From 726da40b8c272d181a41686195f91b914363167b Mon Sep 17 00:00:00 2001
From: Tim Gover <tim.gover@raspberrypi.org>
Date: Tue, 22 Jan 2019 10:49:41 +0000
Subject: [PATCH] overlays: Add the spi-gpio40-45 overlay

The 2711 B0 boot EEPROM is programmed via SPI0 on GPIO
pins 40-43 CS0. Add a device tree overlay to optionally
change the SPI0 pinmux from the external GPIO pins to
the boot EEPROM pins.
---
 arch/arm/boot/dts/overlays/Makefile           |  1 +
 arch/arm/boot/dts/overlays/README             |  6 ++++
 .../dts/overlays/spi-gpio40-45-overlay.dts    | 36 +++++++++++++++++++
 3 files changed, 43 insertions(+)
 create mode 100644 arch/arm/boot/dts/overlays/spi-gpio40-45-overlay.dts

--- a/arch/arm/boot/dts/overlays/Makefile
+++ b/arch/arm/boot/dts/overlays/Makefile
@@ -135,6 +135,7 @@ dtbo-$(CONFIG_ARCH_BCM2835) += \
 	smi-dev.dtbo \
 	smi-nand.dtbo \
 	spi-gpio35-39.dtbo \
+	spi-gpio40-45.dtbo \
 	spi-rtc.dtbo \
 	spi0-cs.dtbo \
 	spi0-hw-cs.dtbo \
--- a/arch/arm/boot/dts/overlays/README
+++ b/arch/arm/boot/dts/overlays/README
@@ -1967,6 +1967,12 @@ Load:   dtoverlay=spi-gpio35-39
 Params: <None>
 
 
+Name:   spi-gpio40-45
+Info:   Move SPI function block to GPIOs 40 to 45
+Load:   dtoverlay=spi-gpio40-45
+Params: <None>
+
+
 Name:   spi-rtc
 Info:   Adds support for a number of SPI Real Time Clock devices
 Load:   dtoverlay=spi-rtc,<param>=<val>
--- /dev/null
+++ b/arch/arm/boot/dts/overlays/spi-gpio40-45-overlay.dts
@@ -0,0 +1,36 @@
+/*
+ * Boot EEPROM overlay
+ */
+
+/dts-v1/;
+/plugin/;
+
+/ {
+	compatible = "brcm,bcm2835";
+
+	fragment@0 {
+		target = <&spi0>;
+		__overlay__ {
+			cs-gpios = <&gpio 43 1>, <&gpio 44 1>, <&gpio 45 1>;
+			status = "okay";
+		};
+	};
+
+	fragment@1 {
+		target = <&spi0_cs_pins>;
+		__overlay__ {
+			brcm,pins = <45 44 43>;
+			brcm,function = <1>; /* output */
+			status = "okay";
+		};
+	};
+
+	fragment@2 {
+		target = <&spi0_pins>;
+		__overlay__ {
+			brcm,pins = <40 41 42>;
+			brcm,function = <3>; /* alt4 */
+			status = "okay";
+		};
+	};
+};