On 6/22/22 15:07, Wolfram Sang wrote:
From the original code, the first mechanism to a recovery is to acquire a
GPIO for the SCL line and send the 9 SCL pulses, after that, it does a reset
of the I2C module. For the SOCFPGA part, there is no GPIO line for the SCL,
thus the I2C module cannot even get a reset. This code allows the function
to reset the I2C module for SOCFPGA, which is the 2nd part of the recovery
The second part is totally useless if the client device is holding SDA
low. Which is exactly the situation that recovery tries to fix. As I
said, if you can't control SCL, you don't have recovery.
This is recovery of the master and not the slave. We have a customer that is the using I2C with the signals routed through the FPGA, and thus are not GPIO. During a timeout, with this code, the driver is able to recover the master.