TM1628 7‑Segment LED Display Kernel Driver for NXP i.MX93

This repository contains a Linux kernel driver for the TM1628 7-segment LED and keypad controller IC, designed for use with the NXP FRDM-i.MX93 board.

✨ Features

• Control of 8-digit 7-segment LED display
• Keypad scanning support (4x4 matrix)
• GPIO-based bit-banging protocol (CLK, DIO, STB)
• Lightweight and modular Linux kernel driver

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📁 Directory Structure

tm1628_driver/
├── Kernel_Driver_tm1628/
│ ├── tm1628.c # Main kernel driver source
│ ├── Kconfig & Makefile
│ └── dts.txt # Device Tree snippet
├── tm1628_dts.txt # Extra DTS sample
├── TM1628_V1.1_EN.pdf # Official datasheet
└── TM1628_Driver_Guide.pdf # Project documentation

🛠️ How to Use This Driver

1️⃣ Add TM1628 Node in Device Tree

Edit your board’s DTS file (`imx93-*.dts`) and add:

tm1628@0 {
    compatible = "essae,tm1628";
    clk-gpio = <&gpio3 18 GPIO_ACTIVE_HIGH>;
    dio-gpio = <&gpio3 20 GPIO_ACTIVE_HIGH>;
    stb-gpio = <&gpio3 19 GPIO_ACTIVE_HIGH>;
};
✅ Ensure the GPIO pins match your hardware connections.

2️⃣ Build the Kernel Module

cd Kernel_Driver_tm1628/
make -C /lib/modules/$(uname -r)/build M=$(pwd) modules

3️⃣ Insert the Module

sudo insmod tm1628.ko
dmesg | grep tm1628

4️⃣ Auto-Load at Boot (Optional)

# Move to kernel driver path
sudo cp tm1628.ko /lib/modules/$(uname -r)/kernel/drivers/misc/

# Register module to load at boot
echo "tm1628" | sudo tee -a /etc/modules

# Rebuild module dependency list
sudo depmod -a

🔌 Hardware Wiring

Signal	TM1628 Pin	i.MX93 GPIO
CLK	SCLK	GPIO3_IO18
DIO	Data	GPIO3_IO20
STB	Strobe	GPIO3_IO19

✅ Ensure proper 3.3V or 5V supply and common GND

⚙️ Kernel Integration (Optional for Yocto/Linux Kernel)

kconfig

config LEDS_TM1628
    tristate "TM1628 LED driver"
    default m
    help
      Kernel driver for TM1628 7-segment LED and keypad controller.
      Uses GPIO bit-banging for communication.

makefile

obj-$(CONFIG_LEDS_TM1628) += tm1628.o

📚 References

• TM1628 Datasheet
• Driver Setup Guide

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👨‍💼 Author

Developed by:

Venkatesh M – venkatesh.muninagaraju@essae.com

Embedded System Engineer

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