return values adjusted to common return values

cpu/stm32f4/periph/dac.c

@@ -48,37 +48,41 @@ int8_t dac_init(dac_t dev, dac_precision_t precision)
             DAC_0_PORT->PUPDR &= ~(3 << (DAC_0_CH0_PIN * 2) | 3 << (DAC_0_CH1_PIN * 2));
             break;
 #endif
+        default:
+            /* Unknown Device */
+            return -1;
     }
 
     /* Select Shift value to normalize given Value */
     switch(precision) {
         case DAC_RES_6BIT:
             dac_config[dev].shift_mod = 0x06;       /* 2^6  << 6 = 2^12 */
             break;
-        case DAC_RES_8BIT:  
-            dac_config[dev].shift_mod = 0x04;       /* 2^8  << 4 = 2^12 */ 
+        case DAC_RES_8BIT:
+            dac_config[dev].shift_mod = 0x04;       /* 2^8  << 4 = 2^12 */
             break;
-        case DAC_RES_10BIT:                     
+        case DAC_RES_10BIT:
             dac_config[dev].shift_mod = 0x02;       /* 2^10 << 2 = 2^12 */
             break;
         case DAC_RES_12BIT:
-            dac_config[dev].shift_mod = 0x00;       /* 2^12 << 0 = 2^12 */ 
+            dac_config[dev].shift_mod = 0x00;       /* 2^12 << 0 = 2^12 */
             break;
         /* Not Supported Resolutions */
         case DAC_RES_14BIT:
         case DAC_RES_16BIT:
+        default:
             dac_poweroff(dev);
-            return -1;
+            return -2;
         break;
     }
 
-    /* Enable Channels, Clear Output */ 
+    /* Enable Channels, Clear Output */
     dac->CR = 0;
     dac->CR |= (DAC_CR_EN1 | DAC_CR_EN2);
     dac->DHR12R1 = 0;
     dac->DHR12R2 = 0;
 
-    return 0; 
+    return 0;
 }
 
 int8_t dac_write(dac_t dev, uint8_t channel, uint16_t value) 
@@ -92,9 +96,9 @@ int8_t dac_write(dac_t dev, uint8_t channel, uint16_t value)
         dac = DAC_0_DEV;
         val = value << dac_config[dev].shift_mod;
 
-        /* Check if given value is in Range. */
         if( DAC_MAX_12BIT < val ){
-            return -1;
+            /* Value out of Range */
+            return -3;
         }
 
         switch(channel){
@@ -104,12 +108,15 @@ int8_t dac_write(dac_t dev, uint8_t channel, uint16_t value)
             case 1: 
                 dac->DHR12R2 = val; 
                 break;
-            /* Unknown Channel */
+            /* Invalid Channel */
             default: 
                 return -2;
         }
         break;
 #endif
+        /* Unknown  Device */
+        default:
+            return -1;
     }
     return 0;
 }
@@ -120,10 +127,13 @@ int8_t dac_poweron(dac_t dev)
 #if DAC_0_EN
         case DAC_0:
             DAC_0_CLKEN();
-            return 0;
+            break;
 #endif
+        default:
+            /* Unknown Device */
+            return -1;
     }
-    return -1;
+    return 0;
 }
 
 int8_t dac_poweroff(dac_t dev) 
@@ -132,10 +142,13 @@ int8_t dac_poweroff(dac_t dev)
 #if DAC_0_EN
         case DAC_0:
             DAC_0_CLKDIS();
-            return 0;
+            break;
 #endif
+        default:
+            /* Unknown Device */
+            return -1;
     }
-    return -1;
+    return 0;
 }
 
 uint16_t dac_map(dac_t dev, int value, int min, int max)

drivers/include/periph/dac.h

@@ -74,7 +74,8 @@ typedef enum {
  * @param[in] precision    the precision to use for conversion
  *  
  * @return                 0 on success
- * @return                 -1 on precision not available
+ * @return                 -1 on unknown DAC Device
+ * @return                 -2 on precision not available
  */
 int8_t dac_init(dac_t dev, dac_precision_t precision);
 
@@ -86,8 +87,9 @@ int8_t dac_init(dac_t dev, dac_precision_t precision);
  * @param[in] value        the value to write onto DAC. 
  * 
  * @return                 0 on success
- * @return                 -1 if value is out of range. 
+ * @return                 -1 on unknown DAC Device
  * @return                 -2 on invalid channel 
+ * @return                 -3 if value is out of range. 
  */
 int8_t dac_write(dac_t dev, uint8_t channel, uint16_t value);
 
@@ -124,7 +126,7 @@ int8_t dac_poweroff(dac_t dev);
  * @param[in] min          the lower bound of the target interval
  * @param[in] max          the upper bound of the target interval
  *
- * @return                 the mapped value
+ * @return                 the mapped value, in valid DAC range
  */
 uint16_t dac_map(dac_t dev, int value, int min, int max);
 
@@ -138,7 +140,7 @@ uint16_t dac_map(dac_t dev, int value, int min, int max);
  * @param[in] min          the lower bound of the target interval
  * @param[in] max          the upper bound of the target interval
  * 
- * @return                 the mapped value
+ * @return                 the mapped value, in valid DAC range
  */
 uint16_t dac_mapf(dac_t dev, float value, float min, float max);