[PATCH v1 8/9] dt-bindings: iio: afe: add binding for temperature-sense-current

Liam Beguin
2021-05-30T00:59:55Z

From: Liam Beguin <lvb@xiphos.com>

An ADC is often used to measure other quantities indirectly. This
binding describe one cases, the measurement of a temperature through
a current sense amplifier (such as an AD590) and a sense resistor.

Signed-off-by: Liam Beguin <lvb@xiphos.com>
---
.../iio/afe/temperature-sense-current.yaml | 61 +++++++++++++++++++
MAINTAINERS | 1 +
2 files changed, 62 insertions(+)
create mode 100644 Documentation/devicetree/bindings/iio/afe/temperature-sense-current.yaml

diff --git a/Documentation/devicetree/bindings/iio/afe/temperature-sense-current.yaml b/Documentation/devicetree/bindings/iio/afe/temperature-sense-current.yaml
new file mode 100644
index 000000000000..1bac74486102
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/afe/temperature-sense-current.yaml
@@ -0,0 +1,61 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/afe/temperature-sense-current.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Temperature Sense Current
+
+maintainers:
+ - Liam Beguin <lvb@xiphos.com>
+
+description: |
+ When an io-channel measures the output voltage for a temperature current
+ sense amplifier such as the AD950, the interesting measurement is almost
+ always the corresponding temperature, not the voltage output.
+ This binding describes such a circuit.
+
+properties:
+ compatible:
+ const: temperature-sense-current
+
+ io-channels:
+ maxItems: 1
+ description: |
+ Channel node of a voltage io-channel.
+
+ '#io-channel-cells':
+ const: 1
+
+ sense-resistor-ohms:
+ description: The sense resistance.
+
+ alpha-micro-amps-per-degree:
+ description: |
+ Linear output current gain of the temperature IC.
+
+ use-kelvin-scale:
+ type: boolean
+ description: |
+ Boolean indicating if alpha uses Kelvin degrees instead of Celsius.
+
+additionalProperties: false
+required:
+ - compatible
+ - io-channels
+ - sense-resistor-ohms
+ - alpha-micro-amps-per-degree
+
+examples:
+ - |
+ ad590: iio-rescale0 {
+ compatible = "temperature-sense-current";
+ #io-channel-cells = <1>;
+ io-channels = <&temp_adc 2>;
+
+ sense-resistor-ohms = <8060>;
+ use-kelvin-scale;
+ alpha-micro-amps-per-degree = <1>;
+ };
+
+...
diff --git a/MAINTAINERS b/MAINTAINERS
index a7279af85adb..0eb7fcd94b66 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8721,6 +8721,7 @@ L: linux-iio@vger.kernel.org
S: Maintained
F: Documentation/devicetree/bindings/iio/afe/current-sense-amplifier.yaml
F: Documentation/devicetree/bindings/iio/afe/current-sense-shunt.yaml
+F: Documentation/devicetree/bindings/iio/afe/temperature-sense-current.yaml
F: Documentation/devicetree/bindings/iio/afe/temperature-sense-rtd.yaml
F: Documentation/devicetree/bindings/iio/afe/voltage-divider.yaml
F: drivers/iio/afe/iio-rescale.c
--
2.30.1.489.g328c10930387