Adding Stylus-Pen Device Support.

examples/device/hid_composite/src/main.c

@@ -197,18 +197,58 @@ static void send_hid_report(uint8_t report_id, uint32_t btn)
       }
     }
     break;
-
     default: break;
   }
 }
 
+/* use this to send stylus touch signal through USB. */
+static void send_stylus_touch(uint16_t x, uint16_t y, bool state)
+{
+  // skip if hid is not ready yet
+  if ( !tud_hid_ready() ) return;
+
+  static bool has_stylus_pen = false;
+
+  hid_stylus_report_t report =
+  {
+    .attr = 0,
+    .x = 0,
+    .y = 0
+  };
+
+  report.x = x;
+  report.y = y;
+
+  if (state)
+  {
+    report.attr = STYLUS_ATTR_TIP_SWITCH | STYLUS_ATTR_IN_RANGE;
+    tud_hid_report(REPORT_ID_STYLUS_PEN, &report, sizeof(report));
+
+    has_stylus_pen = true;
+  }else
+  {
+    report.attr = 0;
+    if (has_stylus_pen) tud_hid_report(REPORT_ID_STYLUS_PEN, &report, sizeof(report));
+    has_stylus_pen = false;
+  }
+
+}
+
 // Every 10ms, we will sent 1 report for each HID profile (keyboard, mouse etc ..)
 // tud_hid_report_complete_cb() is used to send the next report after previous one is complete
 void hid_task(void)
 {
   // Poll every 10ms
   const uint32_t interval_ms = 10;
   static uint32_t start_ms = 0;
+  static uint32_t touch_ms = 0;
+  static bool touch_state = false;
+
+  if (board_millis() - touch_ms < 100) {
+    touch_ms = board_millis();
+    send_stylus_touch(0, 0, touch_state = !touch_state);
+    return;
+  }
 
   if ( board_millis() - start_ms < interval_ms) return; // not enough time
   start_ms += interval_ms;

examples/device/hid_composite/src/usb_descriptors.c

@@ -79,6 +79,7 @@ uint8_t const desc_hid_report[] =
 {
   TUD_HID_REPORT_DESC_KEYBOARD( HID_REPORT_ID(REPORT_ID_KEYBOARD         )),
   TUD_HID_REPORT_DESC_MOUSE   ( HID_REPORT_ID(REPORT_ID_MOUSE            )),
+  TUD_HID_REPORT_DESC_STYLUS_PEN( HID_REPORT_ID(REPORT_ID_STYLUS_PEN     )),
   TUD_HID_REPORT_DESC_CONSUMER( HID_REPORT_ID(REPORT_ID_CONSUMER_CONTROL )),
   TUD_HID_REPORT_DESC_GAMEPAD ( HID_REPORT_ID(REPORT_ID_GAMEPAD          ))
 };

examples/device/hid_composite/src/usb_descriptors.h

@@ -29,6 +29,7 @@ enum
 {
   REPORT_ID_KEYBOARD = 1,
   REPORT_ID_MOUSE,
+  REPORT_ID_STYLUS_PEN,
   REPORT_ID_CONSUMER_CONTROL,
   REPORT_ID_GAMEPAD,
   REPORT_ID_COUNT

src/class/hid/hid.h

@@ -325,6 +325,29 @@ typedef enum
 
 /// @}
 
+//--------------------------------------------------------------------+
+// Digitizer Stylus Pen
+//--------------------------------------------------------------------+
+/** \addtogroup ClassDriver_HID_Stylus Stylus
+ *  @{ */
+
+// Standard Stylus Pen Report.
+typedef struct TU_ATTR_PACKED
+{
+  uint8_t attr;    /**< Attribute mask for describing current status of the stylus pen. */
+  uint16_t x;      /**< Current x position of the mouse. */
+  uint16_t y;      /**< Current y position of the mouse. */
+} hid_stylus_report_t;
+
+// Standard Stylus Pen Attributes Bitmap.
+typedef enum
+{
+  STYLUS_ATTR_TIP_SWITCH = TU_BIT(0), ///< Tip switch
+  STYLUS_ATTR_IN_RANGE   = TU_BIT(1), ///< In-range bit.
+} hid_stylus_attr_bm_t;
+
+/// @}
+
 //--------------------------------------------------------------------+
 // Keyboard
 //--------------------------------------------------------------------+
@@ -760,7 +783,9 @@ enum {
   HID_USAGE_PAGE_PID                       = 0x0f,
   HID_USAGE_PAGE_UNICODE                   = 0x10,
   HID_USAGE_PAGE_ALPHA_DISPLAY             = 0x14,
+  HID_USAGE_PAGE_IN_RANGE                  = 0x32,
   HID_USAGE_PAGE_MEDICAL                   = 0x40,
+  HID_USAGE_PAGE_TIP_SWITCH                = 0x42,
   HID_USAGE_PAGE_LIGHTING_AND_ILLUMINATION = 0x59,
   HID_USAGE_PAGE_MONITOR                   = 0x80, // 0x80 - 0x83
   HID_USAGE_PAGE_POWER                     = 0x84, // 0x084 - 0x87
@@ -846,6 +871,15 @@ enum {
   HID_USAGE_DESKTOP_SYSTEM_DISPLAY_LCD_AUTOSCALE          = 0xB7
 };
 
+/// HID Usage Table: Digitizer Page (0x0D)
+enum {
+  // Touch Screen.
+  HID_USAGE_DIGITIZER_TOUCH_SCREEN                    = 0x04,
+
+  // Stylus Pen.
+  HID_USAGE_DIGITIZER_STYLUS                          = 0x20,
+};
+
 
 /// HID Usage Table: Consumer Page (0x0C)
 /// Only contains controls that supported by Windows (whole list is too long)

src/class/hid/hid_device.c

@@ -194,6 +194,16 @@ bool tud_hid_n_gamepad_report(uint8_t instance, uint8_t report_id,
   return tud_hid_n_report(instance, report_id, &report, sizeof(report));
 }
 
+bool tud_hid_n_stylus_report(uint8_t instance, uint8_t report_id, uint8_t attrs, uint16_t x, uint16_t y) {
+  hid_stylus_report_t report = {
+    .attr = attrs,
+    .x = x,
+    .y = y,
+  };
+
+  return tud_hid_n_report(instance, report_id, &report, sizeof(report));
+}
+
 //--------------------------------------------------------------------+
 // USBD-CLASS API
 //--------------------------------------------------------------------+

src/class/hid/hid_device.h

@@ -79,6 +79,9 @@ bool tud_hid_n_abs_mouse_report(uint8_t instance, uint8_t report_id, uint8_t but
 // use template layout report TUD_HID_REPORT_DESC_GAMEPAD
 bool tud_hid_n_gamepad_report(uint8_t instance, uint8_t report_id, int8_t x, int8_t y, int8_t z, int8_t rz, int8_t rx, int8_t ry, uint8_t hat, uint32_t buttons);
 
+// STYLUS PEN: convenient helper to send absolute stylus pen report if application
+bool tud_hid_n_stylus_report(uint8_t instance, uint8_t report_id, uint8_t attrs, uint16_t x, uint16_t y);
+
 //--------------------------------------------------------------------+
 // Application API (Single Port)
 //--------------------------------------------------------------------+
@@ -114,6 +117,10 @@ TU_ATTR_ALWAYS_INLINE static inline bool tud_hid_gamepad_report(uint8_t report_i
   return tud_hid_n_gamepad_report(0, report_id, x, y, z, rz, rx, ry, hat, buttons);
 }
 
+TU_ATTR_ALWAYS_INLINE static inline bool tud_hid_stylus_report(uint8_t report_id, uint8_t attrs, uint16_t x, uint16_t y) {
+  return tud_hid_n_stylus_report(0, report_id, attrs, x, y);
+}
+
 //--------------------------------------------------------------------+
 // Application Callbacks
 //--------------------------------------------------------------------+
@@ -257,6 +264,41 @@ void tud_hid_report_failed_cb(uint8_t instance, hid_report_type_t report_type, u
     HID_COLLECTION_END                                            , \
   HID_COLLECTION_END \
 
+// Stylus Pen Report Descriptor Template
+#define TUD_HID_REPORT_DESC_STYLUS_PEN(...) \
+  HID_USAGE_PAGE ( HID_USAGE_PAGE_DIGITIZER )                     , \
+  HID_USAGE      ( HID_USAGE_DIGITIZER_TOUCH_SCREEN )             , \
+  HID_COLLECTION ( HID_COLLECTION_APPLICATION  )                  , \
+    /* Report ID if any */\
+    __VA_ARGS__ \
+    HID_USAGE    ( HID_USAGE_DIGITIZER_STYLUS )                   , \
+    HID_COLLECTION ( HID_COLLECTION_PHYSICAL   )                  , \
+      HID_USAGE_PAGE  ( HID_USAGE_PAGE_TIP_SWITCH  )              , \
+      HID_USAGE_PAGE  ( HID_USAGE_PAGE_IN_RANGE  )                , \
+        HID_LOGICAL_MIN ( 0                                      ), \
+        HID_LOGICAL_MAX ( 1                                      ), \
+        HID_REPORT_SIZE ( 1                                      ), \
+        HID_REPORT_COUNT( 2                                      ), \
+        HID_INPUT       ( HID_DATA | HID_VARIABLE | HID_ABSOLUTE ), \
+        HID_REPORT_SIZE ( 1                                      ), \
+        HID_REPORT_COUNT( 6                                      ), \
+        HID_INPUT       ( HID_CONSTANT | HID_ARRAY | HID_ABSOLUTE), \
+      HID_USAGE_PAGE    ( HID_USAGE_PAGE_DESKTOP                 ), \
+        HID_PHYSICAL_MAX_N( 0x7fff, 2                            ), \
+        HID_LOGICAL_MAX_N ( 0x7fff, 2                            ), \
+        HID_REPORT_SIZE ( 16                                     ), \
+        HID_REPORT_COUNT( 1                                      ), \
+        HID_UNIT_EXPONENT( 0x0f                                  ), \
+        HID_UNIT        ( HID_VARIABLE | HID_NONLINEAR           ), \
+        HID_PHYSICAL_MIN( 0                                      ), \
+        HID_PHYSICAL_MAX( 0                                      ), \
+        HID_USAGE       ( HID_USAGE_DESKTOP_X                    ), \
+        HID_INPUT       ( HID_DATA | HID_VARIABLE | HID_ABSOLUTE ), \
+        HID_USAGE       ( HID_USAGE_DESKTOP_Y                    ), \
+        HID_INPUT       ( HID_DATA | HID_VARIABLE | HID_ABSOLUTE ), \
+    HID_COLLECTION_END                                          , \
+  HID_COLLECTION_END \
+
 // Absolute Mouse Report Descriptor Template
 #define TUD_HID_REPORT_DESC_ABSMOUSE(...) \
   HID_USAGE_PAGE ( HID_USAGE_PAGE_DESKTOP      )                   ,\