Help understand GPIO_DT_SPEC_GET_BY_IDX error with a custom gpio binding/overlay

[lingyuan-he]

Hi all,

I am trying to get a custom gpio matrix overlay to work in a toy driver example. I keep running into compile error related to GPIO_DT_SPEC_GET_BY_IDX when I already have #include <zephyr/drivers/gpio.h>.

The binding:

description: ...

compatible: "ledmatrix"

include: base.yaml

properties:
  row-gpio-pins:
    type: phandle-array
    required: true
    description: ...

  col-gpio-pins:
    type: phandle-array
    required: true
    description: ...

The overlay snippet:

ledmatrix_device: ledmatrix-device {
    compaible = "ledmatrix";
    row-gpio-pins = <&gpio0 21 GPIO_ACTIVE_HIGH>,
                    <&gpio0 22 GPIO_ACTIVE_HIGH>,
                    <&gpio0 15 GPIO_ACTIVE_HIGH>,
                    <&gpio0 24 GPIO_ACTIVE_HIGH>,
                    <&gpio0 19 GPIO_ACTIVE_HIGH>;
    col-gpio-pins = <&gpio0 28 GPIO_ACTIVE_LOW>,
                    <&gpio0 11 GPIO_ACTIVE_LOW>,
                    <&gpio0 31 GPIO_ACTIVE_LOW>,
                    <&gpio1  5 GPIO_ACTIVE_LOW>,
                    <&gpio0 30 GPIO_ACTIVE_LOW>;
    status = "okay";
};

In the driver code, trying to static init gpio specs:

struct ledmatrix_config {
    struct gpio_dt_spec rows[NUM_ROW];
    struct gpio_dt_spec cols[NUM_COL];
};


static const struct ledmatrix_config config = {
    .rows = { DT_FOREACH_PROP_ELEM_SEP(DT_NODELABEL(ledmatrix_device), row_gpio_pins,
                                       GPIO_DT_SPEC_GET_BY_IDX, (, )) },
    .cols = { DT_FOREACH_PROP_ELEM_SEP(DT_NODELABEL(ledmatrix_device), col_gpio_pins,
                                       GPIO_DT_SPEC_GET_BY_IDX, (, )) },
};

Compile fails with:

error: 'GPIO_DT_SPEC_GET_BY_IDX' undeclared here (not in a function)
  221 |                                        GPIO_DT_SPEC_GET_BY_IDX, (, )) },
      |                                        ^~~~~~~~~~~~~~~~~~~~~~~
~/zephyrproject/zephyr/include/zephyr/devicetree.h:3279:61: note: in definition of macro 'DT_FOREACH_PROP_ELEM_SEP'
 3279 |         DT_CAT4(node_id, _P_, prop, _FOREACH_PROP_ELEM_SEP)(fn, sep)
      |                                                             ^~
~/zephyrproject/applications/zephyr-example/custom-module/drivers/ledmatrix/ledmatrix.c:221:66: error: expected expression before ',' token
  221 |                                        GPIO_DT_SPEC_GET_BY_IDX, (, )) },
      |                                                                  ^
~/zephyrproject/zephyr/include/zephyr/devicetree.h:3279:65: note: in definition of macro 'DT_FOREACH_PROP_ELEM_SEP'
 3279 |         DT_CAT4(node_id, _P_, prop, _FOREACH_PROP_ELEM_SEP)(fn, sep)
      |                                                                 ^~~
~/zephyrproject/applications/zephyr-example/custom-module/drivers/ledmatrix/ledmatrix.c:221:66: warning: left-hand operand of comma expression has no effect [-Wunused-value]
  221 |                                        GPIO_DT_SPEC_GET_BY_IDX, (, )) },
      |                                                                  ^
~/zephyrproject/zephyr/include/zephyr/devicetree.h:3279:65: note: in definition of macro 'DT_FOREACH_PROP_ELEM_SEP'
 3279 |         DT_CAT4(node_id, _P_, prop, _FOREACH_PROP_ELEM_SEP)(fn, sep)

There is also the message:

~/zephyrproject/applications/zephyr-example/build/zephyr/include/generated/zephyr/devicetree_generated.h:2028:41: warning: implicit declaration of function 'DT_N_S_ledmatrix_device_P_row_gpio_pins_FOREACH_PROP_ELEM_SEP'; did you mean 'DT_N_S_ledmatrix_device_P_status_FOREACH_PROP_ELEM_SEP'? [-Wimplicit-function-declaration]

Which sounds strange and may have pointed to badly defined attribute?

The board I am using is microbit v2, so it already has nordic LED matrix driver. I did referenced the default device tree, and was trying to replicate a simpler binding.

Sorry for the newbie question, appreciate any help here. Thanks.