gcc-6 warns about passing negative signed integer into swab16()
in the dt282x driver:
drivers/staging/comedi/drivers/dt282x.c: In function 'dt282x_load_changain':
include/uapi/linux/swab.h:14:33: warning: integer overflow in expression [-Woverflow]
(((__u16)(x) & (__u16)0xff00U) >> 8)))
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~
include/uapi/linux/swab.h:107:2: note: in expansion of macro '___constant_swab16'
___constant_swab16(x) : \
^~~~~~~~~~~~~~~~~~
include/uapi/linux/byteorder/big_endian.h:34:43: note: in expansion of macro '__swab16'
#define __cpu_to_le16(x) ((__force __le16)__swab16((x)))
^~~~~~~~
include/linux/byteorder/generic.h:89:21: note: in expansion of macro '__cpu_to_le16'
#define cpu_to_le16 __cpu_to_le16
^~~~~~~~~~~~~
arch/arm/include/asm/io.h:250:6: note: in expansion of macro 'cpu_to_le16'
cpu_to_le16(v),__io(p)); })
^~~~~~~~~~~
drivers/staging/comedi/drivers/dt282x.c:566:2: note: in expansion of macro 'outw'
outw(DT2821_CHANCSR_LLE | DT2821_CHANCSR_NUMB(n),
^~~~
The warning makes sense, though the code is correct as far as I
can tell.
This disambiguates the operation by making the constant expressions
we pass here explicitly 'unsigned', which helps to avoid the warning.
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
drivers/staging/comedi/drivers/dt282x.c | 62 ++++++++++++++++-----------------
1 file changed, 31 insertions(+), 31 deletions(-)
diff --git a/drivers/staging/comedi/drivers/dt282x.c b/drivers/staging/comedi/drivers/dt282x.c
index 40bf00984fa5..d4d45c759c62 100644
--- a/drivers/staging/comedi/drivers/dt282x.c
+++ b/drivers/staging/comedi/drivers/dt282x.c
@@ -69,48 +69,48 @@
* 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 (1u << 15)
+#define DT2821_ADCSR_ADCLK (1u << 9)
+#define DT2821_ADCSR_MUXBUSY (1u << 8)
+#define DT2821_ADCSR_ADDONE (1u << 7)
+#define DT2821_ADCSR_IADDONE (1u << 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_LLE (1u << 15)
#define DT2821_CHANCSR_PRESLA(x) (((x) & 0xf) >> 8)
#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 (1u << 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 (1u << 8)
+#define DT2821_DACSR_DACRDY (1u << 7)
+#define DT2821_DACSR_IDARDY (1u << 6)
+#define DT2821_DACSR_DACLK (1u << 5)
+#define DT2821_DACSR_HBOE (1u << 1)
+#define DT2821_DACSR_LBOE (1u << 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 (1u << 15)
+#define DT2821_SUPCSR_ERRINTEN (1u << 14)
+#define DT2821_SUPCSR_CLRDMADNE (1u << 13)
+#define DT2821_SUPCSR_DDMA (1u << 12)
+#define DT2821_SUPCSR_DS_PIO (0u << 10)
+#define DT2821_SUPCSR_DS_AD_CLK (1u << 10)
+#define DT2821_SUPCSR_DS_DA_CLK (2u << 10)
+#define DT2821_SUPCSR_DS_AD_TRIG (3u << 10)
+#define DT2821_SUPCSR_BUFFB (1u << 9)
+#define DT2821_SUPCSR_SCDN (1u << 8)
+#define DT2821_SUPCSR_DACON (1u << 7)
+#define DT2821_SUPCSR_ADCINIT (1u << 6)
+#define DT2821_SUPCSR_DACINIT (1u << 5)
+#define DT2821_SUPCSR_PRLD (1u << 4)
+#define DT2821_SUPCSR_STRIG (1u << 3)
+#define DT2821_SUPCSR_XTRIG (1u << 2)
+#define DT2821_SUPCSR_XCLK (1u << 1)
+#define DT2821_SUPCSR_BDINIT (1u << 0)
#define DT2821_TMRCTR_REG 0x0e
static const struct comedi_lrange range_dt282x_ai_lo_bipolar = {
--
2.7.0
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