diff --git a/src/arch/avr/i2c_slave.c b/src/arch/avr/i2c_slave.c
index 107ea14..548558b 100644
--- a/src/arch/avr/i2c_slave.c
+++ b/src/arch/avr/i2c_slave.c
@@ -40,7 +40,7 @@ void i2c_slave_init(
     sei();
 }
 
-void i2c_slave_stop() {
+void i2c_slave_stop(void) {
     // clear interrupts
     cli();
 
diff --git a/src/arch/avr/include/arch/i2c_slave.h b/src/arch/avr/include/arch/i2c_slave.h
index cbaf788..fffa96a 100644
--- a/src/arch/avr/include/arch/i2c_slave.h
+++ b/src/arch/avr/include/arch/i2c_slave.h
@@ -9,6 +9,6 @@ void i2c_slave_init(
     void (*recv_cb)(uint8_t),
     uint8_t (*send_cb)()
 );
-void i2c_slave_stop();
+void i2c_slave_stop(void);
 
 #endif // _ARCH_I2C_SLAVE_H
diff --git a/src/arch/avr/include/arch/uart.h b/src/arch/avr/include/arch/uart.h
index 19f1233..a3da1a9 100644
--- a/src/arch/avr/include/arch/uart.h
+++ b/src/arch/avr/include/arch/uart.h
@@ -21,7 +21,7 @@ struct Uart {
 
 void uart_init(struct Uart *uart, uint32_t baud);
 
-int16_t uart_count();
+int16_t uart_count(void);
 struct Uart *uart_new(int16_t num);
 
 uint8_t uart_can_read(struct Uart *uart);
diff --git a/src/arch/avr/uart.c b/src/arch/avr/uart.c
index a56a872..8ab2d95 100644
--- a/src/arch/avr/uart.c
+++ b/src/arch/avr/uart.c
@@ -42,7 +42,7 @@
 #endif
 // clang-format on
 
-int16_t uart_count() {
+int16_t uart_count(void) {
     return sizeof(UARTS) / sizeof(struct Uart);
 }
 
diff --git a/src/board/system76/addw1/gpio.c b/src/board/system76/addw1/gpio.c
index db88614..e204aa7 100644
--- a/src/board/system76/addw1/gpio.c
+++ b/src/board/system76/addw1/gpio.c
@@ -44,7 +44,7 @@ struct Gpio __code WLAN_EN =        GPIO(J, 2);
 struct Gpio __code WLAN_PWR_EN =    GPIO(B, 0);
 // clang-format on
 
-void gpio_init() {
+void gpio_init(void) {
     // Enable LPC reset on GPD2
     GCR = 0x04;
 
diff --git a/src/board/system76/addw2/gpio.c b/src/board/system76/addw2/gpio.c
index 5755eb5..bc2ec21 100644
--- a/src/board/system76/addw2/gpio.c
+++ b/src/board/system76/addw2/gpio.c
@@ -42,7 +42,7 @@ struct Gpio __code WLAN_PWR_EN =    GPIO(J, 7);
 struct Gpio __code XLP_OUT =        GPIO(B, 4);
 // clang-format on
 
-void gpio_init() {
+void gpio_init(void) {
     // PWRSW WDT 2 Enable 2
     GCR9 = BIT(5);
     // PWRSW WDT 2 Enable 1
diff --git a/src/board/system76/addw3/gpio.c b/src/board/system76/addw3/gpio.c
index c01706b..0bc16fe 100644
--- a/src/board/system76/addw3/gpio.c
+++ b/src/board/system76/addw3/gpio.c
@@ -34,7 +34,7 @@ struct Gpio __code WLAN_PWR_EN =    GPIO(D, 3);
 struct Gpio __code XLP_OUT =        GPIO(B, 4);
 // clang-format on
 
-void gpio_init() {
+void gpio_init(void) {
     // PWRSW WDT 2 Enable 2
     GCR9 = BIT(5);
     // PWRSW WDT 2 Enable 1
diff --git a/src/board/system76/bonw14/gpio.c b/src/board/system76/bonw14/gpio.c
index f413281..2506088 100644
--- a/src/board/system76/bonw14/gpio.c
+++ b/src/board/system76/bonw14/gpio.c
@@ -41,7 +41,7 @@ struct Gpio __code WLAN_PWR_EN =    GPIO(A, 3);
 struct Gpio __code XLP_OUT =        GPIO(B, 4); // renamed to EN_3V
 // clang-format on
 
-void gpio_init() {
+void gpio_init(void) {
     // PWRSW WDT 2 Enable 2
     GCR9 = BIT(5);
     // PWRSW WDT 2 Enable 1
diff --git a/src/board/system76/bonw15/gpio.c b/src/board/system76/bonw15/gpio.c
index 7a25af1..dce4969 100644
--- a/src/board/system76/bonw15/gpio.c
+++ b/src/board/system76/bonw15/gpio.c
@@ -36,7 +36,7 @@ struct Gpio __code WLAN_PWR_EN =    GPIO(B, 5);
 struct Gpio __code XLP_OUT =        GPIO(B, 4);
 // clang-format on
 
-void gpio_init() {
+void gpio_init(void) {
     // PWRSW WDT 2 Enable 2
     GCR9 = BIT(5);
     // PWRSW WDT 2 Enable 1
diff --git a/src/board/system76/darp5/gpio.c b/src/board/system76/darp5/gpio.c
index b4f55fd..f106049 100644
--- a/src/board/system76/darp5/gpio.c
+++ b/src/board/system76/darp5/gpio.c
@@ -45,7 +45,7 @@ struct Gpio __code WLAN_EN =        GPIO(H, 5);
 struct Gpio __code WLAN_PWR_EN =    GPIO(J, 4);
 // clang-format on
 
-void gpio_init() {
+void gpio_init(void) {
     // Enable LPC reset on GPD2
     GCR = 0x04;
 
diff --git a/src/board/system76/darp7/gpio.c b/src/board/system76/darp7/gpio.c
index ee4538f..d4f84d1 100644
--- a/src/board/system76/darp7/gpio.c
+++ b/src/board/system76/darp7/gpio.c
@@ -42,7 +42,7 @@ struct Gpio __code WLAN_PWR_EN =    GPIO(A, 3);
 struct Gpio __code XLP_OUT =        GPIO(B, 4);
 // clang-format on
 
-void gpio_init() {
+void gpio_init(void) {
     // PWRSW WDT 2 Enable 2
     GCR9 = BIT(5);
     // PWRSW WDT 2 Enable 1
diff --git a/src/board/system76/galp3-c/gpio.c b/src/board/system76/galp3-c/gpio.c
index 4e4703f..7bfafff 100644
--- a/src/board/system76/galp3-c/gpio.c
+++ b/src/board/system76/galp3-c/gpio.c
@@ -44,7 +44,7 @@ struct Gpio __code WLAN_EN =        GPIO(H, 5);
 struct Gpio __code WLAN_PWR_EN =    GPIO(J, 4);
 // clang-format on
 
-void gpio_init() {
+void gpio_init(void) {
     // Enable LPC reset on GPD2
     GCR = 0x04;
 
diff --git a/src/board/system76/galp5/gpio.c b/src/board/system76/galp5/gpio.c
index 40f5513..65eba23 100644
--- a/src/board/system76/galp5/gpio.c
+++ b/src/board/system76/galp5/gpio.c
@@ -43,7 +43,7 @@ struct Gpio __code WLAN_PWR_EN =    GPIO(A, 3);
 struct Gpio __code XLP_OUT =        GPIO(B, 4);
 // clang-format on
 
-void gpio_init() {
+void gpio_init(void) {
     // PWRSW WDT 2 Enable 2
     GCR9 = BIT(5);
     // PWRSW WDT 2 Enable 1
diff --git a/src/board/system76/gaze15/gpio.c b/src/board/system76/gaze15/gpio.c
index f6f192d..69b89f5 100644
--- a/src/board/system76/gaze15/gpio.c
+++ b/src/board/system76/gaze15/gpio.c
@@ -40,7 +40,7 @@ struct Gpio __code WLAN_PWR_EN =    GPIO(A, 3);
 struct Gpio __code XLP_OUT =        GPIO(B, 4);
 // clang-format on
 
-void gpio_init() {
+void gpio_init(void) {
     // PWRSW WDT 2 Enable 2
     GCR9 = BIT(5);
     // PWRSW WDT 2 Enable 1
diff --git a/src/board/system76/gaze16-3050/gpio.c b/src/board/system76/gaze16-3050/gpio.c
index 3c0d080..8d138b0 100644
--- a/src/board/system76/gaze16-3050/gpio.c
+++ b/src/board/system76/gaze16-3050/gpio.c
@@ -38,7 +38,7 @@ struct Gpio __code WLAN_PWR_EN =    GPIO(A, 3);
 struct Gpio __code XLP_OUT =        GPIO(B, 4);
 // clang-format on
 
-void gpio_init() {
+void gpio_init(void) {
     // PWRSW WDT 2 Enable 2
     GCR9 = BIT(5);
     // PWRSW WDT 2 Enable 1
diff --git a/src/board/system76/gaze16-3060/gpio.c b/src/board/system76/gaze16-3060/gpio.c
index 1cfa9cd..7890be7 100644
--- a/src/board/system76/gaze16-3060/gpio.c
+++ b/src/board/system76/gaze16-3060/gpio.c
@@ -39,7 +39,7 @@ struct Gpio __code WLAN_PWR_EN =    GPIO(A, 3);
 struct Gpio __code XLP_OUT =        GPIO(B, 4);
 // clang-format on
 
-void gpio_init() {
+void gpio_init(void) {
     // PWRSW WDT 2 Enable 2
     GCR9 = BIT(5);
     // PWRSW WDT 2 Enable 1
diff --git a/src/board/system76/gaze17-3050/gpio.c b/src/board/system76/gaze17-3050/gpio.c
index aa0beb7..3203b9d 100644
--- a/src/board/system76/gaze17-3050/gpio.c
+++ b/src/board/system76/gaze17-3050/gpio.c
@@ -38,7 +38,7 @@ struct Gpio __code WLAN_PWR_EN =    GPIO(A, 3);
 struct Gpio __code XLP_OUT =        GPIO(B, 4);
 // clang-format on
 
-void gpio_init() {
+void gpio_init(void) {
     // PWRSW WDT 2 Enable 2
     GCR9 = BIT(5);
     // PWRSW WDT 2 Enable 1
diff --git a/src/board/system76/gaze17-3060/gpio.c b/src/board/system76/gaze17-3060/gpio.c
index 60fb109..dcbfeae 100644
--- a/src/board/system76/gaze17-3060/gpio.c
+++ b/src/board/system76/gaze17-3060/gpio.c
@@ -38,7 +38,7 @@ struct Gpio __code WLAN_PWR_EN =    GPIO(D, 3);
 struct Gpio __code XLP_OUT =        GPIO(B, 4);
 // clang-format on
 
-void gpio_init() {
+void gpio_init(void) {
     // PWRSW WDT 2 Enable 2
     GCR9 = BIT(5);
     // PWRSW WDT 2 Enable 1
diff --git a/src/board/system76/gaze18/gpio.c b/src/board/system76/gaze18/gpio.c
index f42e96d..6a3bd79 100644
--- a/src/board/system76/gaze18/gpio.c
+++ b/src/board/system76/gaze18/gpio.c
@@ -35,7 +35,7 @@ struct Gpio __code WLAN_PWR_EN =    GPIO(A, 3);
 struct Gpio __code XLP_OUT =        GPIO(B, 4);
 // clang-format on
 
-void gpio_init() {
+void gpio_init(void) {
     // Not documented
     //GCR22 = BIT(7);
     GCR10 = 0x02;
diff --git a/src/board/system76/lemp10/gpio.c b/src/board/system76/lemp10/gpio.c
index 387868a..dc1f7e4 100644
--- a/src/board/system76/lemp10/gpio.c
+++ b/src/board/system76/lemp10/gpio.c
@@ -41,7 +41,7 @@ struct Gpio __code WLAN_PWR_EN =    GPIO(A, 3);
 struct Gpio __code XLP_OUT =        GPIO(B, 4);
 // clang-format on
 
-void gpio_init() {
+void gpio_init(void) {
     // PWRSW WDT 2 Enable 2
     GCR9 = BIT(5);
     // PWRSW WDT 2 Enable 1
diff --git a/src/board/system76/lemp9/gpio.c b/src/board/system76/lemp9/gpio.c
index 5302724..bf54c84 100644
--- a/src/board/system76/lemp9/gpio.c
+++ b/src/board/system76/lemp9/gpio.c
@@ -42,7 +42,7 @@ struct Gpio __code WLAN_PWR_EN =    GPIO(A, 3);
 struct Gpio __code XLP_OUT =        GPIO(B, 4);
 // clang-format on
 
-void gpio_init() {
+void gpio_init(void) {
     // Enable LPC reset on GPD2
     GCR = 0x04;
     // Enable SMBus channel 4
diff --git a/src/board/system76/oryp11/gpio.c b/src/board/system76/oryp11/gpio.c
index 432a39d..ca562b3 100644
--- a/src/board/system76/oryp11/gpio.c
+++ b/src/board/system76/oryp11/gpio.c
@@ -36,7 +36,7 @@ struct Gpio __code WLAN_PWR_EN =    GPIO(D, 3);
 struct Gpio __code XLP_OUT =        GPIO(B, 4);
 // clang-format on
 
-void gpio_init() {
+void gpio_init(void) {
     // PWRSW WDT 2 Enable 2
     GCR9 = BIT(5);
     // PWRSW WDT 2 Enable 1
diff --git a/src/board/system76/oryp6/gpio.c b/src/board/system76/oryp6/gpio.c
index 6e583dd..b1abe04 100644
--- a/src/board/system76/oryp6/gpio.c
+++ b/src/board/system76/oryp6/gpio.c
@@ -40,7 +40,7 @@ struct Gpio __code WLAN_PWR_EN =    GPIO(A, 3);
 struct Gpio __code XLP_OUT =        GPIO(B, 4);
 // clang-format on
 
-void gpio_init() {
+void gpio_init(void) {
     // PWRSW WDT 2 Enable 2
     GCR9 = BIT(5);
     // PWRSW WDT 2 Enable 1
diff --git a/src/board/system76/oryp7/gpio.c b/src/board/system76/oryp7/gpio.c
index 75efc0d..a79f9d6 100644
--- a/src/board/system76/oryp7/gpio.c
+++ b/src/board/system76/oryp7/gpio.c
@@ -39,7 +39,7 @@ struct Gpio __code WLAN_PWR_EN =    GPIO(H, 4);
 struct Gpio __code XLP_OUT =        GPIO(B, 4);
 // clang-format on
 
-void gpio_init() {
+void gpio_init(void) {
     // PWRSW WDT 2 Enable 2
     GCR9 = BIT(5);
     // PWRSW WDT 2 Enable 1
diff --git a/src/board/system76/oryp8/gpio.c b/src/board/system76/oryp8/gpio.c
index 81e7f7b..d12694a 100644
--- a/src/board/system76/oryp8/gpio.c
+++ b/src/board/system76/oryp8/gpio.c
@@ -37,7 +37,7 @@ struct Gpio __code WLAN_PWR_EN =    GPIO(H, 4);
 struct Gpio __code XLP_OUT =        GPIO(B, 4);
 // clang-format on
 
-void gpio_init() {
+void gpio_init(void) {
     // PWRSW WDT 2 Enable 2
     GCR9 = BIT(5);
     // PWRSW WDT 2 Enable 1