4.14-stable review patch. If anyone has any objections, please let me know.
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From: Bartosz Golaszewski brgl@bgdev.pl
commit 5478e478eee3b096b8d998d4ed445da30da2dfbc upstream.
There's an ilog2() expansion in AT24_DEVICE_MAGIC() which rounds down the actual size of EUI-48 byte array in at24mac402 eeproms to 4 from 6, making it impossible to read it all.
Fix it by manually adjusting the value in probe().
This patch contains a temporary fix that is suitable for stable branches. Eventually we'll probably remove the call to ilog2() while converting the magic values to actual structs.
Fixes: 0b813658c115 ("eeprom: at24: add support for at24mac series") Signed-off-by: Bartosz Golaszewski brgl@bgdev.pl Reviewed-by: Andy Shevchenko andy.shevchenko@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/misc/eeprom/at24.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
--- a/drivers/misc/eeprom/at24.c +++ b/drivers/misc/eeprom/at24.c @@ -632,6 +632,16 @@ static int at24_probe(struct i2c_client dev_warn(&client->dev, "page_size looks suspicious (no power of 2)!\n");
+ /* + * REVISIT: the size of the EUI-48 byte array is 6 in at24mac402, while + * the call to ilog2() in AT24_DEVICE_MAGIC() rounds it down to 4. + * + * Eventually we'll get rid of the magic values altoghether in favor of + * real structs, but for now just manually set the right size. + */ + if (chip.flags & AT24_FLAG_MAC && chip.byte_len == 4) + chip.byte_len = 6; + /* Use I2C operations unless we're stuck with SMBus extensions. */ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { if (chip.flags & AT24_FLAG_ADDR16)