r/embeddedlinux

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I have a background in embedded systems and currently work mainly on MCUs, writing firmware in C/C++. I'm comfortable with topics like peripherals, RTOS, debugging, communication protocols (UART, SPI, I2C, CAN), and general embedded development.

Now I want to transition into Embedded Linux and would like some guidance on the best learning path and resources.

Specifically, I'm interested in learning:

Linux internals relevant to embedded systems

Device drivers

Device Tree

Bootloaders (U-Boot, etc.)

Kernel basics

Build systems like Yocto or Buildroot

Debugging techniques (JTAG, GDB, tracing tools)

Practical projects that can help me gain hands-on experience

I prefer learning through books, courses, and real projects rather than just theoretical material.

For those who made a similar transition from bare-metal/RTOS development to Embedded Linux, what resources, books, courses, or project ideas would you recommend?

Hi everyone,
I’m working on an embedded Linux platform (Qualcomm SA8797) and validating I2C communication with MAX96861 devices.
I have successfully identified the I2C buses from the device tree and confirmed communication with two devices:
MAX96861_1 on /dev/i2c-0 (7-bit address 0x42)
MAX96861_2 on /dev/i2c-9 (7-bit address 0x60)
Communication is working (no I2C errors), but I’m seeing behavior that I don’t fully understand.
For example, on MAX96861_2:
i2cset -f -y 9 0x60 0x00 0x55

i2cget -f -y 9 0x60 0x00
0x34

i2cget -f -y 9 0x60 0x00
0x50

i2cget -f -y 9 0x60 0x00
0x00

i2cget -f -y 9 0x60 0x00
0x41

i2cget -f -y 9 0x60 0x00
0x98
Interestingly, performing the exact same test on MAX96861_1 (/dev/i2c-0, address 0x42) produces a very similar sequence.
I also dumped registers 0x00–0x0F several times and noticed that many registers change between successive reads, even without performing any writes.
I don’t currently have access to the MAX96861 register documentation, so I don’t know whether these are status registers, indirect registers, or whether a page-selection mechanism is required before accessing the register map.
My questions are:
Is this expected behavior for MAX96861 devices?
Do these devices require indirect/page-based register access instead of simple SMBus byte reads?
Could i2cget/i2cset be using an access mode that is not appropriate for this device?
Has anyone worked with MAX96861 and can suggest the correct Linux access method or register sequence?
Thanks in advance for any pointers.

I am setting a gpio to high
After setting when I am trying to read it , it is returning 0. Not the value that I set.

Also i see the direction if the pin is changed to input

Hello everyone.
I'm trying connect tft display (Red 2.8" TFT 240x320 V1.1) to SBC called Luckfox Pico but my brightness are inverted (black = white) and I'm don't know whats wrong. I change some variables in device tree but it didn't help me, i'm trying tft,invert=<1>; and backlight pins but this makes nothing whatever i use it or manually enable PWM.
I'm making this for fun and learning and use X11 so maybe there some way to invert colors in X11? But i heard something usual like xcalib didn't work with fbtft driver so i hope there are other way...
Thank you.

fbtft@0 {
compatible = "sitronix,st7789v";
reg = <0>;
spi-max-frequency = <20000000>;
fps = <30>;
buswidth = <8>;
debug = <0x7>;
led-gpios = <&gpio0 RK_PA4 GPIO_ACTIVE_LOW>;//BL
dc-gpios = <&gpio1 RK_PA2 GPIO_ACTIVE_HIGH>;//DC
reset-gpios = <&gpio1 RK_PC3 GPIO_ACTIVE_LOW>;//RES
rotate = <90>;
bgr = <1>;
invert = <1>; 
};