mirrors
/
linux-stable
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
1
0
Fork 0
Code Issues Releases Wiki Activity

Documentation: gpio: consistently use logical line value terminology 

Consistently use active/inactive to describe logical line values, rather
than high/low, which is used for physical values, or asserted/de-asserted
which is awkward.

Signed-off-by: Kent Gibson <warthog618@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
[Bartosz: tweaked the commit subject to use imperative mood]
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
This commit is contained in:
Kent Gibson 2024-02-13 22:12:22 +08:00 committed by Bartosz Golaszewski
parent 9e69d6d84e
commit e3f927f2b0
1 changed files with 5 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
Documentation/driver-api/gpio/consumer.rst
View File

@ -222,9 +222,9 @@ Use the following calls to access GPIOs from an atomic context::
int gpiod_get_value(const struct gpio_desc *desc);
void gpiod_set_value(struct gpio_desc *desc, int value);
The values are boolean, zero for low, nonzero for high. When reading the value
of an output pin, the value returned should be what's seen on the pin. That
won't always match the specified output value, because of issues including
The values are boolean, zero for inactive, nonzero for active. When reading the
value of an output pin, the value returned should be what's seen on the pin.
That won't always match the specified output value, because of issues including
open-drain signaling and output latencies.
The get/set calls do not return errors because "invalid GPIO" should have been
@ -277,11 +277,11 @@ switch their output to a high impedance value. The consumer should not need to
care. (For details read about open drain in driver.rst.)
With this, all the gpiod_set_(array)_value_xxx() functions interpret the
parameter "value" as "asserted" ("1") or "de-asserted" ("0"). The physical line
parameter "value" as "active" ("1") or "inactive" ("0"). The physical line
level will be driven accordingly.
As an example, if the active low property for a dedicated GPIO is set, and the
gpiod_set_(array)_value_xxx() passes "asserted" ("1"), the physical line level
gpiod_set_(array)_value_xxx() passes "active" ("1"), the physical line level
will be driven low.
To summarize::