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From:   Linus Walleij <linus.walleij@linaro.org>
Date:   Tue, 12 Sep 2023 15:44:30 +0200
Subject: [PATCH 1/2] dt-bindings: leds: Mention GPIO triggers
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Message-Id: <20230912-gpio-led-trigger-dt-v1-1-1b50e3756dda@linaro.org>
References: <20230912-gpio-led-trigger-dt-v1-0-1b50e3756dda@linaro.org>
In-Reply-To: <20230912-gpio-led-trigger-dt-v1-0-1b50e3756dda@linaro.org>
To:     =?utf-8?q?Jan_Kundr=C3=A1t?= <jan.kundrat@cesnet.cz>,
        Pavel Machek <pavel@ucw.cz>, Lee Jones <lee@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Jacek Anaszewski <jacek.anaszewski@gmail.com>
Cc:     linux-leds@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Linus Walleij <linus.walleij@linaro.org>
Precedence: bulk

We reuse the trigger-sources phandle to just point to
GPIOs we may want to use as LED triggers.

Example:

gpio: gpio@0 {
    compatible "my-gpio";
    gpio-controller;
    #gpio-cells = <2>;
    interrupt-controller;
    #interrupt-cells = <2>;
    #trigger-source-cells = <2>;
};

leds {
    compatible = "gpio-leds";
    led-my-gpio {
        label = "device:blue:myled";
        gpios = <&gpio 0 GPIO_ACTIVE_HIGH>;
        default-state = "off";
        linux,default-trigger = "gpio";
        trigger-sources = <&gpio 1 GPIO_ACTIVE_HIGH>;
    };
};

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 Documentation/devicetree/bindings/leds/common.yaml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/leds/common.yaml b/Documentation/devicetree/bindings/leds/common.yaml
index 5fb7007f3618..b42950643b9d 100644
--- a/Documentation/devicetree/bindings/leds/common.yaml
+++ b/Documentation/devicetree/bindings/leds/common.yaml
@@ -191,6 +191,8 @@ properties:
       each of them having its own LED assigned (assuming they are not
       hardwired). In such cases this property should contain phandle(s) of
       related source device(s).
+      Another example is a GPIO line that will be monitored and mirror the
+      state of the line (with or without inversion flags) to the LED.
       In many cases LED can be related to more than one device (e.g. one USB LED
       vs. multiple USB ports). Each source should be represented by a node in
       the device tree and be referenced by a phandle and a set of phandle

-- 
2.34.1