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Questions tagged [device-tree]

A data structure for describing hardware. passed in boot time to kernel

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How to work around the lack of device tree on amd64 arch?

I have a mainboard with several I2C, SPI and I2S devices. It's a mainboard with a CPU/RAM daughterboard. I'm currently using arm64 CPUs (iMX8M). I let the kernel drivers know about the I2C addresses ...
fadedbee's user avatar
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Define GPIO name/status in Device Tree and have it accessible from userspace

I have a custom board with several GPIO. I'd like to: give them a friendly name be able to get the level at boot time define active high/low I defined the GPIO as hogs like this &gpio5 { ...
il_mix's user avatar
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Multiple I2C GPIO Expander give probing error due to shared reset pin

I'm editing the kernel device tree for a custom board. I have two GPIO expanders (pcal6416) connected to i2c3 bus. The two expanders share the same CPU pin as reset. Here is the initial device tree &...
il_mix's user avatar
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Fail to set a touchscreen in Device Tree

I'm trying to connect a touch controller via I2C to my DART6UL linux embedded board. The follwoing if what I add to my device tree; egalax_ts@2a { compatible = "eeti,egalax_ts"; ...
LittleSaints's user avatar
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Unable to communicate with I2C fuel gauge

I'm trying to communicate with an LTC2959 (datasheet) battery fuel gauge via I2C from my linux-based SBC. I'm not succeeding and I suspect a hardware or device-tree issue. The IC address is 0xC6 which ...
davegravy's user avatar
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What is the best location to store binary overlays that are applied at runtime?

Binary overlays that are applied while booting would probably best be stored in /boot/overlays or similar. However, what is the best location for binary device-tree overlay files that are intended to ...
Lukas's user avatar
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How do I configure device nodes for simple-pm-bus probe?

Inside a soc node I have a watchdog node with a simple-mdf device. soc { #address-cells = <2>; #size-cells = <2>; compatible = "simple-bus"; ...
Bret Joseph's user avatar
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What are pinctrl states and handles in relation to the device tree?

I have a node with the following mmc0: mmc@11230000 { compatible = "mediatek,mt8186-mmc", "mediatek,mt8183-mmc"; pinctrl-names = "default",...
Bret Joseph's user avatar
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186 views

Will a platform device with waiting for supplier eventually probe?

I have defined a platform device in the Device tree. The following shows the file tree walk for its folder. /sys/devices/platform/device /sys/devices/platform/device/uevent /sys/devices/platform/...
Bret Joseph's user avatar
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How do we configure musb-hdrc driver?

I would like to use a USB gadget device (phone) as a host via configfs. After setting up configfs, no gadget is being set up on the host peripheral (phone). The init script executes with the following ...
Bret Joseph's user avatar
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dtb phandle Failed to add to the IOMMU

I have this error : (XEN) *** LOADING DOMAIN 0 *** (XEN) Loading d0 kernel from boot module @ 0000000018000000 (XEN) Allocating 1:1 mappings totalling 1024MB for dom0: (XEN) BANK[0] 0x00000020000000-...
rBeal's user avatar
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uboot kernel and dtb calculation

What is the method to calculate these parameters in uboot ? : bootm_low=0 bootm_size=7ff00000 fdt_addr_r=0x40000000 fdt_high=0x100000 fdt_size_r=0x400000 fdtcontroladdr=7bc971c0 kernel_addr_r=...
rBeal's user avatar
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Can we automatically label device tree with symbols?

Is it possible to use device tree compiler to automatically label nodes when generating device tree source from device tree binary/source? I can assign the labels from the symbols to their respectful ...
Bret Joseph's user avatar
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191 views

unable to boot kernel on A53 (devicetree?)

I am trying to boot a Linux kernel on an A53 cpu (inside a ZU5 from xilinx). I have two hard. The first is a custom PCB with a ZU5. The second is the ZCU102 SDK with the zu9eg. Here the boot log : [ ...
rBeal's user avatar
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tlv320aicx(audio codec) device tree

I'm trying to get solve a kernel message that I'm getting from the tlv320aicx driver. (linux-5.4) The original error was Invalid supply voltage(s) AVDD: -22, DVDD: -22 I was able to locate to the ...
Dukel's user avatar
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How to ensure the probing order of SPI bus?

I've an embedded linux system based on a iMX8 CPU. I'm upgrading the yocto-version and therefore the kernel version. I've two SPI devices on two SPI buses. The device on the second bus has a driver ...
xavor's user avatar
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Why does linux freezes when trying to access peripherals connected to the lightweight hps-to-fpga bridge (or any bridge)?

I have been working on a Altera DE1-SoC Development Board for 8 months. The system I was working on includes a Cyclone V FPGA chip, particularly the 5CSEMA5F31C6N. It was running an embedded Linux ...
SMAero22's user avatar
1 vote
1 answer
678 views

mkdir in configfs not permitted

On my embedded System I enabled the CONFIG_CONFIGFS_FS=y to have access to the configFS. When booted, I mounted it with help of mount -t configfs none /sys/kernel/config. That works like charm: # ...
Tom Mekken's user avatar
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An rcu_preempt detected stall on Embedded Linux bootup due to USB device tree?

Can anyone point me in the right direction to solve (or at least debug) this rcu_preempt problem I'm experiencing at bootup as shown in the log info below? I think the problem is related to the device ...
Terence D's user avatar
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How is MTD partition layout detected/parsed in Linux?

I am working on an embedded Linux system, which uses kernel-5.10.24. There is a NAND FLASH used as storage in system, and it has 4 partitons. When the kernel boots up, there shows 4 partitions as ...
wangt13's user avatar
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Understanding dsi system in device tree

Let's say there is a video bridge like sn65dsi86. It has a driver ti-sn65dsi86.c in kernel source tree. It should be enabled with device trees. There an example for device tree. But it is not complete....
ptiza_v_nebe's user avatar
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Writing device tree file for ti sn65dsi86

I'm new to device trees, but from all the research I can't find a comprehensive tutorial on writing device trees. If concrete I have an ti sn65dsi86 and I want to connect it to an imx8 chip. Linux has ...
ptiza_v_nebe's user avatar
2 votes
1 answer
532 views

How do I reference a port in the device tree?

Edit: this is a general question about referencing ports with phandles and the example I posted i.e. my particular case is not that relevant because meanwhile I have observed the same behaviour with ...
ldd3's user avatar
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362 views

Adding an LCD to Device Tree

I am attempting to define panel-info and display-timings for my SHARP Parallel 24bit LCD Screen within the Device Tree of my Beaglebone Black Debian Image. To do this I am using an overlay .dtbo file. ...
Dillon McCardell's user avatar
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Some "disappeared" dm-? files under the /dev directory

Recently I took over a few RHEL systems running with the native DM-multipath, which had been installed & configured by other persons. My doubts focus on the following questions: 1). Why there ...
lylklb's user avatar
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How to name a device in the device tree?

I have used a device tree overlay file (dtbo) to add a hardware reference over the i2c-2 node to my device tree. This device is an accelerometer that implements an existing driver that can be found ...
Dillon McCardell's user avatar
1 vote
1 answer
877 views

How to implement i2c device in Device Tree?

I currently attempting to implement the mma8452 driver for my mma8451Q accelerometer by adding it to the the Linux Device Tree. Currently I am taking the route of creating a device tree overlay file (...
Dillon McCardell's user avatar
1 vote
2 answers
5k views

How to load device-tree overlays

I know this is a topic, on which there are several other posts. However none? of them has an accepted answer or even a helpful comment. But in short, how can load a device tree module (without ...
flobue's user avatar
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Where can I find the device tree source include (.dtsi) files?

I am attempting to review my device tree to learn more about how the usb endpoints are defined, and also just to learn more about device trees. I am currently using a BeagleBone Black image, and I ...
Dillon McCardell's user avatar
1 vote
0 answers
125 views

Does a kernel driver get loaded before device tree parsing

When a device tree is getting processed by the kernel on startup, does the kernel load its correct device driver there and then, or it must already be loaded? Let's take a special I2C device for ...
Engineer999's user avatar
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Yocto - check if a device tree is enabled in the image

I am currently generating a specialized Yocto image for a Beaglebone device. In the resulting /tmp/deploy/images folder I can see the resulting image, plus alot of device tree files .dtb for different ...
Engineer999's user avatar
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Use device tree or Kconfig to load a driver

I would like to add and enable a new device in an embedded Linux image. Is it enough to just specify the information in a device tree file and then the driver for the device will get loaded based on ...
Engineer999's user avatar
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1 vote
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95 views

Investigate Device Tree Problems (with NVIDIA Xavier NX and a custom board)

I have a NVIDIA Xavier NX (aarch64) with a custom board. It worked well with 4.x kernel and Cboot. Now after migrating to 5.x kernel and UEFI it hangs on boot with the following error: "...
hutcruchi's user avatar
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101 views

Understand device tree entries and values

I'm new to device tree source editing. I understand the concept and learned from the bootlin talk: https://www.youtube.com/watch?v=Nz6aBffv-Ek I have two .dtsi files: The first is for 4.X kernel(left) ...
hutcruchi's user avatar
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718 views

i2c device node from device tree is not being probed

I am having trouble troubleshooting my problem where in my i2c pca9546 mux is not being probed by the corresponding driver, i2c-mux-pca954x.c. Here is my device tree node: &i2c0 { status = "...
MandM's user avatar
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135 views

Complete kernel hang after adding bluetooth to system devicetree

I am working right now at adapting yocto distro to run on custom, imx8mm-evk based hardware. I was mostly changing linux devicetree to fit new board needs and everything was fine, but when I added ...
Leonid's user avatar
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1 vote
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299 views

How does /sys/class/pci_bus correlate the physical PCIe lanes?

On a Dell R7525 I see the following output: [root@r7525 ~]# ls -al /sys/class/pci_bus/ total 0 drwxr-xr-x. 2 root root 0 May 10 10:38 . drwxr-xr-x. 62 root root 0 May 10 10:38 .. lrwxrwxrwx. 1 root ...
Grant Curell's user avatar
1 vote
0 answers
696 views

/aliases: Reference to non-existent node or label "mmc0"

I'm trying to upstream support for u-boot and buildroot for a SoC, I'm merging some changes into master from the vendor's BSP and am having some issues with their dts. [machinehum@whitebox u-boot]$ ...
user3666672's user avatar
1 vote
0 answers
896 views

UIO instance of a device-tree subnode

I have the following device-tree node which is auto generated by Xilinx PetaLinux in a proper dtsi file (which cannot be modified): axi_dma_0: dma@a0000000 { #dma-cells = <1>; ...
xyx's user avatar
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About 'unit-address' in Linux devicetree

In Linux devicetree specification v0.3, p. 8, there is one sentence: The unit-address must match the first address specified in the reg property of the node. If the node has no reg property, the @...
diverger's user avatar
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411 views

When is the devicetree parsed to populate the device list on arm64 architecture?

This question comes from my attempts to understand how a built-in platform device driver is initialized at boot time. I am using an embedded linux distro (Yocto) on a SoC (ARM + FPGA). The device ...
Fra93's user avatar
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1 answer
123 views

gpio_name_to_desc in gpiolib.c in Linux kernel should be externalized?

We have an embedded project, and for our purposes, it seems handy to name all the gpios in the gpio controller device tree stanza using gpio-line-names feature in device tree, mentioned in ...
John Klug's user avatar
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387 views

Unable to enable TLV320AIC3104 codec driver /simple sound card for iMx8M with SAI2 BCLK/MCLK provided with external clock

I am trying to access codec driver (TLV320AIC3104) connected to iMX8M over I2C3 and SAI2 lines. The codec clocks bclk is 4096000 and it is provided from an FPGA and its mclk is grounded. iMx8M SOM ...
user480313's user avatar
0 votes
1 answer
339 views

Linux 4.19: apply devicetree overlay on live system

Is it possible to apply a devictree overlay on a live system? We have an embedded system that has some optional hardware. We would like to load the devicetree information after Linux booted. Reqaon ...
Ayrton Leyssens's user avatar
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635 views

BeagleBone Black UART 1 config

Recently I compiled my own linux system using kernel 5.10.23, and I made modifications to the device tree in order to activate UART 1 PIN (9-24) and (9-26). I have /dev/ttyS1 available for R/W ...
midototo's user avatar
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533 views

How to disable TX path of ethernet PHY in embedded linux?

In a yocto-based embedded device I use ethernet only to receive UDP packets. Now I want save energy as the device (as well as the UDP transmitter) is battery powered, and the ethernet PHY (a micrel ...
Philippos's user avatar
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1 vote
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131 views

Modified kernel module doesn't load on boot- is the old one being cached somewhere

I'm modifying the qca7000 kernel module slightly by adding some debug messages (qcaspi.ko). I compile, run depmod then reboot. However my debug messages do not show up on dmesg. If I rmmod qcaspi then ...
JC123's user avatar
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3 votes
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1k views

Platform driver's probe function isn't called

I am developing a simple platform driver for beaglebone (but currently running on my virtual machine running Ubuntu) that uses device tree, but it doesn't seem like the probe function is being called. ...
xyf's user avatar
  • 141
1 vote
1 answer
1k views

Linux, how to add "missing" i2c interface?

I'm working on an embedded project utilizing a Digi ConnectCore 6UL SBC Pro, and I know that dmesg should show me the three I2C interfaces after boot up like: i2c i2c-0: IMX I2C adapter registered i2c ...
stdcerr's user avatar
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1 vote
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647 views

Definition and usage of Kernel/Linux DTS file with more than one MIPI DSI Display panel

I actually need some help of defining the kernel/linux DTS file and use it together with the uboot videoargs. In use is the 5.4.47 uboot and kernel/linux from a NXP imx8m YOCTO project. In uboot I ...
Cedric's user avatar
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