Questions tagged [device-tree]
a Device Tree (DT) is a description of the hardware in a system
54
questions
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DS18B20 does not have a unique adress in /sys/bus/w1/devices
The problem:
I am trying to use a RW1820 (DS18B20), to display the temperature.
yet it does not show up in devices. Only w1_bus_master 1 appears.
Setup:
Raspberry Pi 4
1-Wire Temperature Sensor ...
0
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0answers
21 views
LAN_RUN device tree dt-blob.dts for LAN95XX
I have setup Compute Module 3+ with LAN9512 for ethernet port.
The only problem is the ethernet chip needs a pull_up for shutdown
I have connected GPIO31 to LAN_RESET in my circuit
I am trying to ...
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1answer
71 views
Device Tree configuration for I2S sound (MAX98357A)?
What needs to be done to run an I2S DAC/Amplifier board based on MAX98357A (datasheet) that appears to be a clone of this well-documented Adafruit product with the corresponding Device Tree overlay?
...
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14 views
Raspberry Pi 3 : how to find device number and card number with bluetooth
I'm trying to set up google assistant on my raspberry pi with this guide:
https://pimylifeup.com/raspberry-pi-google-assistant/comment-page-2/?unapproved=27549&moderation-hash=...
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18 views
Problem in initiating i2c driver module for bmp180 i2c based sensor at kernel level
For leaning purpose i am writing a i2c client kernel module for bmp180 pressure sensor.
My kernel code is ->
#include <linux/version.h>
#include <linux/module.h>
#include <linux/init....
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19 views
Need help with Compute Module 3 PCB development
I am designing a Compute Module 3 based PCB online on : Gumstix
I can download the CAD files and it automatically generates the device tree so it seemed convenient. I created a custom design and ...
1
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1answer
234 views
Error when connecting more than ten USB devices on Raspberry Pi 4 [duplicate]
What is the limit of USB devices in raspberry pi4?
We have an external USB hub with its power supply and 10 devices fall off with errors.
[Wed Mar 11 09:04:43 2020] usb 1-1.3.4-port1: Cannot enable. ...
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1answer
461 views
Re configuring GPIO pins for SPI protocol
GPIO pins 19,21,23,24,26,35,38,40 are dedicated for SPI protocol. Is it possible to use other GPIO pins for SPI? If yes, how do we do it?
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116 views
Applying dwc2.dtbo to bcm2711-rpi-4-b.dtb at build time triggering FDT_ERR_NOTFOUND
I'm trying to build a NixOS image for my Raspberry Pi 4b with the dwc2 device tree overlay applied.
Per advice from the #nixos-aarch64 IRC channel, doing this the Nix Way calls for configuring ...
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141 views
(Pi4) No Display when in OTG mode unless HDMI_safe=1
Im officially stumped. I have connected my Pi4 to my PC via USB to USB-C for OTG connection. Whenever I boot with the normal PSU to the USB-C port on the Pi4, everything boots correctly (display and ...
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1answer
65 views
Trouble adding a gpio device to the device tree
I'm trying to connect an hx711 to GPIO23 and GPIO24 pins on an RPI3 A+, and I need to specify this in the device tree to have the hx711.ko driver be probed. I've been stuck on this problem for some ...
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1answer
49 views
Why DMA uses bus address rather than physical address?
Why DMA uses bus address rather than physical address?
And do we provide bus address or physical address in the device tree?
Where do we get to know these addresses that needs to be provided to the ...
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0answers
218 views
Creating a Device Tree Overlay for i2c device
I'm trying to create a Device Tree overlay for a i2c touch screen.
Things are a bit strange as the screen is a 16bit DPI so all usual i2c pins are consumed. I'm using a i2c-tiny-usb adapter to get an ...
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26 views
I2C client driver instantiation using Device Tree - probe did not get called
I am writing a sample and simple i2c driver in which I am trying to instantiate the
i2c client device using device tree overlay. I have got some DTE overlay sample which i have complied to .dtbo and ...
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0answers
150 views
Simple Sound Card with I2S - how do I switch frequencies?
I asked this a month ago, but didn't get an answer and so the thread was auto-deleted. It is becoming critical that this be solved, so I am reposting.
I have the simple sound card working with a ...
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67 views
Using waveshare LCD and SPI1 for LEDs
My problem is that I cant get SPI1 and the LCD screen to work at the same time.
Only SPI1 with the spi1-1cs overlay worked and only the waveshare35a overlay working, I tried to make my own overlay ...
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1answer
180 views
Can I run 2 device tree overlay at the same time?
I'm trying to monitor some 4-20mA current loops and 0-10V generators with a RPi 3. I found these modules which would do the job:
https://widgetlords.com/products/pi-spi-2a0-raspberry-pi-analog-output-...
2
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1answer
96 views
Building an old kernel is not possible because the arch/arm/boot/dts/overlays/ directory does not exist
I've been trying to build a kernel from the 4.14.85 version. I followed the instructions from the official documentation but instead of using the latest version you can find in the repository I ...
1
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1answer
505 views
Use internal pull up resistors with the gpio-keys module in the device-tree
I have an external board with some buttons that are attached to gpio 20 and 21 which connects these pins to ground when pressed:
simulate this circuit – Schematic created using CircuitLab
I'd ...
3
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1answer
788 views
How do I add an i2c device to the device tree?
I am trying to add an mpu 9250 to the device tree of my RPi 3 A+ so that my custom driver's probe function will be called. I have followed this documentation about the Raspberry Pi device tree and ...
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49 views
What could trigger the removal of the WiFi device?
I discovered this morning that wlan0 on my RPi vanished during the night (at 04:14:13 in the unaltered log below):
Dec 18 03:38:46 rpi1 wpa_supplicant[407]: wlan0: WPA: Group rekeying completed with ...
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2answers
1k views
gpio-shutdown doesn't seem to have an effect
We are trying to have the Pi shut down gracefully when power is removed. We have a battery connected so that it will have time to shut down. So far, our attempts to use gpio-shutdown have been ...
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4answers
5k views
Emulate Raspberry Pi zero W with Qemu failed due to missing dtb
I am trying to emulate a Raspberry Pi zero W with Qemu based on an image I used on a real Raspberry Pi zero W.
The command I am using is:
sudo qemu-system-arm \ ...
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0answers
381 views
Connecting RAW NAND through GPIO
I'm trying to define a device tree for connecting an external raw NAND using GPIO on RPI3.
I found that there are available drivers, and I found an example in the sources' "Documentation" directory
...
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1answer
395 views
How and from where is the ENC28J60 driver loaded?
I have a raspberry CM3 setup where I added an external eNet port so that I have internet connectivity. It is very similar to the break-out board setup such as this one which is also based on the ...
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2answers
4k views
Rpi3 is the hardware watchdog enabled by default
I have RaspberryPI's 3 (running both Jessie and Stretch) and tested on both
In order to enable the watchdog timer, In many posts I saw that add in the /boot/config.txt a line with:
dtparam=watchdog=...
2
votes
1answer
395 views
Change Device Tree to pullup pin at boot
I trie to add a LTC2954 to the raspberry pi zero w. I designed and produced a prototype pcb with an lipo management system for load and loadsharing. My problem is, that the KILL Pin of the LTC2954 has ...
0
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0answers
171 views
Difference between sound and audio nodes in RPi 3 device tree?
I looked a bit into the device tree of Raspbian 9 on Raspberry Pi 3, using:
dtc -I fs /proc/device-tree > myrpi-dev-tree.txt 2>&1
I've noticed there is a node called audio:
audio {
...
2
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0answers
200 views
Raspberry Pi remap DPI pins [closed]
I'm trying to hook up my Raspberry Pi a to custom display hat via the parallel display interface (GPIO Pins, not ribbon cable). The problem I'm facing is that the DPI pins are rather awkwardly placed ...
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0answers
130 views
Access more than two (2) slaves on spi0
Supposedly, there is a new driver that supports arbitrary GPIOs for SPI0 channel select, that is configurable via the device tree.
Everything I try only half works. The hard works. If I toggle the ...
2
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0answers
394 views
Accessing 3+ SD/MMC /dev/mmcblk devices
I've successfully followed some instructions for access 2 SD cards via SPI on a Raspberry Pi 3: https://ralimtek.com/Raspberry_Pi_Secondary_SD_Card/
How do I configure it to access more than 2 SD ...
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0answers
123 views
In simultaneous use of SPI0 and DPI Mode 3 interfaces, can SPI0 CS0 be moved to a pin other than 8?
I am attempting to design a device using a Pi Zero which needs to connect to both an ENC18J60 SPI ethernet controller, and a VGA monitor via Mode 3 DPI and the Mincepi Pi Zero pi2vga schematic. While ...
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1answer
2k views
dtoverlay=gpio-poweroff not working on raspberry pi 3 B
Problem:
I have a Raspi 3B rev: a02082 (Q1 2016 3 Model B 1.2 1 GB (Mfg by Sony)) running raspbian jessie kernel 4.9.35-v7
I want to signal to a power management circuit that filesystems ...
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0answers
552 views
SPI doesn't work because of device tree
I have the same problem as this person:
SPI enabled in device tree, but I can't use it
I tried commenting in the original thread but the community rules don't allow me to comment because I don't ...
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vote
1answer
3k views
How do i use DeviceTree to init GPIO to a set value?
Hello i've got a board connected to my raspberry pi 3 and according to the pin set on boot of the raspberry this shield reboot which is problematic. I need to be able to reset the board and control ...
3
votes
1answer
61 views
DeviceTree magic strings
I recently stumbled over the MagPi Essentials Camera. In chapter 7 "Flash photography using an LED" (p.41+), they show how to configure pin BCM17 to act as a flash for the official Raspberry Pi Camera....
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0answers
462 views
device tree and led blink
I am trying to create one led driver via device tree in Rpi 3
I had created the dtsi file
/dts-v1/;
/plugin/;
/ {
compatible = "brcm,bcm2837";
fragment@0 {
target = <&...
4
votes
1answer
5k views
SPI enabled in device tree, but I can't use it
I am trying to use SPI interface on Raspberry Pi 1 B (OS: Raspbian July 2017, kerenl 4.9.5). To do this, I am using wiringPi. I confirmed that wiringPi works via gpio readall
To load SPI:
gpio load ...
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votes
2answers
1k views
How to use advanced GPIO functions via sysfs?
The GPIO ports can be accessed using sysfs interface located in /sys/class/gpio. However, I failed to found more detailed documentation, most of which only describes plain read/write operation.
What ...
3
votes
1answer
3k views
How to build my very own device tree (and if I need to)
Let me preface this by saying I don't know much about device trees. I do know a bit about ATAGs, since I'm working with this operating system that currently only uses ATAGs.
I'm modifying the ...
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vote
1answer
530 views
apds 9960 on raspberry pi zero
I would like to use the apds9960 (light/gesture sensor) on rp0 - utilizing the kernel iio driver, which is already available, but there is no dt overlay yet. I guess I need to:
write the dts file
...
0
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1answer
2k views
Compile a dts file (dt overlay)
Hello folks maybe I have misunderstood something but I am not sure how to compile my dt overlay file with the etc command (!) I already know that I have to use the @ parameter .
The effect of ...
2
votes
1answer
3k views
How to use BMP280 SPI Kernel Module
I got a adafruit BME280 sensor board and I wired it to the raspberry pi zero via spi. According to the datasheet I can read sensor data from the device via the userspace spi interface. Everything ...
0
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1answer
1k views
Disable pull-up resistor on pps-gpio pin
I am using the pps-gpio dtoverlay. My /boot/config.txt has these lines:
# Expect the GPS 1PPS pin to be connected to GPIO3
dtoverlay=pps-gpio,gpiopin=3
Problem is, that the GPS Module (SkyTraq Venus)...
2
votes
1answer
6k views
Missing configuration options on raspi-config screen??? No SPI or Device Tree
Downloaded NOOBS onto my SD card and got my RPi3 up and running.
I'm trying to enable Device Tree and SPI via the advanced options bit on the raspi-config blue screen (so i can install my 3.5inch ...
1
vote
1answer
1k views
How to detect a device tree overlay at run time?
What is the best way to check at run time if a device tree overlay is loaded?
I've found info about checking individual GPIO pin status, and info about how to load the overlay (via config.txt), but I'...
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vote
2answers
5k views
how to enable spi1? / pi 3 and two rc522 RFID readers
Is it possible to connect two RC522 readers with one RaspberryPi 3?
As far as I know I should just choose different CS pins for them (Add more than 2 SPI slaves).
I have following connections:
1st ...
1
vote
2answers
585 views
Raspberry pi HAT device-tree
I'm currently developping a Raspberry pi HAT. The Raspberry pi HAT must contain a EEPROM with several information in it. This information will be read at boot time in order to configure the Raspberry ...
0
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1answer
326 views
device tree and spi controller file
why is the file spi_bcm2708.c is not present inside the path linux/drivers/spi and while inside the boot partition of pi the bcm2708-rpi-version.dts file is only present.how come kernal use the ...
3
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1answer
1k views
i2c on a rpi-basic-image created with yocto
I'm attempting to get the i2c bus to work from a raspberry pi image created from yocto. I have looked at other peoples solutions but they are all o do with raspbian or some other flavour of os.
My /...
