On Thu, 18 Oct 2018 12:10:28 +0200, Philipp K wrote:

Hi,

I tried compiling the cs8247 sound module with clang and hit the following warning:

sound/i2c/cs8427.c:141:31: warning: implicit conversion from 'int' to 'char' changes value from 160 to -96 [-Wconstant-conversion] data[0] = CS8427_REG_AUTOINC | CS8427_REG_CORU_DATABUF; ~ ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

data is a char array, and CS8427_REG_AUTOINC is defined as 0x80 (dec 128) which is too big for a (signed) char.

Looking at other code in the same file, we usually use unsigned chars.

So is there a reason for data being signed in this case? Otherwise we could just change data to unsigned char and be on the safe side.

No any reason I know of. It must be just an old convention.

If you want I can send in a patch.

Yes, please. thanks, Takashi