From 970f3553c40a49cc7364b43fed68412b8b44c9fb Mon Sep 17 00:00:00 2001
From: Federico Amedeo Izzo <federico@izzo.pro>
Date: Mon, 14 Dec 2020 15:06:11 +0100
Subject: [PATCH] kbd_task refactoring, add long-press detection logic

---
 openrtx/include/event.h               |  4 +--
 openrtx/include/interfaces/keyboard.h | 33 ++++++++++++++++--
 openrtx/src/threads.c                 | 50 ++++++++++++++++++++++-----
 3 files changed, 74 insertions(+), 13 deletions(-)

diff --git a/openrtx/include/event.h b/openrtx/include/event.h
index cdfa76c7..b681d14d 100644
--- a/openrtx/include/event.h
+++ b/openrtx/include/event.h
@@ -44,8 +44,8 @@ typedef union
 {
     struct
     {
-        uint32_t type    : 3,
-                 payload : 29;
+        uint32_t type    : 2,
+                 payload : 30;
     };
 
     void *value;
diff --git a/openrtx/include/interfaces/keyboard.h b/openrtx/include/interfaces/keyboard.h
index f00ccbd0..6d145f18 100644
--- a/openrtx/include/interfaces/keyboard.h
+++ b/openrtx/include/interfaces/keyboard.h
@@ -27,7 +27,7 @@
  * The following enum provides a set of flags to be used to check which buttons
  * are pressed by bit-masking the uint32_t value returned by kbd_getKeys().
  */
-enum keys
+enum key
 {
     KEY_0     = (1 << 0),   /* Keypad digit "0"                  */
     KEY_1     = (1 << 1),   /* Keypad digit "1"                  */
@@ -61,9 +61,36 @@ enum keys
 };
 
 /**
- * The status of the keyboard keys is provided as an uint32_t.
+ * Number of supported keys
+ */
+static const uint8_t kbd_num_keys = 29;
+
+/**
+ * Time interval in ticks after which a keypress is considered a long-press
+ */
+static const uint8_t kbd_long_interval = 29;
+
+/**
+ * Structure that represents a keyboard event payload
+ * The maximum size of an event payload is 30 bits
+ * For a keyboard event we use 1 bit to signal a short or long press
+ * And the remaining 29 bits to communicate currently pressed keys.
+ */
+typedef union
+{
+    struct
+    {
+        uint32_t long_press : 1,
+                 keys : 29;
+    };
+    
+    uint32_t value;
+} kbd_msg_t;
+
+/**
+ * We encode the status of all the keys with a uint32_t value
  * To check which buttons are pressed one can bit-mask the 
- * uint32_t value keyboard_t with one of the values defined in keys.
+ * keys value with one of the enum values defined in key.
  * Example:
  * keyboard_t keys = kbd_getKeys();
  * if(keys & KEY_ENTER) do_stuff();
diff --git a/openrtx/src/threads.c b/openrtx/src/threads.c
index 7a4a2458..6b6e6bad 100644
--- a/openrtx/src/threads.c
+++ b/openrtx/src/threads.c
@@ -128,20 +128,54 @@ static void kbd_task(void *arg)
     // Initialize keyboard driver
     kbd_init();
 
+    // Allocate timestamp array
+    OS_TICK key_ts[kbd_num_keys];
+    OS_TICK now;
+
+    // Variable for saving previous and current keyboard status
+    keyboard_t prev_keys = 0;
+    keyboard_t keys = 0;
+
     while(1)
     {
-        keyboard_t keys = kbd_getKeys();
-		// Check if some key is pressed
-        if(keys != 0)
+        // Get currently pressed keys
+        keys = kbd_getKeys();
+        // Compare with previous keyboard status
+        if(keys != prev_keys)
         {
+            bool long_press = false;
+            bool send_event = false;
+            now = OSTimeGet(&os_err);
+            for(uint8_t k=0; k < kbd_num_keys; k++)
+            {
+                // Key has been pressed
+                if(!(prev_keys & k) && (keys & k))
+                {
+                    // Save timestamp
+                    key_ts[k] = now;
+                }
+                // Key has been released
+                else if((prev_keys & k) && !(keys & k))
+                {
+                    send_event = true;
+                    // Check timestamp
+                    if((now - key_ts[k]) >= kbd_long_interval)
+                        long_press = true;
+                }
+            }
+            if(send_event)
+            {
+            kbd_msg_t msg;
+            msg.long_press = long_press;
+            msg.keys = keys;
             // Send event_t as void * message to use with OSQPost
-            event_t kbd_msg;
-            kbd_msg.type = EVENT_KBD;
-            kbd_msg.payload = keys;
-
+            event_t event;
+            event.type = EVENT_KBD;
+            event.payload = msg.value;
             // Send keyboard status in queue
-            OSQPost(&ui_queue, (void *)kbd_msg.value, sizeof(event_t), 
+            OSQPost(&ui_queue, (void *)event.value, sizeof(event_t), 
                     OS_OPT_POST_FIFO + OS_OPT_POST_NO_SCHED, &os_err);
+            }
         }
         // Read keyboard state at 5Hz
         OSTimeDlyHMSM(0u, 0u, 0u, 200u, OS_OPT_TIME_HMSM_STRICT, &os_err);