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Subject[PATCH v3 1/3] dt-bindings: hwmon: pmbus: Add Maxim MAX31785 documentation
Date
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
---
.../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
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