Thanks, Jason. Your magic i2cset commands worked and now I can use analog input 7.
Ken On Tue, Dec 5, 2017 at 11:39 AM, Jason Kridner <[email protected] > wrote: > > > On Tue, Dec 5, 2017 at 2:21 PM Ken Shirriff <[email protected]> > wrote: > >> Thanks Robert and Jason. For pin 5 and 6, your solution works: >> >> Pin 5: >> $ config-pin P2_35 gpio >> $ echo in > /sys/class/gpio/gpio86/direction >> $ cat /sys/bus/iio/devices/iio:device0/in_voltage5_raw >> 1571 >> >> Pin 6: >> $ config-pin P1_2 gpio >> $ echo in > /sys/class/gpio/gpio87/direction >> $ cat /sys/bus/iio/devices/iio:device0/in_voltage6_raw >> 1571 >> >> Because of the voltage divider, the values are half of the "normal" >> values. >> >> But I still can't get pin 7 to work: >> $ while [ 1 ]; do cat /sys/bus/iio/devices/iio:device0/in_voltage7_raw; >> done >> This gives me a sequence of values starting around 1600 dropping by about >> 10 every second, unrelated to my input, slowing down to about 658. Sort of >> like the voltage if you were discharging a capacitor. >> >> So analog input 7 seems to be measuring something, but I don't know what. >> Maybe some PMIC thing? >> > > I'm not sure how to check the status of the analog mux. Someone posted a > driver patch on the TI e2e forum to change the status. Maybe we should > carry that patch or help submit to mainline? > > https://e2e.ti.com/support/arm/sitara_arm/f/791/t/256567 > > Out of curiosity, can you try: > > sudo i2cset -y -f 0 0x24 9 5 > sudo i2cget -y -f 0 0x24 9 > sudo cat /sys/bus/iio/devices/iio:device0/in_voltage7_raw > > I pulled the magic numbers from the patch and the files it references. > > >> >> (I'm using Linux beaglebone 4.4.91-ti-r133 #1 SMP Tue Oct 10 05:18:08 UTC >> 2017 armv7l GNU/Linux) >> >> Ken >> >> >> On Tuesday, December 5, 2017 at 10:03:06 AM UTC-8, Jason Kridner wrote: >>> >>> >>> >>> On Tue, Dec 5, 2017 at 10:00 AM Robert Nelson <[email protected]> >>> wrote: >>> >> On Sun, Dec 3, 2017 at 1:07 PM, Ken Shirriff <[email protected]> wrote: >>>> > I can read analog inputs 0-4 from >>>> > /sys/bus/iio/devices/iio:device0/in_voltageN_raw but I can't get >>>> analog >>>> > inputs 5-7 to work. Inputs 5 and 6 don't have analog as a choice in >>>> > config-pin: >>>> > >>>> > $ config-pin -l P1_2 >>>> > default gpio gpio_pu gpio_pd pruout pruin >>>> > >>>> > Analog input 7 (P2_36) doesn't have any other function, but it >>>> ignores any >>>> > analog input voltage. >>>> > >>>> > Is there a trick to using inputs 5-7 or is support under development? >>>> >>>> Since 5-7 ADC's are shared with a normal pin, you need to stick the >>>> gpio in gpio mode with config-pin.. (no pull-up, no pull-down) then it >>>> might work.. >>>> >>>> Haven't personally tried this yet.. >>>> >>> >>> I tested all 3 inputs as part of the board bring-up/validation process, >>> but I was using a different device tree. I'm trying to get back to it with >>> what Robert ships in the latest images, hopefully in the next day or so, >>> but I'd like to provide some notes that might be of some use: >>> >>> For 5 and 6, yeah, Robert's right on making sure the GPIO is set to >>> input mode (should be default?) and that there is no pull-up/pull-down >>> enabled on the pin. Do note, however, that there is a 10k pull-down due to >>> the resistor divider on the input. All voltages on the ADC will be half of >>> what they are on the headerpin. >>> >>> For 7, there is an analog mux, but it should default to the status of >>> the pin. There are some voltages internal to the PMIC that could be read, >>> put the header pin status should be the default. >>> >>> >> >>>> Regards, >>>> >>>> -- >>>> Robert Nelson >>>> https://rcn-ee.com/ >>>> >>>> -- >>>> For more options, visit http://beagleboard.org/discuss >>>> --- >>>> You received this message because you are subscribed to the Google >>>> Groups "BeagleBoard" group. >>>> >>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to [email protected]. >>> >>> >>>> To view this discussion on the web visit https://groups.google.com/d/ >>>> msgid/beagleboard/CAOCHtYjKoCF5-ZULWhZUdefCMZo84H1g_ >>>> 1tmPQjaUFOO4v8Xpg%40mail.gmail.com. >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>> -- >>> https://beagleboard.org/about >>> >> -- >> For more options, visit http://beagleboard.org/discuss >> --- >> You received this message because you are subscribed to the Google Groups >> "BeagleBoard" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To view this discussion on the web visit https://groups.google.com/d/ >> msgid/beagleboard/8a366e68-aa6f-4847-9a14-d2abb782d351%40googlegroups.com >> <https://groups.google.com/d/msgid/beagleboard/8a366e68-aa6f-4847-9a14-d2abb782d351%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> For more options, visit https://groups.google.com/d/optout. >> > -- > https://beagleboard.org/about > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to a topic in the > Google Groups "BeagleBoard" group. > To unsubscribe from this topic, visit https://groups.google.com/d/ > topic/beagleboard/ryYJflyy2N8/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > [email protected]. > To view this discussion on the web visit https://groups.google.com/d/ > msgid/beagleboard/CA%2BT6QPkYrrtzEeVM7dXeTnWh3Qp2uT > fvZoVDWnfa%2BHi2mVXhdg%40mail.gmail.com > <https://groups.google.com/d/msgid/beagleboard/CA%2BT6QPkYrrtzEeVM7dXeTnWh3Qp2uTfvZoVDWnfa%2BHi2mVXhdg%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > > For more options, visit https://groups.google.com/d/optout. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. 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