Move Zephyr app into subdirectory.

app/src/usb_hid.c

@@ -0,0 +1,58 @@
+
+#include <device.h>
+
+#include <usb/usb_device.h>
+#include <usb/class/usb_hid.h>
+#include <dt-bindings/zmk/keys.h>
+
+#include <zmk/hid.h>
+#include <zmk/keymap.h>
+
+LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
+
+static enum usb_dc_status_code usb_status;
+
+static struct device *hid_dev;
+
+int zmk_usb_hid_send_report(const u8_t *report, size_t len)
+{
+	if (usb_status == USB_DC_SUSPEND)
+	{
+		return usb_wakeup_request();
+	}
+
+	return hid_int_ep_write(hid_dev, report, len, NULL);
+}
+
+void usb_hid_status_cb(enum usb_dc_status_code status, const u8_t *params)
+{
+	usb_status = status;
+};
+
+int zmk_usb_hid_init()
+{
+	int usb_enable_ret;
+
+	hid_dev = device_get_binding("HID_0");
+	if (hid_dev == NULL)
+	{
+		LOG_ERR("Unable to locate HID device");
+		return -EINVAL;
+	}
+
+	usb_hid_register_device(hid_dev,
+							zmk_hid_report_desc, sizeof(zmk_hid_report_desc),
+							NULL);
+
+	usb_hid_init(hid_dev);
+
+	usb_enable_ret = usb_enable(usb_hid_status_cb);
+
+	if (usb_enable_ret != 0)
+	{
+		LOG_ERR("Unable to enable USB");
+		return -EINVAL;
+	}
+
+	return 0;
+}