[PATCH v3 2/4] Input: adc-keys - support EV_SW as well, not just EV_KEY.

Nicolas Frattaroli
2026-04-08T17:50:32Z

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.

Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.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);

--
2.53.0