Input: touchscreen - avoid bitwise vs logical OR warning

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>

diff --git a/drivers/input/touchscreen.c b/drivers/input/touchscreen.c
index dd18cb9..4620e20 100644 (file)
--- a/drivers/input/touchscreen.c
+++ b/drivers/input/touchscreen.c
@@ -80,27 +80,27 @@ void touchscreen_parse_properties(struct input_dev *input, bool multitouch,
 
        data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-x",
                                                input_abs_get_min(input, axis_x),
-                                               &minimum) |
-                      touchscreen_get_prop_u32(dev, "touchscreen-size-x",
-                                               input_abs_get_max(input,
-                                                                 axis_x) + 1,
-                                               &maximum) |
-                      touchscreen_get_prop_u32(dev, "touchscreen-fuzz-x",
-                                               input_abs_get_fuzz(input, axis_x),
-                                               &fuzz);
+                                               &minimum);
+       data_present |= touchscreen_get_prop_u32(dev, "touchscreen-size-x",
+                                                input_abs_get_max(input,
+                                                                  axis_x) + 1,
+                                                &maximum);
+       data_present |= touchscreen_get_prop_u32(dev, "touchscreen-fuzz-x",
+                                                input_abs_get_fuzz(input, axis_x),
+                                                &fuzz);
        if (data_present)
                touchscreen_set_params(input, axis_x, minimum, maximum - 1, fuzz);
 
        data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-y",
                                                input_abs_get_min(input, axis_y),
-                                               &minimum) |
-                      touchscreen_get_prop_u32(dev, "touchscreen-size-y",
-                                               input_abs_get_max(input,
-                                                                 axis_y) + 1,
-                                               &maximum) |
-                      touchscreen_get_prop_u32(dev, "touchscreen-fuzz-y",
-                                               input_abs_get_fuzz(input, axis_y),
-                                               &fuzz);
+                                               &minimum);
+       data_present |= touchscreen_get_prop_u32(dev, "touchscreen-size-y",
+                                                input_abs_get_max(input,
+                                                                  axis_y) + 1,
+                                                &maximum);
+       data_present |= touchscreen_get_prop_u32(dev, "touchscreen-fuzz-y",
+                                                input_abs_get_fuzz(input, axis_y),
+                                                &fuzz);
        if (data_present)
                touchscreen_set_params(input, axis_y, minimum, maximum - 1, fuzz);
 
@@ -108,11 +108,11 @@ 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, 0, maximum, fuzz);