qmk-firmware/keyboards/tzarc/djinn/djinn_portscan_matrix.c

// Copyright 2018-2022 Nick Brassel (@tzarc)
// SPDX-License-Identifier: GPL-2.0-or-later
#include "quantum.h"
#include <hal_pal.h>
#include "djinn.h"

#define GPIOB_BITMASK (1 << 13 | 1 << 14 | 1 << 15) // B13, B14, B15
#define GPIOB_OFFSET 13
#define GPIOB_COUNT 3
#define GPIOC_BITMASK (1 << 6 | 1 << 7 | 1 << 8) // C6, C7, C8
#define GPIOC_OFFSET 6

// Pin definitions
static const pin_t row_pins[MATRIX_ROWS] = MATRIX_ROW_PINS;
static const pin_t col_pins[MATRIX_COLS] = MATRIX_COL_PINS;

void matrix_wait_for_pin(pin_t pin, uint8_t target_state) {
    rtcnt_t start = chSysGetRealtimeCounterX();
    rtcnt_t end   = start + 5000;
    while (chSysIsCounterWithinX(chSysGetRealtimeCounterX(), start, end)) {
        if (readPin(pin) == target_state) {
            break;
        }
    }
}

void matrix_wait_for_port(stm32_gpio_t *port, uint32_t target_bitmask) {
    rtcnt_t start = chSysGetRealtimeCounterX();
    rtcnt_t end   = start + 5000;
    while (chSysIsCounterWithinX(chSysGetRealtimeCounterX(), start, end)) {
        if ((palReadPort(port) & target_bitmask) == target_bitmask) {
            break;
        }
    }
}

void matrix_init_custom(void) {
    for (int i = 0; i < MATRIX_ROWS; ++i) {
        setPinInputHigh(row_pins[i]);
    }
    for (int i = 0; i < MATRIX_COLS; ++i) {
        setPinInputHigh(col_pins[i]);
    }
}

bool matrix_scan_custom(matrix_row_t current_matrix[]) {
    static matrix_row_t temp_matrix[MATRIX_ROWS] = {0};

    for (int current_col = 0; current_col < MATRIX_COLS; ++current_col) {
        // Keep track of the pin we're working with
        pin_t curr_col_pin = col_pins[current_col];

        // Setup the output column pin
        setPinOutput(curr_col_pin);
        writePinLow(curr_col_pin);
        matrix_wait_for_pin(curr_col_pin, 0);

        // Read the row ports
        uint32_t gpio_b = palReadPort(GPIOB);
        uint32_t gpio_c = palReadPort(GPIOC);

        // Unselect the row pin
        setPinInputHigh(curr_col_pin);

        // Construct the packed bitmask for the pins
        uint32_t readback = ~(((gpio_b & GPIOB_BITMASK) >> GPIOB_OFFSET) | (((gpio_c & GPIOC_BITMASK) >> GPIOC_OFFSET) << GPIOB_COUNT));

        // Inject values into the matrix
        for (int i = 0; i < MATRIX_ROWS; ++i) {
            if (readback & (1 << i)) {
                temp_matrix[i] |= (1ul << current_col);
            } else {
                temp_matrix[i] &= ~(1ul << current_col);
            }
        }

        // Wait for readback of the unselected column to go high
        matrix_wait_for_pin(curr_col_pin, 1);

        // Wait for readback of each port to go high -- unselecting the row would have been completed
        matrix_wait_for_port(GPIOB, GPIOB_BITMASK);
        matrix_wait_for_port(GPIOC, GPIOC_BITMASK);
    }

    // Check if we've changed, return the last-read data
    bool changed = memcmp(current_matrix, temp_matrix, sizeof(temp_matrix)) != 0;
    if (changed) {
        memcpy(current_matrix, temp_matrix, sizeof(temp_matrix));
    }
    return changed;
}

void matrix_wait_for_interrupt(void) {
    // Set up row/col pins and attach callback
    for (int i = 0; i < ARRAY_SIZE(col_pins); ++i) {
        setPinOutput(col_pins[i]);
        writePinLow(col_pins[i]);
    }
    for (int i = 0; i < ARRAY_SIZE(row_pins); ++i) {
        setPinInputHigh(row_pins[i]);
        palEnableLineEvent(row_pins[i], PAL_EVENT_MODE_BOTH_EDGES);
    }

    // Wait for an interrupt
    __WFI();

    // Now that the interrupt has woken us up, reset all the row/col pins back to defaults
    for (int i = 0; i < ARRAY_SIZE(row_pins); ++i) {
        palDisableLineEvent(row_pins[i]);
        writePinHigh(row_pins[i]);
        setPinInputHigh(row_pins[i]);
    }
    for (int i = 0; i < ARRAY_SIZE(col_pins); ++i) {
        writePinHigh(col_pins[i]);
        setPinInputHigh(col_pins[i]);
    }
}