mtd: nand: davinci: add OF support for davinci nand controller

add OF support for the davinci nand controller.
Signed-off-by: Heiko Schocher <hs@denx.de>
Acked-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Documentation/devicetree/bindings/arm/davinci/nand.txt

+* Texas Instruments Davinci NAND
+
+This file provides information, what the device node for the
+davinci nand interface contain.
+
+Required properties:
+- compatible: "ti,davinci-nand";
+- reg : contain 2 offset/length values:
+        - offset and length for the access window
+        - offset and length for accessing the aemif control registers
+- ti,davinci-chipselect: Indicates on the davinci_nand driver which
+                         chipselect is used for accessing the nand.
+
+Recommended properties :
+- ti,davinci-mask-ale: mask for ale
+- ti,davinci-mask-cle: mask for cle
+- ti,davinci-mask-chipsel: mask for chipselect
+- ti,davinci-ecc-mode: ECC mode valid values for davinci driver:
+		- "none"
+		- "soft"
+		- "hw"
+- ti,davinci-ecc-bits: used ECC bits, currently supported 1 or 4.
+- ti,davinci-nand-buswidth: buswidth 8 or 16
+- ti,davinci-nand-use-bbt: use flash based bad block table support.
+
+Example (enbw_cmc board):
+aemif@60000000 {
+	compatible = "ti,davinci-aemif";
+	#address-cells = <2>;
+	#size-cells = <1>;
+	reg = <0x68000000 0x80000>;
+	ranges = <2 0 0x60000000 0x02000000
+		  3 0 0x62000000 0x02000000
+		  4 0 0x64000000 0x02000000
+		  5 0 0x66000000 0x02000000
+		  6 0 0x68000000 0x02000000>;
+	nand@3,0 {
+		compatible = "ti,davinci-nand";
+		reg = <3 0x0 0x807ff
+			6 0x0 0x8000>;
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ti,davinci-chipselect = <1>;
+		ti,davinci-mask-ale = <0>;
+		ti,davinci-mask-cle = <0>;
+		ti,davinci-mask-chipsel = <0>;
+		ti,davinci-ecc-mode = "hw";
+		ti,davinci-ecc-bits = <4>;
+		ti,davinci-nand-use-bbt;
+	};
+};

drivers/mtd/nand/davinci_nand.c

@@ -33,6 +33,7 @@
 #include <linux/mtd/nand.h>
 #include <linux/mtd/partitions.h>
 #include <linux/slab.h>
+#include <linux/of_device.h>
 
 #include <mach/nand.h>
 #include <mach/aemif.h>
@@ -518,9 +519,75 @@ static struct nand_ecclayout hwecc4_2048 __initconst = {
 	},
 };
 
+#if defined(CONFIG_OF)
+static const struct of_device_id davinci_nand_of_match[] = {
+	{.compatible = "ti,davinci-nand", },
+	{},
+}
+MODULE_DEVICE_TABLE(of, davinci_nand_of_match);
+
+static struct davinci_nand_pdata
+	*nand_davinci_get_pdata(struct platform_device *pdev)
+{
+	if (!pdev->dev.platform_data && pdev->dev.of_node) {
+		struct davinci_nand_pdata *pdata;
+		const char *mode;
+		u32 prop;
+		int len;
+
+		pdata =  devm_kzalloc(&pdev->dev,
+				sizeof(struct davinci_nand_pdata),
+				GFP_KERNEL);
+		pdev->dev.platform_data = pdata;
+		if (!pdata)
+			return NULL;
+		if (!of_property_read_u32(pdev->dev.of_node,
+			"ti,davinci-chipselect", &prop))
+			pdev->id = prop;
+		if (!of_property_read_u32(pdev->dev.of_node,
+			"ti,davinci-mask-ale", &prop))
+			pdata->mask_ale = prop;
+		if (!of_property_read_u32(pdev->dev.of_node,
+			"ti,davinci-mask-cle", &prop))
+			pdata->mask_cle = prop;
+		if (!of_property_read_u32(pdev->dev.of_node,
+			"ti,davinci-mask-chipsel", &prop))
+			pdata->mask_chipsel = prop;
+		if (!of_property_read_string(pdev->dev.of_node,
+			"ti,davinci-ecc-mode", &mode)) {
+			if (!strncmp("none", mode, 4))
+				pdata->ecc_mode = NAND_ECC_NONE;
+			if (!strncmp("soft", mode, 4))
+				pdata->ecc_mode = NAND_ECC_SOFT;
+			if (!strncmp("hw", mode, 2))
+				pdata->ecc_mode = NAND_ECC_HW;
+		}
+		if (!of_property_read_u32(pdev->dev.of_node,
+			"ti,davinci-ecc-bits", &prop))
+			pdata->ecc_bits = prop;
+		if (!of_property_read_u32(pdev->dev.of_node,
+			"ti,davinci-nand-buswidth", &prop))
+			if (prop == 16)
+				pdata->options |= NAND_BUSWIDTH_16;
+		if (of_find_property(pdev->dev.of_node,
+			"ti,davinci-nand-use-bbt", &len))
+			pdata->bbt_options = NAND_BBT_USE_FLASH;
+	}
+
+	return pdev->dev.platform_data;
+}
+#else
+#define davinci_nand_of_match NULL
+static struct davinci_nand_pdata
+	*nand_davinci_get_pdata(struct platform_device *pdev)
+{
+	return pdev->dev.platform_data;
+}
+#endif
+
 static int __init nand_davinci_probe(struct platform_device *pdev)
 {
-	struct davinci_nand_pdata	*pdata = pdev->dev.platform_data;
+	struct davinci_nand_pdata	*pdata;
 	struct davinci_nand_info	*info;
 	struct resource			*res1;
 	struct resource			*res2;
@@ -530,6 +597,7 @@ static int __init nand_davinci_probe(struct platform_device *pdev)
 	uint32_t			val;
 	nand_ecc_modes_t		ecc_mode;
 
+	pdata = nand_davinci_get_pdata(pdev);
 	/* insist on board-specific configuration */
 	if (!pdata)
 		return -ENODEV;
@@ -816,6 +884,8 @@ static struct platform_driver nand_davinci_driver = {
 	.remove		= __exit_p(nand_davinci_remove),
 	.driver		= {
 		.name	= "davinci_nand",
+		.owner	= THIS_MODULE,
+		.of_match_table = davinci_nand_of_match,
 	},
 };
 MODULE_ALIAS("platform:davinci_nand");