mtd: nand: add common DT init code

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=5844feeaa4154d1c46d3462c7a4653d22356d8b4
Commit:     5844feeaa4154d1c46d3462c7a4653d22356d8b4
Parent:     7aaea7605c0e19fa7b38d7ac5dcd818942fd17a7
Author:     Brian Norris <computersforpeace at gmail.com>
AuthorDate: Fri Jan 23 00:22:27 2015 -0800
Committer:  Brian Norris <computersforpeace at gmail.com>
CommitDate: Mon May 11 16:22:29 2015 -0700

    mtd: nand: add common DT init code
    
    These are already-documented common bindings for NAND chips. Let's
    handle them in nand_base.
    
    If NAND controller drivers need to act on this data before bringing up
    the NAND chip (e.g., fill out ECC callback functions, change HW modes,
    etc.), then they can do so between calling nand_scan_ident() and
    nand_scan_tail().
    
    Signed-off-by: Brian Norris <computersforpeace at gmail.com>
---
 drivers/mtd/nand/nand_base.c | 41 +++++++++++++++++++++++++++++++++++++++++
 include/linux/mtd/nand.h     |  5 +++++
 2 files changed, 46 insertions(+)

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 0afe763..c4619e3 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -48,6 +48,7 @@
 #include <linux/leds.h>
 #include <linux/io.h>
 #include <linux/mtd/partitions.h>
+#include <linux/of_mtd.h>
 
 /* Define default oob placement schemes for large and small page devices */
 static struct nand_ecclayout nand_oob_8 = {
@@ -3795,6 +3796,39 @@ ident_done:
 	return type;
 }
 
+static int nand_dt_init(struct mtd_info *mtd, struct nand_chip *chip,
+			struct device_node *dn)
+{
+	int ecc_mode, ecc_strength, ecc_step;
+
+	if (of_get_nand_bus_width(dn) == 16)
+		chip->options |= NAND_BUSWIDTH_16;
+
+	if (of_get_nand_on_flash_bbt(dn))
+		chip->bbt_options |= NAND_BBT_USE_FLASH;
+
+	ecc_mode = of_get_nand_ecc_mode(dn);
+	ecc_strength = of_get_nand_ecc_strength(dn);
+	ecc_step = of_get_nand_ecc_step_size(dn);
+
+	if ((ecc_step >= 0 && !(ecc_strength >= 0)) ||
+	    (!(ecc_step >= 0) && ecc_strength >= 0)) {
+		pr_err("must set both strength and step size in DT\n");
+		return -EINVAL;
+	}
+
+	if (ecc_mode >= 0)
+		chip->ecc.mode = ecc_mode;
+
+	if (ecc_strength >= 0)
+		chip->ecc.strength = ecc_strength;
+
+	if (ecc_step > 0)
+		chip->ecc.size = ecc_step;
+
+	return 0;
+}
+
 /**
  * nand_scan_ident - [NAND Interface] Scan for the NAND device
  * @mtd: MTD device structure
@@ -3812,6 +3846,13 @@ int nand_scan_ident(struct mtd_info *mtd, int maxchips,
 	int i, nand_maf_id, nand_dev_id;
 	struct nand_chip *chip = mtd->priv;
 	struct nand_flash_dev *type;
+	int ret;
+
+	if (chip->dn) {
+		ret = nand_dt_init(mtd, chip, chip->dn);
+		if (ret)
+			return ret;
+	}
 
 	/* Set the default functions */
 	nand_set_defaults(chip, chip->options & NAND_BUSWIDTH_16);
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 6c51876..f25e2bd 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -26,6 +26,8 @@
 
 struct mtd_info;
 struct nand_flash_dev;
+struct device_node;
+
 /* Scan and identify a NAND device */
 extern int nand_scan(struct mtd_info *mtd, int max_chips);
 /*
@@ -542,6 +544,7 @@ struct nand_buffers {
  *			flash device
  * @IO_ADDR_W:		[BOARDSPECIFIC] address to write the 8 I/O lines of the
  *			flash device.
+ * @dn:			[BOARDSPECIFIC] device node describing this instance
  * @read_byte:		[REPLACEABLE] read one byte from the chip
  * @read_word:		[REPLACEABLE] read one word from the chip
  * @write_byte:		[REPLACEABLE] write a single byte to the chip on the
@@ -644,6 +647,8 @@ struct nand_chip {
 	void __iomem *IO_ADDR_R;
 	void __iomem *IO_ADDR_W;
 
+	struct device_node *dn;
+
 	uint8_t (*read_byte)(struct mtd_info *mtd);
 	u16 (*read_word)(struct mtd_info *mtd);
 	void (*write_byte)(struct mtd_info *mtd, uint8_t byte);