| Message ID | 1436593562-5119-1-git-send-email-dirk.behme@gmail.com |
|---|---|
| State | New |
| Headers | show |
On Sat, Jul 11, 2015 at 2:46 PM, Dirk Behme <dirk.behme@gmail.com> wrote: > The con_id parameter has to match the GPIO description and is automatically > extended by the GPIO suffix if not NULL. I had to look into the code to > understand this and properly find the GPIO I've been looking for, so document > this. Good idea! > > Signed-off-by: Dirk Behme <dirk.behme@gmail.com> > --- > Documentation/gpio/consumer.txt | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/Documentation/gpio/consumer.txt b/Documentation/gpio/consumer.txt > index 75542b9..d0d1e47 100644 > --- a/Documentation/gpio/consumer.txt > +++ b/Documentation/gpio/consumer.txt > @@ -39,6 +39,18 @@ device that displays digits), an additional index argument can be specified: > const char *con_id, unsigned int idx, > enum gpiod_flags flags) > > +The con_id string parameter has to be either NULL or the prefix of the GPIO > +suffixes ("gpios" or "gpio"): It may be useful to explain that "gpios" and "gpio" are both looked up by gpiod functions, otherwise the reader might wonder how to choose one or the other. > + > +* If the GPIO description is just named with one of the GPIO suffixes > + ("gpios" or "gpio") use NULL. add a comma here: ("gpios" or "gpio"), use NULL. > +* If the GPIO description is prefixed with anything, e.g. "reset-gpios", use the > + prefix without the "-" as con_id parameter (in this example "reset"). > + > +In case con_id is not NULL, the gpiod subsystem prefixes the GPIO suffix s/gpiod/GPIO. gpiod is not a subsystem, just a set of functions. Otherwise it looks good. Feel free to add my Acked-by: Alexandre Courbot <acourbot@nvidia.com> to the next revision. -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/Documentation/gpio/consumer.txt b/Documentation/gpio/consumer.txt index 75542b9..d0d1e47 100644 --- a/Documentation/gpio/consumer.txt +++ b/Documentation/gpio/consumer.txt @@ -39,6 +39,18 @@ device that displays digits), an additional index argument can be specified: const char *con_id, unsigned int idx, enum gpiod_flags flags) +The con_id string parameter has to be either NULL or the prefix of the GPIO +suffixes ("gpios" or "gpio"): + +* If the GPIO description is just named with one of the GPIO suffixes + ("gpios" or "gpio") use NULL. +* If the GPIO description is prefixed with anything, e.g. "reset-gpios", use the + prefix without the "-" as con_id parameter (in this example "reset"). + +In case con_id is not NULL, the gpiod subsystem prefixes the GPIO suffix +("gpios" or "gpio") with the string passed in con_id to get the resulting string +(snprintf(... "%s-%s", con_id, gpio_suffixes[]). + The flags parameter is used to optionally specify a direction and initial value for the GPIO. Values can be:
The con_id parameter has to match the GPIO description and is automatically extended by the GPIO suffix if not NULL. I had to look into the code to understand this and properly find the GPIO I've been looking for, so document this. Signed-off-by: Dirk Behme <dirk.behme@gmail.com> --- Documentation/gpio/consumer.txt | 12 ++++++++++++ 1 file changed, 12 insertions(+)