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@gmail.com>

1 files changed, 41 insertions, 0 deletions

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 0afe76315c38..c4619e3ac4ab 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);