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).

1 files changed, 17 insertions, 56 deletions

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