On 2021-09-22 13:37, Fabio Estevam wrote: > Hi Peter, > > On Wed, Sep 22, 2021 at 4:27 AM Peter Rosin <peda@xxxxxxxxxx> wrote: > >> Basically, the whole point is that you simply don't. The iio-mux exposes >> the channels as 8 new ADCs, and whenever you read a value from one of >> them, the iio-mux operates the gpios for you, giving you the impression >> that you have 8 independet ADCs. They are of course not independent, but... > > Thanks for the clarification. It was helpful. > >> That's exposed to user-space as: >> >> $ ls "/sys/bus/iio/devices/iio:device3" >> in_altvoltage2_compare_interval in_altvoltage5_scale >> in_altvoltage2_invert in_altvoltage6_compare_interval >> in_altvoltage2_raw in_altvoltage6_invert >> in_altvoltage2_scale in_altvoltage6_raw >> in_altvoltage3_compare_interval in_altvoltage6_scale >> in_altvoltage3_invert in_altvoltage7_compare_interval >> in_altvoltage3_raw in_altvoltage7_invert >> in_altvoltage3_scale in_altvoltage7_raw >> in_altvoltage4_compare_interval in_altvoltage7_scale >> in_altvoltage4_invert name >> in_altvoltage4_raw of_node >> in_altvoltage4_scale power >> in_altvoltage5_compare_interval subsystem >> in_altvoltage5_invert uevent >> in_altvoltage5_raw >> $ cat "/sys/bus/iio/devices/iio:device3/name" >> envelope-detector-mux > > Ah, so that's my issue then. I don't see a new device inside > /sys/bus/iio/devices/. > > I only see the original stmpe ADC: > > ls "/sys/bus/iio/devices/iio:device0" > dev in_voltage5_raw in_voltage_scale power > in_temp8_input in_voltage6_raw name subsystem > in_voltage4_raw in_voltage7_raw of_node uevent > > Maybe my dts is not correct to make the mux appear under > /sys/bus/iio/devices/iio:device1. > > Here is my dts that shows more context with the STMPE811 ADC: > https://pastebin.com/raw/7Nn2aAtN > > stmpe811 is an mfd device that can be used as a touchscreen and as a normal adc. > > I only use the adc functionality. > > Any suggestions are welcome. Don't you get any output from the iio-mux driver during probe? I'd expect a "failed to get parent channel" or something like that? I don't know, but looking around a bit makes me think you should investigate /arch/arm/boot/dts/am5729-beagleboneai.dts and/or /arch/arm/boot/dts/exynos4412-p4note.dtsi. I think you need to move the adc: label in the dts to the stmpe_adc child node, or something like that? Cheers, Peter
