x86/olpc: fix 'logical not is only applied to the left hand side'

commit 3a2ba42cbd0b669ce3837ba400905f93dd06c79f upstream.

The bitops compile-time optimization series revealed one more
problem in olpc-xo1-sci.c:send_ebook_state(), resulted in GCC
warnings:

arch/x86/platform/olpc/olpc-xo1-sci.c: In function 'send_ebook_state':
arch/x86/platform/olpc/olpc-xo1-sci.c:83:63: warning: logical not is only applied to the left hand side of comparison [-Wlogical-not-parentheses]
   83 |         if (!!test_bit(SW_TABLET_MODE, ebook_switch_idev->sw) == state)
      |                                                               ^~
arch/x86/platform/olpc/olpc-xo1-sci.c:83:13: note: add parentheses around left hand side expression to silence this warning

Despite this code working as intended, this redundant double
negation of boolean value, together with comparing to `char`
with no explicit conversion to bool, makes compilers think
the author made some unintentional logical mistakes here.
Make it the other way around and negate the char instead
to silence the warnings.

Fixes: d2aa37411b8e ("x86/olpc/xo1/sci: Produce wakeup events for buttons and switches")
Cc: stable@vger.kernel.org # 3.5+
Reported-by: Guenter Roeck <linux@roeck-us.net>
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-and-tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/platform/olpc/olpc-xo1-sci.c b/arch/x86/platform/olpc/olpc-xo1-sci.c
index 7fa8b3b53bc0a563737f1d32de8e467b79d85ce0..193860d7f2c406271b091ee9458c41408d0d5786 100644 (file)
--- a/arch/x86/platform/olpc/olpc-xo1-sci.c
+++ b/arch/x86/platform/olpc/olpc-xo1-sci.c
@@ -85,7 +85,7 @@ static void send_ebook_state(void)
                return;
        }
 
-       if (!!test_bit(SW_TABLET_MODE, ebook_switch_idev->sw) == state)
+       if (test_bit(SW_TABLET_MODE, ebook_switch_idev->sw) == !!state)
                return; /* Nothing new to report. */
 
        input_report_switch(ebook_switch_idev, SW_TABLET_MODE, state);