I am attempting to use a TCA8418 keypad (which operates over I2C) and I have the driver loaded into the kernel, but the device was not recognized so I am instantiating it myself and am unable to bind the driver. I get the following error:

# echo -n "1-0034" > /sys/bus/i2c/drivers/tca8418_keypad/bind
-bash: echo: write error: No such device

This is after having tried the following (as root):

# echo -n "tca8418_keypad" 0x34 > /sys/bus/i2c/devices/i2c-1/new_device

I have the following device and driver trees, respectively:

|-- modalias
|-- name
|-- power
|   |-- autosuspend_delay_ms
|   |-- control
|   |-- runtime_active_time
|   |-- runtime_status
|   `-- runtime_suspended_time
|-- subsystem -> ../../../../../bus/i2c
`-- uevent

|-- bind
|-- module -> ../../../../module/tca8418_keypad
|-- uevent
`-- unbind

I have used the following for reference thus far, but neither seems to work completely:

I have run out of ideas and could use some suggestions. Am I even approaching this the right way?

I'm running Debian on an ARM single board computer if that matters.


I have since discovered that I am receiving the following error when I instantiate the new device:

tca8418_keypad: probe of 1-0034 failed with error -22

I was missing platform data for this device.

I was able to get it working by inserting the platform data directly into the code for the driver module:

static uint32_t tca8418_km_data[] = {
    KEY(0, 0, KEY_F1),
    KEY(0, 1, KEY_F2),
    KEY(0, 2, KEY_F3),

static const struct matrix_keymap_data tca8418_mk_data = {
    .keymap         = tca8418_km_data,
    .keymap_size    = ARRAY_SIZE(tca8418_km_data),

static struct tca8418_keypad_platform_data my_tca8418_plat_data = {
    .keymap_data    = &tca8418_mk_data,
    .rows           = 6,
    .cols           = 8,
    .rep            = 1,
    .irq_is_gpio    = 1,

static struct i2c_board_info tca8418_board_info __initdata = {
    I2C_BOARD_INFO("tca8418_keypad", 0x34),
    .platform_data  = &my_tca8418_plat_data,
    .irq            = 16, // GPIO pin 16

Then adding this to the __init function:

static int __init tca8418_keypad_init(void)
    struct i2c_adapter *i2c_adap;
    i2c_adap = i2c_get_adapter(1);
    i2c_new_device(i2c_adap, &tca8418_board_info);

This is not the most elegant of fixes, but it worked for me. I would have preferred a userspace solution, but I was unable to find one.

  • It should be done via DT or ACPI.
    – 0andriy
    Nov 17 '19 at 11:56

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