mtd: cfi_util: add support for switching SST 39VF640xB chips into QRY mode

Signed-off-by: Guillaume LECERF <glecerf@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/drivers/mtd/chips/cfi_util.c b/drivers/mtd/chips/cfi_util.c
index e503b2c..360525c 100644
--- a/drivers/mtd/chips/cfi_util.c
+++ b/drivers/mtd/chips/cfi_util.c
@@ -77,6 +77,13 @@
 	cfi_send_gen_cmd(0x98, 0x5555, base, map, cfi, cfi->device_type, NULL);
 	if (cfi_qry_present(map, base, cfi))
 		return 1;
+	/* SST 39VF640xB */
+	cfi_send_gen_cmd(0xF0, 0, base, map, cfi, cfi->device_type, NULL);
+	cfi_send_gen_cmd(0xAA, 0x555, base, map, cfi, cfi->device_type, NULL);
+	cfi_send_gen_cmd(0x55, 0x2AA, base, map, cfi, cfi->device_type, NULL);
+	cfi_send_gen_cmd(0x98, 0x555, base, map, cfi, cfi->device_type, NULL);
+	if (cfi_qry_present(map, base, cfi))
+		return 1;
 	/* QRY not found */
 	return 0;
 }