| 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. |
| |
| - 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 : a fixed clock providing input clock frequency(PWM |
| and Fan Tach clock) |
| |
| 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. |
| |
| 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. |
| |
| - 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_fixed_clk: fixedclk { |
| compatible = "fixed-clock"; |
| #clock-cells = <0>; |
| clock-frequency = <24000000>; |
| }; |
| |
| pwm_tacho: pwmtachocontroller@1e786000 { |
| #address-cells = <1>; |
| #size-cells = <1>; |
| reg = <0x1E786000 0x1000>; |
| compatible = "aspeed,ast2500-pwm-tacho"; |
| clocks = <&pwm_tacho_fixed_clk>; |
| pinctrl-names = "default"; |
| pinctrl-0 = <&pinctrl_pwm0_default &pinctrl_pwm1_default>; |
| |
| fan@0 { |
| reg = <0x00>; |
| aspeed,fan-tach-ch = /bits/ 8 <0x00>; |
| }; |
| |
| fan@1 { |
| reg = <0x01>; |
| aspeed,fan-tach-ch = /bits/ 8 <0x01 0x02>; |
| }; |
| }; |
