Getting EQEP2 to work on the PocketBeagle

[Ric Klaren]

Hi,

I'm trying to hook up a PocketBeagle to a pololu Zumo chassis. After getting QEP0 to function I'm now struggling to get QEP2 going. Once I add the U-Boot overlay for it the PocketBeagle does not boot anymore. I'm guessing that I'm missing something in the device tree stuff for the PocketBeagle, and by now could use a nudge in the right direction :)

I verified that the hardware is ok by hooking things up to my old beaglebone white and the EQEP there reads things correctly.

I'm using bone-debian-9.2-iot-armhf-2017-10-10-4gb.img with kernel 4.4.91-ti-r133 and the latest package updates.

In my boot/uEnv.txt I have made the following changes:

  enable_uboot_overlays=1
  uboot_overlay_addr0=/lib/firmware/pb_eqep0.dtbo
  #uboot_overlay_addr1=/lib/firmware/pb_eqep2.dtbo
  disable_uboot_overlay_emmc=1
  disable_uboot_overlay_video=1
  disable_uboot_overlay_audio=1
  disable_uboot_overlay_wireless=1
  #disable_uboot_overlay_adc=1
  enable_uboot_cape_universal=1

For the pb_eqep0.dts I used the latest https://github.com/beagleboard/bb.org-overlays.git as a basis. With this overlay the eqep sysfs entries appear and the position can be read like on my BeagleBone.

Once I uncomment the line with pb_eqep2.dtbo in the uEnv.txt the boot fails. I have collected the dts files and  the u-boot output in this gist:

https://gist.github.com/rklaren/09cf8a0a031a857421ae1501ca6d59dc

I have tried:

• just enabling the EQEP's by using config-pin but then the sysfs entries do not appear (or maybe something else needs to be disabled in the device-tree to make that work).
• Merging the two dts/dtbo's but that leads to the same U-Boot output.

Any pointers would be appreciated.

Cheers,

Ric

[Robert Nelson]

Using config-pin to enable the eqep's by default is all you should
need, no extra overlay..

Which pin's are you using, and please share the output of this script:

sudo /opt/scripts/tools/version.sh


Regards,

--
Robert Nelson
https://rcn-ee.com/

[Ric Klaren]

Hi,

Thank you for the help.

I'm trying to use both QEP0 and QEP2. If I use config-pin like the following the QEP entries in the sysfs do not appear:

config-pin -a P2_34 qep
config-pin -a P1_31 qep

config-pin -a P2_24 qep
config-pin -a P2_33 qep

ls /sys/devices/platform/ocp/*.epwmss/
/sys/devices/platform/ocp/48300000.epwmss/:
48300200.pwm  driver  driver_override  modalias  of_node  power  subsystem  uevent

/sys/devices/platform/ocp/48302000.epwmss/:
48302200.pwm  driver  driver_override  modalias  of_node  power  subsystem  uevent

/sys/devices/platform/ocp/48304000.epwmss/:
48304200.pwm  driver  driver_override  modalias  of_node  power  subsystem  uevent

The output of /opt/scripts/tools/version.sh is in this gist: https://gist.github.com/rklaren/e2cf4bee8b708226843c51572a74a93d

This is with a very plain /boot/uEnv.txt. Note the tieqep kernel module is already loaded before invoking config-pin.

Aside note: In this setup /proc/cmdline will not contain bone_capemgr.uboot_capemgr_enabled=1 either. Which seems to be expected by Adafruit-BBIO which results in 'RuntimeError: Problem with the cape manager' messages (for instance when attempting to use pwm).

If I enable the overlay for QEP0 I get:

ls /sys/devices/platform/ocp/*epwmss/
/sys/devices/platform/ocp/48300000.epwmss/:
48300180.eqep  48300200.pwm  driver  driver_override  modalias  of_node  power  subsystem  uevent

/sys/devices/platform/ocp/48302000.epwmss/:
48302200.pwm  driver  driver_override  modalias  of_node  power  subsystem  uevent

/sys/devices/platform/ocp/48304000.epwmss/:
48304200.pwm  driver  driver_override  modalias  of_node  power  subsystem  uevent

And EQEP0 works. But as mentioned before I have trouble getting QEP2 configured. Will config-pin become the standard way of doing things? In stead of u-boot overlays?

Aside note: Also /prod/cmdline will now contain bone_capemgr.uboot_capemgr_enabled=1 and the Adafruit-BBIO library starts to work (for PWM and EQEP0). I suspect the adafruit library needs an update/tweak.

Any thoughts?

Cheers,

Ric

[Ric Klaren]

Hi,

Update: It seems I was not fully paying attention when running config-pin (I ran it from a script) I actually get an error when attempting to configure P2_24:

config-pin -a P2_24 qep
dash: echo: I/O error
Cannot write pinmux file: /sys/devices/platform/ocp/ocp:P2_24_pinmux/state

config-pin -q P2_24 qep
P2_24 Mode: default Direction: pin_not_exported Value: pin_not_exported

dmesg shows this error:

[   68.234357] bone-pinmux-helper ocp:P2_24_pinmux: Failed to find state qep

Cheers,

Ric

[Ric Klaren]

Hi,

Answering myself: upgrading to bone-debian-9.3-iot-armhf-2018-01-28-4gb.img, with kernel 4.9.78-ti-r94 improves the situation.

The pins can be configured with config-pin but sysfs entries for the eqep do not appear, I assume that is a bug?

The overlays I created earlier now work though, so pins are configured correctly at bootup and the sysfs entries appear.

https://gist.github.com/rklaren/09cf8a0a031a857421ae1501ca6d59dc

Cheers,

Ric

[mplan...@gmail.com]

This has been very helpful but I have a problem - the position counter only decrements in my python code. The signals from my AMT103-V capacitive encoder from CUI, Inc, look good on my oscilloscope but unplugging P2_33 doesn't change a thing (position continues to decrement) while unplugging P2_24 stops eqep2 from counting. Reversing the two external signal wires produces the same output so this is consistent with P2_24 being the only active pin.


###after bootup use config-pin:
config-pin -a p2_24 qep
config-pin -a p2_33 qep

###Code:
from Adafruit_BBIO.Encoder import RotaryEncoder, eQEP2
import time
myEncoder = RotaryEncoder(eQEP2)
while (1):
    cur_position = myEncoder.position
    print cur_position
    time.sleep(1)

###Output:
-1
-120
-239
-364
-486

### output of sudo /opt/scripts/tools/version.sh (note I also tried to enable eQEP0 as a test of the A/B signals but P1_31 in error)
git:/opt/scripts/:[e307a944e0be0610ff5296e0abe4ad31a6e70daa]
eeprom:[A335PBGL00A21736GPB20285]
model:[TI_AM335x_PocketBeagle]
dogtag:[BeagleBoard.org Debian Image 2018-03-05]
bootloader:[microSD]:[/dev/mmcblk0]:[U-Boot 2018.01-00002-ge9ff418fb8]:[location: dd MBR]
kernel:[4.9.82-ti-r102]
nodejs:[v6.13.0]
uboot_overlay_options:[enable_uboot_overlays=1]
uboot_overlay_options:[uboot_overlay_addr0=/lib/firmware/bone_eqep0-00A0.dtbo]
uboot_overlay_options:[uboot_overlay_addr2=/lib/firmware/bone_eqep2-00A0.dtbo]
uboot_overlay_options:[enable_uboot_cape_universal=1]
pkg:[bb-cape-overlays]:[4.4.20180305.0-0rcnee0~stretch+20180305]
pkg:[bb-wl18xx-firmware]:[1.20170829-0rcnee2~stretch+20180104]
pkg:[firmware-ti-connectivity]:[20170823-1rcnee0~stretch+20170830]
groups:[debian : debian adm kmem dialout cdrom floppy audio dip video plugdev users systemd-journal i2c bluetooth netdev cloud9ide gpio pwm eqep admin spi tisdk weston-launch xenomai]
cmdline:[console=ttyO0,115200n8 bone_capemgr.uboot_capemgr_enabled=1 root=/dev/mmcblk0p1 ro rootfstype=ext4 rootwait coherent_pool=1M net.ifnames=0 quiet]
dmesg | grep pinctrl-single
[    1.424230] pinctrl-single 44e10800.pinmux: 142 pins at pa f9e10800 size 568
[   19.138778] pinctrl-single 44e10800.pinmux: pin PIN104 already requested by ocp:P1_31_pinmux; cannot claim for 48300180.eqep
[   19.205338] pinctrl-single 44e10800.pinmux: pin-104 (48300180.eqep) status -22
[   19.257765] pinctrl-single 44e10800.pinmux: could not request pin 104 (PIN104) from group pinctrl_eqep0_pins  on device pinctrl-single
dmesg | grep gpio-of-helper
[    1.432715] gpio-of-helper ocp:cape-universal: ready
END

###/boot/uEnv.txt
#Docs: http://elinux.org/Beagleboard:U-boot_partitioning_layout_2.0

uname_r=4.9.82-ti-r102
#uuid=
#dtb=


###U-Boot Overlays###
###Documentation: http://elinux.org/Beagleboard:BeagleBoneBlack_Debian#U-Boot_Overlays
###Master Enable
enable_uboot_overlays=1
###
###Overide capes with eeprom
uboot_overlay_addr0=/lib/firmware/bone_eqep0-00A0.dtbo
#uboot_overlay_addr1=/lib/firmware/bone_eqep1-00A0.dtbo
uboot_overlay_addr2=/lib/firmware/bone_eqep2-00A0.dtbo
#uboot_overlay_addr3=/lib/firmware/bone_eqep2a-00A0.dtbo
###
###Additional custom capes
#uboot_overlay_addr4=/lib/firmware/<file4>.dtbo
#uboot_overlay_addr5=/lib/firmware/<file5>.dtbo
#uboot_overlay_addr6=/lib/firmware/<file6>.dtbo
#uboot_overlay_addr7=/lib/firmware/<file7>.dtbo
###
###Custom Cape
#dtb_overlay=/lib/firmware/<file8>.dtbo
###
###Disable auto loading of virtual capes (emmc/video/wireless/adc)
#disable_uboot_overlay_emmc=1
#disable_uboot_overlay_video=1
#disable_uboot_overlay_audio=1
#disable_uboot_overlay_wireless=1
#disable_uboot_overlay_adc=1
###
###PRUSS OPTIONS
###pru_rproc (4.4.x-ti kernel)
#uboot_overlay_pru=/lib/firmware/AM335X-PRU-RPROC-4-4-TI-00A0.dtbo
###pru_uio (4.4.x-ti, 4.14.x-ti & mainline/bone kernel)
#uboot_overlay_pru=/lib/firmware/AM335X-PRU-UIO-00A0.dtbo
###
###Cape Universal Enable
enable_uboot_cape_universal=1
###
###Debug: disable uboot autoload of Cape
#disable_uboot_overlay_addr0=1
#disable_uboot_overlay_addr1=1
#disable_uboot_overlay_addr2=1
#disable_uboot_overlay_addr3=1
###
###U-Boot fdt tweaks... (60000 = 384KB)
#uboot_fdt_buffer=0x60000
###U-Boot Overlays###

cmdline=coherent_pool=1M net.ifnames=0 quiet

#In the event of edid real failures, uncomment this next line:
#cmdline=coherent_pool=1M net.ifnames=0 quiet video=HDMI-A-1:1024x768@60e

##enable Generic eMMC Flasher:
##make sure, these tools are installed: dosfstools rsync
#cmdline=init=/opt/scripts/tools/eMMC/init-eMMC-flasher-v3.sh

[mplan...@gmail.com]

Ric and Robert,

THANK YOU! It was a slog getting Ric's overlays compiled (for an old guy) but both encoder channels work well and simultaneously on the PocketBeagle. Config-pin doesn't work as the pinmux files for p1_31, p2_34, p2_24, and p2_33 aren't there -- I suspect there is something in the overlays which also must be for the case when using the provided bone_eqep0-00A0.dtbo and bone-eqep2-00A0.dtbo files. So, I've still got a lot to learn but this should allow me to point a 175 year old telescope at any object in the sky -- at least that is the plan.

Thanks again!

Mark

#################### Original problem posting

On Saturday, April 14, 2018 at 6:17:08 PM UTC-4, mplan...@gmail.com wrote:

This has been very helpful but I have a problem - the position counter only decrements in my python code. The signals from my AMT103-V capacitive encoder from CUI, Inc, look good on my oscilloscope but unplugging P2_33 doesn't change a thing (position continues to decrement) while unplugging P2_24 stops eqep2 from counting. Reversing the two external signal wires produces the same output so this is consistent with P2_24 being the only active pin.

###Code:
from Adafruit_BBIO.Encoder import RotaryEncoder, eQEP0

from Adafruit_BBIO.Encoder import RotaryEncoder, eQEP2
import time

myEncoder0 = RotaryEncoder(eQEP0)
myEncoder2 = RotaryEncoder(eQEP2)
while (1):
    cur_position0 = myEncoder0.position
    cur_position2 = myEncoder2.position
    print cur_position0, cur_position2
    time.sleep(1)


################ output of sudo /opt/scripts/tools/version.sh
git:/opt/scripts/:[a890d66119f9b84505b4c162ce90ffce977475b5]
eeprom:[A335PBGL00A21736GPB20285]
model:[TI_AM335x_PocketBeagle]
dogtag:[BeagleBoard.org Debian Image 2018-04-07]
bootloader:[microSD]:[/dev/mmcblk0]:[U-Boot 2018.03-00002-gac9cce7c6a]:[location: dd MBR]
kernel:[4.4.113-ti-r149]
nodejs:[v4.9.1]
uboot_overlay_options:[enable_uboot_overlays=1]
uboot_overlay_options:[uboot_overlay_addr0=/lib/firmware/pb_eqep0.dtbo]
uboot_overlay_options:[uboot_overlay_addr1=/lib/firmware/pb_eqep2.dtbo]
uboot_overlay_options:[disable_uboot_overlay_emmc=1]
uboot_overlay_options:[disable_uboot_overlay_video=1]
uboot_overlay_options:[disable_uboot_overlay_audio=1]
uboot_overlay_options:[disable_uboot_overlay_wireless=1]
uboot_overlay_options:[disable_uboot_overlay_adc=1]
uboot_overlay_options:[uboot_overlay_pru=/lib/firmware/AM335X-PRU-RPROC-4-4-TI-00A0.dtbo]
uboot_overlay_options:[enable_uboot_cape_universal=1]
pkg:[bb-cape-overlays]:[4.4.20180405.0-0rcnee0~jessie+20180405]
pkg:[bb-wl18xx-firmware]:[1.20180328-0rcnee2~jessie+20180328]
pkg:[firmware-ti-connectivity]:[20170823-1rcnee1~jessie+20180328]
groups:[debian : debian adm kmem dialout cdrom floppy audio dip video plugdev users systemd-journal netdev i2c bluetooth cloud9ide gpio pwm eqep admin spi tisdk weston-launch xenomai]

cmdline:[console=ttyO0,115200n8 bone_capemgr.uboot_capemgr_enabled=1 root=/dev/mmcblk0p1 ro rootfstype=ext4 rootwait coherent_pool=1M net.ifnames=0 quiet]
dmesg | grep pinctrl-single

[    1.218276] pinctrl-single 44e10800.pinmux: 142 pins at pa f9e10800 size 568
dmesg | grep gpio-of-helper

##############/boot/uEnv.txt
#Docs: http://elinux.org/Beagleboard:U-boot_partitioning_layout_2.0

uname_r=4.4.113-ti-r149

#uuid=
#dtb=


###U-Boot Overlays###
###Documentation: http://elinux.org/Beagleboard:BeagleBoneBlack_Debian#U-Boot_Overlays
###Master Enable
enable_uboot_overlays=1
###
###Overide capes with eeprom

uboot_overlay_addr0=/lib/firmware/pb_eqep0.dtbo
uboot_overlay_addr1=/lib/firmware/pb_eqep2.dtbo
#uboot_overlay_addr2=/lib/firmware/<file2>.dtbo
#uboot_overlay_addr3=/lib/firmware/<file3>.dtbo

###
###Additional custom capes
#uboot_overlay_addr4=/lib/firmware/<file4>.dtbo
#uboot_overlay_addr5=/lib/firmware/<file5>.dtbo
#uboot_overlay_addr6=/lib/firmware/<file6>.dtbo
#uboot_overlay_addr7=/lib/firmware/<file7>.dtbo
###
###Custom Cape
#dtb_overlay=/lib/firmware/<file8>.dtbo
###
###Disable auto loading of virtual capes (emmc/video/wireless/adc)

disable_uboot_overlay_emmc=1
disable_uboot_overlay_video=1
disable_uboot_overlay_audio=1
disable_uboot_overlay_wireless=1

disable_uboot_overlay_adc=1
###
###PRUSS OPTIONS
###pru_rproc (4.4.x-ti kernel)

uboot_overlay_pru=/lib/firmware/AM335X-PRU-RPROC-4-4-TI-00A0.dtbo
###pru_rproc (4.9.x-ti kernel)
#uboot_overlay_pru=/lib/firmware/AM335X-PRU-RPROC-4-9-TI-00A0.dtbo
###pru_rproc (4.14.x-ti kernel)
#uboot_overlay_pru=/lib/firmware/AM335X-PRU-RPROC-4-14-TI-00A0.dtbo
###pru_uio (4.4.x-ti, 4.9.x-ti, 4.14.x-ti & mainline/bone kernel)