eeprom: at24: correctly set the size for at24mac402

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. Cc: [email protected] Fixes: 0b81365 ("eeprom: at24: add support for at24mac series") Signed-off-by: Bartosz Golaszewski <[email protected]> Reviewed-by: Andy Shevchenko <[email protected]>
agners · Nov 29, 2017 · 5478e47 · 5478e47
1 parent 4fbd8d1
commit 5478e47
Showing 1 changed file with 10 additions and 0 deletions.
diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
@@ -730,6 +730,16 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 		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)