gpioset: reword note on post-exit behaviour

The note regarding the state of a line after gpioset exits is confusing
and unhelpful to the average reader, if not outright incorrect.

A common mis-interpretation is that this behaviour is arbitrarily chosen
by spiteful implementors. The note also specifies that the line reverts
to default, but that is not always the case, or is at least out of the
control of gpioset or libgpiod.

Reword the note to constrain the scope to that relevant to the likely
reader, and to emphasize that the behaviour is inherent in the kernel
GPIO interface, not in the gpioset implementation.

Signed-off-by: Kent Gibson <warthog618@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

diff --git a/tools/gpioset.c b/tools/gpioset.c
index 9dc5aeb8b28661ed87efccaf00ba600ad01a51aa..f2f9a1557d2023852f82f987e623541c1f2ceb26 100644 (file)
--- a/tools/gpioset.c
+++ b/tools/gpioset.c
@@ -76,11 +76,10 @@ static void print_help(void)
        print_period_help();
        printf("\n");
        printf("*Note*\n");
-       printf("    The state of a GPIO line controlled over the character device reverts to default\n");
-       printf("    when the last process referencing the file descriptor representing the device file exits.\n");
-       printf("    This means that it's wrong to run gpioset, have it exit and expect the line to continue\n");
-       printf("    being driven high or low. It may happen if given pin is floating but it must be interpreted\n");
-       printf("    as undefined behavior.\n");
+       printf("    It should not be assumed that a line will retain its state after gpioset exits.\n");
+       printf("    When a process exits, any GPIO lines it has requested are automatically released.\n");
+       printf("    Once released, the state of a line may be modified by the kernel or another process.\n");
+       printf("    To guarantee the requested value, by default gpioset does not exit.\n");
 }
 
 static int parse_drive_or_die(const char *option)