SAMA5 ADC: Seems functional in all modes including DMA

drivers/analog/Kconfig

@@ -11,37 +11,50 @@ config ADC
 		not only Analog-to-Digital Converters (ADC) but also amplifiers and
 		analog multiplexers.
 
+if ADC
+
+config ADC_FIFOSIZE
+	int "ADC buffer size"
+	default 8
+	---help---
+		This variable defines the size of the ADC ring buffer that is used
+		to queue received ADC data until they can be retrieved by the
+		application by reading from the ADC character device.  NOTE:  Since
+		this is a ring buffer, the actual number of bytes that can be
+		retained in buffer is (ADC_FIFOSIZE - 1).
+
 config ADC_ADS125X
 	bool "TI ADS1255/ADS1256 support"
 	default n
-	depends on ADC
 	select SPI
 
+if ADC_ADS125X
+
 config ADS1255_FREQUENCY
 	int "ADS1255/ADS1256 SPI frequency"
 	default 1000000
-	depends on ADC_ADS125X
+
+endif # ADC_ADS125X
 
 config ADC_PGA11X
 	bool "TI PGA112/3/6/7 support"
 	default n
-	depends on ADC
 	select SPI
 	---help---
 		Enables support for the  PGA112, PGA113, PGA116, PGA117 Zerø-Drift
 		PROGRAMMABLE GAIN AMPLIFIER with MUX
 
+if ADC_PGA11X
+
 config PGA11X_SPIFREQUENCY
 	int "TI PGA112/3/6/7 SPI frequency"
 	default 1000000
-	depends on ADC_PGA11X
 	---help---
 		PGA11x SPI frequency.
 
 config PGA11X_SPIMODE
 	int "TI PGA112/3/6/7 SPI mode"
 	default 0
-	depends on ADC_PGA11X
 	---help---
 		PGA11x SPI mode.  The specification says that the device operates in Mode 0 or
 		Mode 3.  But sometimes you need to tinker with this to get things to work
@@ -50,28 +63,33 @@ config PGA11X_SPIMODE
 config PGA11X_DAISYCHAIN
 	bool "TI PGA112/3/6/7 daisy chain mode"
 	default n
-	depends on ADC_PGA11X
 	---help---
 		Enable support to use two PGA116/7's in Daisy Chain configuration.
 
 config PGA11X_MULTIPLE
 	bool "Multiple TI PGA112/3/6/7 support"
 	default n
-	depends on ADC_PGA11X && !PGA11X_DAISYCHAIN
+	depends on !PGA11X_DAISYCHAIN
 	---help---
 		Can be defined to support multiple PGA11X devices on board with separate
 		chip selects (not daisy chained).  Each device will require a customized
 		SPI interface to distinguish them when SPI_SELECT is called with
 		devid=SPIDEV_MUX.
 
+endif # if ADC_PGA11X
+endif # ADC
+
 config DAC
 	bool "Digital-to-Analog Conversion"
-	default n	
+	default n
 	---help---
 		Select to enable support for Digital-to-Analog Converters (DACs).
 
+if DAC
+
 config DAC_AD5410
 	bool "AD5410 support"
 	default n
-	depends on DAC
 	select SPI
+
+endif # DAC

drivers/analog/adc.c

@@ -158,6 +158,7 @@ static int adc_open(FAR struct file *filep)
 
       sem_post(&dev->ad_closesem);
     }
+
   return ret;
 }
 
@@ -207,6 +208,7 @@ static int adc_close(FAR struct file *filep)
           sem_post(&dev->ad_closesem);
         }
     }
+
   return ret;
 }