Input

Events

An event is a type, a code and a value:

• PBL_INPUT_EV_KEY: a key or button, with value 1 when pressed and 0 when released. The codes PBL_INPUT_KEY_BACK, _UP, _SELECT and _DOWN are the watch buttons, set per button in the board configuration; PBL_INPUT_BTN_TOUCH is the touch contact.

• PBL_INPUT_EV_ABS: an absolute axis, PBL_INPUT_ABS_X and _Y in pixels for touch.

• PBL_INPUT_EV_GES: a gesture recognized by the device (tap, double tap, palm), located at the report’s ABS_X and ABS_Y.

Events are grouped in reports, the last one carrying sync. A touch sample is BTN_TOUCH, ABS_X, ABS_Y (sync); a gesture is ABS_X, ABS_Y, GES (sync); a button is a single KEY event with sync.

Delivery

pbl_input_report() calls every listener before it returns, in the context of the report: the debounce ISR for buttons, the system task for touch, the calling thread for injected input. There is no queue or thread of its own; the listeners that need to defer work already have the kernel event queue.

Listeners are registered with PBL_INPUT_CALLBACK_DEFINE() and must not block. Those that use APIs that are not ISR-safe check pbl_in_isr().

static void prv_input_cb(const struct pbl_input_event *evt, void *user_data) {
  if (evt->type == PBL_INPUT_EV_KEY && evt->code == PBL_INPUT_KEY_BACK && evt->value) {
    ...
  }
}

PBL_INPUT_CALLBACK_DEFINE(prv_input_cb, NULL);

The firmware has two listeners:

• fw/kernel/input_buttons.c turns key events into PEBBLE_BUTTON_DOWN_EVENT / PEBBLE_BUTTON_UP_EVENT, so the click recognizers and everything above them are unchanged.

• The touch service (fw/services/touch/touch.c) collects each report and passes it to touch_handle_update() and touch_handle_gesture().

The SELECT+BACK hard reset stays in the button drivers: it has to work when every thread is wedged, so it runs in the debounce timer ISR that also times how long the buttons are held.

Injection

Injected input goes through the same path as the hardware:

• input report <key|abs|ges> <code> <value> [sync] reports any event, and input dump on logs every event (CONFIG_INPUT_SHELL).

• button raw <btn> <0|1> reports a button transition.

• button click / hold / multi and the remote input endpoint (fw/kernel/remote_input.c) report their button presses.

Injected touch gestures (touch_handle_injected_update()) still go straight to the touch service, which arbitrates between them and the physical sensor.