1 files changed, 114 insertions, 0 deletions
diff --git a/users/drashna/pimoroni_trackball.c b/users/drashna/pimoroni_trackball.c
new file mode 100644
index 000000000..c5bb560b3
--- /dev/null
+++ b/users/drashna/pimoroni_trackball.c
@@ -0,0 +1,114 @@
+#include "pimoroni_trackball.h"
+#include "i2c_master.h"
+
+static uint8_t scrolling      = 0;
+static int16_t x_offset       = 0;
+static int16_t y_offset       = 0;
+static int16_t h_offset       = 0;
+static int16_t v_offset       = 0;
+static float precisionSpeed = 1;
+
+#ifndef I2C_TIMEOUT
+#    define I2C_TIMEOUT 100
+#endif
+#ifndef MOUSE_DEBOUNCE
+#    define MOUSE_DEBOUNCE 5
+#endif
+
+void trackball_set_rgbw(uint8_t red, uint8_t green, uint8_t blue, uint8_t white) {
+    uint8_t data[] = {0x00, red, green, blue, white};
+    i2c_transmit(TRACKBALL_WRITE, data, sizeof(data), I2C_TIMEOUT);
+}
+
+int16_t mouse_offset(uint8_t positive, uint8_t negative, int16_t scale) {
+    int16_t offset    = (int16_t)positive - (int16_t)negative;
+    int16_t magnitude = (int16_t)(scale * offset * offset * precisionSpeed);
+    return offset < 0 ? -magnitude : magnitude;
+}
+
+void update_member(int8_t* member, int16_t* offset) {
+    if (*offset > 127) {
+        *member = 127;
+        *offset -= 127;
+    } else if (*offset < -127) {
+        *member = -127;
+        *offset += 127;
+    } else {
+        *member = *offset;
+        *offset = 0;
+    }
+}
+
+__attribute__((weak)) void trackball_check_click(bool pressed, report_mouse_t* mouse) {
+    if (pressed) {
+        mouse->buttons |= MOUSE_BTN1;
+    } else {
+        mouse->buttons &= ~MOUSE_BTN1;
+    }
+}
+
+float trackball_get_precision(void) { return precisionSpeed; }
+void    trackball_set_precision(float precision) { precisionSpeed = precision; }
+bool    trackball_is_scrolling(void) { return scrolling; }
+void    trackball_set_scrolling(bool scroll) { scrolling = scroll; }
+
+__attribute__((weak)) void pointing_device_init(void) { trackball_set_rgbw(0x00,0x00,0x00,0x4F); }
+
+void pointing_device_task(void) {
+    static bool debounce;
+    static uint16_t debounce_timer;
+    uint8_t state[5] = {};
+    if (i2c_readReg(TRACKBALL_WRITE, 0x04, state, 5, I2C_TIMEOUT) == I2C_STATUS_SUCCESS) {
+        if (!state[4] && !debounce) {
+            if (scrolling) {
+#ifdef PIMORONI_TRACKBALL_INVERT_X
+                h_offset += mouse_offset(state[2], state[3], 1);
+#else
+                h_offset -= mouse_offset(state[2], state[3], 1);
+#endif
+#ifdef PIMORONI_TRACKBALL_INVERT_Y
+                v_offset += mouse_offset(state[1], state[0], 1);
+#else
+                v_offset -= mouse_offset(state[1], state[0], 1);
+#endif
+            } else {
+#ifdef PIMORONI_TRACKBALL_INVERT_X
+                x_offset -= mouse_offset(state[2], state[3], 5);
+#else
+                x_offset += mouse_offset(state[2], state[3], 5);
+#endif
+#ifdef PIMORONI_TRACKBALL_INVERT_Y
+                y_offset -= mouse_offset(state[1], state[0], 5);
+#else
+                y_offset += mouse_offset(state[1], state[0], 5);
+#endif
+            }
+        } else {
+            if (state[4]) {
+                debounce = true;
+                debounce_timer = timer_read();
+            }
+        }
+    }
+
+    if (timer_elapsed(debounce_timer) > MOUSE_DEBOUNCE) debounce = false;
+
+    report_mouse_t mouse = pointing_device_get_report();
+
+    trackball_check_click(state[4] & (1 << 7), &mouse);
+
+
+#ifndef PIMORONI_TRACKBALL_ROTATE
+    update_member(&mouse.x, &x_offset);
+    update_member(&mouse.y, &y_offset);
+    update_member(&mouse.h, &h_offset);
+    update_member(&mouse.v, &v_offset);
+#else
+    update_member(&mouse.x, &y_offset);
+    update_member(&mouse.y, &x_offset);
+    update_member(&mouse.h, &v_offset);
+    update_member(&mouse.v, &h_offset);
+#endif
+    pointing_device_set_report(mouse);
+    pointing_device_send();
+}