board: rockchip: Add minimal generic RK3328 board

Add a minimal generic RK3328 board that only have eMMC, SDMMC, SPI flash
and USB OTG enabled. This defconfig can be used to boot from eMMC,
SD-card or SPI flash on most RK3328 boards that follow reference board
design.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Christopher Obbard <christopher.obbard@linaro.org>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/arch/arm/dts/rk3328-generic.dts b/arch/arm/dts/rk3328-generic.dts
new file mode 100644
index 0000000..af0da84
--- /dev/null
+++ b/arch/arm/dts/rk3328-generic.dts
@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * Minimal generic DT for RK3328 with eMMC, SD-card, SPI flash and USB OTG enabled
+ */
+
+/dts-v1/;
+#include "rk3328.dtsi"
+
+/ {
+	model = "Generic RK3328";
+	compatible = "rockchip,rk3328";
+
+	aliases {
+		mmc0 = &emmc;
+		mmc1 = &sdmmc;
+	};
+
+	chosen {
+		stdout-path = "serial2:1500000n8";
+	};
+};
+
+&emmc {
+	bus-width = <8>;
+	cap-mmc-highspeed;
+	mmc-ddr-1_8v;
+	mmc-hs200-1_8v;
+	no-sd;
+	no-sdio;
+	non-removable;
+	pinctrl-names = "default";
+	pinctrl-0 = <&emmc_clk &emmc_cmd &emmc_bus8>;
+	status = "okay";
+};
+
+&sdmmc0m1_pin {
+	rockchip,pins = <0 RK_PD6 RK_FUNC_GPIO &pcfg_pull_down_4ma>;
+};
+
+&sdmmc {
+	bus-width = <4>;
+	cap-sd-highspeed;
+	disable-wp;
+	no-mmc;
+	no-sdio;
+	pinctrl-names = "default";
+	pinctrl-0 = <&sdmmc0_clk &sdmmc0_cmd &sdmmc0_dectn &sdmmc0_bus4 &sdmmc0m1_pin>;
+	status = "okay";
+};
+
+&spi0 {
+	status = "okay";
+
+	flash@0 {
+		compatible = "jedec,spi-nor";
+		reg = <0>;
+		spi-max-frequency = <25000000>;
+	};
+};
+
+&u2phy {
+	status = "okay";
+};
+
+&u2phy_otg {
+	status = "okay";
+};
+
+&uart2 {
+	status = "okay";
+};
+
+&usb20_otg {
+	dr_mode = "peripheral";
+	status = "okay";
+};