first commit (probably doesnt work)

.gitignore

@@ -0,0 +1,2 @@
+.vscode/
+*.ko

Makefile

@@ -0,0 +1,15 @@
+obj-m = lcd.o
+lcd-y = src/lcd.o src/io.o
+
+KVERSION = $(shell uname -r)
+
+all: module clean_int
+
+module:
+	make -C /lib/modules/$(KVERSION)/build M=$(PWD) modules
+
+clean_int:
+	rm */*.o *.o */.*.cmd .*.cmd *.mod *.c *.symvers *.order
+
+clean:
+	make -C /lib/modules/$(KVERSION)/build M=$(PWD) clean

install.sh

@@ -0,0 +1,14 @@
+#!/bin/sh
+
+module=lcd
+device=lcd
+
+/sbin/insmod ./$module.ko $* || exit 1
+
+rm -rf /dev/$device
+
+major=$(awk "\$2 == \"$module\" { print \$1 }" /proc/devices)
+echo $major
+
+mknod /dev/$device c $major 0
+chmod 664 /dev/$device

src/io.c

@@ -0,0 +1,36 @@
+#ifndef LCD_IO_H_
+#define LCD_IO_H_
+
+#include "lcd.h"
+
+loff_t lcd_llseek(struct file* filp, loff_t where, int whence)
+{
+    return 0;
+}
+
+ssize_t lcd_read(struct file* filp, char __user* buf, size_t count, loff_t* off)
+{
+    return 0;
+}
+
+ssize_t lcd_write(struct file* filp, const char __user* buf, size_t size, loff_t* off)
+{
+    return 0;
+}
+
+long lcd_ioctl(struct file* filp, unsigned int cmd, unsigned long arg)
+{
+    return 0;
+}
+
+int lcd_open(struct inode* inode, struct file* file)
+{
+    return 0;
+}
+
+int lcd_release(struct inode* inode, struct file* file)
+{
+    return 0;
+}
+
+#endif

src/lcd.c

@@ -0,0 +1,96 @@
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/fs.h>
+
+#include "lcd.h"
+
+MODULE_LICENSE("GPL");
+
+int lcd_major = LCD_MAJOR;
+int lcd_minor = LCD_MINOR;
+
+module_param(lcd_major, int, S_IRUGO);
+module_param(lcd_minor, int, S_IRUGO);
+
+static struct lcd_dev lcddev = { 0 };
+static int  __init lcd_init_cdev(void);
+static void __exit lcd_exit_cdev(void);
+
+extern loff_t   lcd_llseek  (struct file*, loff_t, int);
+extern ssize_t  lcd_read    (struct file*, char __user*, size_t, loff_t*);
+extern ssize_t  lcd_write   (struct file*, const char __user*, size_t, loff_t*);
+extern long     lcd_ioctl   (struct file*, unsigned int, unsigned long);
+extern int      lcd_open    (struct inode*, struct file*);
+extern int      lcd_release (struct inode*, struct file*);
+
+static struct file_operations lcd_fops = 
+{
+    .owner          = THIS_MODULE,
+    .llseek         = lcd_llseek,
+    .read           = lcd_read,
+    .write          = lcd_write,
+    .unlocked_ioctl = lcd_ioctl,
+    .open           = lcd_open,
+    .release        = lcd_release
+};
+
+static int __init lcd_init_module(void)
+{
+    int result = 0;
+
+    if(lcd_major)
+    {
+        lcddev.devno = MKDEV(lcd_major, lcd_minor);
+        result = register_chrdev_region(lcddev.devno, 1, "lcd");
+    }
+    else
+    {
+        result = alloc_chrdev_region(&lcddev.devno, lcd_minor, 1, "lcd");
+        lcd_major = MAJOR(lcddev.devno);
+    }
+
+    if(result < 0)
+    {
+        printk(KERN_ERR "%s: Failed to register character device\n", THIS_MODULE->name);
+        return result;
+    }
+
+    result = lcd_init_cdev();
+    if(result < 0)
+        return result;
+
+    printk(KERN_INFO "%s: Module loaded!\n", THIS_MODULE->name);
+    return result;
+}
+
+static void __exit lcd_exit_module(void)
+{
+    lcd_exit_cdev();
+    unregister_chrdev_region(lcddev.devno, 1);
+
+    printk(KERN_INFO "%s: Module removed!\n", THIS_MODULE->name);
+}
+
+module_init(lcd_init_module);
+module_exit(lcd_exit_module);
+
+static int  __init lcd_init_cdev(void)
+{
+    int result;
+
+    cdev_init(&lcddev.dev, &lcd_fops);
+    lcddev.dev.owner = THIS_MODULE;
+    lcddev.dev.ops = NULL;
+
+    result = cdev_add(&lcddev.dev, lcddev.devno, 1);
+    if(result < 0)
+        printk(KERN_ERR "%s: Failed to add device\n", THIS_MODULE->name);
+
+    return result;
+}
+
+static void __exit lcd_exit_cdev(void)
+{
+    cdev_del(&lcddev.dev);
+}

src/lcd.h

@@ -0,0 +1,18 @@
+#ifndef _LCD_H
+#define _LCD_H
+
+#include <linux/cdev.h>
+
+#define LCD_MAJOR 0
+#define LCD_MINOR 0
+
+extern int lcd_major;
+extern int lcd_minor;
+
+struct lcd_dev
+{
+    dev_t devno;
+    struct cdev dev;
+};
+
+#endif

unload.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+module=lcd
+device=lcd
+
+rmmod $module || exit 1
+rm -rf /dev/$device