From 9ec39de1d095af6d9f690c63c00f1383d29c358d Mon Sep 17 00:00:00 2001
From: Kaspar Schleiser <kaspar@schleiser.de>
Date: Thu, 2 Jun 2016 22:15:46 +0200
Subject: [PATCH] cpu: samd21: misc Wextra fixes

---
 cpu/samd21/periph/gpio.c | 2 +-
 cpu/samd21/periph/spi.c  | 9 ++++++++-
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/cpu/samd21/periph/gpio.c b/cpu/samd21/periph/gpio.c
index 80e31f0162..e9d58d8cce 100644
--- a/cpu/samd21/periph/gpio.c
+++ b/cpu/samd21/periph/gpio.c
@@ -212,7 +212,7 @@ void gpio_write(gpio_t pin, int value)
 
 void isr_eic(void)
 {
-    for (int i = 0; i < NUMOF_IRQS; i++) {
+    for (unsigned i = 0; i < NUMOF_IRQS; i++) {
         if (EIC->INTFLAG.reg & (1 << i)) {
             EIC->INTFLAG.reg = (1 << i);
             if(EIC->INTENSET.reg & (1 << i)) {
diff --git a/cpu/samd21/periph/spi.c b/cpu/samd21/periph/spi.c
index 58ccc90a7e..f7eef079f6 100644
--- a/cpu/samd21/periph/spi.c
+++ b/cpu/samd21/periph/spi.c
@@ -208,13 +208,20 @@ int spi_init_master(spi_t dev, spi_conf_t conf, spi_speed_t speed)
 
 int spi_init_slave(spi_t dev, spi_conf_t conf, char (*cb)(char))
 {
+    (void)dev;
+    (void)conf;
+    (void)cb;
     /* TODO */
+    assert(false);
     return -1;
 }
 
 void spi_transmission_begin(spi_t dev, char reset_val)
 {
-    /* TODO*/
+    (void)dev;
+    (void)reset_val;
+    /* TODO */
+    assert(false);
 }
 
 int spi_acquire(spi_t dev)