[PATCH 1/2] mtd: spinand: Add support for 5-byte IDs

Ezra Buehler ezra at easyb.ch
Thu Jan 25 12:01:07 PST 2024


From: Ezra Buehler <ezra.buehler at husqvarnagroup.com>

E.g. ESMT chips will return an identification code with a length of 5
bytes. In order to prevent ambiguity, flash chips would actually need to
return IDs that are up to 17 or more bytes long due to JEDEC's
continuation scheme. I understand that if a manufacturer ID is located
in bank N of JEDEC's database (there are currently 16 banks), N - 1
continuation codes (7Fh) need to be added to the identification code
(comprising of manufacturer ID and device ID). However, most flash chip
manufacturers don't seem to implement this (correctly).

Signed-off-by: Ezra Buehler <ezra.buehler at husqvarnagroup.com>
---
 include/linux/mtd/spinand.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/mtd/spinand.h b/include/linux/mtd/spinand.h
index badb4c1ac079..5c19ead60499 100644
--- a/include/linux/mtd/spinand.h
+++ b/include/linux/mtd/spinand.h
@@ -169,7 +169,7 @@
 struct spinand_op;
 struct spinand_device;
 
-#define SPINAND_MAX_ID_LEN	4
+#define SPINAND_MAX_ID_LEN	5
 /*
  * For erase, write and read operation, we got the following timings :
  * tBERS (erase) 1ms to 4ms
-- 
2.43.0




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