{"id":2229728,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2229728/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-gpio/patch/20260428-ltc4283-support-v10-1-4f26f46491c3@analog.com/","project":{"id":42,"url":"http://patchwork.ozlabs.org/api/1.1/projects/42/?format=json","name":"Linux GPIO development","link_name":"linux-gpio","list_id":"linux-gpio.vger.kernel.org","list_email":"linux-gpio@vger.kernel.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20260428-ltc4283-support-v10-1-4f26f46491c3@analog.com>","date":"2026-04-28T16:07:26","name":"[v10,1/3] dt-bindings: hwmon: Document the LTC4283 Swap Controller","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"affa0a7b13a6fd0aacfd65a27a1a1d86b4118201","submitter":{"id":87565,"url":"http://patchwork.ozlabs.org/api/1.1/people/87565/?format=json","name":"Nuno Sá via B4 Relay","email":"devnull+nuno.sa.analog.com@kernel.org"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/linux-gpio/patch/20260428-ltc4283-support-v10-1-4f26f46491c3@analog.com/mbox/","series":[{"id":501894,"url":"http://patchwork.ozlabs.org/api/1.1/series/501894/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-gpio/list/?series=501894","date":"2026-04-28T16:07:25","name":"hwmon: Add support for the LTC4283 Hot Swap Controller","version":10,"mbox":"http://patchwork.ozlabs.org/series/501894/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2229728/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2229728/checks/","tags":{},"headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-gpio@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256\n header.s=k20201202 header.b=LLPsDGU1;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c04:e001:36c::12fc:5321; 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charset=\"utf-8\"","Content-Transfer-Encoding":"8bit","Message-Id":"<20260428-ltc4283-support-v10-1-4f26f46491c3@analog.com>","References":"<20260428-ltc4283-support-v10-0-4f26f46491c3@analog.com>","In-Reply-To":"<20260428-ltc4283-support-v10-0-4f26f46491c3@analog.com>","To":"linux-gpio@vger.kernel.org, linux-hwmon@vger.kernel.org,\n devicetree@vger.kernel.org, linux-doc@vger.kernel.org","Cc":"Guenter Roeck , Rob Herring ,\n Krzysztof Kozlowski ,\n Conor Dooley , Jonathan Corbet ,\n Linus Walleij , Bartosz Golaszewski ","X-Mailer":"b4 0.15.2","X-Developer-Signature":"v=1; a=ed25519-sha256; t=1777392450; l=9689;\n i=nuno.sa@analog.com; s=20231116; h=from:subject:message-id;\n bh=MUdw9MgEtSe5cQUGEWnL9j0RY+iBReWR/+IVYDATZQw=;\n b=BG00MNekXvs1VujFMAfdWny82rvSBAXb9d7afcVa2Akg6PK0Hn7zLKobXXYI0vHUqLmI7E7pv\n EUm4oXfly3+DUiVhJ3IZho71i74O8jyVhaqGrKChszKFrxkJx/Llhqd","X-Developer-Key":"i=nuno.sa@analog.com; a=ed25519;\n pk=3NQwYA013OUYZsmDFBf8rmyyr5iQlxV/9H4/Df83o1E=","X-Endpoint-Received":"by B4 Relay for nuno.sa@analog.com/20231116 with\n auth_id=100","X-Original-From":"=?utf-8?q?Nuno_S=C3=A1?= ","Reply-To":"nuno.sa@analog.com"},"content":"From: Nuno Sá \n\nThe LTC4283 is a negative voltage hot swap controller that drives an\nexternal N-channel MOSFET to allow a board to be safely inserted and\nremoved from a live backplane.\n\nSpecial note for the \"adi,vpower-drns-enable\" property. It allows to choose\nbetween the attenuated MOSFET drain voltage or the attenuated input\nvoltage at the RTNS pin (effectively choosing between input or output\npower). This is a system level decision not really intended to change at\nruntime and hence is being added as a Firmware property.\n\nReviewed-by: Rob Herring (Arm) \nSigned-off-by: Nuno Sá \n---\n .../devicetree/bindings/hwmon/adi,ltc4283.yaml | 272 +++++++++++++++++++++\n MAINTAINERS | 6 +\n 2 files changed, 278 insertions(+)","diff":"diff --git a/Documentation/devicetree/bindings/hwmon/adi,ltc4283.yaml b/Documentation/devicetree/bindings/hwmon/adi,ltc4283.yaml\nnew file mode 100644\nindex 000000000000..05e2132ad4d8\n--- /dev/null\n+++ b/Documentation/devicetree/bindings/hwmon/adi,ltc4283.yaml\n@@ -0,0 +1,272 @@\n+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)\n+%YAML 1.2\n+---\n+$id: http://devicetree.org/schemas/hwmon/adi,ltc4283.yaml#\n+$schema: http://devicetree.org/meta-schemas/core.yaml#\n+\n+title: LTC4283 Negative Voltage Hot Swap Controller\n+\n+maintainers:\n+ - Nuno Sá \n+\n+description: |\n+ The LTC4283 negative voltage hot swap controller drives an external N-channel\n+ MOSFET to allow a board to be safely inserted and removed from a live\n+ backplane.\n+\n+ https://www.analog.com/media/en/technical-documentation/data-sheets/ltc4283.pdf\n+\n+properties:\n+ compatible:\n+ enum:\n+ - adi,ltc4283\n+\n+ reg:\n+ maxItems: 1\n+\n+ adi,rsense-nano-ohms:\n+ description: Value of the sense resistor.\n+\n+ adi,current-limit-sense-microvolt:\n+ description:\n+ The current limit sense voltage of the chip is adjustable between\n+ 15mV and 30mV in 1mV steps. This effectively limits the current\n+ on the load.\n+ minimum: 15000\n+ maximum: 30000\n+ default: 15000\n+\n+ adi,current-limit-foldback-factor:\n+ description:\n+ Specifies the foldback factor for the current limit. The current limit\n+ can be reduced (folded back) to one of four preset levels. The value\n+ represents the percentage of the current limit sense voltage to use\n+ during foldback. A value of 100 means no foldback.\n+ $ref: /schemas/types.yaml#/definitions/uint32\n+ enum: [10, 20, 50, 100]\n+ default: 100\n+\n+ adi,cooling-delay-ms:\n+ description:\n+ Cooling time to apply after an overcurrent fault, FET bad or\n+ external fault.\n+ enum: [512, 1002, 2005, 4100, 8190, 16400, 32800, 65600]\n+ default: 512\n+\n+ adi,fet-bad-timer-delay-ms:\n+ description:\n+ FET bad timer delay. After a FET bad status condition is detected,\n+ this timer is started. If the condition persists for the\n+ specified time, the FET is turned off and a fault is logged.\n+ enum: [256, 512, 1002, 2005]\n+ default: 256\n+\n+ adi,power-good-reset-on-fet:\n+ description:\n+ If set, resets the power good status when the MOSFET is turned off.\n+ Otherwise, it resets when a low output voltage is detected.\n+ type: boolean\n+\n+ adi,fet-turn-off-disable:\n+ description:\n+ If set, the MOSFET is not turned off when a FET fault is detected.\n+ type: boolean\n+\n+ adi,tmr-pull-down-disable:\n+ description: Disables 2uA pull-down current on the TMR pin.\n+ type: boolean\n+\n+ adi,dvdt-inrush-control-disable:\n+ description:\n+ Disables dV/dt inrush control during startup. In dV/dt mode, the inrush\n+ current is limited by controlling a constant output voltage ramp rate.\n+ When disabled, the inrush control mechanism is active current limiting.\n+ type: boolean\n+\n+ adi,fault-log-enable:\n+ description:\n+ If set, enables logging fault registers and ADC data into EEPROM upon a\n+ fault.\n+ type: boolean\n+\n+ adi,vpower-drns-enable:\n+ description:\n+ If set, enables the attenuated MOSFET drain voltage to be monitored. This\n+ effectively means that the MOSFET power is monitored. If not set, the\n+ attenuated input voltage (and hence input power) is monitored.\n+ type: boolean\n+\n+ adi,external-fault-fet-off-enable:\n+ description: Turns MOSFET off following an external fault.\n+ type: boolean\n+\n+ adi,undervoltage-retry-disable:\n+ description: Do not retry to turn on the MOSFET after an undervoltage fault.\n+ type: boolean\n+\n+ adi,overvoltage-retry-disable:\n+ description: Do not retry to turn on the MOSFET after an overvoltage fault.\n+ type: boolean\n+\n+ adi,external-fault-retry-enable:\n+ description: Retry to turn on the MOSFET after an external fault.\n+ type: boolean\n+\n+ adi,overcurrent-retries:\n+ description: Configures auto-retry following an Overcurrent fault.\n+ $ref: /schemas/types.yaml#/definitions/string\n+ enum: [latch-off, \"1\", \"7\", unlimited]\n+ default: latch-off\n+\n+ adi,fet-bad-retries:\n+ description:\n+ Configures auto-retry following a FET bad fault and a consequent MOSFET\n+ turn off.\n+ $ref: /schemas/types.yaml#/definitions/string\n+ enum: [latch-off, \"1\", \"7\", unlimited]\n+ default: latch-off\n+\n+ adi,pgio1-func:\n+ description: Configures the function of the PGIO1 pin.\n+ $ref: /schemas/types.yaml#/definitions/string\n+ enum: [inverted_power_good, power_good, gpio]\n+ default: inverted_power_good\n+\n+ adi,pgio2-func:\n+ description: Configures the function of the PGIO2 pin.\n+ $ref: /schemas/types.yaml#/definitions/string\n+ enum: [inverted_power_good, power_good, gpio, active_current_limiting]\n+ default: inverted_power_good\n+\n+ adi,pgio3-func:\n+ description: Configures the function of the PGIO3 pin.\n+ $ref: /schemas/types.yaml#/definitions/string\n+ enum: [inverted_power_good_input, power_good_input, gpio]\n+ default: inverted_power_good_input\n+\n+ adi,pgio4-func:\n+ description: Configures the function of the PGIO4 pin.\n+ $ref: /schemas/types.yaml#/definitions/string\n+ enum: [inverted_external_fault, external_fault, gpio]\n+ default: inverted_external_fault\n+\n+ adi,gpio-on-adio1:\n+ description: If set, the ADIO1 pin is used as a GPIO.\n+ type: boolean\n+\n+ adi,gpio-on-adio2:\n+ description: If set, the ADIO2 pin is used as a GPIO.\n+ type: boolean\n+\n+ adi,gpio-on-adio3:\n+ description: If set, the ADIO3 pin is used as a GPIO.\n+ type: boolean\n+\n+ adi,gpio-on-adio4:\n+ description: If set, the ADIO4 pin is used as a GPIO.\n+ type: boolean\n+\n+ gpio-controller: true\n+\n+ '#gpio-cells':\n+ const: 2\n+\n+dependencies:\n+ adi,gpio-on-adio1:\n+ - gpio-controller\n+ - '#gpio-cells'\n+ adi,gpio-on-adio2:\n+ - gpio-controller\n+ - '#gpio-cells'\n+ adi,gpio-on-adio3:\n+ - gpio-controller\n+ - '#gpio-cells'\n+ adi,gpio-on-adio4:\n+ - gpio-controller\n+ - '#gpio-cells'\n+ adi,external-fault-retry-enable:\n+ - adi,pgio4-func\n+ adi,external-fault-fet-off-enable:\n+ - adi,pgio4-func\n+\n+required:\n+ - compatible\n+ - reg\n+ - adi,rsense-nano-ohms\n+\n+allOf:\n+ - if:\n+ properties:\n+ adi,pgio1-func:\n+ const: gpio\n+ required:\n+ - adi,pgio1-func\n+ then:\n+ required:\n+ - gpio-controller\n+ - '#gpio-cells'\n+\n+ - if:\n+ properties:\n+ adi,pgio2-func:\n+ const: gpio\n+ required:\n+ - adi,pgio2-func\n+ then:\n+ required:\n+ - gpio-controller\n+ - '#gpio-cells'\n+\n+ - if:\n+ properties:\n+ adi,pgio3-func:\n+ const: gpio\n+ required:\n+ - adi,pgio3-func\n+ then:\n+ required:\n+ - gpio-controller\n+ - '#gpio-cells'\n+\n+ - if:\n+ properties:\n+ adi,pgio4-func:\n+ const: gpio\n+ required:\n+ - adi,pgio4-func\n+ then:\n+ properties:\n+ adi,external-fault-retry-enable: false\n+ adi,external-fault-fet-off-enable: false\n+ required:\n+ - gpio-controller\n+ - '#gpio-cells'\n+\n+additionalProperties: false\n+\n+examples:\n+ - |\n+ i2c {\n+ #address-cells = <1>;\n+ #size-cells = <0>;\n+\n+ swap-controller@15 {\n+ compatible = \"adi,ltc4283\";\n+ reg = <0x15>;\n+\n+ adi,rsense-nano-ohms = <500>;\n+ adi,current-limit-sense-microvolt = <25000>;\n+ adi,current-limit-foldback-factor = <10>;\n+ adi,cooling-delay-ms = <8190>;\n+ adi,fet-bad-timer-delay-ms = <512>;\n+\n+ adi,external-fault-fet-off-enable;\n+ adi,pgio4-func = \"external_fault\";\n+\n+ adi,gpio-on-adio1;\n+ adi,pgio1-func = \"gpio\";\n+ gpio-controller;\n+ #gpio-cells = <2>;\n+ };\n+ };\n+...\ndiff --git a/MAINTAINERS b/MAINTAINERS\nindex e008c2bcc187..3f727d7fdfa4 100644\n--- a/MAINTAINERS\n+++ b/MAINTAINERS\n@@ -15161,6 +15161,12 @@ F:\tDocumentation/devicetree/bindings/hwmon/adi,ltc4282.yaml\n F:\tDocumentation/hwmon/ltc4282.rst\n F:\tdrivers/hwmon/ltc4282.c\n \n+LTC4283 HARDWARE MONITOR AND GPIO DRIVER\n+M:\tNuno Sá \n+L:\tlinux-hwmon@vger.kernel.org\n+S:\tSupported\n+F:\tDocumentation/devicetree/bindings/hwmon/adi,ltc4283.yaml\n+\n LTC4286 HARDWARE MONITOR DRIVER\n M:\tDelphine CC Chiu \n L:\tlinux-hwmon@vger.kernel.org\n","prefixes":["v10","1/3"]}