1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
|
From 56e726d1631c9551530b8db4127352c64c3cb94d Mon Sep 17 00:00:00 2001
From: Dougie Lawson <dl1ims@gmail.com>
Date: Mon, 27 Jul 2020 23:52:40 +0100
Subject: [PATCH] overlays: Add maxtherm overlay for MAX6675/31855
Add an overlay - maxtherm - to support the MAX6675 and MAX31855 family
of thermocouples.
Developed from an original set of overlays by Dougie Lawson.
See: https://github.com/raspberrypi/linux/pull/3763
Signed-off-by: Phil Elwell <phil@raspberrypi.com>
---
arch/arm/boot/dts/overlays/Makefile | 1 +
arch/arm/boot/dts/overlays/README | 30 ++++
.../boot/dts/overlays/maxtherm-overlay.dts | 166 ++++++++++++++++++
3 files changed, 197 insertions(+)
create mode 100644 arch/arm/boot/dts/overlays/maxtherm-overlay.dts
--- a/arch/arm/boot/dts/overlays/Makefile
+++ b/arch/arm/boot/dts/overlays/Makefile
@@ -98,6 +98,7 @@ dtbo-$(CONFIG_ARCH_BCM2835) += \
justboom-digi.dtbo \
ltc294x.dtbo \
max98357a.dtbo \
+ maxtherm.dtbo \
mbed-dac.dtbo \
mcp23017.dtbo \
mcp23s17.dtbo \
--- a/arch/arm/boot/dts/overlays/README
+++ b/arch/arm/boot/dts/overlays/README
@@ -1622,6 +1622,36 @@ Params: no-sdmode Driver d
of the DAC (default GPIO4 if parameter omitted).
+Name: maxtherm
+Info: Configure a MAX6675 or MAX31855 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
+
+Load: dtoverlay=maxtherm,<param>=<val>
+Params: spi<n>-<m> Configure device at spi<n>, cs<m>
+ (boolean, required)
+ max6675 Enable support for the MAX6675 (default)
+ max31855 Enable support for the MAX31855
+ max31855e Enable support for the MAX31855E
+ max31855j Enable support for the MAX31855J
+ max31855k Enable support for the MAX31855K
+ max31855n Enable support for the MAX31855N
+ max31855r Enable support for the MAX31855R
+ max31855s Enable support for the MAX31855S
+ max31855t Enable support for the MAX31855T
+
+
Name: mbed-dac
Info: Configures the mbed AudioCODEC (TLV320AIC23B)
Load: dtoverlay=mbed-dac
--- /dev/null
+++ b/arch/arm/boot/dts/overlays/maxtherm-overlay.dts
@@ -0,0 +1,166 @@
+/*
+ * Universal device tree overlay for SPI devices
+ */
+
+/dts-v1/;
+/plugin/;
+
+/ {
+ compatible = "brcm,bcm2835";
+
+ fragment@0 {
+ target = <&spidev0>;
+ __dormant__ {
+ status = "disabled";
+ };
+ };
+
+ fragment@1 {
+ target = <&spidev1>;
+ __dormant__ {
+ status = "disabled";
+ };
+ };
+
+ fragment@2 {
+ target-path = "spi1/spidev@0";
+ __dormant__ {
+ status = "disabled";
+ };
+ };
+
+ fragment@3 {
+ target-path = "spi1/spidev@1";
+ __dormant__ {
+ status = "disabled";
+ };
+ };
+
+ fragment@4 {
+ target-path = "spi1/spidev@2";
+ __dormant__ {
+ status = "disabled";
+ };
+ };
+
+ fragment@5 {
+ target-path = "spi2/spidev@0";
+ __dormant__ {
+ status = "disabled";
+ };
+ };
+
+ fragment@6 {
+ target-path = "spi2/spidev@1";
+ __dormant__ {
+ status = "disabled";
+ };
+ };
+
+ fragment@7 {
+ target-path = "spi2/spidev@2";
+ __dormant__ {
+ status = "disabled";
+ };
+ };
+
+ maxfrag: fragment@8 {
+ target = <&spi0>;
+ __overlay__ {
+ status = "okay";
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ max: maxtherm@0 {
+ compatible = "maxim,max6675";
+ reg = <0>;
+ spi-max-frequency = <500000>;
+ };
+ };
+ };
+
+ fragment@9 {
+ target = <&max>;
+ __dormant__ {
+ compatible = "maxim,max31855e", "maxim,max31855";
+ };
+ };
+
+ fragment@10 {
+ target = <&max>;
+ __dormant__ {
+ compatible = "maxim,max31855j", "maxim,max31855";
+ };
+ };
+
+ fragment@11 {
+ target = <&max>;
+ __dormant__ {
+ compatible = "maxim,max31855k", "maxim,max31855";
+ };
+ };
+
+ fragment@12 {
+ target = <&max>;
+ __dormant__ {
+ compatible = "maxim,max31855n", "maxim,max31855";
+ };
+ };
+
+ fragment@13 {
+ target = <&max>;
+ __dormant__ {
+ compatible = "maxim,max31855r", "maxim,max31855";
+ };
+ };
+
+ fragment@14 {
+ target = <&max>;
+ __dormant__ {
+ compatible = "maxim,max31855s", "maxim,max31855";
+ };
+ };
+
+ fragment@15 {
+ target = <&max>;
+ __dormant__ {
+ compatible = "maxim,max31855t", "maxim,max31855";
+ };
+ };
+
+ __overrides__ {
+ spi0-0 = <0>, "+0",
+ <&maxfrag>,"target:0=",<&spi0>,
+ <&max>,"reg:0=0";
+ spi0-1 = <0>, "+1",
+ <&maxfrag>,"target:0=",<&spi0>,
+ <&max>,"reg:0=1";
+ spi1-0 = <0>, "+2",
+ <&maxfrag>,"target:0=",<&spi1>,
+ <&max>,"reg:0=0";
+ spi1-1 = <0>, "+3",
+ <&maxfrag>,"target:0=",<&spi1>,
+ <&max>,"reg:0=1";
+ spi1-2 = <0>, "+4",
+ <&maxfrag>,"target:0=",<&spi1>,
+ <&max>,"reg:0=2";
+ spi2-0 = <0>, "+5",
+ <&maxfrag>,"target:0=",<&spi2>,
+ <&max>,"reg:0=0";
+ spi2-1 = <0>, "+6",
+ <&maxfrag>,"target:0=",<&spi2>,
+ <&max>,"reg:0=1";
+ spi2-2 = <0>, "+7",
+ <&maxfrag>,"target:0=",<&spi2>,
+ <&max>,"reg:0=2";
+ max6675 = <&max>,"compatible=maxim,max6675";
+ max31855 = <&max>,"compatible=maxim,max31855";
+ max31855e = <0>,"+9";
+ max31855j = <0>,"+10";
+ max31855k = <0>,"+11";
+ max31855n = <0>,"+12";
+ max31855r = <0>,"+13";
+ max31855s = <0>,"+14";
+ max31855t = <0>,"+15";
+ };
+};
|
