[PATCH 4.14 6/6] Input: touchscreen - avoid bitwise vs logical OR warning
From: Anders Roxell <hidden>
Date: 2021-12-20 12:26:00
Also in:
linux-arm-kernel, linux-input, linux-usb, linux-wireless, lkml, stable
Subsystem:
input (keyboard, mouse, joystick, touchscreen) drivers, the rest · Maintainers:
Dmitry Torokhov, Linus Torvalds
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 <redacted>
Reviewed-by: Nick Desaulniers <redacted>
Link: https://lore.kernel.org/r/20211014205757.3474635-1-nathan@kernel.org (local)
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Anders Roxell <redacted>
---
drivers/input/touchscreen/of_touchscreen.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/input/touchscreen/of_touchscreen.c b/drivers/input/touchscreen/of_touchscreen.c
index 8d7f9c8f2771..db499ef6ccff 100644
--- a/drivers/input/touchscreen/of_touchscreen.c
+++ b/drivers/input/touchscreen/of_touchscreen.c@@ -79,8 +79,8 @@ void touchscreen_parse_properties(struct input_dev *input, bool multitouch, data_present = 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)
@@ -90,8 +90,8 @@ void touchscreen_parse_properties(struct input_dev *input, bool multitouch, data_present = 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)
@@ -101,11 +101,11 @@ void touchscreen_parse_properties(struct input_dev *input, bool multitouch, 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, maximum, fuzz);
--
2.34.1