Re: [PATCH 4.4,4.9] power: reset: ltc2952: Fix use of floating point literals

[Greg KH <gregkh@linuxfoundation.org>]

On Sun, Jan 09, 2022 at 11:59:02AM -0700, Nathan Chancellor wrote:
> commit 644106cdb89844be2496b21175b7c0c2e0fab381 upstream.
> 
> A new commit in LLVM causes an error on the use of 'long double' when
> '-mno-x87' is used, which the kernel does through an alias,
> '-mno-80387' (see the LLVM commit below for more details around why it
> does this).
> 
> drivers/power/reset/ltc2952-poweroff.c:162:28: error: expression requires  'long double' type support, but target 'x86_64-unknown-linux-gnu' does not support it
>         data->wde_interval = 300L * 1E6L;
>                                   ^
> drivers/power/reset/ltc2952-poweroff.c:162:21: error: expression requires  'long double' type support, but target 'x86_64-unknown-linux-gnu' does not support it
>         data->wde_interval = 300L * 1E6L;
>                            ^
> drivers/power/reset/ltc2952-poweroff.c:163:41: error: expression requires  'long double' type support, but target 'x86_64-unknown-linux-gnu' does not support it
>         data->trigger_delay = ktime_set(2, 500L*1E6L);
>                                                ^
> 3 errors generated.
> 
> This happens due to the use of a 'long double' literal. The 'E6' part of
> '1E6L' causes the literal to be a 'double' then the 'L' suffix promotes
> it to 'long double'.
> 
> There is no visible reason for floating point values in this driver, as
> the values are only assigned to integer types. Use NSEC_PER_MSEC, which
> is the same integer value as '1E6L', to avoid changing functionality but
> fix the error.
> 
> Fixes: 6647156c00cc ("power: reset: add LTC2952 poweroff driver")
> Link: https://github.com/ClangBuiltLinux/linux/issues/1497
> Link: https://github.com/llvm/llvm-project/commit/a8083d42b1c346e21623a1d36d1f0cadd7801d83
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
> Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
> [nathan: Resolve conflict due to lack of 8b0e195314fab]
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> ---
>  drivers/power/reset/ltc2952-poweroff.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

Now queued up, thanks.

greg k-h