Squashed commit of the following:

STM32, STM32 F7:  LTDC and DMA2D drivers are not permitted to set the errno.

    SIM LPC31xx:  Serial and console drivers are not permitted to set the errno.

    SAMv7, STM32, STM32 L4:  DAC and ADC drivers are not permitted to set the errno.

arch/arm/src/lpc31xx/lpc31_serial.c

@@ -621,8 +621,7 @@ static int up_ioctl(struct file *filep, int cmd, unsigned long arg)
       break;
 
     default:
-      errno = ENOTTY;
+      ret = -ENOTTY;
-      ret = ERROR;
       break;
     }
 

arch/arm/src/samv7/sam_dac.c

@@ -627,7 +627,6 @@ FAR struct dac_dev_s *sam_dac_initialize(int intf)
 #endif
     {
       aerr("ERROR: No such DAC interface: %d\n", intf);
-      errno = ENODEV;
       return NULL;
     }
 
@@ -637,7 +636,6 @@ FAR struct dac_dev_s *sam_dac_initialize(int intf)
   if (ret < 0)
     {
       aerr("ERROR: Failed to initialize the DAC peripheral module: %d\n", ret);
-      errno = -ret;
       return NULL;
     }
 
@@ -648,7 +646,6 @@ FAR struct dac_dev_s *sam_dac_initialize(int intf)
   if (ret < 0)
     {
       aerr("ERROR: Failed to initialize DAC channel %d: %d\n", intf, ret);
-      errno = -ret;
       return NULL;
     }
 

arch/arm/src/stm32/stm32_adc.c

@@ -2705,14 +2705,12 @@ static int adc_ioctl(FAR struct adc_dev_s *dev, int cmd, unsigned long arg)
           ret = adc_ioc_wait_rcnr_zeroed(priv);
           if (ret < 0)
             {
-              set_errno(-ret);
               return ret;
             }
 
           ret = adc_set_ch(dev, ch);
           if (ret < 0)
             {
-              set_errno(-ret);
               return ret;
             }
 

arch/arm/src/stm32/stm32_dac.c

@@ -1587,7 +1587,6 @@ FAR struct dac_dev_s *stm32_dacinitialize(int intf)
 #endif  /* CONFIG_STM32_DAC2CH1 */
     {
       aerr("ERROR: No such DAC interface: %d\n", intf);
-      errno = ENODEV;
       return NULL;
     }
 
@@ -1597,7 +1596,6 @@ FAR struct dac_dev_s *stm32_dacinitialize(int intf)
   if (ret < 0)
     {
       aerr("ERROR: Failed to initialize the DAC block: %d\n", ret);
-      errno = -ret;
       return NULL;
     }
 
@@ -1608,7 +1606,6 @@ FAR struct dac_dev_s *stm32_dacinitialize(int intf)
   if (ret < 0)
     {
       aerr("ERROR: Failed to initialize DAC channel %d: %d\n", intf, ret);
-      errno = -ret;
       return NULL;
     }
 

arch/arm/src/stm32/stm32_dma2d.c

@@ -1945,7 +1945,7 @@ static int stm32_dma2dfillarea(FAR struct dma2d_layer_s *layer,
  *
  ****************************************************************************/
 
-FAR struct dma2d_layer_s * up_dma2dgetlayer(int lid)
+FAR struct dma2d_layer_s *up_dma2dgetlayer(int lid)
 {
   if (lid < DMA2D_LAYER_NSIZE)
     {
@@ -1957,8 +1957,7 @@ FAR struct dma2d_layer_s * up_dma2dgetlayer(int lid)
       return &priv->dma2d;
     }
 
-  lcderr("ERROR: EINVAL, Unknown layer identifier\n");
+  lcderr("ERROR: lid invalid: %d\n", lid);
-  errno = EINVAL;
   return NULL;
 }
 
@@ -1975,10 +1974,7 @@ FAR struct dma2d_layer_s * up_dma2dgetlayer(int lid)
  *
  * Return:
  *   On success - A valid dma2d layer reference
- *   On error   - NULL and errno is set to
+ *   On error   - NULL
- *                -EINVAL if one of the parameter is invalid
- *                -ENOMEM if no memory available or exceeds
- *                 CONFIG_STM32_DMA2D_NLAYERS
  *
  ****************************************************************************/
 
@@ -1986,11 +1982,11 @@ FAR struct dma2d_layer_s *up_dma2dcreatelayer(fb_coord_t width,
                                               fb_coord_t height,
                                               uint8_t fmt)
 {
+  FAR struct stm32_dma2d_s *layer = NULL;
   int        ret;
   int        lid;
   uint8_t    fmtmap;
   uint8_t    bpp = 0;
-  FAR struct stm32_dma2d_s *layer = NULL;
 
   lcdinfo("width=%d, height=%d, fmt=%02x \n", width, height, fmt);
 
@@ -2000,7 +1996,6 @@ FAR struct dma2d_layer_s *up_dma2dcreatelayer(fb_coord_t width,
 
   if (ret != OK)
     {
-      errno = -ret;
       return NULL;
     }
 
@@ -2069,24 +2064,21 @@ FAR struct dma2d_layer_s *up_dma2dcreatelayer(fb_coord_t width,
             }
           else
             {
-              /* free the layer struture */
+              /* Free the layer struture */
 
+              lcderr("ERROR: ENOMEM, Unable to allocate layer buffer\n");
               kmm_free(layer);
               layer = NULL;
-              lcderr("ERROR: ENOMEM, Unable to allocate layer buffer\n");
-              errno = ENOMEM;
             }
         }
       else
         {
           lcderr("ERROR: ENOMEM, unable to allocate layer structure\n");
-          errno = ENOMEM;
         }
     }
   else
     {
       lcderr("ERROR: EINVAL, no free layer available\n");
-      errno = EINVAL;
     }
 
   sem_post(&g_lock);
@@ -2262,12 +2254,11 @@ void up_dma2duninitialize(void)
  *
  * Return:
  *   On success - A valid dma2d layer reference
- *   On error   - NULL and errno is set to
+ *   On error   - NULL
- *                -EINVAL if one of the parameter is invalid
  *
  ****************************************************************************/
 
-FAR struct dma2d_layer_s * stm32_dma2dinitltdc(FAR struct stm32_ltdc_s *layer)
+FAR struct dma2d_layer_s *stm32_dma2dinitltdc(FAR struct stm32_ltdc_s *layer)
 {
   int        ret;
   uint8_t    fmt = 0;
@@ -2282,7 +2273,6 @@ FAR struct dma2d_layer_s * stm32_dma2dinitltdc(FAR struct stm32_ltdc_s *layer)
     {
       lcderr("ERROR: Returning -EINVAL, unsupported pixel format: %d\n",
              layer->vinfo.fmt);
-      errno = -EINVAL;
       return NULL;
     }
 

arch/arm/src/stm32/stm32_ltdc.c

@@ -3432,8 +3432,7 @@ FAR struct ltdc_layer_s *stm32_ltdcgetlayer(int lid)
       return (FAR struct ltdc_layer_s *) &LAYER(lid);
     }
 
-  lcderr("ERROR: Returning EINVAL\n");
+  lcderr("ERROR: lid invalid: %d\n", lid);
-  errno = EINVAL;
   return NULL;
 }
 #endif /* CONFIG_STM32_LTDC_INTERFACE */

arch/arm/src/stm32f7/stm32_dma2d.c

@@ -1939,7 +1939,7 @@ static int stm32_dma2dfillarea(FAR struct dma2d_layer_s *layer,
  *
  ****************************************************************************/
 
-FAR struct dma2d_layer_s * up_dma2dgetlayer(int lid)
+FAR struct dma2d_layer_s *up_dma2dgetlayer(int lid)
 {
   if (lid < DMA2D_LAYER_NSIZE)
     {
@@ -1951,8 +1951,7 @@ FAR struct dma2d_layer_s * up_dma2dgetlayer(int lid)
       return &priv->dma2d;
     }
 
-  lcderr("ERROR: EINVAL, Unknown layer identifier\n");
+  lcderr("ERROR: lid invalid: %d\n", lid);
-  errno = EINVAL;
   return NULL;
 }
 
@@ -1969,10 +1968,7 @@ FAR struct dma2d_layer_s * up_dma2dgetlayer(int lid)
  *
  * Return:
  *   On success - A valid dma2d layer reference
- *   On error   - NULL and errno is set to
+ *   On error   - NULL
- *                -EINVAL if one of the parameter is invalid
- *                -ENOMEM if no memory available or exceeds
- *                 CONFIG_STM32F7_DMA2D_NLAYERS
  *
  ****************************************************************************/
 
@@ -1980,11 +1976,11 @@ FAR struct dma2d_layer_s *up_dma2dcreatelayer(fb_coord_t width,
                                               fb_coord_t height,
                                               uint8_t fmt)
 {
+  FAR struct stm32_dma2d_s *layer = NULL;
   int        ret;
   int        lid;
   uint8_t    fmtmap;
   uint8_t    bpp = 0;
-  FAR struct stm32_dma2d_s *layer = NULL;
 
   lcdinfo("width=%d, height=%d, fmt=%02x \n", width, height, fmt);
 
@@ -1994,7 +1990,6 @@ FAR struct dma2d_layer_s *up_dma2dcreatelayer(fb_coord_t width,
 
   if (ret != OK)
     {
-      errno = -ret;
       return NULL;
     }
 
@@ -2066,19 +2061,16 @@ FAR struct dma2d_layer_s *up_dma2dcreatelayer(fb_coord_t width,
               kmm_free(layer);
               layer = NULL;
               lcderr("ERROR: ENOMEM, Unable to allocate layer buffer\n");
-              errno = ENOMEM;
             }
         }
       else
         {
           lcderr("ERROR: ENOMEM, unable to allocate layer structure\n");
-          errno = ENOMEM;
         }
     }
   else
     {
       lcderr("ERROR: EINVAL, no free layer available\n");
-      errno = EINVAL;
     }
 
   sem_post(&g_lock);
@@ -2254,12 +2246,11 @@ void up_dma2duninitialize(void)
  *
  * Return:
  *   On success - A valid dma2d layer reference
- *   On error   - NULL and errno is set to
+ *   On error   - NULL
- *                -EINVAL if one of the parameter is invalid
  *
  ****************************************************************************/
 
-FAR struct dma2d_layer_s * stm32_dma2dinitltdc(FAR struct stm32_ltdc_s *layer)
+FAR struct dma2d_layer_s *stm32_dma2dinitltdc(FAR struct stm32_ltdc_s *layer)
 {
   int        ret;
   uint8_t    fmt = 0;

arch/arm/src/stm32f7/stm32_ltdc.c

@@ -3431,8 +3431,7 @@ FAR struct ltdc_layer_s *stm32_ltdcgetlayer(int lid)
       return (FAR struct ltdc_layer_s *) &LAYER(lid);
     }
 
-  lcderr("ERROR: Returning EINVAL\n");
+  lcderr("ERROR: lid invalid: %d\n", lid);
-  errno = EINVAL;
   return NULL;
 }
 #endif /* CONFIG_STM32F7_LTDC_INTERFACE */

arch/arm/src/stm32l4/stm32l4_dac.c

@@ -1181,7 +1181,6 @@ FAR struct dac_dev_s *stm32l4_dacinitialize(int intf)
 #endif
       default:
         aerr("ERROR: No such DAC interface: %d\n", intf);
-        errno = ENODEV;
         return NULL;
     }
 
@@ -1196,7 +1195,6 @@ FAR struct dac_dev_s *stm32l4_dacinitialize(int intf)
   if (ret < 0)
     {
       aerr("ERROR: Failed to initialize DAC channel %d: %d\n", intf, ret);
-      errno = -ret;
       return NULL;
     }
 

arch/sim/src/up_devconsole.c

@@ -141,8 +141,7 @@ static ssize_t devconsole_write(struct file *filep, const char *buffer, size_t l
 
   if (ret < 0)
     {
-      set_errno(EIO);
+      return -ret;
-      return ERROR;
     }
 
   return len;