I use Arria 10 Soc kit.
First operation
root@arria10:~# i2cdetect -y -r 0
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: – -- – -- – -- – -- – -- – -- –
10: – -- – -- 14 – 16 – -- – -- – -- – -- –
20: – -- – -- – -- – -- UU – -- – -- – -- –
30: – -- – -- – -- – -- – -- – -- – -- – --
40: – -- – -- – -- – -- – -- – -- UU – -- –
50: – UU – -- – -- – -- – -- – -- – -- – --
60: – -- – -- – -- – -- UU – -- – -- – -- –
70: 70 71 – 73 – -- – --
root@arria10:~#
This is OK.
But second operation
root@arria10:~# i2cdetect -y -r 0
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: – -- – -- – -- – -- – -- – -- –
10: – -- – -- 14 – i2c_designware ffc02300.i2c: controller timed out
– i2c_designware ffc02300.i2c: controller timed out
– i2c_designware ffc02300.i2c: controller timed out
– i2c_designware ffc02300.i2c: controller timed out
– i2c_designware ffc02300.i2c: controller timed out
– i2c_designware ffc02300.i2c: controller timed out
Why?