Re: [PATCH v2 2/4] Input: adc-keys - support EV_SW as well, not just EV_KEY.

Alexandre Belloni
2025-12-16T08:46:17Z

On 15/12/2025 13:29:30+0100, Nicolas Frattaroli wrote:
> Instead of doing something like what gpio-keys is doing, adc-keys
> hardcodes that all keycodes must be of type EV_KEY.
>
> This limits the usefulness of adc-keys, and overcomplicates the code
> with manual bit-setting logic.
>
> Instead, refactor the code to read the linux,input-type fwnode property,
> and get rid of the custom bit setting logic, replacing it with
> input_set_capability instead. input_report_key is replaced with
> input_event, which allows us to explicitly pass the type.
>
> Only EV_KEY and EV_SW is allowed at this stage.
>
> Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>

Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

> ---
> drivers/input/keyboard/adc-keys.c | 37 +++++++++++++++++++++++++------------
> 1 file changed, 25 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/input/keyboard/adc-keys.c b/drivers/input/keyboard/adc-keys.c
> index f1753207429d..62376f34f7d0 100644
> --- a/drivers/input/keyboard/adc-keys.c
> +++ b/drivers/input/keyboard/adc-keys.c
> @@ -18,13 +18,15 @@
>
> struct adc_keys_button {
> u32 voltage;
> - u32 keycode;
> + u32 code;
> + u32 type;
> };
>
> struct adc_keys_state {
> struct iio_channel *channel;
> u32 num_keys;
> u32 last_key;
> + u32 last_type;
> u32 keyup_voltage;
> const struct adc_keys_button *map;
> };
> @@ -34,7 +36,8 @@ static void adc_keys_poll(struct input_dev *input)
> struct adc_keys_state *st = input_get_drvdata(input);
> int i, value, ret;
> u32 diff, closest = 0xffffffff;
> - int keycode = 0;
> + u32 code = 0;
> + u32 type = EV_KEY;
>
> ret = iio_read_channel_processed(st->channel, &value);
> if (unlikely(ret < 0)) {
> @@ -45,22 +48,24 @@ static void adc_keys_poll(struct input_dev *input)
> diff = abs(st->map[i].voltage - value);
> if (diff < closest) {
> closest = diff;
> - keycode = st->map[i].keycode;
> + code = st->map[i].code;
> + type = st->map[i].type;
> }
> }
> }
>
> if (abs(st->keyup_voltage - value) < closest)
> - keycode = 0;
> + code = 0;
>
> - if (st->last_key && st->last_key != keycode)
> - input_report_key(input, st->last_key, 0);
> + if (st->last_key && st->last_key != code)
> + input_event(input, st->last_type, st->last_key, 0);
>
> - if (keycode)
> - input_report_key(input, keycode, 1);
> + if (code)
> + input_event(input, type, code, 1);
>
> input_sync(input);
> - st->last_key = keycode;
> + st->last_key = code;
> + st->last_type = type;
> }
>
> static int adc_keys_load_keymap(struct device *dev, struct adc_keys_state *st)
> @@ -88,11 +93,20 @@ static int adc_keys_load_keymap(struct device *dev, struct adc_keys_state *st)
> map[i].voltage /= 1000;
>
> if (fwnode_property_read_u32(child, "linux,code",
> - &map[i].keycode)) {
> + &map[i].code)) {
> dev_err(dev, "Key with invalid or missing linux,code\n");
> return -EINVAL;
> }
>
> + if (fwnode_property_read_u32(child, "linux,input-type",
> + &map[i].type))
> + map[i].type = EV_KEY;
> +
> + if (map[i].type != EV_KEY && map[i].type != EV_SW)
> + return dev_err_probe(dev, -EINVAL,
> + "Invalid linux,input-type: 0x%x\n",
> + map[i].type);
> +
> i++;
> }
>
> @@ -156,9 +170,8 @@ static int adc_keys_probe(struct platform_device *pdev)
> input->id.product = 0x0001;
> input->id.version = 0x0100;
>
> - __set_bit(EV_KEY, input->evbit);
> for (i = 0; i < st->num_keys; i++)
> - __set_bit(st->map[i].keycode, input->keybit);
> + input_set_capability(input, st->map[i].type, st->map[i].code);
>
> if (device_property_read_bool(dev, "autorepeat"))
> __set_bit(EV_REP, input->evbit);
>
> --
> 2.52.0
>

--
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering