Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: GPIO bindings guidelines (Was: Re: [PATCH v5 10/12] gpio: Support for unified device properties interface) | Date | Wed, 22 Oct 2014 10:33:32 +0200 |
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On Wednesday 22 October 2014 11:10:44 Mika Westerberg wrote: > > It expects that GPIOs returned from _CRS are in specific order. Since we > can't change these existing ACPI tables, we must support them somehow. > > This patch series handles it so that: > > 1) If we can't find given property (e.g "reset-gpios" or > "shutdown-gpios") the index above will refer directly to the GPIO > resource returned from _CRS. > > 2) If the property is found we ignore index and take it from the > property instead. > > This has the drawback that we cannot support this: > > Package () { "reset-gpios", Package () { ^GPIO, 0, 0, 0, ^GPIO, 1, 0, 0}} > ^^^^^^^^^^^^^^ > So the second entry in the above is not accessible using > gpiod_get_index() and the reason is that we want to support the existing > and new ACPI tables where _DSD is not being used.
So this is not using the DT binding but does thing slightly differently then. In this case (supporting two incompatible bindings for DT and ACPI), I think the only sensible driver implementation would be to know what we are asking for and use different devm_gpiod_get_index statements based on the firmware interface.
Arnd
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