mtd: nand: pxa3xx: Use ECC strength and step size devicetree binding

This commit adds support for the user to specify the ECC strength
and step size through the devicetree. We keep the previous behavior,
when there is no DT parameter provided.
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

drivers/mtd/nand/pxa3xx_nand.c

@@ -1519,8 +1519,13 @@ static int pxa3xx_nand_scan(struct mtd_info *mtd)
 		}
 	}
 
-	ecc_strength = chip->ecc_strength_ds;
-	ecc_step = chip->ecc_step_ds;
+	if (pdata->ecc_strength && pdata->ecc_step_size) {
+		ecc_strength = pdata->ecc_strength;
+		ecc_step = pdata->ecc_step_size;
+	} else {
+		ecc_strength = chip->ecc_strength_ds;
+		ecc_step = chip->ecc_step_ds;
+	}
 
 	/* Set default ECC strength requirements on non-ONFI devices */
 	if (ecc_strength < 1 && ecc_step < 1) {
@@ -1729,6 +1734,14 @@ static int pxa3xx_nand_probe_dt(struct platform_device *pdev)
 	of_property_read_u32(np, "num-cs", &pdata->num_cs);
 	pdata->flash_bbt = of_get_nand_on_flash_bbt(np);
 
+	pdata->ecc_strength = of_get_nand_ecc_strength(np);
+	if (pdata->ecc_strength < 0)
+		pdata->ecc_strength = 0;
+
+	pdata->ecc_step_size = of_get_nand_ecc_step_size(np);
+	if (pdata->ecc_step_size < 0)
+		pdata->ecc_step_size = 0;
+
 	pdev->dev.platform_data = pdata;
 
 	return 0;

include/linux/platform_data/mtd-nand-pxa3xx.h

@@ -58,6 +58,9 @@ struct pxa3xx_nand_platform_data {
 	/* use an flash-based bad block table */
 	bool	flash_bbt;
 
+	/* requested ECC strength and ECC step size */
+	int ecc_strength, ecc_step_size;
+
 	const struct mtd_partition		*parts[NUM_CHIP_SELECT];
 	unsigned int				nr_parts[NUM_CHIP_SELECT];