On Fri, Feb 05, 2016 at 03:17:18PM +0200, Daniel Baluta wrote: > The driver has sysfs readings with runtime PM support for power saving. > It also offers buffer support that can be used together with IIO software > triggers. > Daniel, So I noticed something yesterday while testing new boards. The channels are occassionally swapping when accessing data from multiple channels. I wrote a simple bash script to demonstrate. root@dragonboard-410c:~# cat test-analog.sh while [ 1 ]; do voltage0=`cat /sys/bus/iio/devices/iio\:device0/in_voltage0_raw` voltage1=`cat /sys/bus/iio/devices/iio\:device0/in_voltage1_raw` voltage2=`cat /sys/bus/iio/devices/iio\:device0/in_voltage2_raw` voltage3=`cat /sys/bus/iio/devices/iio\:device0/in_voltage3_raw` echo ain0 = $voltage0 ain1 = $voltage1 ain2 = $voltage2 ain3 = $voltage3 done root@dragonboard-410c:~# ./test-analog.sh ain0 = 266 ain1 = 291 ain2 = 268 ain3 = 291 ain0 = 287 ain1 = 294 ain2 = 289 ain3 = 292 ain0 = 284 ain1 = 294 ain2 = 286 ain3 = 0 ain0 = 285 ain1 = 288 ain2 = 287 ain3 = 0 ain0 = 287 ain1 = 286 ain2 = 287 ain3 = 0 ain0 = 285 ain1 = 287 ain2 = 293 ain3 = 0 ain0 = 0 ain1 = 289 ain2 = 293 ain3 = 0 ain0 = 0 ain1 = 289 ain2 = 290 ain3 = 291 ain0 = 287 ain1 = 289 ain2 = 289 ain3 = 0 ain0 = 0 ain1 = 285 ain2 = 288 ain3 = 0 ain0 = 285 ain1 = 286 ain2 = 288 ain3 = 0 ain0 = 286 ain1 = 288 ain2 = 285 ain3 = 0 ain0 = 287 ain1 = 293 ain2 = 289 ain3 = 292 ain0 = 288 ain1 = 292 ain2 = 287 ain3 = 293 ain0 = 286 ain1 = 287 ain2 = 289 ain3 = 0 ain0 = 283 ain1 = 289 ain2 = 289 ain3 = 0 ain0 = 0 ain1 = 287 ain2 = 287 ain3 = 0 ain0 = 0 ain1 = 286 ain2 = 288 ain3 = 0 ain0 = 286 ain1 = 288 ain2 = 289 ain3 = 0 ain0 = 287 ain1 = 286 ain2 = 290 ain3 = 0 ain0 = 289 ain1 = 291 ain2 = 287 ain3 = 0 ain0 = 284 ain1 = 286 ain2 = 292 ain3 = 0 ain0 = 286 ain1 = 291 ain2 = 289 ain3 = 292 ain0 = 284 ain1 = 292 ain2 = 291 ain3 = 291 ain0 = 285 ain1 = 287 ain2 = 287 ain3 = 0 ain0 = 0 ain1 = 289 ain2 = 291 ain3 = 0 ain0 = 0 ain1 = 288 ain2 = 291 ain3 = 0 ain0 = 0 ain1 = 286 ain2 = 288 ain3 = 0 ain0 = 286 ain1 = 287 ain2 = 290 ain3 = 0 ain0 = 286 ain1 = 286 ain2 = 288 ain3 = 0 ain0 = 286 ain1 = 286 ain2 = 287 ain3 = 0 ain0 = 285 ain1 = 289 ain2 = 288 ain3 = 288 ain0 = 289 ain1 = 292 ain2 = 289 ain3 = 293 ain0 = 287 ain1 = 292 ain2 = 290 ain3 = 0 ain0 = 286 ain1 = 286 ain2 = 291 ain3 = 0 ain0 = 0 ain1 = 287 ain2 = 290 ain3 = 0 ain0 = 0 ain1 = 286 ain2 = 289 ain3 = 0 ain0 = 284 ain1 = 285 ain2 = 292 ain3 = 0 ain0 = 285 ain1 = 289 ain2 = 289 ain3 = 0 ain0 = 287 ain1 = 287 ain2 = 287 ain3 = 0 ain0 = 287 ain1 = 291 ain2 = 287 ain3 = 291 ain0 = 288 ain1 = 291 ain2 = 290 ain3 = 293 ain0 = 285 ain1 = 290 ain2 = 287 ain3 = 292 ain0 = 285 ain1 = 289 ain2 = 289 ain3 = 292 ain0 = 286 ain1 = 289 ain2 = 288 ain3 = 0 ain0 = 0 ain1 = 286 ain2 = 291 ain3 = 0 ain0 = 0 ain1 = 287 ain2 = 291 ain3 = 0 ain0 = 287 ain1 = 286 ain2 = 291 ain3 = 0 ain0 = 288 ain1 = 286 ain2 = 289 ain3 = 0 ain0 = 284 ain1 = 289 ain2 = 288 ain3 = 0 ain0 = 287 ain1 = 290 ain2 = 287 ain3 = 292 ain0 = 285 ain1 = 292 ain2 = 289 ain3 = 292 ain0 = 289 ain1 = 292 ain2 = 290 ain3 = 0 . . The in_voltage3_raw channel is connected to GND the rest are left floating. This does not happen if only one channels is accessed at a time. I have not yet found the solution. Please left me know if this can be duplicated on your end. Regards, Michael -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
