[solved] macro expansion in kscan [wasn't detecting dts bindings] | ZMK | Page 1

haughty harness Sep 26, 2025, 10:46 AM

#

I am getting an error when trying to compile my custom kscan, due to an error in the expansion of this macro (error and devicetree bindings attached in next message):

#define KSCAN_JOYSTICK_INIT(n)                                                                      \
    static struct kscan_joystick_data kscan_joystick_data_##n = {};                                 \
                                                                                                    \
    static const struct kscan_joystick_config kscan_joystick_config_##n = {                         \
        .idle_period_ms = DT_INST_PROP_OR(n, idle_period_ms, 100),                                  \
        .poll_period_ms = DT_INST_PROP_OR(n, poll_period_ms, 10),                                   \
        .adc_0 = ADC_DT_SPEC_GET_BY_IDX(DT_DRV_INST(n), 0),                                         \
        .adc_1 = ADC_DT_SPEC_GET_BY_IDX(DT_DRV_INST(n), 1),                                         \
        .angle_offset  = DT_INST_PROP_OR(n, angle_offset, 0),                                       \
    };                                                                                              \
                                                                                                    \
    PM_DEVICE_DT_INST_DEFINE(n, kscan_joystick_pm_action);                                          \
                                                                                                    \
    DEVICE_DT_INST_DEFINE(n, &kscan_joystick_init, PM_DEVICE_DT_INST_GET(n),                        \
                          &kscan_joystick_data_##n, &kscan_joystick_config_##n, POST_KERNEL,        \
                          CONFIG_KSCAN_INIT_PRIORITY, &kscan_joystick_api);

DT_INST_FOREACH_STATUS_OKAY(KSCAN_JOYSTICK_INIT);

#

devicetree bindings

# Copyright (c) 2020, Pete Johanson
# SPDX-License-Identifier: MIT

description: Joystick as a directional switch

compatible: "zmk,kscan-joystick"

include: kscan.yaml

properties:
  io-channels:
    type: phandle-array
    required: true
    description: |
      ADC channels connected to joystick axes.
      First channel is for X-axis, second for Y-axis.
  idle-period-ms:
    type: int
    default: 100
    description: Time between reads in milliseconds when joystick is in the center.
  poll-period-ms:
    type: int
    default: 10
    description: Time between reads in milliseconds when joystick is not in the center.
  angle-offset:
    type: int
    default: 0
    description: The amount of degrees which the angle will be offset by. Must not be negative.

#

error (from github actions)

📎 message.txt

#

github: https://github.com/letmegobacktosleep/zmk-keyboard-joystick-wasd/blob/2c0be5169c6f64c85d2108e15354c9a64fab7671/module/drivers/kscan/kscan_joystick.c#L240-L258

GitHub

zmk-keyboard-joystick-wasd/module/drivers/kscan/kscan_joystick.c at...

An attempt at making a joystick act as a four-directional switch, in a keyboard. - letmegobacktosleep/zmk-keyboard-joystick-wasd

#

help with macro expansion in kscan

#

oh wait

#

my devicetree is wrong
but that doesn't change the error

#

I think the issue is the expansion of this
https://docs.zephyrproject.org/apidoc/latest/group__devicetree-inst.html#ga219f413efba2f4c0151468b9a25a8dc1
https://docs.zephyrproject.org/apidoc/latest/group__adc__interface.html#gae9867df7a034d45ed3d3c58c69c246ed
and it is related to whatever is going on in this DT_DRV_INST(n)
DT_DRV_COMPAT was defined as #define DT_DRV_COMPAT zmk_kscan_joystick
(not sure if this is relevant, but apparently you need DT_DRV_COMPAT defined to use DT_DRV_INST)

haughty harness Sep 26, 2025, 12:55 PM

#

https://devzone.nordicsemi.com/f/nordic-q-a/110807/nrf5340_audio
"It looks like you are missing a configuration for your custom board"

#

I have no clue what this means

#

https://github.com/letmegobacktosleep/zmk-keyboard-joystick-wasd/actions/runs/18033066283/job/51313734115#step:11:421

haughty harness Sep 27, 2025, 7:45 AM

#

this is the devicetree_generated.h when I tried to compile with the following macro definition

#define KSCAN_JOYSTICK_INIT(n)                                                                 \
    static struct kscan_joystick_data kscan_joystick_data_##n = {};                            \
                                                                                               \
    const struct device *adc_dev = DT_DRV_INST(n);                                             \
                                                                                               \
    static const struct kscan_joystick_config kscan_joystick_config_##n = {                    \
        .idle_period_ms = DT_INST_PROP_OR(n, idle_period_ms, 100),                             \
        .poll_period_ms = DT_INST_PROP_OR(n, poll_period_ms, 10),                              \
        /*.adc_0 = ADC_DT_SPEC_GET_BY_IDX(adc_dev, 0),                                         \
        .adc_1 = ADC_DT_SPEC_GET_BY_IDX(adc_dev, 1),*/                                         \
        .angle_offset  = DT_INST_PROP_OR(n, angle_offset, 0),                                  \
    };                                                                                         \
                                                                                               \
    PM_DEVICE_DT_INST_DEFINE(n, kscan_joystick_pm_action);                                     \
                                                                                               \
    DEVICE_DT_INST_DEFINE(n, &kscan_joystick_init, PM_DEVICE_DT_INST_GET(n),                   \
                          &kscan_joystick_data_##n, &kscan_joystick_config_##n, POST_KERNEL,   \
                          CONFIG_KSCAN_INIT_PRIORITY, &kscan_joystick_api);

DT_INST_FOREACH_STATUS_OKAY(KSCAN_JOYSTICK_INIT);

line 4475 is the devicetree node for kscan_joystick in the attached file:

📎 devicetree_generated.h

haughty harness Sep 27, 2025, 7:46 AM

#

haughty harness this is the devicetree_generated.h when I tried to compile with the following ma...

this was the error when I compiled with this

📎 message.txt

#

it compiles just fine if I comment out the code which fetches the ADC using ADC_DT_SPEC_GET_BY_IDX
but when I tried to add in const struct device *adc_dev = DT_DRV_INST(n); to see why getting the device node identifier fails, then the above error occurs

#

which is really confusing since DT_INST_PROP_OR(n, idle_period_ms, 100) expands to DT_PROP_OR(DT_DRV_INST(n), idle_period_ms, 100) and it doesn't raise any compile errors

opal bridge Sep 27, 2025, 8:05 AM

#

if it compiles just fine, something may be related or may not. https://github.com/badjeff/zmk-analog-input-driver?tab=readme-ov-file#troubleshooting

#

need patching oversampling value for nrf5 mcu for your kscan bits

haughty harness Sep 27, 2025, 8:14 AM

#

opal bridge if it compiles just fine, something may be related or may not. https://github.co...

changing the oversampling to 0 does not fix the error, the error is still the exact same

#

the "compiles just fine" is when there's nothing related to DT_DRV_INST(n) or DT_INST(n, zmk_kscan_joystick) or ADC_DT_SPEC_GET_BY_IDX

#define KSCAN_JOYSTICK_INIT(n)                                                                 \
                                                                                               \
    static struct kscan_joystick_data kscan_joystick_data_##n = {};                            \
                                                                                               \
    static const struct kscan_joystick_config kscan_joystick_config_##n = {                    \
        .idle_period_ms = DT_INST_PROP_OR(n, idle_period_ms, 100),                             \
        .poll_period_ms = DT_INST_PROP_OR(n, poll_period_ms, 10),                              \
        .angle_offset  = DT_INST_PROP_OR(n, angle_offset, 0),                                  \
    };                                                                                         \
                                                                                               \
    PM_DEVICE_DT_INST_DEFINE(n, kscan_joystick_pm_action);                                     \
                                                                                               \
    DEVICE_DT_INST_DEFINE(n, &kscan_joystick_init, PM_DEVICE_DT_INST_GET(n),                   \
                          &kscan_joystick_data_##n, &kscan_joystick_config_##n, POST_KERNEL,   \
                          CONFIG_KSCAN_INIT_PRIORITY, &kscan_joystick_api);

DT_INST_FOREACH_STATUS_OKAY(KSCAN_JOYSTICK_INIT);

#

but I do need to fetch the io-channels

haughty harness Sep 27, 2025, 8:39 AM

#

haughty harness changing the oversampling to 0 does not fix the error, the error is still the ex...

the compilation for battery_nrf_vddh.c occurs after it attempts to compile my kscan so I dont' think this is relevant

opal bridge Sep 27, 2025, 8:39 AM

#

better to usezephyr way to obtain ADC device by ADC_DT_SPEC_GET_BY_IDX

haughty harness Sep 27, 2025, 8:41 AM

#

haughty harness I am getting an error when trying to compile my custom kscan, due to an error in...

I was using ADC_DT_SPEC_GET_BY_IDX but regardless of whether I use

ADC_DT_SPEC_GET_BY_IDX(DT_DRV_INST(n), 0)
ADC_DT_SPEC_GET_BY_IDX(DT_INST(n, zmk_kscan_joystick), 0)
// DT_DRV_INST(n) or DT_INST(n, zmk_kscan_joystick) should return a node identifier but the macro doesn't expand properly i.e. either can't find the node or the compiler is bugging out
ADC_DT_SPEC_GET_BY_IDX(n, 0)
// this shouldn't work as n isn't a node

it has some issue with macro expansion

opal bridge Sep 27, 2025, 8:47 AM

#

i think you can useADC_DT_SPEC_GET_BY_IDX(n, 0) only if it was called in a macro argument of DT_INST_FOREACH_STATUS_OKAY. Here is an another example from George.

haughty harness Sep 27, 2025, 8:48 AM

#

KSCAN_JOYSTICK_INIT is being called by DT_INST_FOREACH_STATUS_OKAY(KSCAN_JOYSTICK_INIT);
I'll have a look at the example you sent

opal bridge Sep 27, 2025, 8:50 AM

#

FWIW ADC_DT_SPEC_INST_GET_BY_IDX is hardcoded to read attributes fromio-channels = <&adc 5>, <&adc 7>;

haughty harness Sep 27, 2025, 8:51 AM

#

my overlay defines them like this inside the root? node (the one that starts with /{):

    kscan3: kscan_joystick {
        compatible = "zmk,kscan-joystick";
        status = "okay";
        /* Add this back in after it can compile... wakeup-source; */
        io-channels = <&adc 0>, <&adc 7>;
        io-channel-names = "x-axis", "y-axis";
    };

#

ignore what it was before the edit, I was commenting it out to see if it would give a different error

haughty harness Sep 27, 2025, 9:16 AM

#

ohmygod

#

this is such a stupid mistake

#

I had the dts_root misconfigured in build.yaml

#

welp at least I learnt a lot more about zephyr

#

closing the post

#[solved] macro expansion in kscan [wasn't detecting dts bindings]