[PATCH v2] mtd: rawnand: fsl_elbc: Fix detection when nand_scan_ident() has not selected ecc.mode

["Pali Rohár" <pali@kernel.org>]

ecc.mode is set to 0 (aliased to NAND_ECC_NONE) either when function
nand_scan_ident() has not selected ecc.mode or when it selected it to none
ecc mode.

Distinguish between these two states by checking of node property
"nand-ecc-mode" which function nand_scan_ident() uses for filling ecc.mode.

This change fixes usage of none ecc mode if it is specified in DTS file.

Fixes: c9ea9019c5aa ("mtd: rawnand: fsl_elbc: Use ECC configuration from device tree")
Signed-off-by: Pali Rohár <pali@kernel.org>

---
Changes in v2:
* Add guard for ofnode_read_string()
---
 drivers/mtd/nand/raw/fsl_elbc_nand.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/raw/fsl_elbc_nand.c b/drivers/mtd/nand/raw/fsl_elbc_nand.c
index e734139b5ea5..5d50302eefbe 100644
--- a/drivers/mtd/nand/raw/fsl_elbc_nand.c
+++ b/drivers/mtd/nand/raw/fsl_elbc_nand.c
@@ -744,7 +744,11 @@ static int fsl_elbc_chip_init(int devnum, u8 *addr, ofnode flash_node)
 		return ret;
 
 	/* If nand_scan_ident() has not selected ecc.mode, do it now */
-	if (nand->ecc.mode == NAND_ECC_NONE) {
+	if (nand->ecc.mode == 0
+#if CONFIG_IS_ENABLED(OF_CONTROL)
+	    && !ofnode_read_string(nand->flash_node, "nand-ecc-mode")
+#endif
+	   ) {
 		/* If CS Base Register selects full hardware ECC then use it */
 		if ((br & BR_DECC) == BR_DECC_CHK_GEN) {
 			nand->ecc.mode = NAND_ECC_HW;
-- 
2.20.1