Signed-off-by: Andrew Jeffery <andrew@xxxxxxxx> --- .../devicetree/bindings/hwmon/pmbus/max31785.txt | 158 +++++++++++++++++++++ 1 file changed, 158 insertions(+) create mode 100644 Documentation/devicetree/bindings/hwmon/pmbus/max31785.txt diff --git a/Documentation/devicetree/bindings/hwmon/pmbus/max31785.txt b/Documentation/devicetree/bindings/hwmon/pmbus/max31785.txt new file mode 100644 index 000000000000..af9578e7742c --- /dev/null +++ b/Documentation/devicetree/bindings/hwmon/pmbus/max31785.txt @@ -0,0 +1,158 @@ +Bindings for the Maxim MAX31785 Intelligent Fan Controller +========================================================== + +Reference: + +https://datasheets.maximintegrated.com/en/ds/MAX31785.pdf + +Required properties: +- compatible : One of "maxim,max31785" or "maxim,max31785a" +- reg : I2C address, one of 0x52, 0x53, 0x54, 0x55. +- #address-cells : Must be 1 +- #size-cells : Must be 0 +- #thermal-sensor-cells : Should be 1. The device supports: + - One internal sensor + - Four external I2C digital sensors + - Six external thermal diodes + +Optional properties: +- use-stored-presence : Do not treat the devicetree description as canon for + fan presence (the 'installed' bit of FAN_CONFIG_*). + Instead, rely on the on the default value store of + the device to populate it. + +Capabilities are configured through subnodes of the controller's node. + +Fans +---- + +Only fans with subnodes present will be considered as installed. If +use-stored-presence is present in the parent node, then only fans that are both +defined in the devicetree and have their installed bit set are considered +installed. + +Required subnode properties: +- compatible : Must be "pmbus-fan" +- reg : The PMBus page the properties apply to. +- #cooling-cells : Should be 2. See the thermal bindings at [1]. +- maxim,fan-rotor-input : The type of rotor measurement provided to the + controller. Must be either "tach" for tachometer + pulses or "lock" for a locked-rotor signal. +- maxim,fan-lock-polarity: Required iff maxim,fan-rotor-input is "lock". Valid + values are "low" for active low, "high" for active + high. + +Optional subnode properties: +- fan-mode : "rpm" or "pwm". Default value is "pwm". +- tach-pulses : Tachometer pulses per revolution. Valid values are + 1, 2, 3 or 4. The default is 1. +- cooling-min-level : Smallest cooling state accepted. See [1]. +- cooling-max-level : Largest cooling state accepted. See [1]. +- maxim,fan-no-fault-ramp: Do not ramp the fan to 100% PWM duty on detecting a + fan fault +- maxim,fan-startup : The number of rotations required before taking + emergency action for an unresponsive fan and driving + it with 100% or 0% PWM duty, depending on the state + of maxim,fan-no-fault-ramp. Valid values are 0 + (automatic spin-up disabled), 2, 4, or 8. Default + value is 0. +- maxim,fan-health : Enable automated fan health check +- maxim,fan-ramp : Configures how fast the device ramps the PWM duty + cycle from one value to another. Valid values are 0 + to 7 inclusive, with values 0 - 2 configuring a + 1000ms update rate and 1 - 3% duty respective duty + increase, and 3 - 7 a 200ms update rate with a 1 - + 5% respective duty increase. Default value is 0. +- maxim,fan-no-watchdog : Do not ramp fan to 100% PWM duty on failure to + update desired fan rate inside 10s. This implies + maxim,tmp-no-fault-ramp +- maxim,tmp-no-fault-ramp: Do not ramp fan to 100% PWM duty on temperature + sensor fault detection. This implies + maxim,fan-no-watchdog +- maxim,tmp-hysteresis : The temperature hysteresis used to determine + transitions to lower fan speed bands in the + temperature/fan rate lookup table. Valid values are + 2, 4, 6 or 8 (degrees celcius). Default value is 2. +- maxim,fan-dual-tach : Enable dual tachometer functionality +- maxim,fan-pwm-freq : The PWM frequency. Valid values are 30, 50, 100, 150 + and 25000 (Hz). Default value is 30Hz. +- maxim,fan-lookup-table : A 16-element cell array of alternating temperature + and rate values representing the look up table. The + rate units are set through the fan-mode property. +- maxim,fan-fault-pin-mon: Ramp fans to 100% PWM duty when the FAULT pin is + asserted + +Temperature +----------- + +Required subnode properties: +- compatible : Must be "pmbus-temperature" +- reg : The PMBus page the properties apply to. + +Optional subnode properties: +- maxim,tmp-offset : Valid values are 0 - 30 (degrees celcius) inclusive. + Default value is 0. +- maxim,tmp-fans : An array of phandles to fans controlled by the + current temperature sensor. + +[1] Documentation/devicetree/bindings/thermal/thermal.txt + +Example: + fan-max31785: max31785@52 { + reg = <0x52>; + compatible = "maxim,max31785"; + #address-cells = <1>; + #size-cells = <0>; + #thermal-sensor-cells = <1>; + + fan@0 { + compatible = "pmbus-fan"; + reg = <0>; + mode = "rpm"; + tach-pulses = <1>; + + #cooling-cells = <2>; + cooling-min-level = <0>; + cooling-max-level = <9>; + + maxim,fan-rotor-input = "tach"; + maxim,fan-dual-tach; + }; + + /* + * Hardware controlled fan: Fan speed is controlled by a + * temperature sensor feeding values into the lookup table. The + * fan association is done in the temperature sensor node. One + * sensor can drive multiple fans. + */ + cpu_fan: fan@1 { + compatible = "pmbus-fan"; + reg = <1>; + mode = "rpm"; + tach-pulses = <1>; + + #cooling-cells = <2>; + + maxim,fan-rotor-input = "tach"; + maxim,tmp-hysteresis = <2>; + maxim,fan-lookup-table = < + /* Temperature RPM */ + 0 1000 + 10 2000 + 20 3000 + 30 4000 + 40 5000 + 50 6000 + 60 7000 + 70 8000 + >; + }; + + cpu_temp: sensor@6 { + compatible = "pmbus-temperature"; + reg = <6>; + + maxim,tmp-offset = <0>; + maxim,tmp-fans = <&cpu_fan>; + }; + }; -- 2.11.0 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
