Alright, thanks! I'll try the package installation on Raspbian and report back if I have any issues.

Hi Tomas, did you guys released the new UniPian image with the driver fix? If yes, I would like to test it with the OpenPLC driver.

Thanks!

I've tried the steps on a blank new Raspbian image and encountered the same error while trying to install neuron-kernel:

root@raspberrypi:/home/pi# apt-get install neuron-kernel
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 neuron-kernel : Depends: raspberrypi-kernel (= 1.20180919-1) but 1.20180924-1 is to be installed
E: Unable to correct problems, you have held broken packages.```

Hi Tomas,

Thank you for the replies. As you said, the procedure actually failed on my UniPian image with an error saying that the neuron-kernel depends on raspberrypi-kernel of a more recent version. In any case, I will try the steps on a clean Raspbian image and check how it behaves.

In the mean time, are you guys planning to keep that UniPian image up to date? I'm asking this because I instructed OpenPLC users to download that image to install OpenPLC on their Neurons. If that image won't be getting updated regularly, I rather change the installation instructions to be based on a regular Raspbian image.

Thanks!

And here is my fwspi report:

pi@M503-sn22:/opt/neuron-bin $ sudo ./fwspi -i 1
Boardset:    15 E-4Ai4Ao_U-6Di5Ro              (v1.0)
Baseboard:   11 E-4Ai4Ao                       (v1.0)
Firmware: v5.18

Continuing... here is dmesg after the crash

After

[    0.000000] Booting Linux on physical CPU 0x0
[    0.000000] Linux version 4.14.34-v7+ (dc4@dc4-XPS13-9333) (gcc version 4.9.3 (crosstool-NG crosstool-ng-1.22.0-88-g8460611)) #1110 SMP Mon Apr 16 15:18:51 BST 2018
[    0.000000] CPU: ARMv7 Processor [410fd034] revision 4 (ARMv7), cr=10c5383d
[    0.000000] CPU: div instructions available: patching division code
[    0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
[    0.000000] OF: fdt: Machine model: Raspberry Pi 3 Model B Rev 1.2
[    0.000000] Memory policy: Data cache writealloc
[    0.000000] cma: Reserved 8 MiB at 0x3ac00000
[    0.000000] On node 0 totalpages: 242688
[    0.000000] free_area_init_node: node 0, pgdat 80c84e40, node_mem_map ba3a1000
[    0.000000]   Normal zone: 2133 pages used for memmap
[    0.000000]   Normal zone: 0 pages reserved
[    0.000000]   Normal zone: 242688 pages, LIFO batch:31
[    0.000000] random: fast init done
[    0.000000] percpu: Embedded 17 pages/cpu @ba349000 s38720 r8192 d22720 u69632
[    0.000000] pcpu-alloc: s38720 r8192 d22720 u69632 alloc=17*4096
[    0.000000] pcpu-alloc: [0] 0 [0] 1 [0] 2 [0] 3
[    0.000000] Built 1 zonelists, mobility grouping on.  Total pages: 240555
[    0.000000] Kernel command line: 8250.nr_uarts=0 bcm2708_fb.fbwidth=656 bcm2708_fb.fbheight=416 bcm2708_fb.fbswap=1 vc_mem.mem_base=0x3ec00000 vc_mem.mem_size=0x40000000  dwc_otg.lpm_enable=0 console=ttyS0,115200 console=tty1 root=PARTUUID=52bc33f2-02 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait
[    0.000000] PID hash table entries: 4096 (order: 2, 16384 bytes)
[    0.000000] Dentry cache hash table entries: 131072 (order: 7, 524288 bytes)
[    0.000000] Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)
[    0.000000] Memory: 936296K/970752K available (7168K kernel code, 575K rwdata, 2072K rodata, 1024K init, 706K bss, 26264K reserved, 8192K cma-reserved)
[    0.000000] Virtual kernel memory layout:
                   vector  : 0xffff0000 - 0xffff1000   (   4 kB)
                   fixmap  : 0xffc00000 - 0xfff00000   (3072 kB)
                   vmalloc : 0xbb800000 - 0xff800000   (1088 MB)
                   lowmem  : 0x80000000 - 0xbb400000   ( 948 MB)
                   modules : 0x7f000000 - 0x80000000   (  16 MB)
                     .text : 0x80008000 - 0x80800000   (8160 kB)
                     .init : 0x80b00000 - 0x80c00000   (1024 kB)
                     .data : 0x80c00000 - 0x80c8fd4c   ( 576 kB)
                      .bss : 0x80c96f4c - 0x80d478b4   ( 707 kB)
[    0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
[    0.000000] ftrace: allocating 25231 entries in 74 pages
[    0.000000] Hierarchical RCU implementation.
[    0.000000] NR_IRQS: 16, nr_irqs: 16, preallocated irqs: 16
[    0.000000] arch_timer: cp15 timer(s) running at 19.20MHz (phys).
[    0.000000] clocksource: arch_sys_counter: mask: 0xffffffffffffff max_cycles: 0x46d987e47, max_idle_ns: 440795202767 ns
[    0.000007] sched_clock: 56 bits at 19MHz, resolution 52ns, wraps every 4398046511078ns
[    0.000023] Switching to timer-based delay loop, resolution 52ns
[    0.000274] Console: colour dummy device 80x30
[    0.000819] console [tty1] enabled
[    0.000856] Calibrating delay loop (skipped), value calculated using timer frequency.. 38.40 BogoMIPS (lpj=192000)
[    0.000895] pid_max: default: 32768 minimum: 301
[    0.001221] Mount-cache hash table entries: 2048 (order: 1, 8192 bytes)
[    0.001255] Mountpoint-cache hash table entries: 2048 (order: 1, 8192 bytes)
[    0.002212] Disabling memory control group subsystem
[    0.002310] CPU: Testing write buffer coherency: ok
[    0.002725] CPU0: thread -1, cpu 0, socket 0, mpidr 80000000
[    0.003116] Setting up static identity map for 0x100000 - 0x10003c
[    0.003251] Hierarchical SRCU implementation.
[    0.003901] smp: Bringing up secondary CPUs ...
[    0.004609] CPU1: thread -1, cpu 1, socket 0, mpidr 80000001
[    0.005366] CPU2: thread -1, cpu 2, socket 0, mpidr 80000002
[    0.006104] CPU3: thread -1, cpu 3, socket 0, mpidr 80000003
[    0.006208] smp: Brought up 1 node, 4 CPUs
[    0.006279] SMP: Total of 4 processors activated (153.60 BogoMIPS).
[    0.006300] CPU: All CPU(s) started in HYP mode.
[    0.006318] CPU: Virtualization extensions available.
[    0.007188] devtmpfs: initialized
[    0.018104] VFP support v0.3: implementor 41 architecture 3 part 40 variant 3 rev 4
[    0.018356] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
[    0.018401] futex hash table entries: 1024 (order: 4, 65536 bytes)
[    0.018977] pinctrl core: initialized pinctrl subsystem
[    0.019732] NET: Registered protocol family 16
[    0.022352] DMA: preallocated 1024 KiB pool for atomic coherent allocations
[    0.027049] hw-breakpoint: found 5 (+1 reserved) breakpoint and 4 watchpoint registers.
[    0.027082] hw-breakpoint: maximum watchpoint size is 8 bytes.
[    0.027302] Serial: AMBA PL011 UART driver
[    0.028936] bcm2835-mbox 3f00b880.mailbox: mailbox enabled
[    0.029410] uart-pl011 3f201000.serial: could not find pctldev for node /soc/gpio@7e200000/uart0_pins, deferring probe
[    0.060894] bcm2835-dma 3f007000.dma: DMA legacy API manager at bb813000, dmachans=0x1
[    0.062328] SCSI subsystem initialized
[    0.062564] usbcore: registered new interface driver usbfs
[    0.062632] usbcore: registered new interface driver hub
[    0.062731] usbcore: registered new device driver usb
[    0.070069] raspberrypi-firmware soc:firmware: Attached to firmware from 2018-04-16 18:16
[    0.071387] clocksource: Switched to clocksource arch_sys_counter
[    0.148794] VFS: Disk quotas dquot_6.6.0
[    0.148906] VFS: Dquot-cache hash table entries: 1024 (order 0, 4096 bytes)
[    0.149109] FS-Cache: Loaded
[    0.149320] CacheFiles: Loaded
[    0.158119] NET: Registered protocol family 2
[    0.158860] TCP established hash table entries: 8192 (order: 3, 32768 bytes)
[    0.158990] TCP bind hash table entries: 8192 (order: 4, 65536 bytes)
[    0.159193] TCP: Hash tables configured (established 8192 bind 8192)
[    0.159338] UDP hash table entries: 512 (order: 2, 16384 bytes)
[    0.159399] UDP-Lite hash table entries: 512 (order: 2, 16384 bytes)
[    0.159644] NET: Registered protocol family 1
[    0.160103] RPC: Registered named UNIX socket transport module.
[    0.160128] RPC: Registered udp transport module.
[    0.160147] RPC: Registered tcp transport module.
[    0.160166] RPC: Registered tcp NFSv4.1 backchannel transport module.
[    0.160380] Trying to unpack rootfs image as initramfs...
[    0.497099] Freeing initrd memory: 3936K
[    0.502792] hw perfevents: enabled with armv7_cortex_a7 PMU driver, 7 counters available
[    0.505597] workingset: timestamp_bits=14 max_order=18 bucket_order=4
[    0.513598] FS-Cache: Netfs 'nfs' registered for caching
[    0.514206] NFS: Registering the id_resolver key type
[    0.514253] Key type id_resolver registered
[    0.514272] Key type id_legacy registered
[    0.514301] nfs4filelayout_init: NFSv4 File Layout Driver Registering...
[    0.516149] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 251)
[    0.516295] io scheduler noop registered
[    0.516317] io scheduler deadline registered (default)
[    0.516605] io scheduler cfq registered
[    0.516627] io scheduler mq-deadline registered
[    0.516647] io scheduler kyber registered
[    0.519489] BCM2708FB: allocated DMA memory fad10000
[    0.519535] BCM2708FB: allocated DMA channel 0 @ bb813000
[    0.528062] Console: switching to colour frame buffer device 82x26
[    0.536532] bcm2835-rng 3f104000.rng: hwrng registered
[    0.538989] vc-mem: phys_addr:0x00000000 mem_base=0x3ec00000 mem_size:0x40000000(1024 MiB)
[    0.544128] vc-sm: Videocore shared memory driver
[    0.546711] gpiomem-bcm2835 3f200000.gpiomem: Initialised: Registers at 0x3f200000
[    0.560861] brd: module loaded
[    0.571794] loop: module loaded
[    0.574080] Loading iSCSI transport class v2.0-870.
[    0.577024] libphy: Fixed MDIO Bus: probed
[    0.579388] usbcore: registered new interface driver lan78xx
[    0.581742] usbcore: registered new interface driver smsc95xx
[    0.583906] dwc_otg: version 3.00a 10-AUG-2012 (platform bus)
[    0.814153] Core Release: 2.80a
[    0.816322] Setting default values for core params
[    0.818560] Finished setting default values for core params
[    1.021097] Using Buffer DMA mode
[    1.023408] Periodic Transfer Interrupt Enhancement - disabled
[    1.025784] Multiprocessor Interrupt Enhancement - disabled
[    1.028214] OTG VER PARAM: 0, OTG VER FLAG: 0
[    1.030599] Dedicated Tx FIFOs mode
[    1.033254] WARN::dwc_otg_hcd_init:1046: FIQ DMA bounce buffers: virt = 0xbad04000 dma = 0xfad04000 len=9024
[    1.037963] FIQ FSM acceleration enabled for :
               Non-periodic Split Transactions
               Periodic Split Transactions
               High-Speed Isochronous Endpoints
               Interrupt/Control Split Transaction hack enabled
[    1.049032] dwc_otg: Microframe scheduler enabled
[    1.049087] WARN::hcd_init_fiq:459: FIQ on core 1 at 0x805e6a40
[    1.051375] WARN::hcd_init_fiq:460: FIQ ASM at 0x805e6da8 length 36
[    1.053644] WARN::hcd_init_fiq:486: MPHI regs_base at 0xbb87e000
[    1.055922] dwc_otg 3f980000.usb: DWC OTG Controller
[    1.058246] dwc_otg 3f980000.usb: new USB bus registered, assigned bus number 1
[    1.060627] dwc_otg 3f980000.usb: irq 62, io mem 0x00000000
[    1.062974] Init: Port Power? op_state=1
[    1.065235] Init: Power Port (0)
[    1.067625] usb usb1: New USB device found, idVendor=1d6b, idProduct=0002
[    1.069937] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[    1.072267] usb usb1: Product: DWC OTG Controller
[    1.074517] usb usb1: Manufacturer: Linux 4.14.34-v7+ dwc_otg_hcd
[    1.076792] usb usb1: SerialNumber: 3f980000.usb
[    1.079624] hub 1-0:1.0: USB hub found
[    1.081855] hub 1-0:1.0: 1 port detected
[    1.084440] dwc_otg: FIQ enabled
[    1.084445] dwc_otg: NAK holdoff enabled
[    1.084450] dwc_otg: FIQ split-transaction FSM enabled
[    1.084459] Module dwc_common_port init
[    1.084688] usbcore: registered new interface driver usb-storage
[    1.086974] mousedev: PS/2 mouse device common for all mice
[    1.089193] IR NEC protocol handler initialized
[    1.091360] IR RC5(x/sz) protocol handler initialized
[    1.093584] IR RC6 protocol handler initialized
[    1.095761] IR JVC protocol handler initialized
[    1.097839] IR Sony protocol handler initialized
[    1.099923] IR SANYO protocol handler initialized
[    1.102025] IR Sharp protocol handler initialized
[    1.104021] IR MCE Keyboard/mouse protocol handler initialized
[    1.106048] IR XMP protocol handler initialized
[    1.108720] bcm2835-wdt 3f100000.watchdog: Broadcom BCM2835 watchdog timer
[    1.111062] bcm2835-cpufreq: min=600000 max=1200000
[    1.113596] sdhci: Secure Digital Host Controller Interface driver
[    1.115726] sdhci: Copyright(c) Pierre Ossman
[    1.118167] mmc-bcm2835 3f300000.mmc: could not get clk, deferring probe
[    1.120637] sdhost-bcm2835 3f202000.mmc: could not get clk, deferring probe
[    1.122956] sdhci-pltfm: SDHCI platform and OF driver helper
[    1.126569] ledtrig-cpu: registered to indicate activity on CPUs
[    1.128994] hidraw: raw HID events driver (C) Jiri Kosina
[    1.131471] usbcore: registered new interface driver usbhid
[    1.133778] usbhid: USB HID core driver
[    1.136614] vchiq: vchiq_init_state: slot_zero = bad80000, is_master = 0
[    1.140321] [vc_sm_connected_init]: start
[    1.149779] [vc_sm_connected_init]: end - returning 0
[    1.152653] Initializing XFRM netlink socket
[    1.155034] NET: Registered protocol family 17
[    1.157500] Key type dns_resolver registered
[    1.160266] Registering SWP/SWPB emulation handler
[    1.163371] registered taskstats version 1
[    1.171647] uart-pl011 3f201000.serial: cts_event_workaround enabled
[    1.174215] 3f201000.serial: ttyAMA0 at MMIO 0x3f201000 (irq = 87, base_baud = 0) is a PL011 rev2
[    1.180970] mmc-bcm2835 3f300000.mmc: mmc_debug:0 mmc_debug2:0
[    1.183544] mmc-bcm2835 3f300000.mmc: DMA channel allocated
[    1.242038] sdhost: log_buf @ bad07000 (fad07000)
[    1.280710] mmc1: queuing unknown CIS tuple 0x80 (2 bytes)
[    1.284701] mmc1: queuing unknown CIS tuple 0x80 (3 bytes)
[    1.288551] mmc1: queuing unknown CIS tuple 0x80 (3 bytes)
[    1.293557] mmc1: queuing unknown CIS tuple 0x80 (7 bytes)
[    1.301490] Indeed it is in host mode hprt0 = 00021501
[    1.321405] mmc0: sdhost-bcm2835 loaded - DMA enabled (>1)
[    1.362374] of_cfs_init
[    1.364470] of_cfs_init: OK
[    1.369708] Freeing unused kernel memory: 1024K
[    1.388856] mmc0: host does not support reading read-only switch, assuming write-enable
[    1.396486] mmc0: new high speed SDHC card at address b368
[    1.399727] mmcblk0: mmc0:b368 SDU16 14.9 GiB
[    1.403634]  mmcblk0: p1 p2
[    1.428753] mmc1: new high speed SDIO card at address 0001
[    1.521484] usb 1-1: new high-speed USB device number 2 using dwc_otg
[    1.523775] Indeed it is in host mode hprt0 = 00001101
[    1.761762] usb 1-1: New USB device found, idVendor=0424, idProduct=9514
[    1.764079] usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[    1.767102] hub 1-1:1.0: USB hub found
[    1.769571] hub 1-1:1.0: 5 ports detected
[    1.816259] rtc-ds1307 1-006f: registered as rtc0
[    1.853824] at24 1-0057: 128 byte 24c01 EEPROM, writable, 1 bytes/write
[    1.899674] i2c /dev entries driver
[    2.091430] usb 1-1.1: new high-speed USB device number 3 using dwc_otg
[    2.197832] EXT4-fs (mmcblk0p2): mounted filesystem with ordered data mode. Opts: (null)
[    2.221821] usb 1-1.1: New USB device found, idVendor=0424, idProduct=ec00
[    2.227133] usb 1-1.1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[    2.234589] smsc95xx v1.0.6
[    2.325136] smsc95xx 1-1.1:1.0 eth0: register 'smsc95xx' at usb-3f980000.usb-1.1, smsc95xx USB 2.0 Ethernet, b8:27:eb:bf:f5:2a
[    2.891203] NET: Registered protocol family 10
[    2.895334] Segment Routing with IPv6
[    2.906940] ip_tables: (C) 2000-2006 Netfilter Core Team
[    2.939852] systemd[1]: systemd 232 running in system mode. (+PAM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD +IDN)
[    2.948768] systemd[1]: Detected architecture arm.
[    2.953296] systemd[1]: Set hostname to <unipi>.
[    2.960410] systemd[1]: Hardware watchdog 'Broadcom BCM2835 Watchdog timer', version 0
[    2.960446] systemd[1]: Set hardware watchdog to 10s.
[    3.342703] systemd[1]: [/etc/systemd/system/evok.service:9] Unknown lvalue 'StartLimitIntervalSec' in section 'Service'
[    3.388229] systemd[1]: Listening on fsck to fsckd communication Socket.
[    3.391927] systemd[1]: Listening on /dev/initctl Compatibility Named Pipe.
[    3.412053] systemd[1]: Listening on Syslog Socket.
[    3.415855] systemd[1]: Created slice User and Session Slice.
[    3.777925] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null)
[    3.885148] systemd-journald[207]: Received request to flush runtime journal from PID 1
[    4.452917] snd_bcm2835: module is from the staging directory, the quality is unknown, you have been warned.
[    4.460742] bcm2835_alsa bcm2835_alsa: card created with 8 channels
[    4.595879] brcmfmac: F1 signature read @0x18000000=0x1541a9a6
[    4.609315] brcmfmac: brcmf_fw_map_chip_to_name: using brcm/brcmfmac43430-sdio.bin for chip 0x00a9a6(43430) rev 0x000001
[    4.609563] usbcore: registered new interface driver brcmfmac
[    4.829735] brcmfmac: brcmf_c_preinit_dcmds: Firmware version = wl0: Oct 23 2017 03:55:53 version 7.45.98.38 (r674442 CY) FWID 01-e58d219f
[    4.830625] brcmfmac: brcmf_c_preinit_dcmds: CLM version = API: 12.2 Data: 7.11.15 Compiler: 1.24.2 ClmImport: 1.24.1 Creation: 2014-05-26 10:53:55 Inc Data: 9.10.39 Inc Compiler: 1.29.4 Inc ClmImport: 1.36.3 Creation: 2017-10-23 03:47:14
[    4.889624] unipi: loading out-of-tree module taints kernel.
[    4.889628] unipi: loading out-of-tree module taints kernel.
[    4.892249] NEURONSPI: Neuronspi Probe Started
[    4.895507] NEURONSPI: Probe did not detect a valid Neuron device on CS 3
[    4.895959] NEURONSPI: Neuronspi Probe Started
[    4.899222] NEURONSPI: Probe detected Neuron Board E_4Ai4Ao_U_6Di5Ro (L:f U:5 C:f) Index: 1 Fw: v5.18 on CS 2, Uart count: 1 - reg1000: 512, reg1001: 605, reg1002: 41, reg1003: f10, reg1004: b10
[    4.899237] NEURONSPI: Neuron device E_4Ai4Ao_U_6Di5Ro on CS 2 uses SPI communication freq. 7500000 Hz
[    4.910066] NEURONSPI: Added UART port 0
[    4.916302] NEURONSPI: Neuronspi Probe Started
[    4.918290] NEURONSPI: Probe detected Neuron Board B_1000 (L:0 U:0 C:0) Index: 0 Fw: v5.18 on CS 1, Uart count: 1 - reg1000: 512, reg1001: 404, reg1002: 311, reg1003: 10, reg1004: 10
[    4.918302] NEURONSPI: Neuron device B_1000 on CS 1 uses SPI communication freq. 12000000 Hz
[    4.918426] NEURONSPI: LED model B_1000 with 4 LEDs detected at CS: 1
[    4.918442] NEURONSPI: Detected Neuron board combination corresponding to Neuron M503
[    4.924209] NEURONSPI: Added UART port 1
[    4.926066] NEURONSPI: SPI Driver Registered, Major Version: Development Beta Version 0.11:06:06:2018
[    4.927369] NEURONSPI TTYInit
[    5.765470] uart-pl011 3f201000.serial: no DMA platform data
[    6.309841] EXT4-fs (mmcblk0p2): resizing filesystem from 442368 to 3897088 blocks
[    6.365946] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
[    6.365958] brcmfmac: power management disabled
[    7.211363] random: crng init done
[    7.972551] smsc95xx 1-1.1:1.0 eth0: hardware isn't capable of remote wakeup
[    9.631534] smsc95xx 1-1.1:1.0 eth0: link up, 100Mbps, full-duplex, lpa 0xCDE1
[   12.838396] Bluetooth: Core ver 2.22
[   12.838475] NET: Registered protocol family 31
[   12.838484] Bluetooth: HCI device and connection manager initialized
[   12.838506] Bluetooth: HCI socket layer initialized
[   12.838518] Bluetooth: L2CAP socket layer initialized
[   12.838553] Bluetooth: SCO socket layer initialized
[   13.688340] Bluetooth: HCI UART driver ver 2.3
[   13.688355] Bluetooth: HCI UART protocol H4 registered
[   13.688361] Bluetooth: HCI UART protocol Three-wire (H5) registered
[   13.688589] Bluetooth: HCI UART protocol Broadcom registered
[   18.863561] systemd[1]: apt-daily.timer: Adding 6h 56min 19.812726s random time.
[   18.865315] systemd[1]: apt-daily-upgrade.timer: Adding 57min 19.609548s random time.
[   19.114003] EXT4-fs (mmcblk0p2): resized to 1572864 blocks
[   19.802250] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[   19.802261] Bluetooth: BNEP filters: protocol multicast
[   19.802284] Bluetooth: BNEP socket layer initialized
[   19.863425] Adding 102396k swap on /var/swap.  Priority:-2 extents:1 across:102396k SSFS
[   43.322776] EXT4-fs (mmcblk0p2): resized to 3145728 blocks
[   51.652015] EXT4-fs (mmcblk0p2): resized filesystem to 3897088
[   60.959601] systemd[1]: apt-daily.timer: Adding 6h 35min 27.035347s random time.
[   60.961564] systemd[1]: apt-daily-upgrade.timer: Adding 40min 52.921030s random time.
[   62.394188] nf_conntrack version 0.5.0 (15360 buckets, 61440 max)
[  249.928194] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[  249.932292] pgd = b93d0000
[  249.934319] [00000000] *pgd=38b75835, *pte=00000000, *ppte=00000000
[  249.936514] Internal error: Oops: 80000007 [#1] SMP ARM
[  249.938698] Modules linked in: iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack cmac bnep hci_uart btbcm serdev bluetooth ecdh_generic unipi(O) industrialio spidev brcmfmac brcmutil cfg80211 rfkill snd_bcm2835(C) snd_pcm snd_timer snd spi_bcm2835 uio_pdrv_genirq uio fixed ip_tables x_tables ipv6 i2c_dev rtc_ds1307 at24 hwmon i2c_bcm2835
[  249.950981] CPU: 1 PID: 1091 Comm: cat Tainted: G         C O    4.14.34-v7+ #1110
[  249.956125] Hardware name: BCM2835
[  249.958723] task: b8cfbc00 task.stack: b6dbe000
[  249.961396] PC is at 0x0
[  249.964074] LR is at iio_read_channel_info+0xa8/0xb0 [industrialio]
[  249.966810] pc : [<00000000>]    lr : [<7f416858>]    psr: 60000013
[  249.969569] sp : b6dbfdc8  ip : 00000000  fp : b6dbfe04
[  249.972339] r10: b6dbfe68  r9 : b90c7e00  r8 : b928d818
[  249.975080] r7 : b9dab000  r6 : 8083bd4c  r5 : b9dab000  r4 : b6dbfdd8
[  249.977879] r3 : b6dbfddc  r2 : b6dbfdd8  r1 : 7f48b934  r0 : b928d800
[  249.980601] Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
[  249.983321] Control: 10c5383d  Table: 393d006a  DAC: 00000055
[  249.986084] Process cat (pid: 1091, stack limit = 0xb6dbe210)
[  249.988834] Stack: (0xb6dbfdc8 to 0xb6dc0000)
[  249.991537] fdc0:                   00000000 00000001 00000001 00000002 014000c0 80276984
[  249.996852] fde0: b6dbfe34 b6dbfdf0 80276984 b90c7500 b8bd24c0 8083bd4c b6dbfe1c b6dbfe08
[  250.002114] fe00: 8053d6f8 7f4167bc b90c7500 00001000 b6dbfe44 b6dbfe20 80309218 8053d6d8
[  250.007386] fe20: b90c7500 00000001 00000000 00000001 b881b540 b6dbff80 b6dbfe54 b6dbfe48
[  250.012809] fe40: 80307a6c 8030918c b6dbfea4 b6dbfe58 802b15ec 80307a44 00000000 b90c7530
[  250.018567] fe60: 76c92000 00020000 00000000 00000000 bab5bd68 00000000 b6dbfea4 00020000
[  250.024554] fe80: b6dbff80 76c92000 b6dbff80 00020000 b90c7e00 00000000 b6dbfedc b6dbfea8
[  250.030768] fea0: 80308884 802b1414 00000000 00100073 00000000 b881b540 b6dbff80 76c92000
[  250.037291] fec0: b6dbff80 00020000 b6dbe000 00000000 b6dbff4c b6dbfee0 8028a624 8030875c
[  250.043951] fee0: 76c91000 b6dbffb0 00001000 000001ff b6dbffac b6dbff00 801011e4 807a0468
[  250.050798] ff00: b6dbff48 00000003 00022000 00000000 00000000 80242100 b6dbff74 8028a790
[  250.057783] ff20: 80242100 8016cd34 00020000 b881b540 76c92000 b6dbff80 80108204 b6dbe000
[  250.064012] ff40: b6dbff7c b6dbff50 8028a7b8 8028a5f8 00000022 802aadf8 b6dbff7c b881b540
[  250.067522] ff60: b881b540 00020000 76c92000 80108204 b6dbffa4 b6dbff80 8028ad68 8028a728
[  250.071040] ff80: 00000000 00000000 00020000 7fffe000 00020000 00000003 00000000 b6dbffa8
[  250.074557] ffa0: 80108060 8028ad20 00020000 7fffe000 00000003 76c92000 00020000 00027184
[  250.078074] ffc0: 00020000 7fffe000 00020000 00000003 00000003 00020000 ffffffff 00000000
[  250.081582] ffe0: 00000000 7ec10594 000141cc 76f0f0cc 60000010 00000003 00000000 00000000
[  250.085138] [<7f416858>] (iio_read_channel_info [industrialio]) from [<8053d6f8>] (dev_attr_show+0x2c/0x58)
[  250.088690] [<8053d6f8>] (dev_attr_show) from [<80309218>] (sysfs_kf_seq_show+0x98/0x108)
[  250.092226] [<80309218>] (sysfs_kf_seq_show) from [<80307a6c>] (kernfs_seq_show+0x34/0x38)
[  250.095765] [<80307a6c>] (kernfs_seq_show) from [<802b15ec>] (seq_read+0x1e4/0x504)
[  250.099294] [<802b15ec>] (seq_read) from [<80308884>] (kernfs_fop_read+0x134/0x1a4)
[  250.102845] [<80308884>] (kernfs_fop_read) from [<8028a624>] (__vfs_read+0x38/0x130)
[  250.106407] [<8028a624>] (__vfs_read) from [<8028a7b8>] (vfs_read+0x9c/0x168)
[  250.108236] [<8028a7b8>] (vfs_read) from [<8028ad68>] (SyS_read+0x54/0xb0)
[  250.110040] [<8028ad68>] (SyS_read) from [<80108060>] (ret_fast_syscall+0x0/0x28)
[  250.113482] Code: bad PC value
[  250.115194] ---[ end trace e9215518fd25ea5f ]---

Hi Tomas,

Here is my dmesg before and after touching ao_2_1.

--edit-- apparently my post is too long for this forum, so I will have to split it up in three messages. Sorry!

Before

[    0.000000] Booting Linux on physical CPU 0x0
[    0.000000] Linux version 4.14.34-v7+ (dc4@dc4-XPS13-9333) (gcc version 4.9.3 (crosstool-NG crosstool-ng-1.22.0-88-g8460611)) #1110 SMP Mon Apr 16 15:18:51 BST 2018
[    0.000000] CPU: ARMv7 Processor [410fd034] revision 4 (ARMv7), cr=10c5383d
[    0.000000] CPU: div instructions available: patching division code
[    0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
[    0.000000] OF: fdt: Machine model: Raspberry Pi 3 Model B Rev 1.2
[    0.000000] Memory policy: Data cache writealloc
[    0.000000] cma: Reserved 8 MiB at 0x3ac00000
[    0.000000] On node 0 totalpages: 242688
[    0.000000] free_area_init_node: node 0, pgdat 80c84e40, node_mem_map ba3a1000
[    0.000000]   Normal zone: 2133 pages used for memmap
[    0.000000]   Normal zone: 0 pages reserved
[    0.000000]   Normal zone: 242688 pages, LIFO batch:31
[    0.000000] random: fast init done
[    0.000000] percpu: Embedded 17 pages/cpu @ba349000 s38720 r8192 d22720 u69632
[    0.000000] pcpu-alloc: s38720 r8192 d22720 u69632 alloc=17*4096
[    0.000000] pcpu-alloc: [0] 0 [0] 1 [0] 2 [0] 3
[    0.000000] Built 1 zonelists, mobility grouping on.  Total pages: 240555
[    0.000000] Kernel command line: 8250.nr_uarts=0 bcm2708_fb.fbwidth=656 bcm2708_fb.fbheight=416 bcm2708_fb.fbswap=1 vc_mem.mem_base=0x3ec00000 vc_mem.mem_size=0x40000000  dwc_otg.lpm_enable=0 console=ttyS0,115200 console=tty1 root=PARTUUID=52bc33f2-02 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait
[    0.000000] PID hash table entries: 4096 (order: 2, 16384 bytes)
[    0.000000] Dentry cache hash table entries: 131072 (order: 7, 524288 bytes)
[    0.000000] Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)
[    0.000000] Memory: 936296K/970752K available (7168K kernel code, 575K rwdata, 2072K rodata, 1024K init, 706K bss, 26264K reserved, 8192K cma-reserved)
[    0.000000] Virtual kernel memory layout:
                   vector  : 0xffff0000 - 0xffff1000   (   4 kB)
                   fixmap  : 0xffc00000 - 0xfff00000   (3072 kB)
                   vmalloc : 0xbb800000 - 0xff800000   (1088 MB)
                   lowmem  : 0x80000000 - 0xbb400000   ( 948 MB)
                   modules : 0x7f000000 - 0x80000000   (  16 MB)
                     .text : 0x80008000 - 0x80800000   (8160 kB)
                     .init : 0x80b00000 - 0x80c00000   (1024 kB)
                     .data : 0x80c00000 - 0x80c8fd4c   ( 576 kB)
                      .bss : 0x80c96f4c - 0x80d478b4   ( 707 kB)
[    0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
[    0.000000] ftrace: allocating 25231 entries in 74 pages
[    0.000000] Hierarchical RCU implementation.
[    0.000000] NR_IRQS: 16, nr_irqs: 16, preallocated irqs: 16
[    0.000000] arch_timer: cp15 timer(s) running at 19.20MHz (phys).
[    0.000000] clocksource: arch_sys_counter: mask: 0xffffffffffffff max_cycles: 0x46d987e47, max_idle_ns: 440795202767 ns
[    0.000007] sched_clock: 56 bits at 19MHz, resolution 52ns, wraps every 4398046511078ns
[    0.000023] Switching to timer-based delay loop, resolution 52ns
[    0.000274] Console: colour dummy device 80x30
[    0.000819] console [tty1] enabled
[    0.000856] Calibrating delay loop (skipped), value calculated using timer frequency.. 38.40 BogoMIPS (lpj=192000)
[    0.000895] pid_max: default: 32768 minimum: 301
[    0.001221] Mount-cache hash table entries: 2048 (order: 1, 8192 bytes)
[    0.001255] Mountpoint-cache hash table entries: 2048 (order: 1, 8192 bytes)
[    0.002212] Disabling memory control group subsystem
[    0.002310] CPU: Testing write buffer coherency: ok
[    0.002725] CPU0: thread -1, cpu 0, socket 0, mpidr 80000000
[    0.003116] Setting up static identity map for 0x100000 - 0x10003c
[    0.003251] Hierarchical SRCU implementation.
[    0.003901] smp: Bringing up secondary CPUs ...
[    0.004609] CPU1: thread -1, cpu 1, socket 0, mpidr 80000001
[    0.005366] CPU2: thread -1, cpu 2, socket 0, mpidr 80000002
[    0.006104] CPU3: thread -1, cpu 3, socket 0, mpidr 80000003
[    0.006208] smp: Brought up 1 node, 4 CPUs
[    0.006279] SMP: Total of 4 processors activated (153.60 BogoMIPS).
[    0.006300] CPU: All CPU(s) started in HYP mode.
[    0.006318] CPU: Virtualization extensions available.
[    0.007188] devtmpfs: initialized
[    0.018104] VFP support v0.3: implementor 41 architecture 3 part 40 variant 3 rev 4
[    0.018356] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
[    0.018401] futex hash table entries: 1024 (order: 4, 65536 bytes)
[    0.018977] pinctrl core: initialized pinctrl subsystem
[    0.019732] NET: Registered protocol family 16
[    0.022352] DMA: preallocated 1024 KiB pool for atomic coherent allocations
[    0.027049] hw-breakpoint: found 5 (+1 reserved) breakpoint and 4 watchpoint registers.
[    0.027082] hw-breakpoint: maximum watchpoint size is 8 bytes.
[    0.027302] Serial: AMBA PL011 UART driver
[    0.028936] bcm2835-mbox 3f00b880.mailbox: mailbox enabled
[    0.029410] uart-pl011 3f201000.serial: could not find pctldev for node /soc/gpio@7e200000/uart0_pins, deferring probe
[    0.060894] bcm2835-dma 3f007000.dma: DMA legacy API manager at bb813000, dmachans=0x1
[    0.062328] SCSI subsystem initialized
[    0.062564] usbcore: registered new interface driver usbfs
[    0.062632] usbcore: registered new interface driver hub
[    0.062731] usbcore: registered new device driver usb
[    0.070069] raspberrypi-firmware soc:firmware: Attached to firmware from 2018-04-16 18:16
[    0.071387] clocksource: Switched to clocksource arch_sys_counter
[    0.148794] VFS: Disk quotas dquot_6.6.0
[    0.148906] VFS: Dquot-cache hash table entries: 1024 (order 0, 4096 bytes)
[    0.149109] FS-Cache: Loaded
[    0.149320] CacheFiles: Loaded
[    0.158119] NET: Registered protocol family 2
[    0.158860] TCP established hash table entries: 8192 (order: 3, 32768 bytes)
[    0.158990] TCP bind hash table entries: 8192 (order: 4, 65536 bytes)
[    0.159193] TCP: Hash tables configured (established 8192 bind 8192)
[    0.159338] UDP hash table entries: 512 (order: 2, 16384 bytes)
[    0.159399] UDP-Lite hash table entries: 512 (order: 2, 16384 bytes)
[    0.159644] NET: Registered protocol family 1
[    0.160103] RPC: Registered named UNIX socket transport module.
[    0.160128] RPC: Registered udp transport module.
[    0.160147] RPC: Registered tcp transport module.
[    0.160166] RPC: Registered tcp NFSv4.1 backchannel transport module.
[    0.160380] Trying to unpack rootfs image as initramfs...
[    0.497099] Freeing initrd memory: 3936K
[    0.502792] hw perfevents: enabled with armv7_cortex_a7 PMU driver, 7 counters available
[    0.505597] workingset: timestamp_bits=14 max_order=18 bucket_order=4
[    0.513598] FS-Cache: Netfs 'nfs' registered for caching
[    0.514206] NFS: Registering the id_resolver key type
[    0.514253] Key type id_resolver registered
[    0.514272] Key type id_legacy registered
[    0.514301] nfs4filelayout_init: NFSv4 File Layout Driver Registering...
[    0.516149] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 251)
[    0.516295] io scheduler noop registered
[    0.516317] io scheduler deadline registered (default)
[    0.516605] io scheduler cfq registered
[    0.516627] io scheduler mq-deadline registered
[    0.516647] io scheduler kyber registered
[    0.519489] BCM2708FB: allocated DMA memory fad10000
[    0.519535] BCM2708FB: allocated DMA channel 0 @ bb813000
[    0.528062] Console: switching to colour frame buffer device 82x26
[    0.536532] bcm2835-rng 3f104000.rng: hwrng registered
[    0.538989] vc-mem: phys_addr:0x00000000 mem_base=0x3ec00000 mem_size:0x40000000(1024 MiB)
[    0.544128] vc-sm: Videocore shared memory driver
[    0.546711] gpiomem-bcm2835 3f200000.gpiomem: Initialised: Registers at 0x3f200000
[    0.560861] brd: module loaded
[    0.571794] loop: module loaded
[    0.574080] Loading iSCSI transport class v2.0-870.
[    0.577024] libphy: Fixed MDIO Bus: probed
[    0.579388] usbcore: registered new interface driver lan78xx
[    0.581742] usbcore: registered new interface driver smsc95xx
[    0.583906] dwc_otg: version 3.00a 10-AUG-2012 (platform bus)
[    0.814153] Core Release: 2.80a
[    0.816322] Setting default values for core params
[    0.818560] Finished setting default values for core params
[    1.021097] Using Buffer DMA mode
[    1.023408] Periodic Transfer Interrupt Enhancement - disabled
[    1.025784] Multiprocessor Interrupt Enhancement - disabled
[    1.028214] OTG VER PARAM: 0, OTG VER FLAG: 0
[    1.030599] Dedicated Tx FIFOs mode
[    1.033254] WARN::dwc_otg_hcd_init:1046: FIQ DMA bounce buffers: virt = 0xbad04000 dma = 0xfad04000 len=9024
[    1.037963] FIQ FSM acceleration enabled for :
               Non-periodic Split Transactions
               Periodic Split Transactions
               High-Speed Isochronous Endpoints
               Interrupt/Control Split Transaction hack enabled
[    1.049032] dwc_otg: Microframe scheduler enabled
[    1.049087] WARN::hcd_init_fiq:459: FIQ on core 1 at 0x805e6a40
[    1.051375] WARN::hcd_init_fiq:460: FIQ ASM at 0x805e6da8 length 36
[    1.053644] WARN::hcd_init_fiq:486: MPHI regs_base at 0xbb87e000
[    1.055922] dwc_otg 3f980000.usb: DWC OTG Controller
[    1.058246] dwc_otg 3f980000.usb: new USB bus registered, assigned bus number 1
[    1.060627] dwc_otg 3f980000.usb: irq 62, io mem 0x00000000
[    1.062974] Init: Port Power? op_state=1
[    1.065235] Init: Power Port (0)
[    1.067625] usb usb1: New USB device found, idVendor=1d6b, idProduct=0002
[    1.069937] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[    1.072267] usb usb1: Product: DWC OTG Controller
[    1.074517] usb usb1: Manufacturer: Linux 4.14.34-v7+ dwc_otg_hcd
[    1.076792] usb usb1: SerialNumber: 3f980000.usb
[    1.079624] hub 1-0:1.0: USB hub found
[    1.081855] hub 1-0:1.0: 1 port detected
[    1.084440] dwc_otg: FIQ enabled
[    1.084445] dwc_otg: NAK holdoff enabled
[    1.084450] dwc_otg: FIQ split-transaction FSM enabled
[    1.084459] Module dwc_common_port init
[    1.084688] usbcore: registered new interface driver usb-storage
[    1.086974] mousedev: PS/2 mouse device common for all mice
[    1.089193] IR NEC protocol handler initialized
[    1.091360] IR RC5(x/sz) protocol handler initialized
[    1.093584] IR RC6 protocol handler initialized
[    1.095761] IR JVC protocol handler initialized
[    1.097839] IR Sony protocol handler initialized
[    1.099923] IR SANYO protocol handler initialized
[    1.102025] IR Sharp protocol handler initialized
[    1.104021] IR MCE Keyboard/mouse protocol handler initialized
[    1.106048] IR XMP protocol handler initialized
[    1.108720] bcm2835-wdt 3f100000.watchdog: Broadcom BCM2835 watchdog timer
[    1.111062] bcm2835-cpufreq: min=600000 max=1200000
[    1.113596] sdhci: Secure Digital Host Controller Interface driver
[    1.115726] sdhci: Copyright(c) Pierre Ossman
[    1.118167] mmc-bcm2835 3f300000.mmc: could not get clk, deferring probe
[    1.120637] sdhost-bcm2835 3f202000.mmc: could not get clk, deferring probe
[    1.122956] sdhci-pltfm: SDHCI platform and OF driver helper
[    1.126569] ledtrig-cpu: registered to indicate activity on CPUs
[    1.128994] hidraw: raw HID events driver (C) Jiri Kosina
[    1.131471] usbcore: registered new interface driver usbhid
[    1.133778] usbhid: USB HID core driver
[    1.136614] vchiq: vchiq_init_state: slot_zero = bad80000, is_master = 0
[    1.140321] [vc_sm_connected_init]: start
[    1.149779] [vc_sm_connected_init]: end - returning 0
[    1.152653] Initializing XFRM netlink socket
[    1.155034] NET: Registered protocol family 17
[    1.157500] Key type dns_resolver registered
[    1.160266] Registering SWP/SWPB emulation handler
[    1.163371] registered taskstats version 1
[    1.171647] uart-pl011 3f201000.serial: cts_event_workaround enabled
[    1.174215] 3f201000.serial: ttyAMA0 at MMIO 0x3f201000 (irq = 87, base_baud = 0) is a PL011 rev2
[    1.180970] mmc-bcm2835 3f300000.mmc: mmc_debug:0 mmc_debug2:0
[    1.183544] mmc-bcm2835 3f300000.mmc: DMA channel allocated
[    1.242038] sdhost: log_buf @ bad07000 (fad07000)
[    1.280710] mmc1: queuing unknown CIS tuple 0x80 (2 bytes)
[    1.284701] mmc1: queuing unknown CIS tuple 0x80 (3 bytes)
[    1.288551] mmc1: queuing unknown CIS tuple 0x80 (3 bytes)
[    1.293557] mmc1: queuing unknown CIS tuple 0x80 (7 bytes)
[    1.301490] Indeed it is in host mode hprt0 = 00021501
[    1.321405] mmc0: sdhost-bcm2835 loaded - DMA enabled (>1)
[    1.362374] of_cfs_init
[    1.364470] of_cfs_init: OK
[    1.369708] Freeing unused kernel memory: 1024K
[    1.388856] mmc0: host does not support reading read-only switch, assuming write-enable
[    1.396486] mmc0: new high speed SDHC card at address b368
[    1.399727] mmcblk0: mmc0:b368 SDU16 14.9 GiB
[    1.403634]  mmcblk0: p1 p2
[    1.428753] mmc1: new high speed SDIO card at address 0001
[    1.521484] usb 1-1: new high-speed USB device number 2 using dwc_otg
[    1.523775] Indeed it is in host mode hprt0 = 00001101
[    1.761762] usb 1-1: New USB device found, idVendor=0424, idProduct=9514
[    1.764079] usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[    1.767102] hub 1-1:1.0: USB hub found
[    1.769571] hub 1-1:1.0: 5 ports detected
[    1.816259] rtc-ds1307 1-006f: registered as rtc0
[    1.853824] at24 1-0057: 128 byte 24c01 EEPROM, writable, 1 bytes/write
[    1.899674] i2c /dev entries driver
[    2.091430] usb 1-1.1: new high-speed USB device number 3 using dwc_otg
[    2.197832] EXT4-fs (mmcblk0p2): mounted filesystem with ordered data mode. Opts: (null)
[    2.221821] usb 1-1.1: New USB device found, idVendor=0424, idProduct=ec00
[    2.227133] usb 1-1.1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[    2.234589] smsc95xx v1.0.6
[    2.325136] smsc95xx 1-1.1:1.0 eth0: register 'smsc95xx' at usb-3f980000.usb-1.1, smsc95xx USB 2.0 Ethernet, b8:27:eb:bf:f5:2a
[    2.891203] NET: Registered protocol family 10
[    2.895334] Segment Routing with IPv6
[    2.906940] ip_tables: (C) 2000-2006 Netfilter Core Team
[    2.939852] systemd[1]: systemd 232 running in system mode. (+PAM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD +IDN)
[    2.948768] systemd[1]: Detected architecture arm.
[    2.953296] systemd[1]: Set hostname to <unipi>.
[    2.960410] systemd[1]: Hardware watchdog 'Broadcom BCM2835 Watchdog timer', version 0
[    2.960446] systemd[1]: Set hardware watchdog to 10s.
[    3.342703] systemd[1]: [/etc/systemd/system/evok.service:9] Unknown lvalue 'StartLimitIntervalSec' in section 'Service'
[    3.388229] systemd[1]: Listening on fsck to fsckd communication Socket.
[    3.391927] systemd[1]: Listening on /dev/initctl Compatibility Named Pipe.
[    3.412053] systemd[1]: Listening on Syslog Socket.
[    3.415855] systemd[1]: Created slice User and Session Slice.
[    3.777925] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null)
[    3.885148] systemd-journald[207]: Received request to flush runtime journal from PID 1
[    4.452917] snd_bcm2835: module is from the staging directory, the quality is unknown, you have been warned.
[    4.460742] bcm2835_alsa bcm2835_alsa: card created with 8 channels
[    4.595879] brcmfmac: F1 signature read @0x18000000=0x1541a9a6
[    4.609315] brcmfmac: brcmf_fw_map_chip_to_name: using brcm/brcmfmac43430-sdio.bin for chip 0x00a9a6(43430) rev 0x000001
[    4.609563] usbcore: registered new interface driver brcmfmac
[    4.829735] brcmfmac: brcmf_c_preinit_dcmds: Firmware version = wl0: Oct 23 2017 03:55:53 version 7.45.98.38 (r674442 CY) FWID 01-e58d219f
[    4.830625] brcmfmac: brcmf_c_preinit_dcmds: CLM version = API: 12.2 Data: 7.11.15 Compiler: 1.24.2 ClmImport: 1.24.1 Creation: 2014-05-26 10:53:55 Inc Data: 9.10.39 Inc Compiler: 1.29.4 Inc ClmImport: 1.36.3 Creation: 2017-10-23 03:47:14
[    4.889624] unipi: loading out-of-tree module taints kernel.
[    4.889628] unipi: loading out-of-tree module taints kernel.
[    4.892249] NEURONSPI: Neuronspi Probe Started
[    4.895507] NEURONSPI: Probe did not detect a valid Neuron device on CS 3
[    4.895959] NEURONSPI: Neuronspi Probe Started
[    4.899222] NEURONSPI: Probe detected Neuron Board E_4Ai4Ao_U_6Di5Ro (L:f U:5 C:f) Index: 1 Fw: v5.18 on CS 2, Uart count: 1 - reg1000: 512, reg1001: 605, reg1002: 41, reg1003: f10, reg1004: b10
[    4.899237] NEURONSPI: Neuron device E_4Ai4Ao_U_6Di5Ro on CS 2 uses SPI communication freq. 7500000 Hz
[    4.910066] NEURONSPI: Added UART port 0
[    4.916302] NEURONSPI: Neuronspi Probe Started
[    4.918290] NEURONSPI: Probe detected Neuron Board B_1000 (L:0 U:0 C:0) Index: 0 Fw: v5.18 on CS 1, Uart count: 1 - reg1000: 512, reg1001: 404, reg1002: 311, reg1003: 10, reg1004: 10
[    4.918302] NEURONSPI: Neuron device B_1000 on CS 1 uses SPI communication freq. 12000000 Hz
[    4.918426] NEURONSPI: LED model B_1000 with 4 LEDs detected at CS: 1
[    4.918442] NEURONSPI: Detected Neuron board combination corresponding to Neuron M503
[    4.924209] NEURONSPI: Added UART port 1
[    4.926066] NEURONSPI: SPI Driver Registered, Major Version: Development Beta Version 0.11:06:06:2018
[    4.927369] NEURONSPI TTYInit
[    5.765470] uart-pl011 3f201000.serial: no DMA platform data
[    6.309841] EXT4-fs (mmcblk0p2): resizing filesystem from 442368 to 3897088 blocks
[    6.365946] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
[    6.365958] brcmfmac: power management disabled
[    7.211363] random: crng init done
[    7.972551] smsc95xx 1-1.1:1.0 eth0: hardware isn't capable of remote wakeup
[    9.631534] smsc95xx 1-1.1:1.0 eth0: link up, 100Mbps, full-duplex, lpa 0xCDE1
[   12.838396] Bluetooth: Core ver 2.22
[   12.838475] NET: Registered protocol family 31
[   12.838484] Bluetooth: HCI device and connection manager initialized
[   12.838506] Bluetooth: HCI socket layer initialized
[   12.838518] Bluetooth: L2CAP socket layer initialized
[   12.838553] Bluetooth: SCO socket layer initialized
[   13.688340] Bluetooth: HCI UART driver ver 2.3
[   13.688355] Bluetooth: HCI UART protocol H4 registered
[   13.688361] Bluetooth: HCI UART protocol Three-wire (H5) registered
[   13.688589] Bluetooth: HCI UART protocol Broadcom registered
[   18.863561] systemd[1]: apt-daily.timer: Adding 6h 56min 19.812726s random time.
[   18.865315] systemd[1]: apt-daily-upgrade.timer: Adding 57min 19.609548s random time.
[   19.114003] EXT4-fs (mmcblk0p2): resized to 1572864 blocks
[   19.802250] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[   19.802261] Bluetooth: BNEP filters: protocol multicast
[   19.802284] Bluetooth: BNEP socket layer initialized
[   19.863425] Adding 102396k swap on /var/swap.  Priority:-2 extents:1 across:102396k SSFS
[   43.322776] EXT4-fs (mmcblk0p2): resized to 3145728 blocks
[   51.652015] EXT4-fs (mmcblk0p2): resized filesystem to 3897088
[   60.959601] systemd[1]: apt-daily.timer: Adding 6h 35min 27.035347s random time.
[   60.961564] systemd[1]: apt-daily-upgrade.timer: Adding 40min 52.921030s random time.
[   62.394188] nf_conntrack version 0.5.0 (15360 buckets, 61440 max)

I've finished writing the OpenPLC driver for Neurons. The installation instructions can be found here: http://www.openplcproject.com/getting-started-neuron

All my tests were made on the small Neuron S103 and everything went great. Given that there are several different Neuron models available, I tried to create a generic driver "one-for-all" kinda style. To achieve that, upon driver initialization it scans the entire SYSFS path to find all possible combinations of I/Os so that the driver can map them all and work with different flavors of Neurons.

So I decided to try this new driver with a Neuron M503 my University bought. This is when I found a weird problem. When OpenPLC driver is scanning for I/Os, it fails with weird error messages when it touches /sys/devices/platform/unipi_plc/io_group2/ao_2_1 (which is the first analog output of the second circuit). I found it interesting and decided to just perform a simple sudo cat /sys/devices/platform/unipi_plc/io_group2/ao_2_1/out_voltage0_raw. This is what I'm getting:

pi@M503-sn22:/sys/devices/platform/unipi_plc/io_group2/ao_2_1 $ sudo cat out_voltage0_raw

Message from syslogd@unipi at Oct 11 14:15:54 ...
 kernel:[   71.866261] Internal error: Oops: 80000007 [#1] SMP ARM

Message from syslogd@unipi at Oct 11 14:15:54 ...
 kernel:[   71.916128] Process cat (pid: 1007, stack limit = 0xb90a4210)

Message from syslogd@unipi at Oct 11 14:15:54 ...
 kernel:[   71.918862] Stack: (0xb90a5dc8 to 0xb90a6000)

Message from syslogd@unipi at Oct 11 14:15:54 ...
 kernel:[   71.921548] 5dc0:                   00000000 00000001 00000001 00000002 014000c0 80276984

Message from syslogd@unipi at Oct 11 14:15:54 ...
 kernel:[   71.926833] 5de0: b90a5e34 b90a5df0 80276984 b6acbb00 b90e8280 8083bd4c b90a5e1c b90a5e08

Message from syslogd@unipi at Oct 11 14:15:54 ...
 kernel:[   71.932061] 5e00: 8053d6f8 7f4147bc b6acbb00 00001000 b90a5e44 b90a5e20 80309218 8053d6d8

Message from syslogd@unipi at Oct 11 14:15:54 ...
 kernel:[   71.937300] 5e20: b6acbb00 00000001 00000000 00000001 b6a2c000 b90a5f80 b90a5e54 b90a5e48

Message from syslogd@unipi at Oct 11 14:15:54 ...
 kernel:[   71.942696] 5e40: 80307a6c 8030918c b90a5ea4 b90a5e58 802b15ec 80307a44 00000000 b6acbb30

Message from syslogd@unipi at Oct 11 14:15:54 ...
 kernel:[   71.948424] 5e60: 76c6d000 00020000 00000000 00000000 bab4d488 00000000 b90a5ea4 00020000

Message from syslogd@unipi at Oct 11 14:15:54 ...
 kernel:[   71.954374] 5e80: b90a5f80 76c6d000 b90a5f80 00020000 b6acbf00 00000000 b90a5edc b90a5ea8

Message from syslogd@unipi at Oct 11 14:15:54 ...
 kernel:[   71.960555] 5ea0: 80308884 802b1414 00000000 00100073 00000000 b6a2c000 b90a5f80 76c6d000

Message from syslogd@unipi at Oct 11 14:15:54 ...
 kernel:[   71.967044] 5ec0: b90a5f80 00020000 b90a4000 00000000 b90a5f4c b90a5ee0 8028a624 8030875c

Message from syslogd@unipi at Oct 11 14:15:54 ...
 kernel:[   71.973667] 5ee0: 76c6c000 b90a5fb0 00001000 000001ff b90a5fac b90a5f00 801011e4 807a0468

Message from syslogd@unipi at Oct 11 14:15:54 ...
 kernel:[   71.980479] 5f00: b90a5f48 00000003 00022000 00000000 00000000 80242100 b90a5f74 8028a790

Message from syslogd@unipi at Oct 11 14:15:54 ...
 kernel:[   71.987419] 5f20: 80242100 8016cd34 00020000 b6a2c000 76c6d000 b90a5f80 80108204 b90a4000

Message from syslogd@unipi at Oct 11 14:15:54 ...
 kernel:[   71.994397] 5f40: b90a5f7c b90a5f50 8028a7b8 8028a5f8 00000022 802aadf8 b90a5f7c b6a2c000

Message from syslogd@unipi at Oct 11 14:15:54 ...
 kernel:[   72.001376] 5f60: b6a2c000 00020000 76c6d000 80108204 b90a5fa4 b90a5f80 8028ad68 8028a728

Message from syslogd@unipi at Oct 11 14:15:54 ...
 kernel:[   72.005460] 5f80: 00000000 00000000 00020000 7fffe000 00020000 00000003 00000000 b90a5fa8

Message from syslogd@unipi at Oct 11 14:15:54 ...
 kernel:[   72.008963] 5fa0: 80108060 8028ad20 00020000 7fffe000 00000003 76c6d000 00020000 00027184

Message from syslogd@unipi at Oct 11 14:15:54 ...
 kernel:[   72.012467] 5fc0: 00020000 7fffe000 00020000 00000003 00000003 00020000 ffffffff 00000000

Message from syslogd@unipi at Oct 11 14:15:54 ...
 kernel:[   72.015970] 5fe0: 00000000 7eccf584 000141cc 76eea0cc 60000010 00000003 00000000 00000000

Message from syslogd@unipi at Oct 11 14:15:54 ...
 kernel:[   72.047731] Code: bad PC value
Segmentation fault

I thought it could be a bad image or corrupted filesystem, so I removed the SD card, reflashed it with a brand new image of UniPian freshly downloaded from here: https://kb.unipi.technology/files:software:os-images:00-start

Without even touching on anything, I just restarted the device, waited for a few minutes and repeat the simple cat command. Same error. I don't know if I have a faulty device or if the SYSFS driver is buggy. I don't have this problem with any other IO besides analog outputs on the second circuit (i.e. sudo cat /sys/devices/platform/unipi_plc/io_group2/ai_2_4/in_voltage0_raw works fine). Any hints?

Hi Tomas! Wow, I wish I had found those documents before. This is exactly what I need. Well, it took me 30 seconds to configure the built-in UniPi Modbus server as a slave device on OpenPLC. I just had to provide the Modbus addresses on the web interface and boom, everything working. This by itself is already a lot faster than using EVOK, however, I think that using SYSFS on a specially crafted driver for UniPi will be a better approach. So now I'll convert the OpenPLC driver I wrote using EVOK to read/write directly from SYSFS.

Once everything is working and tested appropriately, would you mind putting OpenPLC as an open source option on the softwares page for the Neuron?

Tomas,

So far my experience with EVOK has been interesting. The system offers a lot of capability, but at the same time it seems to be a heavy layer between the hardware. OpenPLC needs a faster way to access GPIO. While using EVOK, OpenPLC slows down considerably. I believe that there might be optimizations that can be done on the OpenPLC hardware driver side, but still I'm not expecting to achieve great speeds with this.

For UniPi v1.1 I wrote a driver that has direct access to hardware, so now I would like to do the same thing with the Neuron devices. I know that the Neuron architecture is a lot more complicated than the first UniPi, but still I would like to try writing a rudimentary driver that allows at least to read and write local I/O.

So, could you explain a bit how EVOK communicates with the internal microcontroller? Are they using Modbus? If so, what is the configuration (baud rate, etc, etc) and the register addresses? If the internal communication is in fact Modbus, I can use OpenPLC's Modbus driver to talk to it, and done!