feat(mouse): Add support for PIM447 trackball.

app/CMakeLists.txt

@@ -30,6 +30,7 @@ target_sources(app PRIVATE src/hid.c)
 target_sources(app PRIVATE src/mouse/key_listener.c)
 target_sources(app PRIVATE src/mouse/main.c)
 target_sources(app PRIVATE src/mouse/tick_listener.c)
+target_sources_ifdef(CONFIG_ZMK_TRACKBALL_PIM447 app PRIVATE src/mouse/trackball_pim447.c)
 target_sources(app PRIVATE src/sensors.c)
 target_sources_ifdef(CONFIG_ZMK_WPM app PRIVATE src/wpm.c)
 target_sources(app PRIVATE src/event_manager.c)

app/src/mouse/trackball_pim447.c

@@ -0,0 +1,132 @@
+/*
+ * Copyright (c) 2021 Cedric VINCENT
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <drivers/sensor.h>
+#include <logging/log.h>
+#include <zmk/hid.h>
+#include <zmk/endpoints.h>
+
+LOG_MODULE_REGISTER(PIM447, CONFIG_SENSOR_LOG_LEVEL);
+
+/*
+ * It feels more natural and more confortable to convert the speed
+ * reported by the PIM447 trackball.
+ */
+static int16_t convert_speed(int32_t value)
+{
+    bool negative = (value < 0);
+
+    if (negative) {
+        value = -value;
+    }
+
+    switch (value) {
+        case 0:  value = 0;   break;
+        case 1:  value = 1;   break;
+        case 2:  value = 4;   break;
+        case 3:  value = 8;   break;
+        case 4:  value = 18;  break;
+        case 5:  value = 32;  break;
+        case 6:  value = 50;  break;
+        case 7:  value = 72;  break;
+        case 8:  value = 98;  break;
+        default: value = 127; break;
+    }
+
+    if (negative) {
+        value = -value;
+    }
+
+    return value;
+}
+
+static void thread_code(void *p1, void *p2, void *p3)
+{
+    const struct device *dev;
+    int result;
+
+    /* PIM447 trackball initialization. */
+
+    const char *label = DT_LABEL(DT_INST(0, pimoroni_trackball_pim447));
+    dev = device_get_binding(label);
+    if (dev == NULL) {
+        LOG_ERR("Cannot get TRACKBALL_PIM447 device");
+        return;
+    }
+
+    /* Event loop. */
+
+    bool button_press_sent   = false;
+    bool button_release_sent = false;
+
+    while (true) {
+        struct sensor_value pos_dx, pos_dy, pos_dz;
+        bool send_report = false;
+
+        result = sensor_sample_fetch(dev);
+        if (result < 0) {
+            LOG_ERR("Failed to fetch TRACKBALL_PIM447 sample");
+            return;
+        }
+
+        result = sensor_channel_get(dev, SENSOR_CHAN_POS_DX, &pos_dx);
+        if (result < 0) {
+            LOG_ERR("Failed to get TRACKBALL_PIM447 pos_dx channel value");
+            return;
+        }
+
+        result = sensor_channel_get(dev, SENSOR_CHAN_POS_DY, &pos_dy);
+        if (result < 0) {
+            LOG_ERR("Failed to get TRACKBALL_PIM447 pos_dy channel value");
+            return;
+        }
+
+        result = sensor_channel_get(dev, SENSOR_CHAN_POS_DZ, &pos_dz);
+        if (result < 0) {
+            LOG_ERR("Failed to get TRACKBALL_PIM447 pos_dz channel value");
+            return;
+        }
+
+        if (pos_dx.val1 != 0 || pos_dy.val1 != 0) {
+            zmk_hid_mouse_movement_update(convert_speed(pos_dx.val1),
+                                          convert_speed(pos_dy.val1));
+            send_report = true;
+        }
+
+        if (pos_dz.val1 == 0x80 && button_press_sent == false) {
+            zmk_hid_mouse_button_press(0);
+            button_press_sent   = true;
+            button_release_sent = false;
+            send_report = true;
+        } else if (pos_dz.val1 == 0x01 && button_release_sent == false) {
+            zmk_hid_mouse_button_release(0);
+            button_press_sent   = false;
+            button_release_sent = true;
+            send_report = true;
+        }
+
+        if (send_report) {
+            zmk_endpoints_send_mouse_report();
+            zmk_hid_mouse_clear();
+        }
+
+        k_sleep(K_MSEC(10));
+    }
+}
+
+#define STACK_SIZE 1024
+
+static K_THREAD_STACK_DEFINE(thread_stack, STACK_SIZE);
+static struct k_thread thread;
+
+int zmk_trackball_pim447_init()
+{
+    k_thread_create(&thread, thread_stack, STACK_SIZE, thread_code,
+                    NULL, NULL, NULL, K_PRIO_PREEMPT(8), 0, K_NO_WAIT);
+    return 0;
+}
+
+SYS_INIT(zmk_trackball_pim447_init, APPLICATION, CONFIG_APPLICATION_INIT_PRIORITY);