Messages in this thread | | | Date | Fri, 23 Sep 2016 20:39:01 +0200 (CEST) | From | Stefan Wahren <> | Subject | Re: [PATCH 1/3] dt-bindings: Add a binding for the RPi firmware GPIO driver. |
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Hi Eric,
> Eric Anholt <eric@anholt.net> hat am 19. September 2016 um 18:13 geschrieben: > > > The RPi firmware exposes all of the board's GPIO lines through > property calls. Linux chooses to control most lines directly through > the pinctrl driver, but for the FXL6408 GPIO expander on the Pi3, we > need to access them through the firmware. > > Signed-off-by: Eric Anholt <eric@anholt.net> > --- > .../bindings/gpio/gpio-raspberrypi-firmware.txt | 22 > ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) > create mode 100644 > Documentation/devicetree/bindings/gpio/gpio-raspberrypi-firmware.txt > > diff --git > a/Documentation/devicetree/bindings/gpio/gpio-raspberrypi-firmware.txt > b/Documentation/devicetree/bindings/gpio/gpio-raspberrypi-firmware.txt > new file mode 100644 > index 000000000000..2b635c23a6f8 > --- /dev/null > +++ b/Documentation/devicetree/bindings/gpio/gpio-raspberrypi-firmware.txt > @@ -0,0 +1,22 @@ > +Raspberry Pi power domain driver > + > +Required properties: > + > +- compatible: Should be "raspberrypi,firmware-gpio"
i think the compatible should be more specific like
raspberrypi,rpi3-firmware-gpio
and all information which aren't requestable from the firmware should be stored in a info structure. This makes the driver easier to extend in the future by adding new compatibles and their info structures.
> +- gpio-controller: Marks the device node as a gpio controller > +- #gpio-cells: Should be <2> for GPIO number and flags > +- ngpios: Number of GPIO lines to control. See gpio.txt > +- firmware: Reference to the RPi firmware device node > +- raspberrypi,firmware-gpio-offset: > + Number the firmware uses for the first GPIO line > + controlled by this driver
We should avoid such properties because they don't really describe the hardware.
Stefan
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