From: Nathan Chancellor nathan@kernel.org
commit a02dcde595f7cbd240ccd64de96034ad91cffc40 upstream.
A new warning in clang points out a few places in this driver where a bitwise OR is being used with boolean types:
drivers/input/touchscreen.c:81:17: warning: use of bitwise '|' with boolean operands [-Wbitwise-instead-of-logical] data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-x", ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This use of a bitwise OR is intentional, as bitwise operations do not short circuit, which allows all the calls to touchscreen_get_prop_u32() to happen so that the last parameter is initialized while coalescing the results of the calls to make a decision after they are all evaluated.
To make this clearer to the compiler, use the '|=' operator to assign the result of each touchscreen_get_prop_u32() call to data_present, which keeps the meaning of the code the same but makes it obvious that every one of these calls is expected to happen.
Signed-off-by: Nathan Chancellor nathan@kernel.org Reported-by: Nick Desaulniers ndesaulniers@google.com Reviewed-by: Nick Desaulniers ndesaulniers@google.com Link: https://lore.kernel.org/r/20211014205757.3474635-1-nathan@kernel.org Signed-off-by: Dmitry Torokhov dmitry.torokhov@gmail.com Signed-off-by: Anders Roxell anders.roxell@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/input/touchscreen/of_touchscreen.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-)
--- a/drivers/input/touchscreen/of_touchscreen.c +++ b/drivers/input/touchscreen/of_touchscreen.c @@ -81,8 +81,8 @@ void touchscreen_parse_properties(struct touchscreen_get_prop_u32(dev, "touchscreen-size-x", input_abs_get_max(input, axis) + 1, - &maximum) | - touchscreen_get_prop_u32(dev, "touchscreen-fuzz-x", + &maximum); + data_present |= touchscreen_get_prop_u32(dev, "touchscreen-fuzz-x", input_abs_get_fuzz(input, axis), &fuzz); if (data_present) @@ -95,8 +95,8 @@ void touchscreen_parse_properties(struct touchscreen_get_prop_u32(dev, "touchscreen-size-y", input_abs_get_max(input, axis) + 1, - &maximum) | - touchscreen_get_prop_u32(dev, "touchscreen-fuzz-y", + &maximum); + data_present |= touchscreen_get_prop_u32(dev, "touchscreen-fuzz-y", input_abs_get_fuzz(input, axis), &fuzz); if (data_present) @@ -106,11 +106,11 @@ void touchscreen_parse_properties(struct data_present = touchscreen_get_prop_u32(dev, "touchscreen-max-pressure", input_abs_get_max(input, axis), - &maximum) | - touchscreen_get_prop_u32(dev, - "touchscreen-fuzz-pressure", - input_abs_get_fuzz(input, axis), - &fuzz); + &maximum); + data_present |= touchscreen_get_prop_u32(dev, + "touchscreen-fuzz-pressure", + input_abs_get_fuzz(input, axis), + &fuzz); if (data_present) touchscreen_set_params(input, axis, 0, maximum, fuzz);