dt-bindings: iio: adc: meson-saradc: add temperature sensor support

The 32-bit Meson8 SoC can use the SAR ADC to read the chip temperature.
This requires setting the correct TSC (temperature sensor coefficient),
which is programmed into the eFuse during the manufacturing process.
Meson8b and Meson8m2 are not supported yet because they have a 5-bit TSC
and only the first four bits are stored inside the SAR ADC registers.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/Documentation/devicetree/bindings/iio/adc/amlogic,meson-saradc.txt b/Documentation/devicetree/bindings/iio/adc/amlogic,meson-saradc.txt
index 54b823f3a45301d63ff594783f07b015e7f6c5d2..325090e43ce6b226972ea1b0efbd1df5157133cf 100644 (file)
--- a/Documentation/devicetree/bindings/iio/adc/amlogic,meson-saradc.txt
+++ b/Documentation/devicetree/bindings/iio/adc/amlogic,meson-saradc.txt
@@ -22,6 +22,12 @@ Required properties:
 - vref-supply: the regulator supply for the ADC reference voltage
 - #io-channel-cells: must be 1, see ../iio-bindings.txt
 
+Optional properties:
+- nvmem-cells:         phandle to the temperature_calib eFuse cells
+- nvmem-cell-names:    if present (to enable the temperature sensor
+                       calibration) this must contain "temperature_calib"
+
+
 Example:
        saradc: adc@8680 {
                compatible = "amlogic,meson-gxl-saradc", "amlogic,meson-saradc";