the range 0 through 15, that represent
the fan tach channel number that used.
At least one Fan tach input channel is required
Optional property for each child node:
- cooling-levels: PWM duty cycle values in a range from 0 to 255
which correspond to thermal cooling states.
Examples:
pwm_fan:pwm-fan-controller@103000 {
#address-cells = <1>;
#size-cells = <0>;
compatible = "nuvoton,npcm750-pwm-fan";
reg = <0x103000 0x2000>,
<0x180000 0x8000>;
reg-names = "pwm", "fan";
clocks = <&clk NPCM7XX_CLK_APB3>,
<&clk NPCM7XX_CLK_APB4>;
clock-names = "pwm","fan";
interrupts = <GIC_SPI 96 IRQ_TYPE_LEVEL_HIGH>,
<GIC_SPI 97 IRQ_TYPE_LEVEL_HIGH>,
<GIC_SPI 98 IRQ_TYPE_LEVEL_HIGH>,
<GIC_SPI 99 IRQ_TYPE_LEVEL_HIGH>,
<GIC_SPI 100 IRQ_TYPE_LEVEL_HIGH>,
<GIC_SPI 101 IRQ_TYPE_LEVEL_HIGH>,
<GIC_SPI 102 IRQ_TYPE_LEVEL_HIGH>,
<GIC_SPI 103 IRQ_TYPE_LEVEL_HIGH>;
pinctrl-names = "default";
pinctrl-0 = <&pwm0_pins &pwm1_pins &pwm2_pins
&fanin0_pins &fanin1_pins &fanin2_pins
&fanin3_pins &fanin4_pins>;
fan@0 {
reg = <0x00>;
fan-tach-ch = /bits/ 8 <0x00 0x01>;
cooling-levels = <127 255>;
};
fan@1 {
reg = <0x01>;
fan-tach-ch = /bits/ 8 <0x02 0x03>;
};
fan@2 {
reg = <0x02>;
fan-tach-ch = /bits/ 8 <0x04>;
};
};