From 644a1f19c6c8393d0c4168a5adf79056da6822eb Mon Sep 17 00:00:00 2001
From: Heiner Kallweit <hkallweit1@gmail.com>
Date: Mon, 27 Nov 2017 20:46:22 +0100
Subject: [PATCH] eeprom: at24: fix reading from 24MAC402/24MAC602

References: bsc#1052766
Patch-mainline: v4.15-rc2
Git-commit: 644a1f19c6c8393d0c4168a5adf79056da6822eb

Chip datasheet mentions that word addresses other than the actual
start position of the MAC delivers undefined results. So fix this.
Current implementation doesn't work due to this wrong offset.

Cc: stable@vger.kernel.org
Fixes: 0b813658c115 ("eeprom: at24: add support for at24mac series")
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 drivers/misc/eeprom/at24.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 783244b485cc..8ca6772b3baf 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -425,7 +425,8 @@ static ssize_t at24_eeprom_read_mac(struct at24_data *at24, char *buf,
 	memset(msg, 0, sizeof(msg));
 	msg[0].addr = client->addr;
 	msg[0].buf = addrbuf;
-	addrbuf[0] = 0x90 + offset;
+	/* EUI-48 starts from 0x9a, EUI-64 from 0x98 */
+	addrbuf[0] = 0xa0 - at24->chip.byte_len + offset;
 	msg[0].len = 1;
 	msg[1].addr = client->addr;
 	msg[1].flags = I2C_M_RD;
-- 
2.13.6