On Wed, Oct 8, 2014 at 9:09 AM, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote: > On Tuesday, October 07, 2014 07:52:02 PM Alexandre Courbot wrote: >> On Tue, Oct 7, 2014 at 7:40 PM, Mika Westerberg >> <mika.westerberg@xxxxxxxxxxxxxxx> wrote: >> > 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. >> >> Right. Another thing is that the property handling code (active low >> only for now) is duplicated again, but that can be addressed >> separately. >> >> I will have a look at gpio-leds and gpio_keys_polled to see if we >> cannot make this work at a higher level. It's easier to have the >> bindings respected if the code itself enforces them. > > I'm wondering if that can be done after merging the current work? > > We'll be able to use the drivers in question with our hardware in the > meantime then ... Yeah, that's probably ok. The properties in question already exist so we will have to support them anyway ; it's just a matter of seeing whether we can improve the proposed way. So for now: Acked-by: Alexandre Courbot <acourbot@xxxxxxxxxx> -- 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
