Hello, so I’ve created a custom Yocto image for use with the CN0540 from Analog Devices and the DE10-Nano. The image uses the ADI kernel fork, socfpga_adi_defconfig kernel config, the CN0540 device tree for the DE10-Nano, and programs the FPGA with CN0540 HDL at U-boot. I’ve also added libiio to the image.
The device programs the FPGA and boots without issue, > iio_info returns:
Library version: 0.23 (git tag: 92d6a35)
Compiled with backends: local xml ip usb serial
IIO context created with local backend.
Backend version: 0.23 (git tag: 92d6a35)
Backend description string: Linux VibMonProto 5.15.0-yocto-standard-adi #1 SMP Thu Apr 27 16:34:06 UTC 2023 armv7l
IIO context has 2 attributes:
local,kernel: 5.15.0-yocto-standard-adi
uri: local:
IIO context has 5 devices:
iio:device0: ad7768-1 (buffer capable)
1 channels found:
voltage0: (input, index: 0, format: le:s24/32>>8)
3 channel-specific attributes found:
attr 0: label value: (null)
attr 1: raw value: -2246463
attr 2: scale value: 0.000488281
4 device-specific attributes found:
attr 0: common_mode_voltage value: (AVDD1-AVSS)/2
attr 1: common_mode_voltage_available value: (AVDD1-AVSS)/2 2V5 2V05 1V9 1V65 1V1 0V9 OFF
attr 2: sampling_frequency value: 256000
attr 3: sampling_frequency_available value: 256000 128000 64000 32000 16000 8000 4000 2000 1000
3 buffer-specific attributes found:
attr 0: data_available value: 0
attr 1: length_align_bytes value: 16
attr 2: watermark value: 2048
1 debug attributes found:
debug attr 0: direct_reg_access value: 0x0
No trigger on this device
iio:device1: ltc2308
8 channels found:
voltage6: (input)
2 channel-specific attributes found:
attr 0: raw value: 175
attr 1: scale value: 1.000000000
voltage3: (input)
2 channel-specific attributes found:
attr 0: raw value: 163
attr 1: scale value: 1.000000000
voltage7: (input)
2 channel-specific attributes found:
attr 0: raw value: 166
attr 1: scale value: 1.000000000
voltage0: (input)
2 channel-specific attributes found:
attr 0: raw value: 162
attr 1: scale value: 1.000000000
voltage4: (input)
2 channel-specific attributes found:
attr 0: raw value: 169
attr 1: scale value: 1.000000000
voltage1: (input)
2 channel-specific attributes found:
attr 0: raw value: 165
attr 1: scale value: 1.000000000
voltage5: (input)
2 channel-specific attributes found:
attr 0: raw value: 168
attr 1: scale value: 1.000000000
voltage2: (input)
2 channel-specific attributes found:
attr 0: raw value: 161
attr 1: scale value: 1.000000000
2 device-specific attributes found:
attr 0: sleep_mode value: DISABLED
attr 1: sleep_mode_available value: DISABLED ENABLED
No trigger on this device
iio:device2: one-bit-adc-dac
8 channels found:
voltage0: (input)
2 channel-specific attributes found:
attr 0: label value: cn0540_sw_ff_gpio
attr 1: raw value: 0
voltage1: (output)
2 channel-specific attributes found:
attr 0: label value: cn0540_red_led
attr 1: raw value: 0
voltage5: (output)
2 channel-specific attributes found:
attr 0: label value: cn0540_FDA_DIS
attr 1: raw value: 0
voltage0: (output)
2 channel-specific attributes found:
attr 0: label value: cn0540_blue_led
attr 1: raw value: 0
voltage3: (output)
2 channel-specific attributes found:
attr 0: label value: cn0540_ad7768-1-gpio0
attr 1: raw value: 0
voltage6: (output)
2 channel-specific attributes found:
attr 0: label value: cn0540_FDA_MODE
attr 1: raw value: 0
voltage2: (output)
2 channel-specific attributes found:
attr 0: label value: cn0540_shutdown_gpio
attr 1: raw value: 0
voltage4: (output)
2 channel-specific attributes found:
attr 0: label value: cn0540_ad7768-1-gpio1
attr 1: raw value: 0
No trigger on this device
iio:device3: ltc2606
1 channels found:
voltage0: (output)
5 channel-specific attributes found:
attr 0: powerdown value: 0
attr 1: powerdown_mode value: 90kohm_to_gnd
attr 2: powerdown_mode_available value: 90kohm_to_gnd
attr 3: raw value: 32768
attr 4: scale value: 0.062500000
No trigger on this device
iio_sysfs_trigger:
0 channels found:
2 device-specific attributes found:
attr 0: add_trigger ERROR: Permission denied (13)
attr 1: remove_trigger ERROR: Permission denied (13)
No trigger on this device
but when I run > iio_readdev ad7768-1 I get Unable to refill buffer: Connection timed out (110)
If I use sysfs at /sys/bus/iio I can read a single reading, but the buffer doesn’t work. If I try to read the buffer with cat /dev/iio:device0 | hexdump the device crashes, unless I set the length of the buffer to 1 then it gives the output:
[ 441.310599] rcu: INFO: rcu_sched self-detected stall on CPU
[ 441.316258] rcu: 0-....: (2099 ticks this GP) idle=10f/1/0x40000002 softirq=2509/2509 fqs=1033
[ 441.325163] (t=2100 jiffies g=497 q=7)
[ 441.329057] NMI backtrace for cpu 0
[ 441.332592] CPU: 0 PID: 163 Comm: cat Not tainted 5.15.0-yocto-standard-adi #1
[ 441.339927] Hardware name: Altera SOCFPGA
[ 441.343988] Backtrace:
[ 441.346453] [<c0d914b0>] (dump_backtrace) from [<c0d916fc>] (show_stack+0x20/0x24)
[ 441.354073] r7:c010edfc r6:00000000 r5:60070193 r4:c143b218
[ 441.359801] [<c0d916dc>] (show_stack) from [<c0d94ecc>] (dump_stack_lvl+0x48/0x54)
[ 441.367360] [<c0d94e84>] (dump_stack_lvl) from [<c0d94ef0>] (dump_stack+0x18/0x1c)
[ 441.374907] r5:00000000 r4:20070193
[ 441.378525] [<c0d94ed8>] (dump_stack) from [<c05850fc>] (nmi_cpu_backtrace+0xe0/0x114)
[ 441.386424] [<c058501c>] (nmi_cpu_backtrace) from [<c0585218>] (nmi_trigger_cpumask_backtrace+0xe8/0x134)
[ 441.395965] r7:c010edfc r6:c0e01ee4 r5:c170469c r4:00000000
[ 441.401597] [<c0585130>] (nmi_trigger_cpumask_backtrace) from [<c010fd68>] (arch_trigger_cpumask_backtrace+0x20/0x24)
[ 441.412180] r9:c1703f10 r8:c0e01ee0 r7:c1835438 r6:00000000 r5:c1703fa4 r4:c171e840
[ 441.419886] [<c010fd48>] (arch_trigger_cpumask_backtrace) from [<c0d9340c>] (rcu_dump_cpu_stacks+0x144/0x174)
[ 441.429922] [<c0d932c8>] (rcu_dump_cpu_stacks) from [<c0198490>] (rcu_sched_clock_irq+0x6a8/0xa58)
[ 441.438860] r10:2e138000 r9:c1702d00 r8:c1693f40 r7:c18361a0 r6:00000000 r5:ef7cbf40
[ 441.446784] r4:c171e840
[ 441.449304] [<c0197de8>] (rcu_sched_clock_irq) from [<c01a354c>] (update_process_times+0x98/0xc4)
[ 441.458174] r10:c1702d80 r9:c1702d40 r8:c184fd40 r7:2e138000 r6:c1702d00 r5:00000000
[ 441.465969] r4:ef7c5540
[ 441.468524] [<c01a34b4>] (update_process_times) from [<c01b74e0>] (tick_sched_timer+0x88/0x2d8)
[ 441.477198] r7:c1ea9dc0 r6:00000066 r5:bf87a4da r4:ef7c6128
[ 441.482830] [<c01b7458>] (tick_sched_timer) from [<c01a4260>] (__hrtimer_run_queues+0x1fc/0x36c)
[ 441.491730] r10:ef7c5e14 r9:ef7c6128 r8:20070193 r7:00000000 r6:c01b7458 r5:ef7c5dc0
[ 441.499645] r4:ef7c5e00
[ 441.502183] [<c01a4064>] (__hrtimer_run_queues) from [<c01a5158>] (hrtimer_interrupt+0x13c/0x2c8)
[ 441.511041] r10:ef7c5e98 r9:ef7c5e70 r8:ef7c5e48 r7:ef7c5dcc r6:00000003 r5:20070193
[ 441.518836] r4:ef7c5dc0
[ 441.521357] [<c01a501c>] (hrtimer_interrupt) from [<c0110744>] (twd_handler+0x44/0x4c)
[ 441.529394] r10:c1ea8000 r9:c1ea9dc0 r8:f080210c r7:c1d08240 r6:00000018 r5:c17046b4
[ 441.537301] r4:00000001
[ 441.539821] [<c0110700>] (twd_handler) from [<c01838c8>] (handle_percpu_devid_irq+0x9c/0x200)
[ 441.548321] r5:c17046b4 r4:c1d09000
[ 441.551888] [<c018382c>] (handle_percpu_devid_irq) from [<c017ced4>] (handle_domain_irq+0x6c/0x88)
[ 441.560961] r7:0000001d r6:00000000 r5:00000000 r4:c1692a14
[ 441.566593] [<c017ce68>] (handle_domain_irq) from [<c0101300>] (gic_handle_irq+0x88/0x9c)
[ 441.574767] r7:c1692a20 r6:f0802100 r5:c177a344 r4:c17046b4
[ 441.580494] [<c0101278>] (gic_handle_irq) from [<c0100afc>] (__irq_svc+0x5c/0x78)
[ 441.587952] Exception stack(0xc1ea9dc0 to 0xc1ea9e08)
[ 441.593047] 9dc0: c28b3700 00000000 00000000 00000003 00001000 c28b3700 c2b47f40 befe9c04
[ 441.601193] 9de0: c28b3774 befe9c04 c1ea8000 c1ea9e24 c1ea9e28 c1ea9e10 c0a95530 c0a949ac
[ 441.609342] 9e00: 20070013 ffffffff
[ 441.612863] r9:c1ea8000 r8:c28b3774 r7:c1ea9df4 r6:ffffffff r5:20070013 r4:c0a949ac
[ 441.620699] [<c0a949a0>] (iio_dma_buffer_dequeue) from [<c0a95530>] (iio_dma_buffer_read+0x148/0x19c)
[ 441.629894] r5:c28b3700 r4:00001000
[ 441.633452] [<c0a953e8>] (iio_dma_buffer_read) from [<c0952618>] (iio_buffer_read+0x178/0x228)
[ 441.642168] r10:c1ea8000 r9:befe9c04 r8:00001000 r7:00000400 r6:00000002 r5:c1e43000
[ 441.649962] r4:c28b3700
[ 441.652483] [<c09524a0>] (iio_buffer_read) from [<c0954b24>] (iio_buffer_read_wrapper+0x2c/0x38)
[ 441.661248] r10:00000003 r9:c0954af8 r8:00001000 r7:00000001 r6:c1ea8000 r5:c1ea9f60
[ 441.669050] r4:c2b28540
[ 441.671571] [<c0954af8>] (iio_buffer_read_wrapper) from [<c02b2da8>] (vfs_read+0xc4/0x320)
[ 441.679817] [<c02b2ce4>] (vfs_read) from [<c02b348c>] (ksys_read+0x74/0xec)
[ 441.686766] r10:00000003 r9:00000000 r8:00000000 r7:befe9c04 r6:c1ea8000 r5:c2b28540
[ 441.694560] r4:c2b28540
[ 441.697081] [<c02b3418>] (ksys_read) from [<c02b351c>] (sys_read+0x18/0x1c)
[ 441.704027] r9:c1ea8000 r8:c0100244 r7:00000003 r6:b6f681a0 r5:befe9c04 r4:00001000
[ 441.711733] [<c02b3504>] (sys_read) from [<c0100060>] (ret_fast_syscall+0x0/0x48)
[ 441.719310] Exception stack(0xc1ea9fa8 to 0xc1ea9ff0)
[ 441.724344] 9fa0: 00001000 befe9c04 00000003 befe9c04 00001000 00000000
[ 441.732488] 9fc0: 00001000 befe9c04 b6f681a0 00000003 00000000 01000000 00000003 befe9c04
[ 441.740769] 9fe0: 00000003 befe9bb8 b6e6070f b6de1ae6
which repeats every ~20 seconds.
Am I missing a step for using iio devices?