Rewrite the Bathroom Epiphanies Frosty Flake matrix and LED handling (#8243)

* Keyboard: revamp frosty-flake leds

This commit transitions bpiphany/frosty_flake to led_update_{kb,user}
and rewrites the AVR bit twiddling logic to use the standard QMK GPIO
API.

* Keyboard: rewrite frosty_flake's matrix reader to be a lite custom matrix

This commit replaces frosty_flake's custom matrix and debounce logic
with a "lite" custom matrix. In addition to being somewhat clearer, this
allows a consumer of the flake board to choose their own debouncing
algorithm. The one closest to the implementation originally in use is
sym_g, but this opens us up to supporting eager_pk and eager_pr.

The original matrix code was 18 columns for 8 rows, but using a single
row read and unpacking the bits into individual columns. To simplify,
I've changed the key layout to be 8C 18R instead of 18C 8R: this lets us
use a single read directly into the matrix _and_ drop down to a uint8_t
instead of a uint32_t for matrix_row_t.

Since we're no longer implementing our own debouncing and row unpacking,
we save ~400 bytes on the final firmware image.

Fully tested against a CM Storm QFR hosting the flake -- this commit
message was written using the new matrix code.

Firmware Sizes (assuming stock configuration as of 42d6270f2)

Matrix+Debounce     Size (bytes)
---------------     ------------
original            17740
new + sym_g         17284
new + eager_pr      18106
new + eager_pk      18204

I expect that there are some scanning speed benefits as well.

* Keyboard: update frosty_flake's UNUSED_PINS

* Keyboard: Remove meaningless weak redefinitions from frosty

These are not necessary (and all of them already live somewhere in
Quantum).

5 files changed, 77 insertions, 168 deletions

diff --git a/keyboards/bpiphany/frosty_flake/config.h b/keyboards/bpiphany/frosty_flake/config.h
index 250a1b775..79bc31aec 100644
--- a/keyboards/bpiphany/frosty_flake/config.h
+++ b/keyboards/bpiphany/frosty_flake/config.h
@@ -36,13 +36,13 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 /* key matrix size */
-#define MATRIX_ROWS 8   // Row0 - Row7 in the schematic
-#define MATRIX_COLS 18  // ColA - ColR in the schematic
+#define MATRIX_ROWS 18 // ColA - ColR in the schematic
+#define MATRIX_COLS 8  // Row0 - Row7 in the schematic
 
 /*
  * Keyboard Matrix Assignments
  */
-#define UNUSED_PINS { B0, C4, D3 }
+#define UNUSED_PINS { C0, C1, C2, C3, C4, D2, D7 }
 
 /* Debounce reduces chatter (unintended double-presses) - set 0 if debouncing is not needed */
 #define DEBOUNCE 5
diff --git a/keyboards/bpiphany/frosty_flake/frosty_flake.c b/keyboards/bpiphany/frosty_flake/frosty_flake.c
index 1cd476038..be4e1a312 100644
--- a/keyboards/bpiphany/frosty_flake/frosty_flake.c
+++ b/keyboards/bpiphany/frosty_flake/frosty_flake.c
@@ -1,63 +1,24 @@
 #include "frosty_flake.h"
 
-void matrix_init_kb(void) {
-    // put your keyboard start-up code here
-    // runs once when the firmware starts up
-
-    matrix_init_user();
+void keyboard_pre_init_kb() {
+    setPinOutput(B7); // num lock
+    writePinHigh(B7);
+    setPinOutput(C5); // caps lock
+    writePinHigh(C7);
+    setPinOutput(C6); // scroll lock
+    writePinHigh(C6);
+
+    keyboard_pre_init_user();
 }
 
-void matrix_scan_kb(void) {
-    // put your looping keyboard code here
-    // runs every cycle (a lot)
-
-    matrix_scan_user();
-}
+bool led_update_kb(led_t usb_led) {
+    // user requests no further processing
+    if (!led_update_user(usb_led))
+        return true;
 
-bool process_record_kb(uint16_t keycode, keyrecord_t *record) {
-    // put your per-action keyboard code here
-    // runs for every action, just before processing by the firmware
+    writePin(C5, !usb_led.caps_lock);
+    writePin(B7, !usb_led.num_lock);
+    writePin(C6, !usb_led.scroll_lock);
 
-    return process_record_user(keycode, record);
+    return true;
 }
-
-void led_set_kb(uint8_t usb_led) {
-    DDRB |= (1<<7);
-    DDRC |= (1<<5) | (1<<6);
-
-    print_dec(usb_led);
-
-    if (usb_led & (1<<USB_LED_CAPS_LOCK))
-        PORTC &= ~(1<<5);
-    else
-        PORTC |=  (1<<5);
-
-    if (usb_led & (1<<USB_LED_NUM_LOCK))
-        PORTB &= ~(1<<7);
-    else
-        PORTB |=  (1<<7);
-
-    if (usb_led & (1<<USB_LED_SCROLL_LOCK))
-        PORTC &= ~(1<<6);
-    else
-        PORTC |=  (1<<6);
-
-    led_set_user(usb_led);
-}
-
-__attribute__ ((weak))
-void matrix_init_user(void) {
-}
-
-__attribute__ ((weak))
-void matrix_scan_user(void) {
-}
-
-__attribute__ ((weak))
-bool process_record_user(uint16_t keycode, keyrecord_t *record) {
-  return true;
-}
-
-__attribute__ ((weak))
-void led_set_user(uint8_t usb_led) {
-}
\ No newline at end of file
diff --git a/keyboards/bpiphany/frosty_flake/frosty_flake.h b/keyboards/bpiphany/frosty_flake/frosty_flake.h
index 824287396..cc870c277 100644
--- a/keyboards/bpiphany/frosty_flake/frosty_flake.h
+++ b/keyboards/bpiphany/frosty_flake/frosty_flake.h
@@ -34,16 +34,25 @@
   KA4, KP2, KC6,                KK6,                KC0, KM3, KD0, KA1,   KO0, KK0, KL0,   KL6,      KQ6       \
 ) \
 { \
-/* Columns and rows need to be swapped in the below definition */ \
-/*          A       B       C       D       E       F       G       H       I       J       K       L       M       N       O       P       Q       R       */ \
-/* 0 */ {   KC_NO,  KB0,    KC0,    KD0,    KC_NO,  KF0,    KG0,    KC_NO,  KC_NO,  KC_NO,  KK0,    KL0,    KC_NO,  KC_NO,  KO0,    KC_NO,  KQ0,    KR0     }, \
-/* 1 */ {   KA1,    KB1,    KC_NO,  KD1,    KE1,    KF1,    KG1,    KH1,    KI1,    KJ1,    KK1,    KL1,    KC_NO,  KC_NO,  KC_NO,  KC_NO,  KQ1,    KC_NO   }, \
-/* 2 */ {   KC_NO,  KB2,    KC_NO,  KD2,    KE2,    KF2,    KG2,    KH2,    KI2,    KJ2,    KK2,    KL2,    KC_NO,  KN2,    KC_NO,  KP2,    KQ2,    KR2     }, \
-/* 3 */ {   KC_NO,  KB3,    KC_NO,  KD3,    KE3,    KF3,    KG3,    KH3,    KI3,    KJ3,    KK3,    KL3,    KM3,    KN3,    KO3,    KC_NO,  KQ3,    KR3     }, \
-/* 4 */ {   KA4,    KB4,    KC_NO,  KD4,    KE4,    KF4,    KG4,    KH4,    KI4,    KJ4,    KK4,    KL4,    KC_NO,  KC_NO,  KO4,    KC_NO,  KQ4,    KR4     }, \
-/* 5 */ {   KA5,    KC_NO,  KC5,    KD5,    KE5,    KF5,    KG5,    KH5,    KI5,    KJ5,    KK5,    KL5,    KC_NO,  KC_NO,  KO5,    KC_NO,  KQ5,    KR5     }, \
-/* 6 */ {   KC_NO,  KB6,    KC6,    KC_NO,  KE6,    KF6,    KG6,    KH6,    KI6,    KJ6,    KK6,    KL6,    KC_NO,  KC_NO,  KO6,    KC_NO,  KQ6,    KR6     }, \
-/* 7 */ {   KA7,    KB7,    KC7,    KD7,    KE7,    KF7,    KG7,    KH7,    KI7,    KJ7,    KC_NO,  KC_NO,  KC_NO,  KC_NO,  KO7,    KC_NO,  KQ7,    KR7     }  \
+/*        0        1        2        3        4        5        6        7        */ \
+/* A */ { KC_NO,   KA1,     KC_NO,   KC_NO,   KA4,     KA5,     KC_NO,   KA7,     }, \
+/* B */ { KB0,     KB1,     KB2,     KB3,     KB4,     KC_NO,   KB6,     KB7,     }, \
+/* C */ { KC0,     KC_NO,   KC_NO,   KC_NO,   KC_NO,   KC5,     KC6,     KC7,     }, \
+/* D */ { KD0,     KD1,     KD2,     KD3,     KD4,     KD5,     KC_NO,   KD7,     }, \
+/* E */ { KC_NO,   KE1,     KE2,     KE3,     KE4,     KE5,     KE6,     KE7,     }, \
+/* F */ { KF0,     KF1,     KF2,     KF3,     KF4,     KF5,     KF6,     KF7,     }, \
+/* G */ { KG0,     KG1,     KG2,     KG3,     KG4,     KG5,     KG6,     KG7,     }, \
+/* H */ { KC_NO,   KH1,     KH2,     KH3,     KH4,     KH5,     KH6,     KH7,     }, \
+/* I */ { KC_NO,   KI1,     KI2,     KI3,     KI4,     KI5,     KI6,     KI7,     }, \
+/* J */ { KC_NO,   KJ1,     KJ2,     KJ3,     KJ4,     KJ5,     KJ6,     KJ7,     }, \
+/* K */ { KK0,     KK1,     KK2,     KK3,     KK4,     KK5,     KK6,     KC_NO,   }, \
+/* L */ { KL0,     KL1,     KL2,     KL3,     KL4,     KL5,     KL6,     KC_NO,   }, \
+/* M */ { KC_NO,   KC_NO,   KC_NO,   KM3,     KC_NO,   KC_NO,   KC_NO,   KC_NO,   }, \
+/* N */ { KC_NO,   KC_NO,   KN2,     KN3,     KC_NO,   KC_NO,   KC_NO,   KC_NO,   }, \
+/* O */ { KO0,     KC_NO,   KC_NO,   KO3,     KO4,     KO5,     KO6,     KO7,     }, \
+/* P */ { KC_NO,   KC_NO,   KP2,     KC_NO,   KC_NO,   KC_NO,   KC_NO,   KC_NO,   }, \
+/* Q */ { KQ0,     KQ1,     KQ2,     KQ3,     KQ4,     KQ5,     KQ6,     KQ7,     }, \
+/* R */ { KR0,     KC_NO,   KR2,     KR3,     KR4,     KR5,     KR6,     KR7,     }, \
 }
 
 /*
@@ -74,16 +83,25 @@
   KA4, KP2, KC6,                KK6,                KC0, KM3, KD0, KA1,   KO0, KK0, KL0  \
 ) \
 { \
-/* Columns and rows need to be swapped in the below definition */ \
-/*          A       B       C       D       E       F       G       H       I       J       K       L       M       N       O       P       Q       R       */ \
-/* 0 */ {   KC_NO,  KB0,    KC0,    KD0,    KC_NO,  KF0,    KG0,    KC_NO,  KC_NO,  KC_NO,  KK0,    KL0,    KC_NO,  KC_NO,  KO0,    KC_NO,  KC_NO,  KR0     }, \
-/* 1 */ {   KA1,    KB1,    KC_NO,  KD1,    KE1,    KF1,    KG1,    KH1,    KI1,    KJ1,    KC_NO,  KC_NO,  KC_NO,  KC_NO,  KC_NO,  KC_NO,  KC_NO,  KC_NO   }, \
-/* 2 */ {   KC_NO,  KB2,    KC_NO,  KD2,    KE2,    KF2,    KG2,    KH2,    KI2,    KJ2,    KC_NO,  KC_NO,  KC_NO,  KN2,    KC_NO,  KP2,    KC_NO,  KR2     }, \
-/* 3 */ {   KC_NO,  KB3,    KC_NO,  KD3,    KE3,    KF3,    KG3,    KH3,    KI3,    KJ3,    KC_NO,  KC_NO,  KM3,    KN3,    KC_NO,  KC_NO,  KC_NO,  KR3     }, \
-/* 4 */ {   KA4,    KB4,    KC_NO,  KD4,    KE4,    KF4,    KG4,    KH4,    KI4,    KJ4,    KK4,    KL4,    KC_NO,  KC_NO,  KO4,    KC_NO,  KQ4,    KR4     }, \
-/* 5 */ {   KA5,    KC_NO,  KC5,    KD5,    KE5,    KF5,    KG5,    KH5,    KI5,    KJ5,    KC_NO,  KC_NO,  KC_NO,  KC_NO,  KC_NO,  KC_NO,  KC_NO,  KR5     }, \
-/* 6 */ {   KC_NO,  KB6,    KC6,    KC_NO,  KE6,    KF6,    KG6,    KH6,    KI6,    KJ6,    KK6,    KC_NO,  KC_NO,  KC_NO,  KO6,    KC_NO,  KC_NO,  KR6     }, \
-/* 7 */ {   KA7,    KB7,    KC7,    KD7,    KE7,    KF7,    KG7,    KH7,    KI7,    KJ7,    KC_NO,  KC_NO,  KC_NO,  KC_NO,  KO7,    KC_NO,  KQ7,    KR7     }  \
+/*        0        1        2        3        4        5        6        7        */ \
+/* A */ { KC_NO,   KA1,     KC_NO,   KC_NO,   KA4,     KA5,     KC_NO,   KA7,     }, \
+/* B */ { KB0,     KB1,     KB2,     KB3,     KB4,     KC_NO,   KB6,     KB7,     }, \
+/* C */ { KC0,     KC_NO,   KC_NO,   KC_NO,   KC_NO,   KC5,     KC6,     KC7,     }, \
+/* D */ { KD0,     KD1,     KD2,     KD3,     KD4,     KD5,     KC_NO,   KD7,     }, \
+/* E */ { KC_NO,   KE1,     KE2,     KE3,     KE4,     KE5,     KE6,     KE7,     }, \
+/* F */ { KF0,     KF1,     KF2,     KF3,     KF4,     KF5,     KF6,     KF7,     }, \
+/* G */ { KG0,     KG1,     KG2,     KG3,     KG4,     KG5,     KG6,     KG7,     }, \
+/* H */ { KC_NO,   KH1,     KH2,     KH3,     KH4,     KH5,     KH6,     KH7,     }, \
+/* I */ { KC_NO,   KI1,     KI2,     KI3,     KI4,     KI5,     KI6,     KI7,     }, \
+/* J */ { KC_NO,   KJ1,     KJ2,     KJ3,     KJ4,     KJ5,     KJ6,     KJ7,     }, \
+/* K */ { KK0,     KC_NO,   KC_NO,   KC_NO,   KK4,     KC_NO,   KK6,     KC_NO,   }, \
+/* L */ { KL0,     KC_NO,   KC_NO,   KC_NO,   KL4,     KC_NO,   KC_NO,   KC_NO,   }, \
+/* M */ { KC_NO,   KC_NO,   KC_NO,   KM3,     KC_NO,   KC_NO,   KC_NO,   KC_NO,   }, \
+/* N */ { KC_NO,   KC_NO,   KN2,     KN3,     KC_NO,   KC_NO,   KC_NO,   KC_NO,   }, \
+/* O */ { KO0,     KC_NO,   KC_NO,   KC_NO,   KO4,     KC_NO,   KO6,     KO7,     }, \
+/* P */ { KC_NO,   KC_NO,   KP2,     KC_NO,   KC_NO,   KC_NO,   KC_NO,   KC_NO,   }, \
+/* Q */ { KC_NO,   KC_NO,   KC_NO,   KC_NO,   KQ4,     KC_NO,   KC_NO,   KQ7,     }, \
+/* R */ { KR0,     KC_NO,   KR2,     KR3,     KR4,     KR5,     KR6,     KR7,     }, \
 }
 
 #define LAYOUT_tkl_ansi( \
diff --git a/keyboards/bpiphany/frosty_flake/matrix.c b/keyboards/bpiphany/frosty_flake/matrix.c
index 3c49e9c00..4517c7af5 100644
--- a/keyboards/bpiphany/frosty_flake/matrix.c
+++ b/keyboards/bpiphany/frosty_flake/matrix.c
@@ -15,42 +15,15 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#include <stdint.h>
-#include <stdbool.h>
-#include <avr/io.h>
 #include <util/delay.h>
-#include "print.h"
-#include "debug.h"
-#include "util.h"
 #include "matrix.h"
 
-#ifndef DEBOUNCE
-#   define DEBOUNCE 5
-#endif
-static uint8_t debouncing = DEBOUNCE;
-
-static matrix_row_t matrix[MATRIX_ROWS];
-static matrix_row_t matrix_debouncing[MATRIX_ROWS];
-
-__attribute__ ((weak))
-void matrix_init_kb(void) {
-    matrix_init_user();
-}
-
-__attribute__ ((weak))
-void matrix_scan_kb(void) {
-    matrix_scan_user();
-}
-
-__attribute__ ((weak))
-void matrix_init_user(void) {
-}
-
-__attribute__ ((weak))
-void matrix_scan_user(void) {
-}
-
 static matrix_row_t scan_col(void) {
+    // Each of the 8 columns is read off pins as below
+    //   7  6  5  4  3  2  1  0
+    // ,--,--,--,--,--,--,--,--,
+    // |B0|B3|B2|B1|B6|B4|B5|C7|
+    // `--`--`--`--`--`--`--`--`
     return (
         (PINC&(1<<7) ? 0 : ((matrix_row_t)1<<0)) |
         (PINB&(1<<5) ? 0 : ((matrix_row_t)1<<1)) |
@@ -63,8 +36,8 @@ static matrix_row_t scan_col(void) {
     );
 }
 
-static void select_col(uint8_t col) {
-    switch (col) {
+static void select_row(uint8_t row) {
+    switch (row) {
         case  0: PORTD = (PORTD & ~0b01111011) | 0b00011011; break;
         case  1: PORTD = (PORTD & ~0b01111011) | 0b01000011; break;
         case  2: PORTD = (PORTD & ~0b01111011) | 0b01101010; break;
@@ -86,7 +59,7 @@ static void select_col(uint8_t col) {
     }
 }
 
-void matrix_init(void) {
+void matrix_init_custom(void) {
     /* Row output pins */
     DDRD  |=  0b01111011;
     /* Column input pins */
@@ -94,62 +67,19 @@ void matrix_init(void) {
     DDRB  &= ~0b01111111;
     PORTC |=  0b10000000;
     PORTB |=  0b01111111;
-
-    for (uint8_t i=0; i < MATRIX_ROWS; i++)
-        matrix[i] = matrix_debouncing[i] = 0;
-
-    matrix_init_quantum();
 }
 
-uint8_t matrix_scan(void) {
-    for (uint8_t col = 0; col < MATRIX_COLS; col++) {
-        select_col(col);
-        _delay_us(3);
-        matrix_row_t col_scan = scan_col();
-        for (uint8_t row = 0; row < MATRIX_ROWS; row++) {
-            bool prev_bit = matrix_debouncing[row] & ((matrix_row_t)1<<col);
-            bool curr_bit = col_scan & (1<<row);
-            if (prev_bit != curr_bit) {
-                matrix_debouncing[row] ^= ((matrix_row_t)1<<col);
-                debouncing = DEBOUNCE;
-            }
-        }
-    }
-
-    if (debouncing) {
-        if (--debouncing)
-            _delay_ms(1);
-        else
-            for (uint8_t i = 0; i < MATRIX_ROWS; i++)
-                matrix[i] = matrix_debouncing[i];
-    }
-
-    matrix_scan_quantum();
-    return 1;
-}
-
-inline matrix_row_t matrix_get_row(uint8_t row) {
-    return matrix[row];
-}
-
-void matrix_print(void) {
-#ifndef NO_PRINT
-    print("\nr\\c ABCDEFGHIJKLMNOPQR\n");
+// matrix is 18 uint8_t.
+// we select the row (one of 18), then read the column
+bool matrix_scan_custom(matrix_row_t current_matrix[]) {
+        bool has_changed = false;
     for (uint8_t row = 0; row < MATRIX_ROWS; row++) {
-        matrix_row_t matrix_row = matrix_get_row(row);
-        xprintf("%02X: ", row);
-        for (uint8_t col = 0; col < MATRIX_COLS; col++) {
-            bool curr_bit = matrix_row & (1<<col);
-            xprintf("%c", curr_bit ? '*' : '.');
-        }
-        print("\n");
+        matrix_row_t orig = current_matrix[row];
+        select_row(row);
+        _delay_us(3);
+        current_matrix[row] = scan_col();
+        has_changed |= (orig != current_matrix[row]);
     }
-#endif
-}
 
-uint8_t matrix_key_count(void) {
-    uint8_t count = 0;
-    for (uint8_t row = 0; row < MATRIX_ROWS; row++)
-        count += bitpop32(matrix[row]);
-    return count;
+    return has_changed;
 }
diff --git a/keyboards/bpiphany/frosty_flake/rules.mk b/keyboards/bpiphany/frosty_flake/rules.mk
index d5f943430..649fe6ee7 100644
--- a/keyboards/bpiphany/frosty_flake/rules.mk
+++ b/keyboards/bpiphany/frosty_flake/rules.mk
@@ -30,7 +30,7 @@ BLUETOOTH_ENABLE = no       # Enable Bluetooth with the Adafruit EZ-Key HID
 AUDIO_ENABLE = no           # Audio output on port C6
 FAUXCLICKY_ENABLE = no      # Use buzzer to emulate clicky switches
 
-CUSTOM_MATRIX = yes
+CUSTOM_MATRIX = lite
 SRC += matrix.c
 
 LAYOUTS = tkl_ansi