some progress indeed

driver/Makefile

@@ -4,7 +4,7 @@ obj-m += $(NAME).o
 all: $(NAME).ko $(NAME).dtbo
 	echo Builded Device Tree Overlay and kernel module
 
-$(NAME).ko:
+$(NAME).ko: $(NAME).c
 	make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules
 
 $(NAME).dtbo: $(NAME).dts

driver/counter.c

@@ -18,7 +18,7 @@ static void dt_remove(struct platform_device *pdev);
 
 static struct of_device_id my_driver_ids[] = {
 	{
-		.compatible = "brightlight,mydev",
+		.compatible = "hottis,counter",
 	}, { /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, my_driver_ids);
@@ -33,7 +33,8 @@ static struct platform_driver my_driver = {
 };
 
 /* GPIO variable */
-static struct gpio_desc *my_led = NULL;
+static struct gpio_desc *red_led = NULL;
+static struct gpio_desc *blue_led = NULL;
 
 
 /**
@@ -41,44 +42,29 @@ static struct gpio_desc *my_led = NULL;
  */
 static int dt_probe(struct platform_device *pdev) {
 	struct device *dev = &pdev->dev;
-	const char *label;
-	int my_value, ret;
 
-	printk("dt_gpio - Now I am in the probe function!\n");
+	printk("counter - probing\n");
 
-	/* Check for device properties */
-	if(!device_property_present(dev, "label")) {
-		printk("dt_gpio - Error! Device property 'label' not found!\n");
+	if(!device_property_present(dev, "red-led-gpio")) {
+		printk("counter - Error! Device property 'red-led-gpio' not found!\n");
 		return -1;
 	}
-	if(!device_property_present(dev, "my_value")) {
-		printk("dt_gpio - Error! Device property 'my_value' not found!\n");
-		return -1;
-	}
-	if(!device_property_present(dev, "green-led-gpio")) {
-		printk("dt_gpio - Error! Device property 'green-led-gpio' not found!\n");
+	if(!device_property_present(dev, "blue-led-gpio")) {
+		printk("counter - Error! Device property 'blue-led-gpio' not found!\n");
 		return -1;
 	}
 
-	/* Read device properties */
-	ret = device_property_read_string(dev, "label", &label);
-	if(ret) {
-		printk("dt_gpio - Error! Could not read 'label'\n");
-		return -1;
-	}
-	printk("dt_gpio - label: %s\n", label);
-	ret = device_property_read_u32(dev, "my_value", &my_value);
-	if(ret) {
-		printk("dt_gpio - Error! Could not read 'my_value'\n");
-		return -1;
-	}
-	printk("dt_gpio - my_value: %d\n", my_value);
 
 	/* Init GPIO */
-	my_led = gpiod_get(dev, "green-led", GPIOD_OUT_LOW);
-	if(IS_ERR(my_led)) {
-		printk("dt_gpio - Error! Could not setup the GPIO\n");
-		return -1 * IS_ERR(my_led);
+	red_led = gpiod_get(dev, "red-led", GPIOD_OUT_LOW);
+	if(IS_ERR(red_led)) {
+		printk("counter - Error! Could not setup the GPIO red-led\n");
+		return -1 * IS_ERR(red_led);
+	}
+	blue_led = gpiod_get(dev, "blue-led", GPIOD_OUT_LOW);
+	if(IS_ERR(blue_led)) {
+		printk("counter - Error! Could not setup the GPIO blue-led\n");
+		return -1 * IS_ERR(blue_led);
 	}
 
 	return 0;
@@ -88,19 +74,24 @@ static int dt_probe(struct platform_device *pdev) {
  * @brief This function is called on unloading the driver 
  */
 static void dt_remove(struct platform_device *pdev) {
-	printk("dt_gpio - Now I am in the remove function\n");
-	gpiod_put(my_led);
+	printk("counter - removing\n");
+	gpiod_put(red_led);
+	gpiod_put(blue_led);
 }
 
 /**
  * @brief This function is called, when the module is loaded into the kernel
  */
 static int __init my_init(void) {
-	printk("dt_gpio - Loading the driver...\n");
+	printk("counter - Loading the driver...\n");
 	if(platform_driver_register(&my_driver)) {
 		printk("dt_gpio - Error! Could not load driver\n");
 		return -1;
 	}
+
+	printk("counter - red led on\n");
+	gpiod_set_value(red_led, 1);
+
 	return 0;
 }
 
@@ -108,7 +99,11 @@ static int __init my_init(void) {
  * @brief This function is called, when the module is removed from the kernel
  */
 static void __exit my_exit(void) {
-	printk("dt_gpio - Unload driver");
+	printk("counter - Unload driver");
+
+	printk("counter - red led off\n");
+	gpiod_set_value(red_led, 0);
+
 	platform_driver_unregister(&my_driver);
 }
 

driver/counter.dts

@@ -5,12 +5,10 @@
   fragment@0 {
     target-path = "/";
     __overlay__ {
-      my_device {
-        compatible = "brightlight,mydev";
-        status = "okay";
-        label = "Test";
-        my_value = <12>;
-        green-led-gpio = <&gpio 21 0>; 
+      counter {
+        compatible = "hottis,counter";
+        red-led-gpio = <&gpio 26 0>; 
+        blue-led-gpio = <&gpio 21 0>; 
       };
     };
   };