On Wed, Sep 03, 2025 at 11:04:59AM +0100, Nuno Sá wrote: > The LTC4283 is a negative voltage hot swap controller that drives an > external N-channel MOSFET to allow a board to be safely inserted and > removed from a live backplane. > > Special note for the "adi,vpower-drns-enable" property. It allows to choose > between the attenuated MOSFET drain voltage or the attenuated input > voltage at the RTNS pin (effectively choosing between input or output > power). This is a system level decision not really intended to change at > runtime and hence is being added as a Firmware property. > > Signed-off-by: Nuno Sá <nuno.sa@xxxxxxxxxx> > --- > .../devicetree/bindings/hwmon/adi,ltc4283.yaml | 280 +++++++++++++++++++++ > MAINTAINERS | 6 + > 2 files changed, 286 insertions(+) > > diff --git a/Documentation/devicetree/bindings/hwmon/adi,ltc4283.yaml b/Documentation/devicetree/bindings/hwmon/adi,ltc4283.yaml > new file mode 100644 > index 0000000000000000000000000000000000000000..ec7768467e66f18f06d8a5258b3b115f23ea996d > --- /dev/null > +++ b/Documentation/devicetree/bindings/hwmon/adi,ltc4283.yaml > @@ -0,0 +1,280 @@ > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) > +%YAML 1.2 > +--- > +$id: http://devicetree.org/schemas/hwmon/adi,ltc4283.yaml# > +$schema: http://devicetree.org/meta-schemas/core.yaml# > + > +title: LTC4283 Negative Voltage Hot Swap Controller > + > +maintainers: > + - Nuno Sá <nuno.sa@xxxxxxxxxx> > + > +description: | > + The LTC4283 negative voltage hot swap controller drives an external N-channel > + MOSFET to allow a board to be safely inserted and removed from a live > + backplane. > + > + https://www.analog.com/media/en/technical-documentation/data-sheets/ltc4283.pdf > + > +properties: > + compatible: > + enum: > + - adi,ltc4283 > + > + reg: > + maxItems: 1 > + > + adi,rsense-nano-ohms: > + description: Value of the sense resistor. > + > + adi,current-limit-sense-microvolt: > + description: > + The current limit sense voltage of the chip is adjustable between > + 15mV and 30mV in 1mV steps. This effectively limits the current > + on the load. > + minimum: 15000 > + maximum: 30000 > + default: 15000 > + > + adi,current-limit-foldback-factor: > + description: > + Specifies the foldback factor for the current limit. The current limit > + can be reduced (folded back) to one of four preset levels. The value > + represents the percentage of the current limit sense voltage to use > + during foldback. A value of 100 means no foldback. > + $ref: /schemas/types.yaml#/definitions/uint32 > + enum: [10, 20, 50, 100] > + default: 100 > + > + adi,cooling-delay-ms: > + description: > + Cooling time to apply after an overcurrent fault, FET bad or > + external fault. > + enum: [512, 1002, 2005, 4100, 8190, 16400, 32800, 65600] > + default: 512 > + > + adi,fet-bad-timer-delay-ms: > + description: > + FET bad timer delay. After a FET bad status condition is detected, > + this timer is started. If the condition persists for the > + specified time, the FET is turned off and a fault is logged. > + enum: [256, 512, 1002, 2005] > + default: 256 > + > + adi,power-good-reset-on-fet: > + description: > + If set, resets the power good status when the MOSFET is turned off. > + Otherwise, it resets when a low output voltage is detected. > + type: boolean > + > + adi,fet-turn-off-disable: > + description: > + If set, the MOSFET is turned off immediately when a FET fault is detected. > + type: boolean > + > + adi,tmr-pull-down-disable: > + description: Disables 2uA pull-down current on the TMR pin. > + type: boolean > + > + adi,dvdt-inrush-control-disable: > + description: > + Enables dV/dt inrush control during startup. In dV/dt mode, the inrush > + current is limited by controlling a constant output voltage ramp rate. > + If not set, the inrush control mechanism is active current limiting. > + type: boolean > + > + adi,fault-log-enable: > + description: > + If set, enables logging fault registers and ADC data into EEPROM upon a > + fault. > + type: boolean > + > + adi,vpower-drns-enable: > + description: > + If set, enables the attenuated MOSFET drain voltage to be monitored. This > + effectively means that the MOSFET power is monitored. If not set, the > + attenuated input voltage (and hence input power) is monitored. > + type: boolean > + > + adi,external-fault-fet-off-enable: > + description: Turns MOSFET off following an external fault. > + type: boolean > + > + adi,undervoltage-retry-disable: > + description: Do not retry to turn on the MOSFET after an undervoltage fault. > + type: boolean > + > + adi,overvoltage-retry-disable: > + description: Do not retry to turn on the MOSFET after an overvoltage fault. > + type: boolean > + > + adi,external-fault-retry-enable: > + description: Retry to turn on the MOSFET retry after an external fault. > + type: boolean > + > + adi,overcurrent-retries: > + description: Configures auto-retry following an Overcurrent fault. > + $ref: /schemas/types.yaml#/definitions/string > + enum: [latch-off, "1", "7", unlimited] > + default: latch-off > + > + adi,fet-bad-retries: > + description: > + Configures auto-retry following a FET bad fault and a consequent MOSFET > + turn off. > + $ref: /schemas/types.yaml#/definitions/string > + enum: [latch-off, "1", "7", unlimited] > + default: latch-off > + > + adi,pgio1-func: > + description: Configures the function of the PGIO1 pin. > + $ref: /schemas/types.yaml#/definitions/string > + enum: [inverted_power_good, power_good, gpio] > + default: inverted_power_good > + > + adi,pgio2-func: > + description: Configures the function of the PGIO2 pin. > + $ref: /schemas/types.yaml#/definitions/string > + enum: [inverted_power_good, power_good, gpio, active_current_limiting] > + default: inverted_power_good > + > + adi,pgio3-func: > + description: Configures the function of the PGIO3 pin. > + $ref: /schemas/types.yaml#/definitions/string > + enum: [inverted_power_good_input, power_good_input, gpio] > + default: inverted_power_good_input > + > + adi,pgio4-func: > + description: Configures the function of the PGIO4 pin. > + $ref: /schemas/types.yaml#/definitions/string > + enum: [inverted_external_fault, external_fault, gpio] > + default: inverted_external_fault > + > + adi,gpio-on-adio1: > + description: If set, the ADIO1 pin is used as a GPIO. > + type: boolean > + > + adi,gpio-on-adio2: > + description: If set, the ADIO2 pin is used as a GPIO. > + type: boolean > + > + adi,gpio-on-adio3: > + description: If set, the ADIO3 pin is used as a GPIO. > + type: boolean > + > + adi,gpio-on-adio4: > + description: If set, the ADIO4 pin is used as a GPIO. > + type: boolean > + > + gpio-controller: true > + > + '#gpio-cells': > + const: 2 > + > +dependencies: > + adi,gpio-on-adio1: > + - gpio-controller > + - '#gpio-cells' > + adi,gpio-on-adio2: > + - gpio-controller > + - '#gpio-cells' > + adi,gpio-on-adio3: > + - gpio-controller > + - '#gpio-cells' > + adi,gpio-on-adio4: > + - gpio-controller > + - '#gpio-cells' > + adi,external-fault-retry-enable: > + - adi,pgio4-func > + adi,external-fault-fet-off-enable: > + - adi,pgio4-func > + > +required: > + - compatible > + - reg > + - adi,rsense-nano-ohms > + > +allOf: > + - if: > + required: > + - adi,pgio1-func > + then: > + if: > + properties: > + adi,pgio1-func: > + const: gpio > + then: > + required: > + - gpio-controller > + - '#gpio-cells' if: properties: adi,pgio1-func: const: gpio required: - adi,pgio1-func then: required: - gpio-controller - '#gpio-cells' With that and the following ones fixed, Reviewed-by: Rob Herring (Arm) <robh@xxxxxxxxxx>
