drivers/hdc1000: (re)add error checks for I2C acces

drivers/hdc1000/hdc1000.c

@@ -76,8 +76,9 @@ int hdc1000_init(hdc1000_t *dev, const hdc1000_params_t *params)
     return HDC1000_OK;
 }
 
-void hdc1000_trigger_conversion(hdc1000_t *dev)
+int hdc1000_trigger_conversion(hdc1000_t *dev)
 {
+    int status = HDC1000_OK;
     assert(dev);
 
     i2c_acquire(dev->p.i2c);
@@ -86,36 +87,48 @@ void hdc1000_trigger_conversion(hdc1000_t *dev)
      * to the address 0x00 (HDC1000_TEMPERATURE).
      * Conversion Time is 6.50ms for each value for 14 bit resolution.
      */
-    i2c_write_byte(dev->p.i2c, dev->p.addr, HDC1000_TEMPERATURE);
+    if (i2c_write_byte(dev->p.i2c, dev->p.addr, HDC1000_TEMPERATURE) != 1) {
+        status = HDC1000_BUSERR;
+    }
 
     i2c_release(dev->p.i2c);
+    return status;
 }
 
-void hdc1000_get_results(hdc1000_t *dev, int16_t *temp, int16_t *hum)
+int hdc1000_get_results(hdc1000_t *dev, int16_t *temp, int16_t *hum)
 {
+    int status = HDC1000_OK;
     assert(dev);
 
     uint8_t buf[4];
 
     /* first we read the RAW results from the device */
     i2c_acquire(dev->p.i2c);
-    i2c_read_bytes(dev->p.i2c, dev->p.addr, buf, 4);
+    if (i2c_read_bytes(dev->p.i2c, dev->p.addr, buf, 4) != 4) {
+        status = HDC1000_BUSERR;
+    }
     i2c_release(dev->p.i2c);
 
-    /* and finally we convert the values to their physical representation */
-    if (temp) {
-        uint16_t traw = ((uint16_t)buf[0] << 8) | buf[1];
-        *temp = (int16_t)((((int32_t)traw * 16500) >> 16) - 4000);
-    }
-    if (hum) {
-        uint16_t hraw = ((uint16_t)buf[2] << 8) | buf[3];
-        *hum  = (int16_t)(((int32_t)hraw * 10000) >> 16);
+    if (status == HDC1000_OK) {
+        /* if all ok, we convert the values to their physical representation */
+        if (temp) {
+            uint16_t traw = ((uint16_t)buf[0] << 8) | buf[1];
+            *temp = (int16_t)((((int32_t)traw * 16500) >> 16) - 4000);
+        }
+        if (hum) {
+            uint16_t hraw = ((uint16_t)buf[2] << 8) | buf[3];
+            *hum  = (int16_t)(((int32_t)hraw * 10000) >> 16);
+        }
     }
+
+    return status;
 }
 
-void hdc1000_read(hdc1000_t *dev, int16_t *temp, int16_t *hum)
+int hdc1000_read(hdc1000_t *dev, int16_t *temp, int16_t *hum)
 {
-    hdc1000_trigger_conversion(dev);
+    if (hdc1000_trigger_conversion(dev) != HDC1000_OK) {
+        return HDC1000_BUSERR;
+    }
     xtimer_usleep(HDC1000_CONVERSION_TIME);
-    hdc1000_get_results(dev, temp, hum);
+    return hdc1000_get_results(dev, temp, hum);
 }

drivers/hdc1000/hdc1000_saul.c

@@ -27,7 +27,9 @@ static int read_temp(void *dev, phydat_t *res)
 {
     hdc1000_t *d = (hdc1000_t *)dev;
 
-    hdc1000_read(d, &(res->val[0]), NULL);
+    if (hdc1000_read(d, &(res->val[0]), NULL) != HDC1000_OK) {
+        return -ECANCELED;
+    }
     memset(&(res->val[1]), 0, 2 * sizeof(int16_t));
     res->unit = UNIT_TEMP_C;
     res->scale = -2;
@@ -39,7 +41,9 @@ static int read_hum(void *dev, phydat_t *res)
 {
     hdc1000_t *d = (hdc1000_t *)dev;
 
-    hdc1000_read(d, NULL, &(res->val[0]));
+    if (hdc1000_read(d, NULL, &(res->val[0])) != HDC1000_OK) {
+        return -ECANCELED;
+    }
     memset(&(res->val[1]), 0, 2 * sizeof(int16_t));
     res->unit = UNIT_PERCENT;
     res->scale = -2;

drivers/include/hdc1000.h

@@ -70,9 +70,10 @@ extern "C"
  * @brief   HDC1000 specific return values
  */
 enum {
-    HDC1000_OK    = 0,      /**< everything went as expected */
-    HDC1000_NODEV = -1,     /**< no HDC1000 device found on the bus */
-    HDC1000_NOBUS = -2,     /**< errors while initializing the I2C bus */
+    HDC1000_OK     = 0,     /**< everything went as expected */
+    HDC1000_NODEV  = -1,    /**< no HDC1000 device found on the bus */
+    HDC1000_NOBUS  = -2,    /**< errors while initializing the I2C bus */
+    HDC1000_BUSERR = -3     /**< error during I2C communication */
 };
 
 /**
@@ -119,8 +120,11 @@ int hdc1000_init(hdc1000_t *dev, const hdc1000_params_t *params);
  * @ref hdc1000_get_results().
  *
  * @param[in]  dev          device descriptor of sensor
+ *
+ * @return                  HDC1000_OK on success
+ * @return                  HDC1000_BUSERR on I2C communication failures
  */
-void hdc1000_trigger_conversion(hdc1000_t *dev);
+int hdc1000_trigger_conversion(hdc1000_t *dev);
 
 /**
  * @brief   Read conversion results for temperature and humidity
@@ -128,8 +132,11 @@ void hdc1000_trigger_conversion(hdc1000_t *dev);
  * @param[in]  dev          device descriptor of sensor
  * @param[out] temp         temperature [in 100 * degree centigrade]
  * @param[out] hum          humidity [in 100 * percent relative]
+ *
+ * @return                  HDC1000_OK on success
+ * @return                  HDC1000_BUSERR on I2C communication failures
  */
-void hdc1000_get_results(hdc1000_t *dev, int16_t *temp, int16_t *hum);
+int hdc1000_get_results(hdc1000_t *dev, int16_t *temp, int16_t *hum);
 
 /**
  * @brief   Convenience function for reading temperature and humidity
@@ -140,8 +147,11 @@ void hdc1000_get_results(hdc1000_t *dev, int16_t *temp, int16_t *hum);
  * @param[in]  dev          device descriptor of sensor
  * @param[out] temp         temperature [in 100 * degree centigrade]
  * @param[out] hum          humidity [in 100 * percent relative]
+ *
+ * @return                  HDC1000_OK on success
+ * @return                  HDC1000_BUSERR on I2C communication failures
  */
-void hdc1000_read(hdc1000_t *dev, int16_t *temp, int16_t *hum);
+int hdc1000_read(hdc1000_t *dev, int16_t *temp, int16_t *hum);
 
 #ifdef __cplusplus
 }