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From 9444edfa8b5b18f8727b82853dd50345a400a316 Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.com>
Date: Thu, 22 Oct 2020 17:11:12 +0100
Subject: [PATCH] overlays: Add MAX31856 support to maxtherm overlay
Extend the maxtherm overlay with support for the MAX31856.
The driver reads the thermocouple type from a property, which is much
more civilised.
See: https://github.com/raspberrypi/linux/issues/3915
Signed-off-by: Phil Elwell <phil@raspberrypi.com>
---
arch/arm/boot/dts/overlays/README | 18 ++++++++++++-----
.../boot/dts/overlays/maxtherm-overlay.dts | 20 +++++++++++++++++++
2 files changed, 33 insertions(+), 5 deletions(-)
--- a/arch/arm/boot/dts/overlays/README
+++ b/arch/arm/boot/dts/overlays/README
@@ -1666,20 +1666,19 @@ Params: no-sdmode Driver d
Name: maxtherm
-Info: Configure a MAX6675 or MAX31855 thermocouple as an IIO device.
+Info: Configure a MAX6675, MAX31855 or MAX31856 thermocouple as an IIO device.
For devices on spi1 or spi2, the interfaces should be enabled
with one of the spi1-1/2/3cs and/or spi2-1/2/3cs overlays.
The overlay expects to disable the relevant spidev node, so also using
e.g. cs0_spidev=off is unnecessary.
- Note: with the 5.7 kernel (and later) there will also be
- overlays for MAX31855E, MAX31855J, MAX31855K,
- MAX31885N, MAX31855R, MAX31855S and MAX31855T.
-
Example:
MAX31855 on /dev/spidev0.0
dtoverlay=maxtherm,spi0-0,max31855
+ MAX31856 using a type J thermocouple on /dev/spidev2.1
+ dtoverlay=spi2-2cs
+ dtoverlay=maxtherm,spi2-1,max31856,type_j
Load: dtoverlay=maxtherm,<param>=<val>
Params: spi<n>-<m> Configure device at spi<n>, cs<m>
@@ -1693,6 +1692,15 @@ Params: spi<n>-<m> Configur
max31855r Enable support for the MAX31855R
max31855s Enable support for the MAX31855S
max31855t Enable support for the MAX31855T
+ max31856 Enable support for the MAX31856 (with type K)
+ type_b Select a type B sensor for max31856
+ type_e Select a type E sensor for max31856
+ type_j Select a type J sensor for max31856
+ type_k Select a type K sensor for max31856
+ type_n Select a type N sensor for max31856
+ type_r Select a type R sensor for max31856
+ type_s Select a type S sensor for max31856
+ type_t Select a type T sensor for max31856
Name: mbed-dac
--- a/arch/arm/boot/dts/overlays/maxtherm-overlay.dts
+++ b/arch/arm/boot/dts/overlays/maxtherm-overlay.dts
@@ -5,6 +5,8 @@
/dts-v1/;
/plugin/;
+#include <dt-bindings/iio/temperature/thermocouple.h>
+
/ {
compatible = "brcm,bcm2835";
@@ -128,6 +130,15 @@
};
};
+ fragment@16 {
+ target = <&max>;
+ __dormant__ {
+ compatible = "maxim,max31856";
+ spi-cpha;
+ thermocouple-type = <THERMOCOUPLE_TYPE_K>;
+ };
+ };
+
__overrides__ {
spi0-0 = <0>, "+0",
<&maxfrag>,"target:0=",<&spi0>,
@@ -162,5 +173,14 @@
max31855r = <0>,"+13";
max31855s = <0>,"+14";
max31855t = <0>,"+15";
+ max31856 = <0>,"+16";
+ type_b = <&max>,"thermocouple-type:0=",<THERMOCOUPLE_TYPE_B>;
+ type_e = <&max>,"thermocouple-type:0=",<THERMOCOUPLE_TYPE_E>;
+ type_j = <&max>,"thermocouple-type:0=",<THERMOCOUPLE_TYPE_J>;
+ type_k = <&max>,"thermocouple-type:0=",<THERMOCOUPLE_TYPE_K>;
+ type_n = <&max>,"thermocouple-type:0=",<THERMOCOUPLE_TYPE_N>;
+ type_r = <&max>,"thermocouple-type:0=",<THERMOCOUPLE_TYPE_R>;
+ type_s = <&max>,"thermocouple-type:0=",<THERMOCOUPLE_TYPE_S>;
+ type_t = <&max>,"thermocouple-type:0=",<THERMOCOUPLE_TYPE_T>;
};
};
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