hardware/ErgoDox: Improved row selection

Improved the ATMega parts of row toggling, similar to how `ATMegaKeyboard` does
it, and separated it from selecting extender rows. This results in a tiny
increase in speed, and better clarity.

Signed-off-by: Gergely Nagy <algernon@keyboard.io>

src/kaleidoscope/hardware/ez/ErgoDox.cpp

@@ -97,13 +97,13 @@ void __attribute__((optimize(3))) ErgoDox::readMatrix() {
   scanner_.reattachExpanderOnError();
 
   for (uint8_t row = 0; row < ROWS / 2; row++) {
-    scanner_.selectRow(row);
-    scanner_.selectRow(row + ROWS / 2);
+    scanner_.selectExtenderRow(row);
+    scanner_.toggleATMegaRow(row);
 
     readMatrixRow(row);
     readMatrixRow(row + ROWS / 2);
 
-    scanner_.unselectRows();
+    scanner_.toggleATMegaRow(row);
   }
 }
 

src/kaleidoscope/hardware/ez/ErgoDox/ErgoDoxScanner.cpp

@@ -85,80 +85,65 @@ out:
   return status;
 }
 
-void
-ErgoDoxScanner::initCols() {
-  DDRF  &= ~(1 << 7 | 1 << 6 | 1 << 5 | 1 << 4 | 1 << 1 | 1 << 0);
-  PORTF |= (1 << 7 | 1 << 6 | 1 << 5 | 1 << 4 | 1 << 1 | 1 << 0);
-}
-
 void
 ErgoDoxScanner::begin() {
   expander_error_ = initExpander();
 
-  unselectRows();
-  initCols();
+  // Init columns
+  DDRF  &= ~(1 << 7 | 1 << 6 | 1 << 5 | 1 << 4 | 1 << 1 | 1 << 0);
+  PORTF |= (1 << 7 | 1 << 6 | 1 << 5 | 1 << 4 | 1 << 1 | 1 << 0);
+
+  // Init rows
+  DDRB  |= (1 << 0 | 1 << 1 | 1 << 2 | 1 << 3);
+  PORTB |= (1 << 0 | 1 << 1 | 1 << 2 | 1 << 3);
+  DDRD  |= (1 << 2 | 1 << 3);
+  PORTD |= (1 << 2 | 1 << 3);
+  DDRC  |= (1 << 6);
+  PORTC |= (1 << 6);
 }
 
-void __attribute__((optimize(3)))
-ErgoDoxScanner::selectRow(int row) {
-  if (row < 7) {
-    if (!expander_error_) {
-      expander_error_ = i2c_start(I2C_ADDR_WRITE);
-      if (expander_error_)
-        goto out;
-      expander_error_ = i2c_write(GPIOA);
-      if (expander_error_)
-        goto out;
-      expander_error_ = i2c_write(0xFF & ~(1 << row));
-      if (expander_error_)
-        goto out;
+void __attribute__((optimize(3))) ErgoDoxScanner::selectExtenderRow(int row) {
+  if (!expander_error_) {
+    expander_error_ = i2c_start(I2C_ADDR_WRITE);
+    if (expander_error_)
+      goto out;
+    expander_error_ = i2c_write(GPIOA);
+    if (expander_error_)
+      goto out;
+    expander_error_ = i2c_write(0xFF & ~(1 << row));
+    if (expander_error_)
+      goto out;
 out:
-      i2c_stop();
-    }
-  } else {
-    switch (row) {
-    case 7:
-      DDRB  |= (1 << 0);
-      PORTB &= ~(1 << 0);
+    i2c_stop();
+  }
+}
+
+void __attribute__((optimize(3))) ErgoDoxScanner::toggleATMegaRow(int row) {
+  switch (row) {
+    case 0:
+      PORTB ^= (1 << 0);
       break;
-    case 8:
-      DDRB  |= (1 << 1);
-      PORTB &= ~(1 << 1);
+    case 1:
+      PORTB ^= (1 << 1);
       break;
-    case 9:
-      DDRB  |= (1 << 2);
-      PORTB &= ~(1 << 2);
+    case 2:
+      PORTB ^= (1 << 2);
       break;
-    case 10:
-      DDRB  |= (1 << 3);
-      PORTB &= ~(1 << 3);
+    case 3:
+      PORTB ^= (1 << 3);
       break;
-    case 11:
-      DDRD  |= (1 << 2);
-      PORTD &= ~(1 << 3);
+    case 4:
+      PORTD ^= (1 << 2);
       break;
-    case 12:
-      DDRD  |= (1 << 3);
-      PORTD &= ~(1 << 3);
+    case 5:
+      PORTD ^= (1 << 3);
       break;
-    case 13:
-      DDRC  |= (1 << 6);
-      PORTC &= ~(1 << 6);
+    case 6:
+      PORTC ^= (1 << 6);
       break;
-    }
   }
 }
 
-void __attribute__((optimize(3)))
-ErgoDoxScanner::unselectRows() {
-  DDRB  &= ~(1 << 0 | 1 << 1 | 1 << 2 | 1 << 3);
-  PORTB &= ~(1 << 0 | 1 << 1 | 1 << 2 | 1 << 3);
-  DDRD  &= ~(1 << 2 | 1 << 3);
-  PORTD &= ~(1 << 2 | 1 << 3);
-  DDRC  &= ~(1 << 6);
-  PORTC &= ~(1 << 6);
-}
-
 uint8_t __attribute__((optimize(3)))
 ErgoDoxScanner::readCols(int row) {
   if (row < 7) {

src/kaleidoscope/hardware/ez/ErgoDox/ErgoDoxScanner.h

@@ -38,9 +38,8 @@ class ErgoDoxScanner {
   ErgoDoxScanner() {}
 
   void begin();
-  void initCols();
-  void selectRow(int row);
-  void unselectRows();
+  void toggleATMegaRow(int row);
+  void selectExtenderRow(int row);
   uint8_t readCols(int row);
 
   void reattachExpanderOnError();