diff --git a/drivers/soft_uart/soft_uart.c b/drivers/soft_uart/soft_uart.c
index 5b9ae4b5ab..99aa8c7e20 100644
--- a/drivers/soft_uart/soft_uart.c
+++ b/drivers/soft_uart/soft_uart.c
@@ -287,7 +287,7 @@ static void soft_uart_write_byte(soft_uart_t uart, uint8_t data)
     mutex_lock(&ctx->sync);
 }
 
-void soft_uart_write(uart_t uart, const uint8_t *data, size_t len)
+void soft_uart_write(soft_uart_t uart, const uint8_t *data, size_t len)
 {
     const soft_uart_conf_t *cfg = &soft_uart_config[uart];
     struct uart_ctx *ctx = &soft_uart_ctx[uart];
diff --git a/tests/driver_soft_uart/main.c b/tests/driver_soft_uart/main.c
index 1104babb8b..d5763a55ad 100644
--- a/tests/driver_soft_uart/main.c
+++ b/tests/driver_soft_uart/main.c
@@ -72,7 +72,7 @@ static int parse_dev(char *arg)
 
 static void rx_cb(void *arg, uint8_t data)
 {
-    uart_t dev = (uart_t)arg;
+    uart_t dev = (soft_uart_t)arg;
 
     ringbuffer_add_one(&(ctx[dev].rx_buf), data);
     if (data == '\n' || ringbuffer_full(&(ctx[dev].rx_buf))) {