On Tue, Oct 07, 2014 at 07:22:13PM +0900, Alexandre Courbot wrote: > On Tue, Oct 7, 2014 at 9:18 AM, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote: > > From: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> > > > > Some drivers need to deal with only firmware representation of its > > GPIOs. An example would be a GPIO button array driver where each button > > is described as a separate firmware node in device tree. Typically these > > child nodes do not have physical representation in the Linux device > > model. > > > > In order to help device drivers to handle such firmware child nodes we > > add dev[m]_get_named_gpiod_from_child() that takes a child firmware > > node pointer as its second argument (the first one is the parent device > > itself), finds the GPIO using whatever is the underlying firmware > > method, and requests the GPIO properly. > > > > Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > > ... > > > +/* Child properties interface */ > > +struct gpio_desc *dev_get_named_gpiod_from_child(struct device *dev, void *child, > > + const char *propname, int index); > > +struct gpio_desc *devm_get_named_gpiod_from_child(struct device *dev, void *child, > > + const char *propname, int index); > > I see the reason for these functions and am not opposed to them. > However, I wonder if we could not replace propname by a con_id that > would be resolved to one of con_id-gpio for DT and whatever naming > convention ACPI is using? The code in gpio-leds.c and gpio_keys_polled.c refers to "gpios" as the property name. If we can change that somehow to work with con_id-gpio instead without breaking things, then why not. > This would prevent users to name GPIOs outside of the conventions > defined in the bindings and be generally safer. Is there a particular > reason (used by some old code?) for the current direct property > access? If not, maybe we could call a slightly-modified of_find_gpio() > to resolve the GPIO property for DT, and the equivalent function for > ACPI? Only reason I can think of is support for the existing properties that are used directly. Drivers using gpiod_get() and friends do not need dev_get_named_gpiod_from_child() anyway. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
