From: Markus Probst <markus.probst@posteo.de>
Add the Synology Microp devicetree bindings. Those devices are
microcontrollers found on Synology NAS devices. They are connected to a
serial port on the host device.
Those devices are used to control certain LEDs, fan speeds, a beeper, to
handle buttons, fan failures and to properly shutdown and reboot the
device.
Signed-off-by: Markus Probst <markus.probst@posteo.de>
---
.../synology,ds923p-microp.yaml | 65 ++++++++++++++++++++++
1 file changed, 65 insertions(+)
diff --git a/Documentation/devicetree/bindings/embedded-controller/synology,ds923p-microp.yaml b/Documentation/devicetree/bindings/embedded-controller/synology,ds923p-microp.yaml
new file mode 100644
index 000000000000..599d32ce2be9
--- /dev/null
+++ b/Documentation/devicetree/bindings/embedded-controller/synology,ds923p-microp.yaml
@@ -0,0 +1,65 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/embedded-controller/synology,ds923p-microp.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Synology NAS on-board Microcontroller
+
+maintainers:
+ - Markus Probst <markus.probst@posteo.de>
+
+description: |
+ Synology Microp is a microcontroller found in Synology NAS devices.
+ It is connected to a serial port on the host device.
+
+ It is necessary to properly shutdown and reboot the NAS device and
+ provides additional functionality such as led control, fan speed control,
+ a beeper and buttons on the NAS device.
+
+properties:
+ compatible:
+ enum:
+ - synology,ds923p-microp
+ - synology,ds918p-microp
+ - synology,ds214play-microp
+ - synology,ds225p-microp
+ - synology,ds425p-microp
+ - synology,ds710p-microp
+ - synology,ds1010p-microp
+ - synology,ds723p-microp
+ - synology,ds1522p-microp
+ - synology,rs422p-microp
+ - synology,ds725p-microp
+ - synology,ds118-microp
+ - synology,ds124-microp
+ - synology,ds223-microp
+ - synology,ds223j-microp
+ - synology,ds1823xsp-microp
+ - synology,rs822p-microp
+ - synology,rs1221p-microp
+ - synology,rs1221rpp-microp
+ - synology,ds925p-microp
+ - synology,ds1525p-microp
+ - synology,ds1825p-microp
+
+ fan-failure-gpios:
+ description: GPIOs needed to determine which fans stopped working on a fan failure event.
+ minItems: 2
+ maxItems: 3
+
+required:
+ - compatible
+
+additionalProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/leds/common.h>
+ #include <dt-bindings/gpio/gpio.h>
+
+ embedded-controller {
+ compatible = "synology,ds923p-microp";
+
+ fan-failure-gpios = <&gpio 68 GPIO_ACTIVE_HIGH>, <&gpio 69 GPIO_ACTIVE_HIGH>;
+ };
--
2.52.0On Sun, Mar 29, 2026 at 08:02:15PM +0200, Markus Probst wrote: > +properties: > + compatible: > + enum: > + - synology,ds923p-microp > + - synology,ds918p-microp > + - synology,ds214play-microp > + - synology,ds225p-microp > + - synology,ds425p-microp > + - synology,ds710p-microp > + - synology,ds1010p-microp > + - synology,ds723p-microp > + - synology,ds1522p-microp > + - synology,rs422p-microp > + - synology,ds725p-microp > + - synology,ds118-microp > + - synology,ds124-microp > + - synology,ds223-microp > + - synology,ds223j-microp > + - synology,ds1823xsp-microp > + - synology,rs822p-microp > + - synology,rs1221p-microp > + - synology,rs1221rpp-microp > + - synology,ds925p-microp > + - synology,ds1525p-microp > + - synology,ds1825p-microp Last time you had one compatible and implied they are all compatible. Now none of them are compatible, which might be accurate, but nothing explains WHY they are not compatible in the commit msg. > + > + fan-failure-gpios: > + description: GPIOs needed to determine which fans stopped working on a fan failure event. > + minItems: 2 > + maxItems: 3 Constraints cannot be flexible. You need allOf:if:then: block to narrow them per variant. Best regards, Krzysztof
On Mon, 2026-03-30 at 08:51 +0200, Krzysztof Kozlowski wrote: > On Sun, Mar 29, 2026 at 08:02:15PM +0200, Markus Probst wrote: > > +properties: > > + compatible: > > + enum: > > + - synology,ds923p-microp > > + - synology,ds918p-microp > > + - synology,ds214play-microp > > + - synology,ds225p-microp > > + - synology,ds425p-microp > > + - synology,ds710p-microp > > + - synology,ds1010p-microp > > + - synology,ds723p-microp > > + - synology,ds1522p-microp > > + - synology,rs422p-microp > > + - synology,ds725p-microp > > + - synology,ds118-microp > > + - synology,ds124-microp > > + - synology,ds223-microp > > + - synology,ds223j-microp > > + - synology,ds1823xsp-microp > > + - synology,rs822p-microp > > + - synology,rs1221p-microp > > + - synology,rs1221rpp-microp > > + - synology,ds925p-microp > > + - synology,ds1525p-microp > > + - synology,ds1825p-microp > > Last time you had one compatible and implied they are all compatible. > Now none of them are compatible, which might be accurate, As you mentioned earlier: Unless exactly same board is used in different models (unlikely) then the compatible defines the LEDs and they are not needed in DT. > > but nothing > explains WHY they are not compatible in the commit msg. Shall all 22 compatible be in the commit msg? Also, might be worth documenting this requirement [1]. > > > + > > + fan-failure-gpios: > > + description: GPIOs needed to determine which fans stopped working on a fan failure event. > > + minItems: 2 > > + maxItems: 3 > > Constraints cannot be flexible. You need allOf:if:then: block to narrow > them per variant. I can disable the property or force the property based on compatible with it. But it seems it won't let me modify the minItems and maxItems constraint. Thanks - Markus Probst [1] https://docs.kernel.org/devicetree/bindings/submitting-patches.html > > Best regards, > Krzysztof
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