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
|
From 4a314a9b9d91cacbf6be9dd521cf3abd3ae8bcef Mon Sep 17 00:00:00 2001
From: menschel <menschel.p@posteo.de>
Date: Wed, 30 Dec 2020 21:55:34 +0100
Subject: [PATCH] Add overlay for Seeed Studio CAN BUS FD HAT (#4034)
This patch adds the overlay for the Seeed Studio CAN BUS FD HAT
with two CAN FD Channels and an RTC.
https://www.seeedstudio.com/CAN-BUS-FD-HAT-for-Raspberry-Pi-p-4742.html
The overlay was generated by
ovmerge -c mcp251xfd-overlay.dts,spi0-0,interrupt=25 \
mcp251xfd-overlay.dts,spi0-1,interrupt=24 \
i2c-rtc-overlay.dts,pcf85063
Also, add description on how to generate overlays
Signed-off-by: Patrick Menschel <menschel.p@posteo.de>
---
arch/arm/boot/dts/overlays/Makefile | 1 +
arch/arm/boot/dts/overlays/README | 46 +++++++
.../dts/overlays/seeed-can-fd-hat-overlay.dts | 117 ++++++++++++++++++
3 files changed, 164 insertions(+)
create mode 100644 arch/arm/boot/dts/overlays/seeed-can-fd-hat-overlay.dts
--- a/arch/arm/boot/dts/overlays/Makefile
+++ b/arch/arm/boot/dts/overlays/Makefile
@@ -159,6 +159,7 @@ dtbo-$(CONFIG_ARCH_BCM2835) += \
sc16is752-spi1.dtbo \
sdhost.dtbo \
sdio.dtbo \
+ seeed-can-fd-hat.dtbo \
sh1106-spi.dtbo \
smi.dtbo \
smi-dev.dtbo \
--- a/arch/arm/boot/dts/overlays/README
+++ b/arch/arm/boot/dts/overlays/README
@@ -81,6 +81,44 @@ Parameters usually have default values,
mandatory. See the list of overlays below for a description of the parameters
and their defaults.
+Making new Overlays based on existing Overlays
+==============================================
+
+Recent overlays have been designed in a more general way, so that they can be
+adapted to hardware by changing their parameters. When you have additional
+hardware with more than one device of a kind, you end up using the same overlay
+multiple times with other parameters, e.g.
+
+ # 2 CAN FD interfaces on spi but with different pins
+ dtoverlay=mcp251xfd,spi0-0,interrupt=25
+ dtoverlay=mcp251xfd,spi0-1,interrupt=24
+
+ # a realtime clock on i2c
+ dtoverlay=i2c-rtc,pcf85063
+
+While this approach does work, it requires knowledge about the hardware design.
+It is more feasible to simplify things for the end user by providing a single
+overlay as it is done the traditional way.
+
+A new overlay can be generated by using ovmerge utility.
+https://github.com/raspberrypi/utils/blob/master/ovmerge/ovmerge
+
+To generate an overlay for the above configuration we pass the configuration
+to ovmerge and add the -c flag.
+
+ ovmerge -c mcp251xfd-overlay.dts,spi0-0,interrupt=25 \
+ mcp251xfd-overlay.dts,spi0-1,interrupt=24 \
+ i2c-rtc-overlay.dts,pcf85063 \
+ >> merged-overlay.dts
+
+The -c option writes the command above as a comment into the overlay as
+a marker that this overlay is generated and how it was generated.
+After compiling the overlay it can be loaded in a single line.
+
+ dtoverlay=merged
+
+It does the same as the original configuration but without parameters.
+
The Overlay and Parameter Reference
===================================
@@ -2422,6 +2460,14 @@ Info: This overlay is now deprecated.
Load: <Deprecated>
+Name: seeed-can-fd-hat
+Info: Overlay for Seeed Studio CAN BUS FD HAT with two CAN FD channels and an
+ RTC.
+ https://www.seeedstudio.com/CAN-BUS-FD-HAT-for-Raspberry-Pi-p-4742.html
+Load: dtoverlay=seeed-can-fd-hat
+Params: <None>
+
+
Name: sh1106-spi
Info: Overlay for SH1106 OLED via SPI using fbtft staging driver.
Load: dtoverlay=sh1106-spi,<param>=<val>
--- /dev/null
+++ b/arch/arm/boot/dts/overlays/seeed-can-fd-hat-overlay.dts
@@ -0,0 +1,117 @@
+// redo: ovmerge -c mcp251xfd-overlay.dts,spi0-0,interrupt=25 mcp251xfd-overlay.dts,spi0-1,interrupt=24 i2c-rtc-overlay.dts,pcf85063
+
+// Device tree overlay for https://www.seeedstudio.com/CAN-BUS-FD-HAT-for-Raspberry-Pi-p-4742.html
+
+/dts-v1/;
+/plugin/;
+
+#include <dt-bindings/gpio/gpio.h>
+#include <dt-bindings/interrupt-controller/irq.h>
+#include <dt-bindings/pinctrl/bcm2835.h>
+
+/ {
+ compatible = "brcm,bcm2835";
+ fragment@0 {
+ target = <&spidev0>;
+ __overlay__ {
+ status = "disabled";
+ };
+ };
+ fragment@1 {
+ target = <&gpio>;
+ __overlay__ {
+ mcp251xfd_pins: mcp251xfd_spi0_0_pins {
+ brcm,pins = <25>;
+ brcm,function = <BCM2835_FSEL_GPIO_IN>;
+ };
+ };
+ };
+ fragment@2 {
+ target-path = "/clocks";
+ __overlay__ {
+ clk_mcp251xfd_osc: mcp251xfd-spi0-0-osc {
+ #clock-cells = <0>;
+ compatible = "fixed-clock";
+ clock-frequency = <40000000>;
+ };
+ };
+ };
+ fragment@3 {
+ target = <&spi0>;
+ __overlay__ {
+ status = "okay";
+ #address-cells = <1>;
+ #size-cells = <0>;
+ mcp251xfd@0 {
+ compatible = "microchip,mcp251xfd";
+ reg = <0>;
+ pinctrl-names = "default";
+ pinctrl-0 = <&mcp251xfd_pins>;
+ spi-max-frequency = <20000000>;
+ interrupt-parent = <&gpio>;
+ interrupts = <25 IRQ_TYPE_LEVEL_LOW>;
+ clocks = <&clk_mcp251xfd_osc>;
+ };
+ };
+ };
+ fragment@4 {
+ target = <&spidev1>;
+ __overlay__ {
+ status = "disabled";
+ };
+ };
+ fragment@5 {
+ target = <&gpio>;
+ __overlay__ {
+ mcp251xfd_pins_1: mcp251xfd_spi0_1_pins {
+ brcm,pins = <24>;
+ brcm,function = <BCM2835_FSEL_GPIO_IN>;
+ };
+ };
+ };
+ fragment@6 {
+ target-path = "/clocks";
+ __overlay__ {
+ clk_mcp251xfd_osc_1: mcp251xfd-spi0-1-osc {
+ #clock-cells = <0>;
+ compatible = "fixed-clock";
+ clock-frequency = <40000000>;
+ };
+ };
+ };
+ fragment@7 {
+ target = <&spi0>;
+ __overlay__ {
+ status = "okay";
+ #address-cells = <1>;
+ #size-cells = <0>;
+ mcp251xfd@1 {
+ compatible = "microchip,mcp251xfd";
+ reg = <1>;
+ pinctrl-names = "default";
+ pinctrl-0 = <&mcp251xfd_pins_1>;
+ spi-max-frequency = <20000000>;
+ interrupt-parent = <&gpio>;
+ interrupts = <24 IRQ_TYPE_LEVEL_LOW>;
+ clocks = <&clk_mcp251xfd_osc_1>;
+ };
+ };
+ };
+ fragment@8 {
+ target = <&i2cbus>;
+ __overlay__ {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ pcf85063@51 {
+ compatible = "nxp,pcf85063";
+ reg = <0x51>;
+ };
+ };
+ };
+ fragment@9 {
+ target = <&i2c_arm>;
+ i2cbus: __overlay__ {
+ status = "okay";
+ };
+ };
+};
|
