Messages in this thread | | | From | Hartley Sweeten <> | Subject | RE: [PATCH] staging/comedi: fix sparse warning: shift too big | Date | Fri, 2 May 2014 18:28:57 +0000 |
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On Friday, May 02, 2014 9:50 AM, Ian Abbott wrote: > On 2014-05-02 15:57, Brilliantov Kirill Vladimirovich wrote: >> Signed-off-by: Brilliantov Kirill Vladimirovich <brilliantov@inbox.ru> >> --- >> drivers/staging/comedi/drivers/ni_stc.h | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/staging/comedi/drivers/ni_stc.h b/drivers/staging/comedi/drivers/ni_stc.h >> index f0630b78..197b568 100644 >> --- a/drivers/staging/comedi/drivers/ni_stc.h >> +++ b/drivers/staging/comedi/drivers/ni_stc.h >> @@ -717,7 +717,7 @@ enum AI_AO_Select_Bits { >> static inline unsigned ni_stc_dma_channel_select_bitfield(unsigned channel) >> { >> if (channel < 4) >> - return 1 << channel; >> + return 1 << (channel & 0x3); >> if (channel == 4) >> return 0x3; >> if (channel == 5) >> > > The warning seems a bit spurious!
The whole mite.c driver and it's users are all a bit of a mess.
I did find the information about the "AI AO Select Register" in the National Instruments PCI E Series manual:
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The AI AO Select Register contains 8 bits that control the logical DMA selection for the analog input and analog output resources. The contents of this register are cleared upon power up and after a reset condition. Address: base address + 0x09 Type: write-only Word size: 8-bit
Bit Name Description 7-4 Reserved Reserved-Always write 0 to these bits (for PCI-6032E and PCI-6033E only). 7-4 Output<D..A> Analog Output Logical Channel D through A-These four bits select the logical channels of the MITE to be used by the analog output. You can only set one of these bits at a time (except for the PCI-6032E and PCI-6033E). 3-0 Input<D..A> Analog Input Logical Channel D through A-These four bits select the logical channels to be used by the analog input. You can only set one of these bits at a time.
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Based on this the ni_stc_dma_channel_select_bitfield() function appears to be incorrect. The "channel"s should only be in the range 0 to 3 and result in a returned bitfield of:
channel bitfield Description 0 0x01 Analog Input or Output Channel A 1 0x02 Analog Input or Output Channel B 2 0x04 Analog Input or Output Channel C 3 0x08 Analog Input or Output Channel D
Just my two cents...
Hartley
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