ARC: HSDK: Enable SPI flash support

HSDK board has sst26wf016 SPI flash IC which we want to support.

Add SPI controller, CS-gpio and SPI flash nodes to hsdk device tree.
Enable corresponding options in hsdk defconfig.

For SPI write functionality to work we need [1] which
adds support of sst26xxx ICs.

[1] https://patchwork.ozlabs.org/project/uboot/list/?series=35796

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>

arch/arc/dts/hsdk.dts

@@ -14,6 +14,7 @@
 
 	aliases {
 		console = &uart0;
+		spi0 = &spi0;
 	};
 
 	cpu_card {
@@ -83,4 +84,29 @@
 		compatible = "generic-ohci";
 		reg = <0xf0060000 0x100>;
 	};
+
+	spi0: spi@f0020000 {
+		compatible = "snps,dw-apb-ssi";
+		reg = <0xf0020000 0x1000>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+		spi-max-frequency = <4000000>;
+		clocks = <&cgu_clk CLK_SYS_SPI_REF>;
+		clock-names = "spi_clk";
+		cs-gpio = <&cs_gpio 0>;
+		spi_flash@0 {
+			compatible = "spi-flash";
+			reg = <0>;
+			spi-max-frequency = <4000000>;
+		};
+	};
+
+	cs_gpio: gpio@f00014b0 {
+		compatible = "snps,hsdk-creg-gpio";
+		reg = <0xf00014b0 0x4>;
+		gpio-controller;
+		#gpio-cells = <1>;
+		gpio-bank-name = "hsdk-spi-cs";
+		gpio-count = <1>;
+	};
 };

configs/hsdk_defconfig

@@ -12,6 +12,8 @@ CONFIG_SYS_PROMPT="hsdk# "
 CONFIG_CMD_ENV_FLAGS=y
 # CONFIG_CMD_FLASH is not set
 CONFIG_CMD_MMC=y
+CONFIG_CMD_SF=y
+CONFIG_CMD_SPI=y
 CONFIG_CMD_USB=y
 # CONFIG_CMD_SETEXPR is not set
 CONFIG_CMD_DHCP=y
@@ -29,12 +31,19 @@ CONFIG_ENV_FAT_DEVICE_AND_PART="0:1"
 CONFIG_NET_RANDOM_ETHADDR=y
 CONFIG_DM=y
 CONFIG_CLK_HSDK=y
+CONFIG_DM_GPIO=y
+CONFIG_HSDK_CREG_GPIO=y
 CONFIG_MMC=y
 CONFIG_MMC_DW=y
+CONFIG_DM_SPI_FLASH=y
+CONFIG_SPI_FLASH=y
+CONFIG_SPI_FLASH_SST=y
 CONFIG_DM_ETH=y
 CONFIG_ETH_DESIGNWARE=y
 CONFIG_DM_SERIAL=y
 CONFIG_SYS_NS16550=y
+CONFIG_DM_SPI=y
+CONFIG_DESIGNWARE_SPI=y
 CONFIG_USB=y
 CONFIG_DM_USB=y
 CONFIG_USB_EHCI_HCD=y