On Sat, Jan 18, 2014 at 12:47 AM, Arnd Bergmann <arnd@xxxxxxxx> wrote: > On Friday 17 January 2014, Chen-Yu Tsai wrote: >> diff --git a/Documentation/devicetree/bindings/rfkill/rfkill-gpio.txt b/Documentation/devicetree/bindings/rfkill/rfkill-gpio.txt >> new file mode 100644 >> index 0000000..8a07ea4 >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/rfkill/rfkill-gpio.txt >> @@ -0,0 +1,26 @@ >> +GPIO controlled RFKILL devices >> + >> +Required properties: >> +- compatible : Must be "rfkill-gpio". >> +- rfkill-name : Name of RFKILL device >> +- rfkill-type : Type of RFKILL device: 1 for WiFi, 2 for BlueTooth >> +- 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. You'll also notice that the shutdown GPIO must be the second phandle, as the driver uses indexed lookup to support ACPI cases. 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. I can do a seperate lookup for the device tree case, with or without fallback to platform lookup tables. Then the names can be "reset-gpio" and "shutdown-gpio". Need to promote gpiod_request to non-static so we can register usage of the gpio, to match non-dt code path. Personally I prefer adding a "label" parameter to gpiod_get_index, so we can use a different name than con_id. con_id isn't used in the ACPI case, and is optional in platform lookup case. However device tree lookup is dependent on this. What I see is non-uniform behavior between the three. In my opinion this is undesirable, but I haven't come up with a good solution yet. About the property string, is the plural form required, even though we only want one? Thanks! ChenYu > The description of hte "rfkill-name" property seems to suggest > that you can only have one logical RFKILL device per device node, > so he names would not be ambiguous. > > Arnd -- 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
