From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Sun, 7 Apr 2024 20:49:45 +0200
Subject: Adding upstream version 6.1.76.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 .../bindings/iio/afe/voltage-divider.yaml          | 86 ++++++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/afe/voltage-divider.yaml

(limited to 'Documentation/devicetree/bindings/iio/afe/voltage-divider.yaml')

diff --git a/Documentation/devicetree/bindings/iio/afe/voltage-divider.yaml b/Documentation/devicetree/bindings/iio/afe/voltage-divider.yaml
new file mode 100644
index 000000000..df2589f21
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/afe/voltage-divider.yaml
@@ -0,0 +1,86 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/afe/voltage-divider.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Voltage divider
+
+maintainers:
+  - Peter Rosin <peda@axentia.se>
+
+description: |
+  When an io-channel measures the midpoint of a voltage divider, the
+  interesting voltage is often the voltage over the full resistance
+  of the divider. This binding describes the voltage divider in such
+  a curcuit.
+
+    Vin ----.
+            |
+         .-----.
+         |  R  |
+         '-----'
+            |
+            +---- Vout
+            |
+         .-----.
+         | Rout|
+         '-----'
+            |
+           GND
+
+
+properties:
+  compatible:
+    const: voltage-divider
+
+  io-channels:
+    maxItems: 1
+    description: |
+      Channel node of a voltage io-channel.
+
+  output-ohms:
+    description:
+      Resistance Rout over which the output voltage is measured. See full-ohms.
+
+  full-ohms:
+    description:
+      Resistance R + Rout for the full divider. The io-channel is scaled by
+      the Rout / (R + Rout) quotient.
+
+required:
+  - compatible
+  - io-channels
+  - output-ohms
+  - full-ohms
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    /*
+     * The system voltage is circa 12V, but divided down with a 22/222
+     * voltage divider (R = 200 Ohms, Rout = 22 Ohms) and fed to an ADC.
+     */
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        maxadc: adc@0 {
+            compatible = "maxim,max1027";
+            reg = <0>;
+            #io-channel-cells = <1>;
+            interrupt-parent = <&gpio5>;
+            interrupts = <15 IRQ_TYPE_EDGE_RISING>;
+            spi-max-frequency = <1000000>;
+        };
+    };
+    sysv {
+        compatible = "voltage-divider";
+        io-channels = <&maxadc 1>;
+
+        /* Scale the system voltage by 22/222 to fit the ADC range. */
+        output-ohms = <22>;
+        full-ohms = <222>; /* 200 + 22 */
+    };
+...
-- 
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