Port DIRECT_PINS from split_common/matrix.c to matrix.c (#5091)

* Port DIRECT_PINS from split_common/matrix.c to matrix.c

* Reorder matrix.c to remove foward declaration and match split_common/matrix.c

* Refactor nano to use DIRECT_PINS

* Reorder matrix.c to remove foward declaration and match split_common/matrix.c

* Add DIRECT_PINS documentation

* Reorder matrix.c to remove foward declaration and match split_common/matrix.c - fix logic from inherited from split_common

* Add DIRECT_PINS documentation - review comments

3 files changed, 22 insertions, 0 deletions

diff --git a/docs/config_options.md b/docs/config_options.md
index c5131a841..bc2a89058 100644
--- a/docs/config_options.md
+++ b/docs/config_options.md
@@ -59,6 +59,8 @@ This is a C header file that is one of the first things included, and will persi
   * define is matrix has ghost (unlikely)
 * `#define DIODE_DIRECTION COL2ROW`
   * COL2ROW or ROW2COL - how your matrix is configured. COL2ROW means the black mark on your diode is facing to the rows, and between the switch and the rows.
+* `#define DIRECT_PINS { { F1, F0, B0, C7 }, { F4, F5, F6, F7 } }`
+  * pins mapped to rows and columns, from left to right. Defines a matrix where each switch is connected to a separate pin and ground.
 * `#define AUDIO_VOICES`
   * turns on the alternate audio voices (to cycle through)
 * `#define C4_AUDIO`
diff --git a/docs/hardware_avr.md b/docs/hardware_avr.md
index 12a0059c3..acf7088a3 100644
--- a/docs/hardware_avr.md
+++ b/docs/hardware_avr.md
@@ -93,6 +93,24 @@ Finally, you can specify the direction your diodes point. This can be `COL2ROW`
 #define DIODE_DIRECTION COL2ROW
 ```
 
+#### Direct Pin Matrix
+To configure a keyboard where each switch is connected to a separate pin and ground instead of sharing row and column pins, use `DIRECT_PINS`. The mapping defines the pins of each switch in rows and columns, from left to right. Must conform to the sizes within `MATRIX_ROWS` and `MATRIX_COLS`, use `NO_PIN` to fill in blank spaces. Overrides the behaviour of `DIODE_DIRECTION`, `MATRIX_ROW_PINS` and `MATRIX_COL_PINS`.
+
+```c
+// #define MATRIX_ROW_PINS { D0, D5 }
+// #define MATRIX_COL_PINS { F1, F0, B0 }
+#define DIRECT_PINS { \
+    { F1, E6, B0, B2, B3 }, \
+    { F5, F0, B1, B7, D2 }, \
+    { F6, F7, C7, D5, D3 }, \
+    { B5, C6, B6, NO_PIN, NO_PIN } \
+}
+#define UNUSED_PINS
+
+/* COL2ROW, ROW2COL */
+//#define DIODE_DIRECTION
+```
+
 ### Backlight Configuration
 
 By default QMK supports backlighting on pins `B5`, `B6`, and `B7`. If you are using one of those you can simply enable it here. For more details see the [Backlight Documentation](feature_backlight.md).
diff --git a/docs/porting_your_keyboard_to_qmk_(arm_and_other_chibios_cpus).md b/docs/porting_your_keyboard_to_qmk_(arm_and_other_chibios_cpus).md
index c32c428cf..d8e084f46 100644
--- a/docs/porting_your_keyboard_to_qmk_(arm_and_other_chibios_cpus).md
+++ b/docs/porting_your_keyboard_to_qmk_(arm_and_other_chibios_cpus).md
@@ -22,6 +22,8 @@ The `MATRIX_ROW_PINS` and `MATRIX_COL_PINS` are the pins your MCU uses on each r
 
 For the `DIODE_DIRECTION`, most hand-wiring guides will instruct you to wire the diodes in the `COL2ROW` position, but it's possible that they are in the other - people coming from EasyAVR often use `ROW2COL`. Nothing will function if this is incorrect.
 
+To configure a keyboard where each switch is connected to a separate pin and ground instead of sharing row and column pins, use `DIRECT_PINS`. The mapping defines the pins of each switch in rows and columns, from left to right. Must conform to the sizes within `MATRIX_ROWS` and `MATRIX_COLS`, use `NO_PIN` to fill in blank spaces. Overrides the behaviour of `DIODE_DIRECTION`, `MATRIX_ROW_PINS` and `MATRIX_COL_PINS`.
+
 `BACKLIGHT_PIN` is the pin that your PWM-controlled backlight (if one exists) is hooked-up to. Currently only B5, B6, and B7 are supported.
 
 `BACKLIGHT_BREATHING` is a fancier backlight feature that adds breathing/pulsing/fading effects to the backlight. It uses the same timer as the normal backlight. These breathing effects must be called by code in your keymap.