diff --git a/firmware/hw_layer/drivers/gpio/core.c b/firmware/hw_layer/drivers/gpio/core.c
index fd7e1dc45f..de6ac43962 100644
--- a/firmware/hw_layer/drivers/gpio/core.c
+++ b/firmware/hw_layer/drivers/gpio/core.c
@@ -49,11 +49,12 @@ static struct gpiochip chips[BOARD_EXT_GPIOCHIPS];
 /* Local functions.															*/
 /*==========================================================================*/
 
-static struct gpiochip *gpiochip_find(unsigned int pin)
+/**
+ * @return pointer to GPIO device for specified pin
+ */
+static struct gpiochip *gpiochip_find(brain_pin_e pin)
 {
-	int i;
-
-	for (i = 0; i < BOARD_EXT_GPIOCHIPS; i++) {
+	for (int i = 0; i < BOARD_EXT_GPIOCHIPS; i++) {
 		struct gpiochip *chip = &chips[i];
 
 		if ((pin >= chip->base) && (pin < (chip->base + chip->size)))
@@ -72,7 +73,7 @@ static struct gpiochip *gpiochip_find(unsigned int pin)
  * @details
  */
 
-int gpiochips_getPinOffset(unsigned int pin)
+int gpiochips_getPinOffset(brain_pin_e pin)
 {
 	struct gpiochip *chip = gpiochip_find(pin);
 
@@ -88,8 +89,7 @@ int gpiochips_getPinOffset(unsigned int pin)
  * @details return gpiochip name
  */
 
-const char *gpiochips_getChipName(unsigned int pin)
-{
+const char *gpiochips_getChipName(brain_pin_e pin) {
 	struct gpiochip *chip = gpiochip_find(pin);
 
 	if (chip)
@@ -103,7 +103,7 @@ const char *gpiochips_getChipName(unsigned int pin)
  * @details return pin name or gpiochip name (if no pins names provided)
  */
 
-const char *gpiochips_getPinName(unsigned int pin)
+const char *gpiochips_getPinName(brain_pin_e pin)
 {
 	int offset;
 	struct gpiochip *chip = gpiochip_find(pin);
@@ -140,6 +140,7 @@ int gpiochip_register(const char *name, struct gpiochip_ops *ops, size_t size, v
 	if ((!ops) || (!size))
 		return -1;
 
+	/* no 'writePad' and no 'readPad' implementation? return error code */
 	if ((!ops->writePad) && (!ops->readPad))
 		return -1;
 
@@ -283,7 +284,7 @@ int gpiochips_readPad(brain_pin_e pin)
 
 /**
  * @brief Get total pin count allocated for external gpio chips.
- * @details Will also include unused pins for chips that was registred
+ * @details Will also include unused pins for chips that was registered
  * but later fails to init.
  */
 
@@ -294,22 +295,19 @@ int gpiochips_get_total_pins(void)
 
 #else /* BOARD_EXT_GPIOCHIPS > 0 */
 
-int gpiochips_getPinOffset(unsigned int pin)
-{
+int gpiochips_getPinOffset(brain_pin_e pin) {
 	(void)pin;
 
 	return -1;
 }
 
-const char *gpiochips_getChipName(unsigned int pin)
-{
+const char *gpiochips_getChipName(brain_pin_e pin) {
 	(void)pin;
 
 	return NULL;
 }
 
-const char *gpiochips_getPinName(unsigned int pin)
-{
+const char *gpiochips_getPinName(brain_pin_e pin) {
 	(void)pin;
 
 	return NULL;
diff --git a/firmware/hw_layer/drivers/gpio/gpio_ext.h b/firmware/hw_layer/drivers/gpio/gpio_ext.h
index d49ef02318..0050c32684 100644
--- a/firmware/hw_layer/drivers/gpio/gpio_ext.h
+++ b/firmware/hw_layer/drivers/gpio/gpio_ext.h
@@ -26,19 +26,19 @@ extern "C"
 #endif /* __cplusplus */
 
 struct gpiochip_ops {
-	int (*setPadMode)(void *data, unsigned int pin, int mode);
-	int (*writePad)(void *data, unsigned int pin, int value);
-	int (*readPad)(void *data, unsigned int pin);
-	int (*getDiag)(void *data, unsigned int pin);
+	int (*setPadMode)(void *data, brain_pin_e pin, int mode);
+	int (*writePad)(void *data, brain_pin_e pin, int value);
+	int (*readPad)(void *data, brain_pin_e pin);
+	int (*getDiag)(void *data, brain_pin_e pin);
 	int (*init)(void *data);
 	int (*deinit)(void *data);
 };
 
-int gpiochips_getPinOffset(unsigned int pin);
-const char *gpiochips_getChipName(unsigned int pin);
-const char *gpiochips_getPinName(unsigned int pin);
+int gpiochips_getPinOffset(brain_pin_e pin);
+const char *gpiochips_getChipName(brain_pin_e pin);
+const char *gpiochips_getPinName(brain_pin_e pin);
 
-/* register gpio cgip */
+/* register GPIO chip */
 int gpiochip_register(const char *name, struct gpiochip_ops *ops, size_t size, void *priv);
 
 void gpiochip_use_gpio_base(int size);
diff --git a/firmware/hw_layer/drivers/gpio/mc33972.c b/firmware/hw_layer/drivers/gpio/mc33972.c
index 0a2e79e122..f32e376bc0 100644
--- a/firmware/hw_layer/drivers/gpio/mc33972.c
+++ b/firmware/hw_layer/drivers/gpio/mc33972.c
@@ -203,7 +203,7 @@ err:
  * @details Wake up driver. Will cause input and diagnostic
  *  update
  */
-
+/* todo: why is this unused? dead code? bug?
 static int mc33972_wake_driver(struct mc33972_priv *chip)
 {
 	(void)chip;
@@ -212,6 +212,7 @@ static int mc33972_wake_driver(struct mc33972_priv *chip)
 
 	return 0;
 }
+*/
 
 /*==========================================================================*/
 /* Driver thread.															*/
@@ -260,8 +261,7 @@ static THD_FUNCTION(mc33972_driver_thread, p)
 /* Driver exported functions.												*/
 /*==========================================================================*/
 
-int mc33972_readPad(void *data, unsigned int pin)
-{
+int mc33972_readPad(void *data, brain_pin_e pin) {
 	struct mc33972_priv *chip;
 
 	if ((pin >= MC33972_INPUTS) || (data == NULL))
@@ -273,8 +273,7 @@ int mc33972_readPad(void *data, unsigned int pin)
 	return !!(chip->i_state & FLAG_PIN(pin));
 }
 
-int mc33972_getDiag(void *data, unsigned int pin)
-{
+int mc33972_getDiag(void *data, brain_pin_e pin) {
 	int diag;
 	struct mc33972_priv *chip;
 
diff --git a/firmware/hw_layer/drivers/gpio/tle6240.c b/firmware/hw_layer/drivers/gpio/tle6240.c
index 0b939a3520..99c577f526 100644
--- a/firmware/hw_layer/drivers/gpio/tle6240.c
+++ b/firmware/hw_layer/drivers/gpio/tle6240.c
@@ -376,7 +376,7 @@ static THD_FUNCTION(tle6240_driver_thread, p)
 /* Driver exported functions.												*/
 /*==========================================================================*/
 
-int tle6240_writePad(void *data, unsigned int pin, int value)
+int tle6240_writePad(void *data, brain_pin_e pin, int value)
 {
 	struct tle6240_priv *chip;
 
@@ -409,7 +409,7 @@ int tle6240_writePad(void *data, unsigned int pin, int value)
 	return 0;
 }
 
-int tle6240_getDiag(void *data, unsigned int pin)
+int tle6240_getDiag(void *data, brain_pin_e pin)
 {
 	int diag;
 	struct tle6240_priv *chip;
diff --git a/firmware/hw_layer/drivers/gpio/tle8888.c b/firmware/hw_layer/drivers/gpio/tle8888.c
index 30ffcb78d0..8ba4773cf5 100644
--- a/firmware/hw_layer/drivers/gpio/tle8888.c
+++ b/firmware/hw_layer/drivers/gpio/tle8888.c
@@ -321,20 +321,19 @@ static THD_FUNCTION(tle8888_driver_thread, p)
 /* Driver exported functions.												*/
 /*==========================================================================*/
 
-int tle8888_writePad(void *data, unsigned int pin, int value)
-{
-	struct tle8888_priv *chip;
+int tle8888_writePad(void *data, brain_pin_e pin, int value) {
 
 	if ((pin >= TLE8888_OUTPUTS) || (data == NULL))
 		return -1;
 
-	chip = (struct tle8888_priv *)data;
+	struct tle8888_priv *chip = (struct tle8888_priv *)data;
 
 	/* TODO: lock */
-	if (value)
+	if (value) {
 		chip->o_state |=  (1 << pin);
-	else
+	} else {
 		chip->o_state &= ~(1 << pin);
+	}
 	/* TODO: unlock */
 	/* direct driven? */
 	if (chip->o_direct_mask & (1 << pin)) {
@@ -514,9 +513,7 @@ struct gpiochip_ops tle8888_ops = {
  * @return return gpio chip base
  */
 
-int tle8888_add(unsigned int index, const struct tle8888_config *cfg)
-{
-	int ret;
+int tle8888_add(unsigned int index, const struct tle8888_config *cfg) {
 	struct tle8888_priv *chip;
 
 	efiAssert(OBD_PCM_Processor_Fault, cfg != NULL, "8888CFG", 0)
@@ -543,7 +540,7 @@ int tle8888_add(unsigned int index, const struct tle8888_config *cfg)
 	chip->drv_state = TLE8888_WAIT_INIT;
 
 	/* register, return gpio chip base */
-	ret = gpiochip_register(DRIVER_NAME, &tle8888_ops, TLE8888_OUTPUTS, chip);
+	int ret = gpiochip_register(DRIVER_NAME, &tle8888_ops, TLE8888_OUTPUTS, chip);
 
 	/* set default pin names, board init code can rewrite */
 	gpiochips_setPinNames(ret, tle8888_pin_names);
diff --git a/unit_tests/tests/test_gpiochip.cpp b/unit_tests/tests/test_gpiochip.cpp
index 9daf6c043d..98172d2909 100644
--- a/unit_tests/tests/test_gpiochip.cpp
+++ b/unit_tests/tests/test_gpiochip.cpp
@@ -10,7 +10,7 @@
 
 using ::testing::_;
 
-static int testchip_readPad(void *data, unsigned int pin)
+static int testchip_readPad(void *data, brain_pin_e pin)
 {
 	if (pin & 0x01)
 		return 1;
@@ -19,7 +19,7 @@ static int testchip_readPad(void *data, unsigned int pin)
 
 static int io_state = 0;
 
-static int testchip_writePad(void *data, unsigned int pin, int value)
+static int testchip_writePad(void *data, brain_pin_e pin, int value)
 {
 	if (value)
 		io_state |=  (1 << value);
@@ -39,7 +39,7 @@ static int testchip_init(void *data)
 }
 
 static int calls_to_failed_chip = 0;
-static int testchip_failed_writePad(void *data, unsigned int pin, int value)
+static int testchip_failed_writePad(void *data, brain_pin_e pin, int value)
 {
 	calls_to_failed_chip++;
 }