On Sat, Jan 18, 2014 at 7:11 AM, Linus Walleij <linus.walleij@xxxxxxxxxx> wrote: > On Fri, Jan 17, 2014 at 6:43 PM, Chen-Yu Tsai <wens@xxxxxxxx> wrote: >> On Sat, Jan 18, 2014 at 12:47 AM, Arnd Bergmann <arnd@xxxxxxxx> wrote: > >>>> +- NAME_shutdown-gpios : GPIO phandle to shutdown control >>>> + (phandle must be the second) >>>> +- NAME_reset-gpios : GPIO phandle to reset control >>>> + >>>> +NAME must match the rfkill-name property. NAME_shutdown-gpios or >>>> +NAME_reset-gpios, or both, must be defined. >>>> + >>> >>> I don't understand this part. Why do you include the name in the >>> gpios property, rather than just hardcoding the property strings >>> to "shutdown-gpios" and "reset-gpios"? >> >> This quirk is a result of how gpiod_get_index implements device tree >> lookup. > > Why can't it just have a single property "gpios", where the first > element is the reset GPIO and the second is the shutdown GPIO? > > rfkill-gpio does this: > > gpio = devm_gpiod_get_index(&pdev->dev, rfkill->reset_name, 0); > gpio = devm_gpiod_get_index(&pdev->dev, rfkill->shutdown_name, 1); > > The passed con ID name parameter is only there for the device > tree case it seems. (ACPI ignores it.) So what about you just > don't pass it at all and patch it to do like this instead: > > gpio = devm_gpiod_get_index(&pdev->dev, NULL, 0); > gpio = devm_gpiod_get_index(&pdev->dev, NULL, 1); I'd like that. It's much cleaner. > Heikki, are you OK with this change? > > I think this is actually necessary if the ACPI and DT unification > pipe dream shall limp forward, we cannot have arguments passed > that have a semantic effect on DT but not on ACPI... Drivers > that are supposed to use both ACPI and DT will always > have to pass NULL as con ID. > >> If con_id is given, it is prepended to "gpios" as the property string. >> con_id is also used as the label passed to gpiod_request, which is >> then shown in /sys/kernel/debug/gpio. > > If your problem is really what turns up in debugfs, then we need > to figure out a way to label gpios outside of the *gpiod_get* calls. Let's add a gpiod_set_label call. Currently there's a desc_set_label in gpiolib, which is static inlined. We can either rename and promote it to non-static, or add a new wrapping function. > The string passed in *gpiod_get* is a "connection ID" not a proper > name for the GPIO. I see. Perhaps we should not pass this to gpiod_request as the label, or add a comment stating consumers can use the new gpiod_set_label call to change it. Cheers, ChenYu -- 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
