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- ASPEED AST2400/AST2500 PWM and Fan Tacho controller device driver
- The ASPEED PWM controller can support upto 8 PWM outputs. The ASPEED Fan Tacho
- controller can support upto 16 Fan tachometer inputs.
- There can be upto 8 fans supported. Each fan can have one PWM output and
- one/two Fan tach inputs.
- Required properties for pwm-tacho node:
- - #address-cells : should be 1.
- - #size-cells : should be 1.
- - #cooling-cells: should be 2.
- - reg : address and length of the register set for the device.
- - pinctrl-names : a pinctrl state named "default" must be defined.
- - pinctrl-0 : phandle referencing pin configuration of the PWM ports.
- - compatible : should be "aspeed,ast2400-pwm-tacho" for AST2400 and
- "aspeed,ast2500-pwm-tacho" for AST2500.
- - clocks : phandle to clock provider with the clock number in the second cell
- - resets : phandle to reset controller with the reset number in the second cell
- fan subnode format:
- ===================
- Under fan subnode there can upto 8 child nodes, with each child node
- representing a fan. If there are 8 fans each fan can have one PWM port and
- one/two Fan tach inputs.
- For PWM port 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 : should specify PWM source port.
- integer value in the range 0 to 7 with 0 indicating PWM port A and
- 7 indicating PWM port H.
- - cooling-levels: PWM duty cycle values in a range from 0 to 255
- which correspond to thermal cooling states.
- - aspeed,fan-tach-ch : should specify the Fan tach input channel.
- integer value in the range 0 through 15, with 0 indicating
- Fan tach channel 0 and 15 indicating Fan tach channel 15.
- Atleast one Fan tach input channel is required.
- Examples:
- pwm_tacho: pwmtachocontroller@1e786000 {
- #address-cells = <1>;
- #size-cells = <1>;
- #cooling-cells = <2>;
- reg = <0x1E786000 0x1000>;
- compatible = "aspeed,ast2500-pwm-tacho";
- clocks = <&syscon ASPEED_CLK_APB>;
- resets = <&syscon ASPEED_RESET_PWM>;
- pinctrl-names = "default";
- pinctrl-0 = <&pinctrl_pwm0_default &pinctrl_pwm1_default>;
- fan@0 {
- reg = <0x00>;
- cooling-levels = /bits/ 8 <125 151 177 203 229 255>;
- aspeed,fan-tach-ch = /bits/ 8 <0x00>;
- };
- fan@1 {
- reg = <0x01>;
- aspeed,fan-tach-ch = /bits/ 8 <0x01 0x02>;
- };
- };
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