[PATCH 5/5] mtd: onenand: samsung: Add device tree support

[Jonathan Bakker <xc-racer2@live.ca>]

From: Tomasz Figa <tomasz.figa@gmail.com>

This patch adds support for instantation using Device Tree.

Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com>
Signed-off-by: Paweł Chmiel <pawel.mikolaj.chmiel@gmail.com>
Signed-off-by: Jonathan Bakker <xc-racer2@live.ca>

---
Changes from previous patchset
- Adjust to having a nand child node as per binding feedback
---
 drivers/mtd/nand/onenand/onenand_samsung.c | 67 +++++++++++++++++++++-
 1 file changed, 65 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/nand/onenand/onenand_samsung.c b/drivers/mtd/nand/onenand/onenand_samsung.c
index 62014f8d27b6..0108c8c75d5b 100644
--- a/drivers/mtd/nand/onenand/onenand_samsung.c
+++ b/drivers/mtd/nand/onenand/onenand_samsung.c
@@ -22,6 +22,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
+#include <linux/of.h>
 
 #include "samsung.h"
 
@@ -832,8 +833,36 @@ static void s3c_onenand_setup(struct mtd_info *mtd)
 	this->write_bufferram = onenand_write_bufferram;
 }
 
+#ifdef CONFIG_OF
+static const struct of_device_id s3c_onenand_of_match[] = {
+	{ .compatible = "samsung,s3c6400-onenand",
+		.data = (void *)TYPE_S3C6400 },
+	{ .compatible = "samsung,s3c6410-onenand",
+		.data = (void *)TYPE_S3C6410 },
+	{ .compatible = "samsung,s5pv210-onenand",
+		.data = (void *)TYPE_S5PC110 },
+	{},
+};
+MODULE_DEVICE_TABLE(of, onenand_s3c_dt_match);
+#endif
+
+static enum soc_type s3c_onenand_get_device_id(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+
+	if (IS_ENABLED(CONFIG_OF) && np) {
+		const struct of_device_id *match;
+
+		match = of_match_node(s3c_onenand_of_match, np);
+		return (enum soc_type)match->data;
+	}
+
+	return platform_get_device_id(pdev)->driver_data;
+}
+
 static int s3c_onenand_probe(struct platform_device *pdev)
 {
+	struct device_node *np = pdev->dev.of_node;
 	struct onenand_platform_data *pdata;
 	struct onenand_chip *this;
 	struct mtd_info *mtd;
@@ -856,9 +885,10 @@ static int s3c_onenand_probe(struct platform_device *pdev)
 	this = (struct onenand_chip *) &mtd[1];
 	mtd->name = dev_name(&pdev->dev);
 	mtd->priv = this;
+	mtd->dev.of_node = np;
 	mtd->dev.parent = &pdev->dev;
 	onenand->pdev = pdev;
-	onenand->type = platform_get_device_id(pdev)->driver_data;
+	onenand->type = s3c_onenand_get_device_id(pdev);
 
 	s3c_onenand_setup(mtd);
 
@@ -867,7 +897,35 @@ static int s3c_onenand_probe(struct platform_device *pdev)
 	if (IS_ERR(onenand->ctrl_base))
 		return PTR_ERR(onenand->ctrl_base);
 
-	r = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	if (np) {
+		/* Determine which CS to use - this driver only supports one */
+		u32 cs = 0;
+		struct device_node *child_np;
+		struct device_node *extra_chip_np;
+
+		child_np = of_get_next_available_child(np, NULL);
+		if (child_np == NULL) {
+			dev_err(&pdev->dev, "failed to get chip node\n");
+			return -EINVAL;
+		}
+
+		/* Warn if more than one chip as this unsupported */
+		extra_chip_np = of_get_next_available_child(np, child_np);
+		if (extra_chip_np != NULL) {
+			dev_warn(&pdev->dev, "multiple chip nodes, using only first\n");
+			of_node_put(extra_chip_np);
+		}
+
+		err = of_property_read_u32(child_np, "reg", &cs);
+		of_node_put(child_np);
+		if (err < 0)
+			return err;
+
+		r = platform_get_resource(pdev, IORESOURCE_MEM, cs + 1);
+	} else {
+		r = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	}
+
 	onenand->chip_base = devm_ioremap_resource(&pdev->dev, r);
 	if (IS_ERR(onenand->chip_base))
 		return PTR_ERR(onenand->chip_base);
@@ -917,6 +975,10 @@ static int s3c_onenand_probe(struct platform_device *pdev)
 	}
 
 	onenand->clk_bus = devm_clk_get(&pdev->dev, "bus");
+	if (np && IS_ERR(onenand->clk_bus)) {
+		dev_err(&pdev->dev, "failed to get bus clock\n");
+		return PTR_ERR(onenand->clk_bus);
+	}
 	if (!IS_ERR(onenand->clk_bus))
 		clk_prepare_enable(onenand->clk_bus);
 
@@ -998,6 +1060,7 @@ static struct platform_driver s3c_onenand_driver = {
 	.driver         = {
 		.name	= "samsung-onenand",
 		.pm	= &s3c_pm_ops,
+		.of_match_table = of_match_ptr(s3c_onenand_of_match),
 	},
 	.id_table	= s3c_onenand_driver_ids,
 	.probe          = s3c_onenand_probe,
-- 
2.30.2