iio: temperature: add support for Maxim thermocouple chips

Add initial driver support for MAX6675, and MAX31855 thermocouple chips.

Cc: Marek Vasut <marex@denx.de>
Cc: Matt Porter <mporter@konsulko.com>
Signed-off-by: Matt Ranostay <mranostay@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

1 files changed, 21 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/iio/temperature/maxim_thermocouple.txt b/Documentation/devicetree/bindings/iio/temperature/maxim_thermocouple.txt
new file mode 100644
index 000000000000..28bc5c4d965b
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/temperature/maxim_thermocouple.txt
@@ -0,0 +1,21 @@
+Maxim thermocouple support
+
+* https://datasheets.maximintegrated.com/en/ds/MAX6675.pdf
+* https://datasheets.maximintegrated.com/en/ds/MAX31855.pdf
+
+Required properties:
+
+	- compatible: must be "maxim,max31855" or "maxim,max6675"
+	- reg: SPI chip select number for the device
+	- spi-max-frequency: must be 4300000
+	- spi-cpha: must be defined for max6675 to enable SPI mode 1
+
+	Refer to spi/spi-bus.txt for generic SPI slave bindings.
+
+Example:
+
+	max31855@0 {
+		compatible = "maxim,max31855";
+		reg = <0>;
+		spi-max-frequency = <4300000>;
+	};