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