Still identical to the one wihtout pointers, but this version is optimised to use a const pointers. So that when we generate more than one pin they all use the same pointer registers without recreating them.

README.md

@@ -36,7 +36,7 @@ Will set GPIO21 pin (HEADER 40) to High
 ```
 Size
 text   data     bss     dec     hex  filename
-3836    332	    16	    4184	1058 ked_executable
+3696   332	    16	    4044	fcc	 ked_executable
 
 ```
 

examples/pin_control.c

@@ -21,13 +21,15 @@ void print_usage(const char* prog_name) {
  * @brief Entry point for GPIO control CLI.
  */
 int main(int argc, char* argv[]) {
+   
+    uint32_t pin = 0;
+    uint8_t action = 0xFF; // 0=set, 1=reset, 2=toggle, 3=read
+	
 	if (argc < 4) {
         print_usage(argv[0]);
         return 1;
     }
 
-    uint32_t pin = 0;
-    uint8_t action = 0xFF; // 0=set, 1=reset, 2=toggle, 3=read
 
     for (int i = 1; i < argc; ++i) {
         if (strcmp(argv[i], "-pin") == 0 && i + 1 < argc) {
@@ -48,36 +50,35 @@ int main(int argc, char* argv[]) {
         return 2;
     }
     
-    gpio_t gpio_conf = {
+	gpio_t led = {
         .chipname = "/dev/gpiochip0",
         .line_offset = pin,
         .direction = (action == 3) ? T_GPIO_DIRECTION_INPUT : T_GPIO_DIRECTION_OUTPUT,
         .bias = T_GPIO_BIAS_DEFAULT,
         .mode = T_GPIO_MODE_DEFAULT,
-        .status = T_GPIO_STATUS_NOT_INIT
+        .status = T_GPIO_STATUS_NOT_INIT,
+		.func = NULL
     };
 
 
-    gpio_fn_ptr_t led = {0};
+	gpio_error_t err = ked_gpio_init(&led);
-	
-	gpio_error_t err = ked_gpio_init(&gpio_conf, &led);
     if (err != T_GPIO_ERR_OK) {
-        if (led.on_error) led.on_error(err);
+        led.func->on_error(err);
         return 1;
     }
 
     switch (action) {
         case 0:
-			if (led.set) led.set(1);
+			led.func->set(1);
             break;
         case 1:
-			if (led.set) led.set(0);
+			led.func->set(0);
             break;
         case 2:
-			if (led.toggle) led.toggle();
+			led.func->toggle();
             break;
         case 3:
-            printf("GPIO%u value: %d\n", pin, led.read());
+            printf("GPIO%u value: %d\n", pin, led.func->read());
             break;
     }
 

ked/peripherals/gpio/gpio.h

@@ -126,6 +126,7 @@ struct gpio_s {
     gpio_direction_t direction;
     gpio_bias_t bias;
     gpio_status_t status;
+	const gpio_fn_ptr_t* func;
 };
 #endif
 
@@ -137,14 +138,14 @@ struct gpio_s {
  * @param gpio Pointer to target gpio_t handle
  * @return GPIO_OK on success, or an appropriate gpio_error_t
  */
-gpio_error_t ked_gpio_init(gpio_t* gpio, const gpio_fn_ptr_t* callbacks);
+gpio_error_t ked_gpio_init(gpio_t* gpio);
 
 /**
  * @brief Deinitialize and release resources associated with a GPIO pin.
  *
  * @param gpio Pointer to GPIO object
  */
-void ked_gpio_deinit(gpio_t* gpio, const gpio_fn_ptr_t* callbacks);
+void ked_gpio_deinit(gpio_t* gpio);
 
 /* === Platform-agnostic GPIO control interface === */
 

peripherals/gpio/gpio.c

@@ -86,6 +86,22 @@ static gpio_error_t gpio_linux_update(void) {
     return T_GPIO_ERR_UNSUPPORTED_MODE;
 }
 
+/* === Static GPIO Function Table Instance === */
+
+/**
+ * @brief Shared Linux GPIO function table for all gpio_t instances.
+ *
+ * Each GPIO object holds a pointer to this table via its `vtable` field.
+ * This avoids redundant copies of function pointers per object.
+ */
+static const gpio_fn_ptr_t gpio_linux_fn = {
+    .set      = gpio_linux_set,
+    .read     = gpio_linux_read,
+    .toggle   = gpio_linux_toggle,
+    .update   = gpio_linux_update,
+    .on_error = gpio_linux_handle_error
+};
+
 /* === Public API Implementation === */
 
 /**
@@ -97,7 +113,7 @@ static gpio_error_t gpio_linux_update(void) {
  * @param callbacks Optional pointer to gpio_fn_ptr_t to receive platform-specific handlers
  * @return T_GPIO_ERR_OK on success, or appropriate error code
  */
-gpio_error_t ked_gpio_init(gpio_t* gpio, const gpio_fn_ptr_t* callbacks) {
+gpio_error_t ked_gpio_init(gpio_t* gpio) {
     gpio_ctx.chip = gpiod_chip_open(gpio->chipname);
     if (!gpio_ctx.chip) {
         gpio_linux_handle_error(T_GPIO_ERR_NOT_AVAILABLE);
@@ -134,13 +150,7 @@ gpio_error_t ked_gpio_init(gpio_t* gpio, const gpio_fn_ptr_t* callbacks) {
         return T_GPIO_ERR_BUS_BUSY;
     }
 
-    if (callbacks) {
+    gpio->func     = &gpio_linux_fn;
-        ((gpio_fn_ptr_t*)callbacks)->set      = gpio_linux_set;
-        ((gpio_fn_ptr_t*)callbacks)->read     = gpio_linux_read;
-        ((gpio_fn_ptr_t*)callbacks)->toggle   = gpio_linux_toggle;
-        ((gpio_fn_ptr_t*)callbacks)->update   = gpio_linux_update;
-        ((gpio_fn_ptr_t*)callbacks)->on_error = gpio_linux_handle_error;
-    }
 
     return T_GPIO_ERR_OK;
 }
@@ -151,7 +161,7 @@ gpio_error_t ked_gpio_init(gpio_t* gpio, const gpio_fn_ptr_t* callbacks) {
  * @param gpio Unused in this implementation
  * @param callbacks Pointer to callback table that includes `deinit`
  */
-void ked_gpio_deinit(gpio_t* gpio, const gpio_fn_ptr_t* callbacks) {
+void ked_gpio_deinit(gpio_t* gpio) {
     if (gpio_ctx.line) {
         gpiod_line_release(gpio_ctx.line);
         gpio_ctx.line = NULL;