The 1-wire gpio master is not able to successfully communicate with slaves on lower cpu frequencies.
Symptoms
Probing the bus is unreliable.
Slaves are only found on first bus scan – if at all.
Slave data are usually garbage or nonexistent.
w1_slave_driver _w1_slave_device_address_: 18S20 doesn't respond to CONVERT_TEMP. error message in kernel log when reading DS18x20 temperature sensors.
Testing
On my Cubieboard 2 with Cubian default settings, the lowest frequency where the majority (~99%+) of slave device reads are successful are at 600MHz.
Solution
Increase minimum cpu frequency in /etc/init.d/cubian-ondemandcpufreq.
The 1-wire gpio master is not able to successfully communicate with slaves on lower cpu frequencies.
Symptoms
w1_slave_driver _w1_slave_device_address_: 18S20 doesn't respond to CONVERT_TEMP.error message in kernel log when reading DS18x20 temperature sensors.Testing
On my Cubieboard 2 with Cubian default settings, the lowest frequency where the majority (~99%+) of slave device reads are successful are at 600MHz.
Solution
/etc/init.d/cubian-ondemandcpufreq.