Questions tagged [device-tree]
a Device Tree (DT) is a description of the hardware in a system
70
questions
1
vote
1
answer
94
views
Why is my measured I2C clock frequency significantly slower than its setting?
I am setting the I2C frequency on the Compute Module 4 (running Ubuntu 22.04.2 LTS) with dtparam=i2c_arm=on,i2c_arm_baudrate=400000. The I2C bus has two parallel 10kOhm pullup (to 3.3V) resistors per ...
- 21
0
votes
1
answer
731
views
can't mount usb drive to Zero W: "can't open blockdev" and "special device /dev/sda does not exist" errors
I have a Pi Zero W, and I want to plug in a USB drive and use it as a tiny little backup server. I have a USB OTG cable, and when I plug in a flash drive (later I hope to use a much larger external ...
- 101
0
votes
2
answers
80
views
gpio-poweroff configured as input: how can I read the input pin?
I am developing a power supply with a supercapacitor to give around 30 seconds of reserve power so the pi can safely shut itself down on power loss.
I have a working gpio-poweroff definition in /boot/...
- 101
3
votes
2
answers
208
views
i2c Real Time Clock IC on Raspberry
I am using an industrial device based on a Compute Module Raspberry Pi 3 called Kunbus RevPi Core 3+.
The device is shipped with Raspbian and a pre compiled Image but I would like to install an ...
- 131
2
votes
1
answer
157
views
2-ch-can-hat (mcp2515) on SPI1 rpi 3 b+
On a
Raspberry Pi 1 Mod. B+
Raspberry Pi reference 2021-01-11
Generated using pi-gen, https://github.com/RPi-Distro/pi-gen, 21090519d85bdaa1615d5d5057d37b09368ea5d2, stage2
Oct 29 2021 10:49:08
...
- 121
0
votes
2
answers
172
views
Adding a `cec-gpio` dtoverlay for CEC debugging
I want to build a CEC Debugger as described in the Kernel.org documentation with my Pi Zero 2 W, I plan on using something like this:
I am having trouble with the final instructions listed to enable ...
- 129
3
votes
2
answers
301
views
i2c_arm bus initialization and device-tree overlay
I've built a Pi1541 HAT, just for fun, and am now playing with the device-tree autoconfiguration in Raspbian. I've made an overlay that autoloads during boot, based on the EEPROM contents, and that ...
- 51
0
votes
0
answers
93
views
Rename gpio-keys input device with label attribute
I have added the following line to my boot.txt to attach a push button input device to my system:
dtoverlay=gpio-key,gpio=26,active_low=0,keycode=256,label="myButton"
Once the OS is booted, ...
- 133
1
vote
1
answer
462
views
1-Wire internal pullup isn't enabled on boot, but can be enabled after boot
On a Pi 4 I have the following lines in /boot/config.txt:
dtoverlay=w1-gpio
gpio=4=op,pu
This should enable 1-wire on the default GPIO pin, which is 4, and then enable the internal pullup resistor.
...
- 131
3
votes
0
answers
121
views
Enabling SPI card reader in device tree on Raspberry Pi
Good evening,
I have MFRC522 card reader. It works well with generic spidev kernel-level driver and high-level python driver. However, as I wanted to learn device trees in linux, I tried to bind ...
- 81
1
vote
1
answer
409
views
Raspberry pi 4, UART4 and SPI0
Raspberry pi 4 has 4 usable uart ports, uart 4 with rx in gpio 9 and tx in gpio 8, share rx pin with SPI0 miso0 pin.
I would like to use both peripherals no ate the same time, but in different moment ...
3
votes
1
answer
1k
views
Using the Dynamic Device Tree to add Overlays at Run Time
I am working on a couple of ideas for device tree overlays for the RPi 3B+ & 4B. It will be useful in my testing to be able to load and unload overlays without having to reboot each time. As ...
- 20.6k
0
votes
1
answer
651
views
Raspberry Pi Compute Module 4 SPI bus not registering on custom Poky OS [Yocto]
I am trying to get a MCP2515 (CAN-bus IC that works on SPI) to work on a Raspberry Pi Compute Module 4 (8GB eMMC, No Wifi, 4GB RAM).
I have been able to get the module working on a regular Raspberry ...
5
votes
2
answers
13k
views
is dtoverlay a general linux concept or RPi specific?
With all the raspberry pi hats popping on and off, dtoverlay and /boot/config.txt is a very nice method to quickly tell the kernel that you've got new device tree information.
But I've never seen this ...
- 153
2
votes
1
answer
164
views
How to configure the device tree for the MAX30102?
I am trying to get the MAX30102 heart sensor to run and have recompiled the kernel with the necessary module. I have loaded the follwing modules to be sure
i2c_dev
i2c-bmc2708
i2c-bmc2835
industrialio
...
- 147
2
votes
0
answers
59
views
The RPi 4 does not support Power Management - is it due to lack of capability, or lack of will?
It's clear enough from this Q&A and the null output from cat /sys/power/state that the Raspberry Pi does not currently support the Linux kernel's Power Management features. This explains why there ...
- 20.6k
-1
votes
1
answer
276
views
Pi zero doesn't fully shut down after adding a gpio-poweroff dtoverlay to /boot/config.txt
Disclaimer
I'm still learning about the device tree in general and am definitely fumbling about a bit.
The problem
Pi Zero W draws basically zero current when shutdown with sudo shutdown now. After ...
3
votes
2
answers
3k
views
Re-configure SPI-CS as gpio while using SPI
I am on a raspberry pi 4. Using both SPI's with no need for either chip select. I'm running out of I/O and could really use those. Does anyone know if there is a way to repurpose the SPI chip selects ...
- 33
1
vote
0
answers
95
views
Device Tree for Generic Output
I'm currently developing my first Pi Hat for a personal project. I've been exploring Device Trees and I'm quite liking the concept from the perspective that the userland code can address specific ...
- 111
0
votes
2
answers
343
views
Location of .dtbs files - specifically uart0.dts and minimart-bt.dts
Does anyone know where I can find the precompiled .dtbs files - specifically uart0.dts and minimart-bt.dts?
- 101
1
vote
2
answers
225
views
How can RpiZW interface three SPI ADS1248 ADC, one microSD adapter, and one Ethernet Adapter?
I'd like to connect multiple different SPI devices to a Raspberry Pi Zero W (at least 5), with a few specific requirements. The devices would be, if possible:
1x ENC28J60 Ethernet SPI adapter - this ...
- 13
0
votes
0
answers
338
views
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
votes
1
answer
3k
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?
...
- 153
2
votes
0
answers
91
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....
1
vote
1
answer
2k
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. ...
- 21
0
votes
1
answer
1k
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?
- 11
2
votes
0
answers
642
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 ...
- 121
1
vote
1
answer
370
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 ...
- 69
2
votes
1
answer
71
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 ...
- 143
1
vote
0
answers
1k
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 ...
- 196
0
votes
0
answers
60
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 ...
- 53
0
votes
0
answers
295
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 ...
- 1
0
votes
0
answers
144
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 ...
- 1
1
vote
1
answer
436
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-...
- 23
2
votes
1
answer
252
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 ...
- 683
1
vote
1
answer
2k
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 ...
5
votes
1
answer
2k
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 ...
- 69
0
votes
0
answers
57
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 ...
- 535
0
votes
2
answers
2k
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 ...
- 125
8
votes
4
answers
10k
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 \ ...
- 81
0
votes
0
answers
887
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
...
- 1
1
vote
1
answer
678
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 ...
- 55
1
vote
2
answers
5k
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=...
- 161
2
votes
1
answer
728
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 ...
- 21
0
votes
0
answers
196
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 {
...
- 201
2
votes
0
answers
264
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 ...
1
vote
0
answers
210
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 ...
- 131
2
votes
0
answers
528
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 ...
- 131
1
vote
0
answers
187
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 ...
- 121
3
votes
2
answers
3k
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 ...
- 561