add PCF8574(A) port expander as passive 4x4 keyboard

platformio.ini

@@ -77,6 +77,7 @@ lib_deps =
   jgromes/RadioLib@~6.5.0
   https://github.com/meshtastic/esp8266-oled-ssd1306.git#ee628ee6c9588d4c56c9e3da35f0fc9448ad54a8 ; ESP8266_SSD1306
   mathertel/OneButton@^2.5.0 ; OneButton library for non-blocking button debounce
+  robtillaart/I2CKeyPad@^0.4.0 ; port extender with keymatrix
   https://github.com/meshtastic/arduino-fsm.git#7db3702bf0cfe97b783d6c72595e3f38e0b19159
   https://github.com/meshtastic/TinyGPSPlus.git#964f75a72cccd6b53cd74e4add1f7a42c6f7344d
   https://github.com/meshtastic/ArduinoThread.git#1ae8778c85d0a2a729f989e0b1e7d7c4dc84eef0

src/configuration.h

@@ -105,10 +105,11 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 // Define if screen should be mirrored left to right
 // #define SCREEN_MIRROR
 
-// I2C Keyboards (M5Stack, RAK14004, T-Deck)
+// I2C Keyboards (M5Stack, RAK14004, T-Deck, PCF8574A passive)
 #define CARDKB_ADDR 0x5F
 #define TDECK_KB_ADDR 0x55
 #define BBQ10_KB_ADDR 0x1F
+#define PCF8574A_ADDRESS 0x20
 
 // -----------------------------------------------------------------------------
 // SENSOR

src/detect/ScanI2C.cpp

@@ -30,8 +30,8 @@ ScanI2C::FoundDevice ScanI2C::firstRTC() const
 
 ScanI2C::FoundDevice ScanI2C::firstKeyboard() const
 {
-    ScanI2C::DeviceType types[] = {CARDKB, TDECKKB, BBQ10KB, RAK14004};
-    return firstOfOrNONE(4, types);
+    ScanI2C::DeviceType types[] = {CARDKB, TDECKKB, BBQ10KB, RAK14004, PCF8574A};
+    return firstOfOrNONE(5, types);
 }
 
 ScanI2C::FoundDevice ScanI2C::firstAccelerometer() const

src/detect/ScanI2C.h

@@ -19,6 +19,7 @@ class ScanI2C
         TDECKKB,
         BBQ10KB,
         RAK14004,
+        PCF8574A,
         PMU_AXP192_AXP2101,
         BME_680,
         BME_280,

src/detect/ScanI2CTwoWire.cpp

@@ -229,6 +229,7 @@ void ScanI2CTwoWire::scanPort(I2CPort port)
                 SCAN_SIMPLE_CASE(TDECK_KB_ADDR, TDECKKB, "T-Deck keyboard found\n");
                 SCAN_SIMPLE_CASE(BBQ10_KB_ADDR, BBQ10KB, "BB Q10 keyboard found\n");
                 SCAN_SIMPLE_CASE(ST7567_ADDRESS, SCREEN_ST7567, "st7567 display found\n");
+                SCAN_SIMPLE_CASE(PCF8574A_ADDRESS, PCF8574A, "PCF8574A based keyboard found\n");
 #ifdef HAS_NCP5623
                 SCAN_SIMPLE_CASE(NCP5623_ADDR, NCP5623, "NCP5623 RGB LED found\n");
 #endif

src/input/cardKbI2cImpl.cpp

@@ -7,7 +7,7 @@ CardKbI2cImpl::CardKbI2cImpl() : KbI2cBase("cardKB") {}
 
 void CardKbI2cImpl::init()
 {
-    if (cardkb_found.address == 0x00) {
+    if ((cardkb_found.address == 0x00) || (kb_model == 0x12)) {
         disable();
         return;
     }

src/input/peMatrixBase.cpp

@@ -0,0 +1,84 @@
+#include "peMatrixBase.h"
+
+#include "configuration.h"
+#include "detect/ScanI2C.h"
+
+extern ScanI2C::DeviceAddress cardkb_found;
+extern uint8_t kb_model;
+
+I2CKeyPad keyPad(cardkb_found.address);
+
+PeMatrixBase::PeMatrixBase(const char *name) : concurrency::OSThread(name)
+{
+    this->_originName = name;
+}
+
+int32_t PeMatrixBase::runOnce()
+{
+    if (kb_model != 0x12) {
+        // Input device is not detected.
+        return disable();
+    }
+
+    if (firstTime) {
+        // This is the first time the OSThread library has called this function, so do port setup
+        firstTime = 0;
+        if (!keyPad.begin()) {
+            LOG_ERROR("Failed to initialize I2C keypad\n");
+            return disable();
+        }
+        keyPad.loadKeyMap(keymap);
+    } else {
+        if (keyPad.isPressed()) {
+            key = keyPad.getChar();
+            // debounce
+            if (key != prevkey) {
+                if (key != 0) {
+                    LOG_DEBUG("Key 0x%x pressed\n", key);
+                    // reset shift now that we have a keypress
+                    InputEvent e;
+                    e.inputEvent = meshtastic_ModuleConfig_CannedMessageConfig_InputEventChar_NONE;
+                    e.source = this->_originName;
+                    switch (key) {
+                    case 0x1b: // ESC
+                        e.inputEvent = meshtastic_ModuleConfig_CannedMessageConfig_InputEventChar_CANCEL;
+                        break;
+                    case 0x08: // Back
+                        e.inputEvent = meshtastic_ModuleConfig_CannedMessageConfig_InputEventChar_BACK;
+                        e.kbchar = key;
+                        break;
+                    case 0xb5: // Up
+                        e.inputEvent = meshtastic_ModuleConfig_CannedMessageConfig_InputEventChar_UP;
+                        break;
+                    case 0xb6: // Down
+                        e.inputEvent = meshtastic_ModuleConfig_CannedMessageConfig_InputEventChar_DOWN;
+                        break;
+                    case 0xb4: // Left
+                        e.inputEvent = meshtastic_ModuleConfig_CannedMessageConfig_InputEventChar_LEFT;
+                        e.kbchar = key;
+                        break;
+                    case 0xb7: // Right
+                        e.inputEvent = meshtastic_ModuleConfig_CannedMessageConfig_InputEventChar_RIGHT;
+                        e.kbchar = key;
+                        break;
+                    case 0x0d: // Enter
+                        e.inputEvent = meshtastic_ModuleConfig_CannedMessageConfig_InputEventChar_SELECT;
+                        break;
+                    case 0x00: // nopress
+                        e.inputEvent = meshtastic_ModuleConfig_CannedMessageConfig_InputEventChar_NONE;
+                        break;
+                    default: // all other keys
+                        e.inputEvent = ANYKEY;
+                        e.kbchar = key;
+                        break;
+                    }
+                    if (e.inputEvent != meshtastic_ModuleConfig_CannedMessageConfig_InputEventChar_NONE) {
+                        this->notifyObservers(&e);
+                    }
+                }
+                prevkey = key;
+            }
+        }
+    }
+    return 50; // Keyscan every 50msec to avoid key bounce
+}

src/input/peMatrixBase.h

@@ -0,0 +1,22 @@
+#pragma once
+
+#include "InputBroker.h"
+#include "concurrency/OSThread.h"
+#include <I2CKeyPad.h>
+
+class PeMatrixBase : public Observable<const InputEvent *>, public concurrency::OSThread
+{
+  public:
+    explicit PeMatrixBase(const char *name);
+
+  protected:
+    virtual int32_t runOnce() override;
+
+  private:
+    const char *_originName;
+    bool firstTime = 1;
+    // char keymap[19] = "123A456B789C*0#DNF";  // N = NoKey, F = Fail
+    char keymap[19] = {0x1b, 0xb5, '3', 'A', 0xb4, 0x0d, 0xb7, 'B', '7', 0xb6, '9', 'C', 0x09, '0', 0x08, 'D', 'N', 'F'};
+    char key = 0;
+    char prevkey = 0;
+};

src/input/peMatrixImpl.cpp

@@ -0,0 +1,16 @@
+#include "peMatrixImpl.h"
+#include "InputBroker.h"
+
+PeMatrixImpl *peMatrixImpl;
+
+PeMatrixImpl::PeMatrixImpl() : PeMatrixBase("matrixPE") {}
+
+void PeMatrixImpl::init()
+{
+    if (kb_model != 0x12) {
+        disable();
+        return;
+    }
+
+    inputBroker->registerSource(this);
+}

src/input/peMatrixImpl.h

@@ -0,0 +1,19 @@
+#pragma once
+#include "main.h"
+#include "peMatrixBase.h"
+
+/**
+ * @brief The idea behind this class to have static methods for the event handlers.
+ *      Check attachInterrupt() at RotaryEncoderInteruptBase.cpp
+ *      Technically you can have as many rotary encoders hardver attached
+ *      to your device as you wish, but you always need to have separate event
+ *      handlers, thus you need to have a RotaryEncoderInterrupt implementation.
+ */
+class PeMatrixImpl : public PeMatrixBase
+{
+  public:
+    PeMatrixImpl();
+    void init();
+};
+
+extern PeMatrixImpl *peMatrixImpl;

src/main.cpp

@@ -484,6 +484,9 @@ void setup()
             // assign an arbitrary value to distinguish from other models
             kb_model = 0x11;
             break;
+        case ScanI2C::DeviceType::PCF8574A:
+            kb_model = 0x12;
+            break;
         default:
             // use this as default since it's also just zero
             LOG_WARN("kb_info.type is unknown(0x%02x), setting kb_model=0x00\n", kb_info.type);

src/modules/Modules.cpp

@@ -6,6 +6,7 @@
 #include "input/UpDownInterruptImpl1.h"
 #include "input/cardKbI2cImpl.h"
 #include "input/kbMatrixImpl.h"
+#include "input/peMatrixImpl.h"
 #endif
 #include "modules/AdminModule.h"
 #if !MESHTASTIC_EXCLUDE_ATAK
@@ -125,6 +126,8 @@ void setupModules()
         kbMatrixImpl = new KbMatrixImpl();
         kbMatrixImpl->init();
 #endif // INPUTBROKER_MATRIX_TYPE
+        peMatrixImpl = new PeMatrixImpl();
+        peMatrixImpl->init();
 #endif // HAS_BUTTON
 #if ARCH_PORTDUINO
         aLinuxInputImpl = new LinuxInputImpl();