Hi Rob,

Thanks again for reviewing.

On Tue, Feb 13, 2018 at 05:20:07PM -0600, Rob Herring wrote:

On Wed, Feb 07, 2018 at 08:35:23PM +0200, Baruch Siach wrote:

quoted

+Raspberry Pi GPIO expander
+
+The Raspberry Pi 3 GPIO expander is controlled by the VC4 firmware. The
+firmware exposes a mailbox interface that allows the ARM core to control the
+GPIO lines on the expander.
+
+Required properties:
+
+- compatible : Should be "raspberrypi,firmware-gpio"
+- gpio-controller : Marks the device node as a gpio controller
+- #gpio-cells : Should be two.  The first cell is the pin number, and
+  the second cell is used to specify the gpio polarity:
+  0 = active high
+  1 = active low
+- firmware : Reference to the RPi firmware device node

This is the parent node. You don't need it.

OK. I guess of_get_parent() will do the trick.

quoted

+Example:
+
+firmware: firmware {
+	compatible = "raspberrypi,bcm2835-firmware";
+	mboxes = <&mailbox>;

No, sorry. /firmware is the container of firmware nodes. So 
something like this:

firmware {
	rpi-firmware {
		compatible = "raspberrypi,bcm2835-firmware";
		mboxes = <&mailbox>;
		gpio {
		 compatible = "raspberrypi,firmware-gpio";

		};
	};
};

This is the hierarchy we currently have at arch/arm/boot/dts/bcm2835-rpi.dtsi:

/ {
        soc {
                firmware: firmware {
                        compatible = "raspberrypi,bcm2835-firmware";
                        mboxes = <&mailbox>;
                };
        };
};


Are you suggesting to add another container between 'soc' and 'firmware'? Or 
is it the 'firmware' node name that we need to change to 'rpi-firmware'?

quoted

+
+	expgpio: gpio {
+		 compatible = "raspberrypi,firmware-gpio";
+		 gpio-controller;
+		 #gpio-cells = <2>;
+		 firmware = <&firmware>;
+	 };
+};

baruch

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