BCM270X_DT: Add at86rf233 overlay

Add an overlay to support the Atmel AT86RF233 WPAN transceiver on spi0.0.

See: https://github.com/raspberrypi/linux/issues/1151

arch/arm/boot/dts/overlays/Makefile

@@ -13,6 +13,7 @@ ifeq ($(CONFIG_ARCH_BCM2835),y)
 endif
 
 dtb-$(RPI_DT_OVERLAYS) += ads7846-overlay.dtb
+dtb-$(RPI_DT_OVERLAYS) += at86rf233-overlay.dtb
 dtb-$(RPI_DT_OVERLAYS) += bmp085_i2c-sensor-overlay.dtb
 dtb-$(RPI_DT_OVERLAYS) += dht11-overlay.dtb
 dtb-$(RPI_DT_OVERLAYS) += enc28j60-overlay.dtb

arch/arm/boot/dts/overlays/README

@@ -69,13 +69,14 @@ DT parameters:
 
 Parameters always have default values, although in some cases (e.g. "w1-gpio")
 it is necessary to provided multiple overlays in order to get the desired
-behaviour. See the list of overlays below for a description of the parameters and their defaults.
+behaviour. See the list of overlays below for a description of the parameters
+and their defaults.
 
 The Overlay and Parameter Reference
 ===================================
 
-N.B. When editing this file, please preserve the indentation levels to make it simple to parse
+N.B. When editing this file, please preserve the indentation levels to make it
-programmatically. NO HARD TABS.
+simple to parse programmatically. NO HARD TABS.
 
 
 Name:   <The base DTB>
@@ -149,7 +150,7 @@ Name:   ads7846
 Info:   ADS7846 Touch controller
 Load:   dtoverlay=ads7846,<param>=<val>
 Params: cs                       SPI bus Chip Select (default 1)
-        speed                    SPI bus speed (default 2Mhz, max 3.25MHz)
+        speed                    SPI bus speed (default 2MHz, max 3.25MHz)
         penirq                   GPIO used for PENIRQ. REQUIRED
         penirq_pull              Set GPIO pull (default 0=none, 2=pullup)
         swapxy                   Swap x and y axis
@@ -170,6 +171,18 @@ Params: cs                       SPI bus Chip Select (default 1)
         www.kernel.org/doc/Documentation/devicetree/bindings/input/ads7846.txt
 
 
+Name:   at86rf233
+Info:   Configures the Atmel AT86RF233 802.15.4 low-power WPAN transceiver,
+        connected to spi0.0
+Load:   dtoverlay=at86rf233,<param>=<val>
+Params: interrupt                GPIO used for INT (default 23)
+        reset                    GPIO used for Reset (default 24)
+        sleep                    GPIO used for Sleep (default 25)
+        speed                    SPI bus speed in Hz (default 750000)
+        trim                     Fine tuning of the internal capacitance
+                                 arrays (0=+0pF, 15=+4.5pF, default 15)
+
+
 Name:   bmp085_i2c-sensor
 Info:   Configures the BMP085/BMP180 digital barometric pressure and temperature
         sensors from Bosch Sensortec

arch/arm/boot/dts/overlays/at86rf233-overlay.dts

@@ -0,0 +1,54 @@
+/dts-v1/;
+/plugin/;
+
+/* Overlay for Atmel AT86RF233 IEEE 802.15.4 WPAN transceiver on spi0.0 */
+
+/ {
+	compatible = "brcm,bcm2835", "brcm,bcm2836", "brcm,bcm2708", "brcm,bcm2709";
+
+	fragment@0 {
+		target = <&spi0>;
+		__overlay__ {
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			status = "okay";
+
+			spidev@0{
+				status = "disabled";
+			};
+
+			lowpan0: at86rf233@0 {
+				compatible = "atmel,at86rf233";
+				reg = <0>;
+				interrupt-parent = <&gpio>;
+				interrupts = <23 4>; /* active high */
+				reset-gpio = <&gpio 24 1>;
+				sleep-gpio = <&gpio 25 1>;
+				spi-max-frequency = <7500000>;
+				xtal-trim = /bits/ 8 <0xf>;
+			};
+		};
+	};
+
+	fragment@1 {
+		target = <&gpio>;
+		__overlay__ {
+			lowpan0_pins: lowpan0_pins {
+				brcm,pins = <23 24 25>;
+				brcm,function = <0 1 1>; /* in out out */
+			};
+		};
+	};
+
+	__overrides__ {
+		interrupt = <&lowpan0>, "interrupts:0",
+			<&lowpan0_pins>, "brcm,pins:0";
+		reset     = <&lowpan0>, "reset-gpio:4",
+			<&lowpan0_pins>, "brcm,pins:4";
+		sleep     = <&lowpan0>, "sleep-gpio:4",
+			<&lowpan0_pins>, "brcm,pins:8";
+		speed     = <&lowpan0>, "spi-max-frequency:0";
+		trim      = <&lowpan0>, "xtal-trim.0";
+	};
+};