This uses the same approach that is already used for spi, i2c and several other controllers to ensure a consistent numbering independent of probe order. This is in use for several gpio drivers that already now use of_alias_get_id(np, "gpio"). Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> --- Hello, Linus requested such a patch as part of a change that introduces this mechanism to the gpio-omap driver[1]. IMHO this is better done in a separate patch, so here it comes. Best regards Uwe [1] http://thread.gmane.org/gmane.linux.kernel.gpio/17399/focus=17629 Documentation/devicetree/bindings/gpio/gpio.txt | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/Documentation/devicetree/bindings/gpio/gpio.txt b/Documentation/devicetree/bindings/gpio/gpio.txt index 68d28f62a6f4..5dbacc8f094a 100644 --- a/Documentation/devicetree/bindings/gpio/gpio.txt +++ b/Documentation/devicetree/bindings/gpio/gpio.txt @@ -227,6 +227,24 @@ Example of two SOC GPIO banks defined as gpio-controller nodes: #gpio-cells = <2>; }; +Usually the GPIO banks in SoCs are ordered, that is there is a dedicated "first +gpio bank". To fix this ordering in the device tree use aliases starting at 0 +(even if the first bank is called "GPIO1" in the hardware reference). +This is necessary/handy to ensure deterministical numbering of GPIOs and GPIO +controllers. + +Example of a machine having 4 GPIO banks. + + / { + aliases { + ... + gpio0 = &gpio1; + gpio1 = &gpio2; + gpio2 = &gpio3; + gpio3 = &gpio4; + }; + }; + 2.1) gpio- and pin-controller interaction ----------------------------------------- -- 2.8.1 -- 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
