Simplify split_common Code significantly (#4772)

* Eliminate separate slave loop

Both master and slave run the standard keyboard_task main loop now.

* Refactor i2c/serial specific code

Simplify some of the preprocessor mess by using common function names.

* Fix missing #endif

* Move direct pin mapping support from miniaxe to split_common

For boards with more pins than sense--sorry, switches.

* Reordering and reformatting only

* Don't run matrix_scan_quantum on slave side

* Clean up the offset/slaveOffset calculations

* Cut undebounced matrix size in half

* Refactor debouncing

* Minor fixups

* Split split_common transport and debounce code into their own files

Can now be replaced with custom versions per keyboard using
CUSTOM_TRANSPORT = yes and CUSTOM_DEBOUNCE = yes

* Refactor debounce for non-split keyboards too

* Update handwired/xealous to build using new split_common

* Fix debounce breaking basic test

* Dodgy method to allow a split kb to only include one of i2c/serial

SPLIT_TRANSPORT = serial or SPLIT_TRANSPORT = i2c will include only
that driver code in the binary.

SPLIT_TRANSPORT = custom (or anything else) will include neither, the
keyboard must supply it's own code

if SPLIT_TRANSPORT is not defined then the original behaviour (include
both avr i2c and serial code) is maintained.

This could be better but it would require explicitly updating all the
existing split keyboards.

* Enable LTO to get lets_split/sockets under the line

* Add docs for SPLIT_TRANSPORT, CUSTOM_MATRIX, CUSTOM_DEBOUNCE

* Remove avr-specific sei() from split matrix_setup

Not needed now that slave doesn't have a separate main loop.
Both sides (on avr) call sei() in lufa's main() after exiting
keyboard_setup().

* Fix QUANTUM_LIB_SRC references and simplify SPLIT_TRANSPORT.

* Add comments and fix formatting.

1 files changed, 47 insertions, 105 deletions

diff --git a/quantum/split_common/split_util.c b/quantum/split_common/split_util.c
index e41b6f6386..5095cb8fdc 100644
--- a/quantum/split_common/split_util.c
+++ b/quantum/split_common/split_util.c
@@ -4,142 +4,84 @@
 #include "config.h"
 #include "timer.h"
 #include "split_flags.h"
+#include "transport.h"
 #include "quantum.h"
 
 #ifdef EE_HANDS
 #   include "tmk_core/common/eeprom.h"
-#endif
-
-#ifdef BACKLIGHT_ENABLE
-#   include "backlight.h"
-#endif
-
-#if defined(USE_I2C) || defined(EH)
-#  include "i2c.h"
+#   include "eeconfig.h"
 #endif
 
 volatile bool isLeftHand = true;
 
-volatile uint8_t setTries = 0;
-
-static void setup_handedness(void) {
+__attribute__((weak))
+bool is_keyboard_left(void) {
   #ifdef SPLIT_HAND_PIN
     // Test pin SPLIT_HAND_PIN for High/Low, if low it's right hand
     setPinInput(SPLIT_HAND_PIN);
-    isLeftHand = readPin(SPLIT_HAND_PIN);
+    return readPin(SPLIT_HAND_PIN);
   #else
     #ifdef EE_HANDS
-      isLeftHand = eeprom_read_byte(EECONFIG_HANDEDNESS);
+      return eeprom_read_byte(EECONFIG_HANDEDNESS);
     #else
       #ifdef MASTER_RIGHT
-        isLeftHand = !has_usb();
+        return !is_keyboard_master();
       #else
-        isLeftHand = has_usb();
+        return is_keyboard_master();
       #endif
     #endif
   #endif
 }
 
-static void keyboard_master_setup(void) {
-#if defined(USE_I2C) || defined(EH)
-  i2c_master_init();
-  #ifdef SSD1306OLED
-    matrix_master_OLED_init ();
-  #endif
-#else
-  serial_master_init();
-#endif
+bool is_keyboard_master(void)
+{
+#ifdef __AVR__
+  static enum { UNKNOWN, MASTER, SLAVE } usbstate = UNKNOWN;
 
-    // For master the Backlight info needs to be sent on startup
-    // Otherwise the salve won't start with the proper info until an update
-    BACKLIT_DIRTY = true;
-}
+  // only check once, as this is called often
+  if (usbstate == UNKNOWN)
+  {
+    USBCON |= (1 << OTGPADE);  // enables VBUS pad
+    wait_us(5);
 
-static void keyboard_slave_setup(void) {
-  timer_init();
-#if defined(USE_I2C) || defined(EH)
-    i2c_slave_init(SLAVE_I2C_ADDRESS);
+    usbstate = (USBSTA & (1 << VBUS)) ? MASTER : SLAVE;  // checks state of VBUS
+  }
+
+  return (usbstate == MASTER);
 #else
-    serial_slave_init();
+  return true;
 #endif
 }
 
-bool has_usb(void) {
-   USBCON |= (1 << OTGPADE); //enables VBUS pad
-   _delay_us(5);
-   return (USBSTA & (1<<VBUS));  //checks state of VBUS
-}
-
-void split_keyboard_setup(void) {
-   setup_handedness();
+static void keyboard_master_setup(void) {
+#if defined(USE_I2C) || defined(EH)
+  #ifdef SSD1306OLED
+    matrix_master_OLED_init ();
+  #endif
+#endif
+  transport_master_init();
 
-   if (has_usb()) {
-      keyboard_master_setup();
-   } else {
-      keyboard_slave_setup();
-   }
-   sei();
+  // For master the Backlight info needs to be sent on startup
+  // Otherwise the salve won't start with the proper info until an update
+  BACKLIT_DIRTY = true;
 }
 
-void keyboard_slave_loop(void) {
-   matrix_init();
-
-   //Init RGB
-   #ifdef RGBLIGHT_ENABLE
-      rgblight_init();
-   #endif
-
-   while (1) {
-    // Matrix Slave Scan
-    matrix_slave_scan();
-
-    // Read Backlight Info
-    #ifdef BACKLIGHT_ENABLE
-        #ifdef USE_I2C
-            if (BACKLIT_DIRTY) {
-                backlight_set(i2c_slave_buffer[I2C_BACKLIT_START]);
-                BACKLIT_DIRTY = false;
-            }
-        #else // USE_SERIAL
-            backlight_set(serial_m2s_buffer.backlight_level);
-        #endif
-    #endif
-    // Read RGB Info
-    #ifdef RGBLIGHT_ENABLE
-        #ifdef USE_I2C
-            if (RGB_DIRTY) {
-                // Disable interupts (RGB data is big)
-                cli();
-                // Create new DWORD for RGB data
-                uint32_t dword;
-
-                // Fill the new DWORD with the data that was sent over
-                uint8_t *dword_dat = (uint8_t *)(&dword);
-                for (int i = 0; i < 4; i++) {
-                    dword_dat[i] = i2c_slave_buffer[I2C_RGB_START+i];
-                }
-
-                // Update the RGB now with the new data and set RGB_DIRTY to false
-                rgblight_update_dword(dword);
-                RGB_DIRTY = false;
-                // Re-enable interupts now that RGB is set
-                sei();
-            }
-        #else // USE_SERIAL
-          #ifdef RGBLIGHT_SPLIT
-            // Add serial implementation for RGB here
-          #endif
-        #endif
-    #endif
-   }
+static void keyboard_slave_setup(void)
+{
+  transport_slave_init();
 }
 
 // this code runs before the usb and keyboard is initialized
-void matrix_setup(void) {
-    split_keyboard_setup();
-
-    if (!has_usb()) {
-        //rgblight_init();
-        keyboard_slave_loop();
-    }
+void matrix_setup(void)
+{
+  isLeftHand = is_keyboard_left();
+
+  if (is_keyboard_master())
+  {
+    keyboard_master_setup();
+  }
+  else
+  {
+    keyboard_slave_setup();
+  }
 }