linux-kernel - [PATCH v5 1/2] dt-bindings: mux: gpio-mux: add enable-gpios support

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20260123145743.75705-2-antoniu.miclaus@analog.com>
Date: Fri, 23 Jan 2026 16:57:31 +0200
From: Antoniu Miclaus <antoniu.miclaus@...log.com>
To: Peter Rosin <peda@...ntia.se>, Rob Herring <robh@...nel.org>,
        Krzysztof
 Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Antoniu
 Miclaus <antoniu.miclaus@...log.com>,
        Srinivas Kandagatla <srini@...nel.org>,
        Bartosz Golaszewski <brgl@...nel.org>,
        Johan Hovold
	<johan+linaro@...nel.org>,
        David Lechner <dlechner@...libre.com>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH v5 1/2] dt-bindings: mux: gpio-mux: add enable-gpios support

Add support for an optional enable GPIO that allows the multiplexer
to be disabled before changing address lines and re-enabled after,
preventing glitches during channel transitions.

This is useful for devices like the Analog Devices ADG2404 (4:1 mux)
that benefit from enable control to ensure clean channel switching.

Signed-off-by: Antoniu Miclaus <antoniu.miclaus@...log.com>
---
Changes in v5:
 - Expand enable-gpios description to explain high-impedance (high-Z)
   behavior when mux is disabled
 - Describe analog multiplexer use case where downstream capacitance
   maintains signal level during brief disconnection
 - Remove separate ADG2404 example, add enable-gpios to existing example
---
 .../devicetree/bindings/mux/gpio-mux.yaml        | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/Documentation/devicetree/bindings/mux/gpio-mux.yaml b/Documentation/devicetree/bindings/mux/gpio-mux.yaml
index ef7e33ec85d4..798e0a73d77b 100644
--- a/Documentation/devicetree/bindings/mux/gpio-mux.yaml
+++ b/Documentation/devicetree/bindings/mux/gpio-mux.yaml
@@ -17,6 +17,9 @@ description: |+
   multiplexer GPIO pins, where the first pin is the least significant
   bit. An active pin is a binary 1, an inactive pin is a binary 0.
 
+  This binding supports GPIO-controlled multiplexers such as the Analog
+  Devices ADG2404 (4:1 mux with enable control).
+
 properties:
   compatible:
     const: gpio-mux
@@ -25,6 +28,18 @@ properties:
     description:
       List of gpios used to control the multiplexer, least significant bit first.
 
+  enable-gpios:
+    description: |
+      Optional GPIO to enable the multiplexer. When present, the mux is
+      disabled before changing address lines and re-enabled after. This
+      prevents glitches where an unintended channel could be briefly activated
+      during address line transitions. When disabled, all outputs enter a
+      high-impedance (high-Z) state rather than holding their previous value.
+      This is suitable for analog multiplexers where downstream capacitance
+      maintains the signal level during the brief disconnection.
+      Required for MUX_IDLE_DISCONNECT idle-state.
+    maxItems: 1
+
   mux-supply:
     description:
       Regulator to power on the multiplexer.
@@ -59,6 +74,7 @@ examples:
 
         mux-gpios = <&pioA 0 GPIO_ACTIVE_HIGH>,
               <&pioA 1 GPIO_ACTIVE_HIGH>;
+        enable-gpios = <&pioA 2 GPIO_ACTIVE_HIGH>;
     };
 
     adc-mux {
-- 
2.43.0