Re: [Outreachy kernel] [PATCH] staging: fbtft: Fix endian sparse warnings

[Greg KH <gregkh@linuxfoundation.org>]

On Wed, Oct 21, 2015 at 08:30:44PM +0530, Amitoj Kaur Chawla wrote:
> Fix a bug found using sparse which generates the following warnings:
> 
> drivers/staging/fbtft/fbtft-io.c:78:29: warning: incorrect type in
> assignment (different base types)
> drivers/staging/fbtft/fbtft-io.c:78:29: expected unsigned long long
> [unsigned] [long] [long long] [usertype] <noident>
> drivers/staging/fbtft/fbtft-io.c:78:29: got restricted __be64
> [usertype] <noident>
> 
> Signed-off-by: Amitoj Kaur Chawla <amitoj1606@gmail.com>
> ---
>  drivers/staging/fbtft/fbtft-io.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/fbtft/fbtft-io.c b/drivers/staging/fbtft/fbtft-io.c
> index a6f091f..a9a46c2 100644
> --- a/drivers/staging/fbtft/fbtft-io.c
> +++ b/drivers/staging/fbtft/fbtft-io.c
> @@ -75,7 +75,7 @@ int fbtft_write_spi_emulate_9(struct fbtft_par *par, void *buf, size_t len)
>  			src++;
>  		}
>  		tmp |= ((*src & 0x0100) ? 1 : 0);
> -		*(u64 *)dst = cpu_to_be64(tmp);
> +		*(__be64 *)dst = cpu_to_be64(tmp);

Are you sure this is correct?  Why isn't dst declared as be64 to start
with?  And don't use the __ form of variables unless they are crossing
the user/kernel boundry in a structure somehow.

thanks,

greg k-h