target/linux/bcm27xx/patches-5.10/950-0420-Add-overlay-for-Seeed-Studio-CAN-BUS-FD-HAT-4034.patch

   1 From 0f49536b413a81aedb9635c7b2613ca5a8d554c4 Mon Sep 17 00:00:00 2001
   2 From: menschel <menschel.p@posteo.de>
   3 Date: Wed, 30 Dec 2020 21:55:34 +0100
   4 Subject: [PATCH] Add overlay for Seeed Studio CAN BUS FD HAT (#4034)
   5
   6 This patch adds the overlay for the Seeed Studio CAN BUS FD HAT
   7 with two CAN FD Channels and an RTC.
   8 https://www.seeedstudio.com/CAN-BUS-FD-HAT-for-Raspberry-Pi-p-4742.html
   9
  10 The overlay was generated by
  11 ovmerge -c mcp251xfd-overlay.dts,spi0-0,interrupt=25 \
  12            mcp251xfd-overlay.dts,spi0-1,interrupt=24 \
  13            i2c-rtc-overlay.dts,pcf85063
  14
  15
  16 Also, add description on how to generate overlays
  17
  18 Signed-off-by: Patrick Menschel <menschel.p@posteo.de>
  19 ---
  20  arch/arm/boot/dts/overlays/Makefile           |   1 +
  21  arch/arm/boot/dts/overlays/README             |  46 +++++++
  22  .../dts/overlays/seeed-can-fd-hat-overlay.dts | 117 ++++++++++++++++++
  23  3 files changed, 164 insertions(+)
  24  create mode 100644 arch/arm/boot/dts/overlays/seeed-can-fd-hat-overlay.dts
  25
  26 --- a/arch/arm/boot/dts/overlays/Makefile
  27 +++ b/arch/arm/boot/dts/overlays/Makefile
  28 @@ -161,6 +161,7 @@ dtbo-$(CONFIG_ARCH_BCM2835) += \
  29         sc16is752-spi1.dtbo \
  30         sdhost.dtbo \
  31         sdio.dtbo \
  32 +       seeed-can-fd-hat.dtbo \
  33         sh1106-spi.dtbo \
  34         smi.dtbo \
  35         smi-dev.dtbo \
  36 --- a/arch/arm/boot/dts/overlays/README
  37 +++ b/arch/arm/boot/dts/overlays/README
  38 @@ -81,6 +81,44 @@ Parameters usually have default values,
  39  mandatory. See the list of overlays below for a description of the parameters
  40  and their defaults.
  41
  42 +Making new Overlays based on existing Overlays
  43 +==============================================
  44 +
  45 +Recent overlays have been designed in a more general way, so that they can be
  46 +adapted to hardware by changing their parameters. When you have additional
  47 +hardware with more than one device of a kind, you end up using the same overlay
  48 +multiple times with other parameters, e.g.
  49 +
  50 +    # 2 CAN FD interfaces on spi but with different pins
  51 +    dtoverlay=mcp251xfd,spi0-0,interrupt=25
  52 +    dtoverlay=mcp251xfd,spi0-1,interrupt=24
  53 +
  54 +    # a realtime clock on i2c
  55 +    dtoverlay=i2c-rtc,pcf85063
  56 +
  57 +While this approach does work, it requires knowledge about the hardware design.
  58 +It is more feasible to simplify things for the end user by providing a single
  59 +overlay as it is done the traditional way.
  60 +
  61 +A new overlay can be generated by using ovmerge utility.
  62 +https://github.com/raspberrypi/utils/blob/master/ovmerge/ovmerge
  63 +
  64 +To generate an overlay for the above configuration we pass the configuration
  65 +to ovmerge and add the -c flag.
  66 +
  67 +    ovmerge -c mcp251xfd-overlay.dts,spi0-0,interrupt=25 \
  68 +               mcp251xfd-overlay.dts,spi0-1,interrupt=24 \
  69 +               i2c-rtc-overlay.dts,pcf85063 \
  70 +    >> merged-overlay.dts
  71 +
  72 +The -c option writes the command above as a comment into the overlay as
  73 +a marker that this overlay is generated and how it was generated.
  74 +After compiling the overlay it can be loaded in a single line.
  75 +
  76 +    dtoverlay=merged
  77 +
  78 +It does the same as the original configuration but without parameters.
  79 +
  80  The Overlay and Parameter Reference
  81  ===================================
  82
  83 @@ -2466,6 +2504,14 @@ Info:   This overlay is now deprecated.
  84  Load:   <Deprecated>
  85
  86
  87 +Name:   seeed-can-fd-hat
  88 +Info:   Overlay for Seeed Studio CAN BUS FD HAT with two CAN FD channels and an
  89 +        RTC.
  90 +        https://www.seeedstudio.com/CAN-BUS-FD-HAT-for-Raspberry-Pi-p-4742.html
  91 +Load:   dtoverlay=seeed-can-fd-hat
  92 +Params: <None>
  93 +
  94 +
  95  Name:   sh1106-spi
  96  Info:   Overlay for SH1106 OLED via SPI using fbtft staging driver.
  97  Load:   dtoverlay=sh1106-spi,<param>=<val>
  98 --- /dev/null
  99 +++ b/arch/arm/boot/dts/overlays/seeed-can-fd-hat-overlay.dts
 100 @@ -0,0 +1,117 @@
 101 +// redo: ovmerge -c mcp251xfd-overlay.dts,spi0-0,interrupt=25 mcp251xfd-overlay.dts,spi0-1,interrupt=24 i2c-rtc-overlay.dts,pcf85063
 102 +
 103 +// Device tree overlay for https://www.seeedstudio.com/CAN-BUS-FD-HAT-for-Raspberry-Pi-p-4742.html
 104 +
 105 +/dts-v1/;
 106 +/plugin/;
 107 +
 108 +#include <dt-bindings/gpio/gpio.h>
 109 +#include <dt-bindings/interrupt-controller/irq.h>
 110 +#include <dt-bindings/pinctrl/bcm2835.h>
 111 +
 112 +/ {
 113 +       compatible = "brcm,bcm2835";
 114 +       fragment@0 {
 115 +               target = <&spidev0>;
 116 +               __overlay__ {
 117 +                       status = "disabled";
 118 +               };
 119 +       };
 120 +       fragment@1 {
 121 +               target = <&gpio>;
 122 +               __overlay__ {
 123 +                       mcp251xfd_pins: mcp251xfd_spi0_0_pins {
 124 +                               brcm,pins = <25>;
 125 +                               brcm,function = <BCM2835_FSEL_GPIO_IN>;
 126 +                       };
 127 +               };
 128 +       };
 129 +       fragment@2 {
 130 +               target-path = "/clocks";
 131 +               __overlay__ {
 132 +                       clk_mcp251xfd_osc: mcp251xfd-spi0-0-osc {
 133 +                               #clock-cells = <0>;
 134 +                               compatible = "fixed-clock";
 135 +                               clock-frequency = <40000000>;
 136 +                       };
 137 +               };
 138 +       };
 139 +       fragment@3 {
 140 +               target = <&spi0>;
 141 +               __overlay__ {
 142 +                       status = "okay";
 143 +                       #address-cells = <1>;
 144 +                       #size-cells = <0>;
 145 +                       mcp251xfd@0 {
 146 +                               compatible = "microchip,mcp251xfd";
 147 +                               reg = <0>;
 148 +                               pinctrl-names = "default";
 149 +                               pinctrl-0 = <&mcp251xfd_pins>;
 150 +                               spi-max-frequency = <20000000>;
 151 +                               interrupt-parent = <&gpio>;
 152 +                               interrupts = <25 IRQ_TYPE_LEVEL_LOW>;
 153 +                               clocks = <&clk_mcp251xfd_osc>;
 154 +                       };
 155 +               };
 156 +       };
 157 +       fragment@4 {
 158 +               target = <&spidev1>;
 159 +               __overlay__ {
 160 +                       status = "disabled";
 161 +               };
 162 +       };
 163 +       fragment@5 {
 164 +               target = <&gpio>;
 165 +               __overlay__ {
 166 +                       mcp251xfd_pins_1: mcp251xfd_spi0_1_pins {
 167 +                               brcm,pins = <24>;
 168 +                               brcm,function = <BCM2835_FSEL_GPIO_IN>;
 169 +                       };
 170 +               };
 171 +       };
 172 +       fragment@6 {
 173 +               target-path = "/clocks";
 174 +               __overlay__ {
 175 +                       clk_mcp251xfd_osc_1: mcp251xfd-spi0-1-osc {
 176 +                               #clock-cells = <0>;
 177 +                               compatible = "fixed-clock";
 178 +                               clock-frequency = <40000000>;
 179 +                       };
 180 +               };
 181 +       };
 182 +       fragment@7 {
 183 +               target = <&spi0>;
 184 +               __overlay__ {
 185 +                       status = "okay";
 186 +                       #address-cells = <1>;
 187 +                       #size-cells = <0>;
 188 +                       mcp251xfd@1 {
 189 +                               compatible = "microchip,mcp251xfd";
 190 +                               reg = <1>;
 191 +                               pinctrl-names = "default";
 192 +                               pinctrl-0 = <&mcp251xfd_pins_1>;
 193 +                               spi-max-frequency = <20000000>;
 194 +                               interrupt-parent = <&gpio>;
 195 +                               interrupts = <24 IRQ_TYPE_LEVEL_LOW>;
 196 +                               clocks = <&clk_mcp251xfd_osc_1>;
 197 +                       };
 198 +               };
 199 +       };
 200 +       fragment@8 {
 201 +               target = <&i2cbus>;
 202 +               __overlay__ {
 203 +                       #address-cells = <1>;
 204 +                       #size-cells = <0>;
 205 +                       pcf85063@51 {
 206 +                               compatible = "nxp,pcf85063";
 207 +                               reg = <0x51>;
 208 +                       };
 209 +               };
 210 +       };
 211 +       fragment@9 {
 212 +               target = <&i2c_arm>;
 213 +               i2cbus: __overlay__ {
 214 +                       status = "okay";
 215 +               };
 216 +       };
 217 +};