| Tom Rini | 53633a8 | 2024-02-29 12:33:36 -0500 | [diff] [blame] | 1 | ASPEED AST2400/AST2500 PWM and Fan Tacho controller device driver |
| 2 | |
| 3 | The ASPEED PWM controller can support upto 8 PWM outputs. The ASPEED Fan Tacho |
| 4 | controller can support upto 16 Fan tachometer inputs. |
| 5 | |
| 6 | There can be upto 8 fans supported. Each fan can have one PWM output and |
| 7 | one/two Fan tach inputs. |
| 8 | |
| 9 | Required properties for pwm-tacho node: |
| 10 | - #address-cells : should be 1. |
| 11 | |
| 12 | - #size-cells : should be 1. |
| 13 | |
| 14 | - #cooling-cells: should be 2. |
| 15 | |
| 16 | - reg : address and length of the register set for the device. |
| 17 | |
| 18 | - pinctrl-names : a pinctrl state named "default" must be defined. |
| 19 | |
| 20 | - pinctrl-0 : phandle referencing pin configuration of the PWM ports. |
| 21 | |
| 22 | - compatible : should be "aspeed,ast2400-pwm-tacho" for AST2400 and |
| 23 | "aspeed,ast2500-pwm-tacho" for AST2500. |
| 24 | |
| 25 | - clocks : phandle to clock provider with the clock number in the second cell |
| 26 | |
| 27 | - resets : phandle to reset controller with the reset number in the second cell |
| 28 | |
| 29 | fan subnode format: |
| 30 | =================== |
| 31 | Under fan subnode there can upto 8 child nodes, with each child node |
| 32 | representing a fan. If there are 8 fans each fan can have one PWM port and |
| 33 | one/two Fan tach inputs. |
| 34 | For PWM port can be configured cooling-levels to create cooling device. |
| 35 | Cooling device could be bound to a thermal zone for the thermal control. |
| 36 | |
| 37 | Required properties for each child node: |
| 38 | - reg : should specify PWM source port. |
| 39 | integer value in the range 0 to 7 with 0 indicating PWM port A and |
| 40 | 7 indicating PWM port H. |
| 41 | |
| 42 | - cooling-levels: PWM duty cycle values in a range from 0 to 255 |
| 43 | which correspond to thermal cooling states. |
| 44 | |
| 45 | - aspeed,fan-tach-ch : should specify the Fan tach input channel. |
| 46 | integer value in the range 0 through 15, with 0 indicating |
| 47 | Fan tach channel 0 and 15 indicating Fan tach channel 15. |
| 48 | At least one Fan tach input channel is required. |
| 49 | |
| 50 | Examples: |
| 51 | |
| 52 | pwm_tacho: pwmtachocontroller@1e786000 { |
| 53 | #address-cells = <1>; |
| 54 | #size-cells = <1>; |
| 55 | #cooling-cells = <2>; |
| 56 | reg = <0x1E786000 0x1000>; |
| 57 | compatible = "aspeed,ast2500-pwm-tacho"; |
| 58 | clocks = <&syscon ASPEED_CLK_APB>; |
| 59 | resets = <&syscon ASPEED_RESET_PWM>; |
| 60 | pinctrl-names = "default"; |
| 61 | pinctrl-0 = <&pinctrl_pwm0_default &pinctrl_pwm1_default>; |
| 62 | |
| 63 | fan@0 { |
| 64 | reg = <0x00>; |
| 65 | cooling-levels = /bits/ 8 <125 151 177 203 229 255>; |
| 66 | aspeed,fan-tach-ch = /bits/ 8 <0x00>; |
| 67 | }; |
| 68 | |
| 69 | fan@1 { |
| 70 | reg = <0x01>; |
| 71 | aspeed,fan-tach-ch = /bits/ 8 <0x01 0x02>; |
| 72 | }; |
| 73 | }; |