ARM: dts: dra7: add support for parallel NAND flash

DRA7xx platform has in-build GPMC and ELM h/w engines which can be used
for accessing externel NAND flash device. This patch:
- adds generic DT binding in dra7.dtsi for enabling GPMC and ELM h/w engines
- adds DT binding for Micron NAND Flash (MT29F2G16AADWP) present on dra7-evm
*Important*
	On DRA7 EVM, GPMC_WPN and NAND_BOOTn are controlled by DIP switch
	So following board settings are required for NAND device detection:
	SW5.9 (GPMC_WPN) = LOW
	SW5.1 (NAND_BOOTn) = HIGH

Signed-off-by: Minal Shah <minalkshah@gmail.com>
Signed-off-by: Pekon Gupta <pekon@ti.com>
Reviewed-by: Javier Martinez Canillas <javier@dowhile0.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/boot/dts/dra7-evm.dts

@@ -120,6 +120,37 @@
 			0x284 (PIN_INPUT_SLEW | MUX_MODE0) /* usb2_drvvbus */
                 >;
         };
+
+	nand_flash_x16: nand_flash_x16 {
+		/* On DRA7 EVM, GPMC_WPN and NAND_BOOTn comes from DIP switch
+		 * So NAND flash requires following switch settings:
+		 * SW5.9 (GPMC_WPN) = LOW
+		 * SW5.1 (NAND_BOOTn) = HIGH */
+		pinctrl-single,pins = <
+			0x0 	(PIN_INPUT  | MUX_MODE0)	/* gpmc_ad0	*/
+			0x4 	(PIN_INPUT  | MUX_MODE0)	/* gpmc_ad1	*/
+			0x8 	(PIN_INPUT  | MUX_MODE0)	/* gpmc_ad2	*/
+			0xc 	(PIN_INPUT  | MUX_MODE0)	/* gpmc_ad3	*/
+			0x10	(PIN_INPUT  | MUX_MODE0)	/* gpmc_ad4	*/
+			0x14	(PIN_INPUT  | MUX_MODE0)	/* gpmc_ad5	*/
+			0x18	(PIN_INPUT  | MUX_MODE0)	/* gpmc_ad6	*/
+			0x1c	(PIN_INPUT  | MUX_MODE0)	/* gpmc_ad7	*/
+			0x20	(PIN_INPUT  | MUX_MODE0)	/* gpmc_ad8	*/
+			0x24	(PIN_INPUT  | MUX_MODE0)	/* gpmc_ad9	*/
+			0x28	(PIN_INPUT  | MUX_MODE0)	/* gpmc_ad10	*/
+			0x2c	(PIN_INPUT  | MUX_MODE0)	/* gpmc_ad11	*/
+			0x30	(PIN_INPUT  | MUX_MODE0)	/* gpmc_ad12	*/
+			0x34	(PIN_INPUT  | MUX_MODE0)	/* gpmc_ad13	*/
+			0x38	(PIN_INPUT  | MUX_MODE0)	/* gpmc_ad14	*/
+			0x3c	(PIN_INPUT  | MUX_MODE0)	/* gpmc_ad15	*/
+			0xd8	(PIN_INPUT_PULLUP  | MUX_MODE0)	/* gpmc_wait0	*/
+			0xcc	(PIN_OUTPUT | MUX_MODE0)	/* gpmc_wen	*/
+			0xb4	(PIN_OUTPUT_PULLUP | MUX_MODE0)	/* gpmc_csn0	*/
+			0xc4	(PIN_OUTPUT | MUX_MODE0)	/* gpmc_advn_ale */
+			0xc8	(PIN_OUTPUT | MUX_MODE0)	/* gpmc_oen_ren	 */
+			0xd0	(PIN_OUTPUT | MUX_MODE0)	/* gpmc_be0n_cle */
+		>;
+	};
 };
 
 &i2c1 {
@@ -377,3 +408,90 @@
 	pinctrl-names = "default";
 	pinctrl-0 = <&usb2_pins>;
 };
+
+&elm {
+	status = "okay";
+};
+
+&gpmc {
+	status = "okay";
+	pinctrl-names = "default";
+	pinctrl-0 = <&nand_flash_x16>;
+	ranges = <0 0 0 0x01000000>;	/* minimum GPMC partition = 16MB */
+	nand@0,0 {
+		reg = <0 0 4>;		/* device IO registers */
+		ti,nand-ecc-opt = "bch8";
+		ti,elm-id = <&elm>;
+		nand-bus-width = <16>;
+		gpmc,device-width = <2>;
+		gpmc,sync-clk-ps = <0>;
+		gpmc,cs-on-ns = <0>;
+		gpmc,cs-rd-off-ns = <40>;
+		gpmc,cs-wr-off-ns = <40>;
+		gpmc,adv-on-ns = <0>;
+		gpmc,adv-rd-off-ns = <30>;
+		gpmc,adv-wr-off-ns = <30>;
+		gpmc,we-on-ns = <5>;
+		gpmc,we-off-ns = <25>;
+		gpmc,oe-on-ns = <2>;
+		gpmc,oe-off-ns = <20>;
+		gpmc,access-ns = <20>;
+		gpmc,wr-access-ns = <40>;
+		gpmc,rd-cycle-ns = <40>;
+		gpmc,wr-cycle-ns = <40>;
+		gpmc,wait-pin = <0>;
+		gpmc,wait-on-read;
+		gpmc,wait-on-write;
+		gpmc,bus-turnaround-ns = <0>;
+		gpmc,cycle2cycle-delay-ns = <0>;
+		gpmc,clk-activation-ns = <0>;
+		gpmc,wait-monitoring-ns = <0>;
+		gpmc,wr-data-mux-bus-ns = <0>;
+		/* MTD partition table */
+		/* All SPL-* partitions are sized to minimal length
+		 * which can be independently programmable. For
+		 * NAND flash this is equal to size of erase-block */
+		#address-cells = <1>;
+		#size-cells = <1>;
+		partition@0 {
+			label = "NAND.SPL";
+			reg = <0x00000000 0x000020000>;
+		};
+		partition@1 {
+			label = "NAND.SPL.backup1";
+			reg = <0x00020000 0x00020000>;
+		};
+		partition@2 {
+			label = "NAND.SPL.backup2";
+			reg = <0x00040000 0x00020000>;
+		};
+		partition@3 {
+			label = "NAND.SPL.backup3";
+			reg = <0x00060000 0x00020000>;
+		};
+		partition@4 {
+			label = "NAND.u-boot-spl-os";
+			reg = <0x00080000 0x00040000>;
+		};
+		partition@5 {
+			label = "NAND.u-boot";
+			reg = <0x000c0000 0x00100000>;
+		};
+		partition@6 {
+			label = "NAND.u-boot-env";
+			reg = <0x001c0000 0x00020000>;
+		};
+		partition@7 {
+			label = "NAND.u-boot-env";
+			reg = <0x001e0000 0x00020000>;
+		};
+		partition@8 {
+			label = "NAND.kernel";
+			reg = <0x00200000 0x00800000>;
+		};
+		partition@9 {
+			label = "NAND.file-system";
+			reg = <0x00a00000 0x0f600000>;
+		};
+	};
+};

arch/arm/boot/dts/dra7.dtsi

@@ -964,6 +964,26 @@
 				dr_mode = "otg";
 			};
 		};
+
+		elm: elm@48078000 {
+			compatible = "ti,am3352-elm";
+			reg = <0x48078000 0xfc0>;      /* device IO registers */
+			interrupts = <GIC_SPI 4 IRQ_TYPE_LEVEL_HIGH>;
+			ti,hwmods = "elm";
+			status = "disabled";
+		};
+
+		gpmc: gpmc@50000000 {
+			compatible = "ti,am3352-gpmc";
+			ti,hwmods = "gpmc";
+			reg = <0x50000000 0x37c>;      /* device IO registers */
+			interrupts = <GIC_SPI 20 IRQ_TYPE_LEVEL_HIGH>;
+			gpmc,num-cs = <8>;
+			gpmc,num-waitpins = <2>;
+			#address-cells = <2>;
+			#size-cells = <1>;
+			status = "disabled";
+		};
 	};
 };