On Fri, Jul 01, 2016 at 08:42:13AM +0200, Uwe Kleine-König wrote: > 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"). Like SPI and I2C, I'm against further abuse of aliases for this purpose [1]. > > 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. Why is deterministic numbering needed? Rob [1] https://lkml.org/lkml/2016/5/24/470 -- 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
