dts: bindings: comparator

add comparator DTS description

Signed-off-by: Alexander Kozhinov <[email protected]>

Author: KozhinovAlexander

dts/bindings/comparator/st,stm32-comp.yaml

@@ -0,0 +1,118 @@
+# Copyright (c) 2025 Alexander Kozhinov <[email protected]>
+# SPDX-License-Identifier: Apache-2.0
+
+description: |
+  STM32 Comparator
+
+  The following example displays the minimum node layout:
+
+    comp1: comparator@deadbeef {
+        compatible = "st,stm32-comp";
+        positive-input = "IN0";
+        negative-input = "VREFINT";
+        status = "disabled";
+    };
+
+  Enabling the comparator node requires setting the minimum default
+  configuration of the comparator. This includes selecting the
+  positive and negative inputs, and routing them using pinctrl:
+
+    &pinctrl {
+        comp1_default: comp1_default {
+            ...
+        };
+    };
+
+    &comp1 {
+        status = "okay";
+        pinctrl-0 = <&comp1_default>;
+        pinctrl-names = "default";
+
+        positive-input = "IN0";
+        negative-input = "VREFINT";
+    };
+
+compatible: "st,stm32-comp"
+
+include:
+  - base.yaml
+  - pinctrl-device.yaml
+
+properties:
+  interrupts:
+    required: true
+
+  reg:
+    required: true
+
+  hysteresis:
+    type: string
+    description: |
+      Selects the hysteresis voltage level.
+      Hysteresis adds a voltage offset to the comparator threshold to prevent
+      unwanted output toggling when the input voltage is noisy or slowly
+      varying around the comparator threshold.
+
+  invert-output:
+    type: string
+    enum:
+      - NONINVERTED
+      - INVERTED
+    default: NONINVERTED
+
+  st,exti-line:
+    required: true
+    type: int
+    description: |
+      Extended Interrupts and Event Controller (EXTI) interrupt
+      line number connected to the COMPx event.
+
+  st,lock-enable:
+    type: boolean
+
+  st,blank-sel:
+    type: string
+    description: |
+      The purpose of the blanking function is to prevent the current regulation
+      from tripping upon short current spikes at the beginning of PWM period
+      (typically the recovery current in power switch anti-parallel diodes).
+      This goes through setting a dead window defined with a timer output
+      compare signal. The blanking source is selected individually per
+      comparator channel. The inverted blanking signal is logical AND-ed with
+      the comparator stage output to produce the comparator channel x output.
+      source: STM32G4 Reference Manual (RM0440 Rev 8, page 768, chapter 24.3.6)
+
+  positive-input:
+    required: true
+    type: string
+    description: |
+      Selects positive input pin given by pinmux controller. This input can be
+      typically assigned to one of the predefinded package pins.
+      IN0 will correspond to first pinmux pin option and IN1 to the second one.
+    enum:
+      - IN0
+      - IN1
+    default: IN0
+
+  negative-input:
+    required: true
+    type: string
+    description: |
+      Selects negative input pin given by pinmux controller.
+      This input can be typically assigned to one of the predefinded package pins
+      or to one of internal signals like VREF_INT or DAC.
+      In case of package pin assignment IN0 will correspond to first pinmux pin
+      option and IN1 to the second one.
+
+  st,miller-effect-hold-enable:
+    type: boolean
+    description: |
+      Miller effect is a hidden feature of stm32, which may be enabled by setting
+      bit 1 of COMP_CxCSR register.
+      for more info see:
+        https://community.st.com/t5/stm32-mcus-products/stm32g431-comparator-bug/m-p/679540#M250779
+
+  st,power-mode:
+    type: string
+    description: |
+      Power mode is not supported by all stm32 series.