Am 27.11.2017 um 13:28 schrieb Bartosz Golaszewski: > 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 creating the magic value manually with the correct size. > > 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. > > This fix will cause a warning message to be emitted by probe() for > at24mac402 chips but theys should be initialized correctly anyway. > > Cc: [email protected] > Fixes: 0b813658c115 ("eeprom: at24: add support for at24mac series") > Signed-off-by: Bartosz Golaszewski <[email protected]> > --- > drivers/misc/eeprom/at24.c | 13 +++++++++++-- > 1 file changed, 11 insertions(+), 2 deletions(-) > > diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c > index e0b4b36ef010..72adf34627f5 100644 > --- a/drivers/misc/eeprom/at24.c > +++ b/drivers/misc/eeprom/at24.c > @@ -141,8 +141,17 @@ static const struct i2c_device_id at24_ids[] = { > { "24c02", AT24_DEVICE_MAGIC(2048 / 8, 0) }, > { "24cs02", AT24_DEVICE_MAGIC(16, > AT24_FLAG_SERIAL | AT24_FLAG_READONLY) }, > - { "24mac402", AT24_DEVICE_MAGIC(48 / 8, > - AT24_FLAG_MAC | AT24_FLAG_READONLY) }, > + /* > + * 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. We > + * might want to eventually remove it altogether or maybe even convert > + * the magic values to real structs. > + * > + * For now just create the magic value manually with the right size. > + */ > + { "24mac402", ((1 << AT24_SIZE_FLAGS | > + (AT24_FLAG_MAC | AT24_FLAG_READONLY)) > + << AT24_SIZE_BYTELEN | (48 / 8)) }, > { "24mac602", AT24_DEVICE_MAGIC(64 / 8, > AT24_FLAG_MAC | AT24_FLAG_READONLY) }, > /* spd is a 24c02 in memory DIMMs */ > I'm afraid this won't work. byte_len = BIT(least 5 bits of magic value) Means byte_len for 24mac402 would be BIT(6) = 64 with your patch.
What we could do, although it seems to be quite ugly: round up the ilog2 value. Instead of ilog2(_len) we could use ilog2((_len) * 2 - 1) Rgds, Heiner
