staging: comedi: dt282x: tidy up register bit defines

Arnd Bergmann pointed out that gcc-6 warns about passing negative signed
integer into swab16() due to the macro expansion of 'outw'.

It appears that the register map constants are causing the warnings.
Actually, it might just be the (1 << 15) ones...

Convert all the constants as suggested by checkpatch.pl:
CHECK: Prefer using the BIT macro

The BIT() macro will make all the constants explicitly 'unsigned', which
helps to avoid the warning.

Fix the, unsused, DT2821_CHANCSR_PRESLA() macro. The "Present List
Address" (PRESLA) bits in the CHANCSR register are read only. This
define was meant to extract the bits from the read value.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reported-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Tested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/dt282x.c

@@ -69,48 +69,49 @@
  * Register map
  */
 #define DT2821_ADCSR_REG		0x00
-#define DT2821_ADCSR_ADERR		(1 << 15)
-#define DT2821_ADCSR_ADCLK		(1 << 9)
-#define DT2821_ADCSR_MUXBUSY		(1 << 8)
-#define DT2821_ADCSR_ADDONE		(1 << 7)
-#define DT2821_ADCSR_IADDONE		(1 << 6)
+#define DT2821_ADCSR_ADERR		BIT(15)
+#define DT2821_ADCSR_ADCLK		BIT(9)
+#define DT2821_ADCSR_MUXBUSY		BIT(8)
+#define DT2821_ADCSR_ADDONE		BIT(7)
+#define DT2821_ADCSR_IADDONE		BIT(6)
 #define DT2821_ADCSR_GS(x)		(((x) & 0x3) << 4)
 #define DT2821_ADCSR_CHAN(x)		(((x) & 0xf) << 0)
 #define DT2821_CHANCSR_REG		0x02
-#define DT2821_CHANCSR_LLE		(1 << 15)
-#define DT2821_CHANCSR_PRESLA(x)	(((x) & 0xf) >> 8)
+#define DT2821_CHANCSR_LLE		BIT(15)
+#define DT2821_CHANCSR_TO_PRESLA(x)	(((x) >> 8) & 0xf)
 #define DT2821_CHANCSR_NUMB(x)		((((x) - 1) & 0xf) << 0)
 #define DT2821_ADDAT_REG		0x04
 #define DT2821_DACSR_REG		0x06
-#define DT2821_DACSR_DAERR		(1 << 15)
+#define DT2821_DACSR_DAERR		BIT(15)
 #define DT2821_DACSR_YSEL(x)		((x) << 9)
-#define DT2821_DACSR_SSEL		(1 << 8)
-#define DT2821_DACSR_DACRDY		(1 << 7)
-#define DT2821_DACSR_IDARDY		(1 << 6)
-#define DT2821_DACSR_DACLK		(1 << 5)
-#define DT2821_DACSR_HBOE		(1 << 1)
-#define DT2821_DACSR_LBOE		(1 << 0)
+#define DT2821_DACSR_SSEL		BIT(8)
+#define DT2821_DACSR_DACRDY		BIT(7)
+#define DT2821_DACSR_IDARDY		BIT(6)
+#define DT2821_DACSR_DACLK		BIT(5)
+#define DT2821_DACSR_HBOE		BIT(1)
+#define DT2821_DACSR_LBOE		BIT(0)
 #define DT2821_DADAT_REG		0x08
 #define DT2821_DIODAT_REG		0x0a
 #define DT2821_SUPCSR_REG		0x0c
-#define DT2821_SUPCSR_DMAD		(1 << 15)
-#define DT2821_SUPCSR_ERRINTEN		(1 << 14)
-#define DT2821_SUPCSR_CLRDMADNE		(1 << 13)
-#define DT2821_SUPCSR_DDMA		(1 << 12)
-#define DT2821_SUPCSR_DS_PIO		(0 << 10)
-#define DT2821_SUPCSR_DS_AD_CLK		(1 << 10)
-#define DT2821_SUPCSR_DS_DA_CLK		(2 << 10)
-#define DT2821_SUPCSR_DS_AD_TRIG	(3 << 10)
-#define DT2821_SUPCSR_BUFFB		(1 << 9)
-#define DT2821_SUPCSR_SCDN		(1 << 8)
-#define DT2821_SUPCSR_DACON		(1 << 7)
-#define DT2821_SUPCSR_ADCINIT		(1 << 6)
-#define DT2821_SUPCSR_DACINIT		(1 << 5)
-#define DT2821_SUPCSR_PRLD		(1 << 4)
-#define DT2821_SUPCSR_STRIG		(1 << 3)
-#define DT2821_SUPCSR_XTRIG		(1 << 2)
-#define DT2821_SUPCSR_XCLK		(1 << 1)
-#define DT2821_SUPCSR_BDINIT		(1 << 0)
+#define DT2821_SUPCSR_DMAD		BIT(15)
+#define DT2821_SUPCSR_ERRINTEN		BIT(14)
+#define DT2821_SUPCSR_CLRDMADNE		BIT(13)
+#define DT2821_SUPCSR_DDMA		BIT(12)
+#define DT2821_SUPCSR_DS(x)		(((x) & 0x3) << 10)
+#define DT2821_SUPCSR_DS_PIO		DT2821_SUPCSR_DS(0)
+#define DT2821_SUPCSR_DS_AD_CLK		DT2821_SUPCSR_DS(1)
+#define DT2821_SUPCSR_DS_DA_CLK		DT2821_SUPCSR_DS(2)
+#define DT2821_SUPCSR_DS_AD_TRIG	DT2821_SUPCSR_DS(3)
+#define DT2821_SUPCSR_BUFFB		BIT(9)
+#define DT2821_SUPCSR_SCDN		BIT(8)
+#define DT2821_SUPCSR_DACON		BIT(7)
+#define DT2821_SUPCSR_ADCINIT		BIT(6)
+#define DT2821_SUPCSR_DACINIT		BIT(5)
+#define DT2821_SUPCSR_PRLD		BIT(4)
+#define DT2821_SUPCSR_STRIG		BIT(3)
+#define DT2821_SUPCSR_XTRIG		BIT(2)
+#define DT2821_SUPCSR_XCLK		BIT(1)
+#define DT2821_SUPCSR_BDINIT		BIT(0)
 #define DT2821_TMRCTR_REG		0x0e
 
 static const struct comedi_lrange range_dt282x_ai_lo_bipolar = {