eeprom: at24: fix reading from 24MAC402/24MAC602

commit 644a1f19c6c8393d0c4168a5adf79056da6822eb upstream.

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.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 051b14766ef964984da6ff487db81f5a782cb3ba..f7de115b2388d879bd2bf5552d2d6c0160716bb4 100644 (file)
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -365,7 +365,8 @@ 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;