From 2edf153cf89bb1597a148880148c78309caa4847 Mon Sep 17 00:00:00 2001
From: fabian18 <fabian.huessler@st.ovgu.de>
Date: Mon, 2 Sep 2019 08:49:27 +0200
Subject: [PATCH] drivers/at86rf2xx: do not hang on no dev

---
 drivers/at86rf2xx/at86rf2xx_netdev.c | 17 +++++++++++++----
 tests/driver_at86rf2xx/main.c        | 11 ++++++++++-
 2 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/drivers/at86rf2xx/at86rf2xx_netdev.c b/drivers/at86rf2xx/at86rf2xx_netdev.c
index c988ac72ba..01a4053e40 100644
--- a/drivers/at86rf2xx/at86rf2xx_netdev.c
+++ b/drivers/at86rf2xx/at86rf2xx_netdev.c
@@ -79,15 +79,24 @@ static int _init(netdev_t *netdev)
     gpio_set(dev->params.reset_pin);
     gpio_init_int(dev->params.int_pin, GPIO_IN, GPIO_RISING, _irq_handler, dev);
 
-    /* reset device to default values and put it into RX state */
-    at86rf2xx_reset(dev);
+    /* Intentionally check if bus can be acquired,
+       since getbus() drops the return value */
+    if (spi_acquire(dev->params.spi, dev->params.cs_pin, SPI_MODE_0,
+                                                dev->params.spi_clk) < 0) {
+        DEBUG("[at86rf2xx] error: unable to acquire SPI bus\n");
+        return -EIO;
+    }
+    spi_release(dev->params.spi);
 
-    /* test if the SPI is set up correctly and the device is responding */
+    /* test if the device is responding */
     if (at86rf2xx_reg_read(dev, AT86RF2XX_REG__PART_NUM) != AT86RF2XX_PARTNUM) {
         DEBUG("[at86rf2xx] error: unable to read correct part number\n");
-        return -1;
+        return -ENOTSUP;
     }
 
+    /* reset device to default values and put it into RX state */
+    at86rf2xx_reset(dev);
+
     return 0;
 }
 
diff --git a/tests/driver_at86rf2xx/main.c b/tests/driver_at86rf2xx/main.c
index a6033208a1..7f1dace64d 100644
--- a/tests/driver_at86rf2xx/main.c
+++ b/tests/driver_at86rf2xx/main.c
@@ -90,6 +90,7 @@ int main(void)
     puts("AT86RF2xx device driver test");
     xtimer_init();
 
+    unsigned dev_success = 0;
     for (unsigned i = 0; i < AT86RF2XX_NUM; i++) {
         netopt_enable_t en = NETOPT_ENABLE;
         const at86rf2xx_params_t *p = &at86rf2xx_params[i];
@@ -98,8 +99,16 @@ int main(void)
         printf("Initializing AT86RF2xx radio at SPI_%d\n", p->spi);
         at86rf2xx_setup(&devs[i], p);
         dev->event_callback = _event_cb;
-        dev->driver->init(dev);
+        if (dev->driver->init(dev) < 0) {
+            continue;
+        }
         dev->driver->set(dev, NETOPT_RX_END_IRQ, &en, sizeof(en));
+        dev_success++;
+    }
+
+    if (!dev_success) {
+        puts("No device could be initialized");
+        return 1;
     }
 
     _recv_pid = thread_create(stack, sizeof(stack), THREAD_PRIORITY_MAIN - 1,