On 3/7/21 8:37 PM, Chris Packham wrote: [ ... ] >> That's from -ENXIO which is used in only one place in i2c-mpc.c. I'll >> enable some debug and see what we get. > > For the errant readings there was nothing abnormal reported by the driver. > > For the "No such device or address" I saw "mpc-i2c ffe119000.i2c: No > RXAK" which matches up with the -ENXIO return. > Id suggest to check the time until not busy and stop in mpc_xfer(). Those hot loops are unusual, and may well mess up the code especially if preempt is enabled. Also, are you using interrupts or polling in your system ? The interrupt handler looks a bit odd, with "Read again to allow register to stabilise". Do you have fsl,timeout set in the devicetree properties and, if so, have you played with it ? Other than that, the only other real idea I have would be to monitor the i2c bus. Guenter
