MLK-19452-3 ARM: dts: Add spi slave support for imx7ulp

Add "spi-slave" attribute for recognizing slave mode.
If it is not in slave mode, please delete this attribute.
Usage can be found at spi-fsl-lpspi.txt.

Modify "Makefile" to build "imx7ulp-evk-spi-slave.dtb".

Signed-off-by: Xiaoning Wang <xiaoning.wang@nxp.com>

Documentation/devicetree/bindings/spi/spi-fsl-lpspi.txt

@@ -7,6 +7,8 @@ Required properties:
 - interrupt-parent : core interrupt controller
 - interrupts : lpspi interrupt
 - clocks : lpspi clock specifier
+- spi-slave : spi slave mode support. In slave mode, add this attribute without
+	      value. In master mode, remove it.
 
 Examples:
 
@@ -16,4 +18,5 @@ lpspi2: lpspi@40290000 {
 	interrupt-parent = <&intc>;
 	interrupts = <GIC_SPI 28 IRQ_TYPE_LEVEL_HIGH>;
 	clocks = <&clks IMX7ULP_CLK_LPSPI2>;
+	spi-slave;
 };

arch/arm/boot/dts/Makefile

@@ -639,6 +639,7 @@ dtb-$(CONFIG_SOC_IMX7D) += \
 dtb-$(CONFIG_SOC_IMX7ULP) += \
 	imx7ulp-14x14-arm2.dtb \
 	imx7ulp-evk.dtb \
+	imx7ulp-evk-spi-slave.dtb \
 	imx7ulp-evk-emmc.dtb \
 	imx7ulp-evk-emmc-qspi.dtb \
 	imx7ulp-evk-ft5416.dtb \

arch/arm/boot/dts/imx7ulp-evk-spi-slave.dts

@@ -0,0 +1,16 @@
+/*
+ * Copyright 2016 Freescale Semiconductor, Inc.
+ * Copyright 2017-2018 NXP.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include "imx7ulp-evk.dts"
+
+/delete-node/&spidev0;
+
+&lpspi3 {
+	spi-slave;
+};