Re: can: usb: PEAK-System Technik PCAN-USB specific part

[Stephane Grosjean <s.grosjean@peak-system.com>]

Hi everybody,

Happy to have seen some of you last Monday, at iCC, it was great. It's 
always easier when we're able to attach a face to a name.

Back to work now:

Le 06/03/2012 12:21, Dan Carpenter a écrit :
> Hello Stephane Grosjean,
>
> The patch 46be265d3388: "can: usb: PEAK-System Technik PCAN-USB
> specific part" from Mar 2, 2012, leads to the following warning:
>
> drivers/net/can/usb/peak_usb/pcan_usb.c:751 pcan_usb_encode_msg()
> 	 error: wrong number of bits for 'cpu_to_le32' (16 vs 32)
>
> drivers/net/can/usb/peak_usb/pcan_usb.c
>     742          /* can id */
>     743          if (cf->can_id&  CAN_EFF_FLAG) {
>     744                  __le32 tmp32 = cpu_to_le32(cf->can_id&  CAN_ERR_MASK);
>     745
>     746                  tmp32<<= 3;
>     747                  *pc |= PCAN_USB_STATUSLEN_EXT_ID;
>     748                  memcpy(++pc,&tmp32, 4);
>     749                  pc += 4;
>     750          } else {
>     751                  __le16 tmp16 = cpu_to_le32(cf->can_id&  CAN_ERR_MASK);
>                          ^^^^^^^^^^^^
> A little endian 32 bit can't fit here.


How may this error happen while it didn't before? Is this is due to some 
(new) options of gcc, or because of a new version used? In the future, 
how could I avoid that? I mean, how to synchronize with the final GCC 
options/version?

FYI, the original code was:

> >  +	else {
> } else {
> >  +		u16 tmp16 = (u16 )*cpu_to_le32*(cf->can_id&  CAN_ERR_MASK);
>                              ^^^^^^^^^^^^^^^^^

cf->can_id is a 32-bits field which I want to keep only the lo-word part...

How to do that in the correct way, please?

Anyway, what next? I suppose I have to submit a new patch, but comparing 
to what?

Thanks for your help and regards,

Stéphane
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