qmk-firmware/platforms/avr/drivers/ssd1306.c

#ifdef SSD1306OLED

#    include "ssd1306.h"
#    include "i2c.h"
#    include <string.h>
#    include "print.h"
#    include "glcdfont.c"
#    ifdef PROTOCOL_LUFA
#        include "lufa.h"
#    endif
#    include "sendchar.h"
#    include "timer.h"

struct CharacterMatrix display;

// Set this to 1 to help diagnose early startup problems
// when testing power-on with ble.  Turn it off otherwise,
// as the latency of printing most of the debug info messes
// with the matrix scan, causing keys to drop.
#    define DEBUG_TO_SCREEN 0

// static uint16_t last_battery_update;
// static uint32_t vbat;
//#define BatteryUpdateInterval 10000 /* milliseconds */
#    define ScreenOffInterval 300000 /* milliseconds */
#    if DEBUG_TO_SCREEN
static uint8_t displaying;
#    endif
static uint16_t last_flush;

// Write command sequence.
// Returns true on success.
static inline bool _send_cmd1(uint8_t cmd) {
    bool res = false;

    if (i2c_start_write(SSD1306_ADDRESS)) {
        xprintf("failed to start write to %d\n", SSD1306_ADDRESS);
        goto done;
    }

    if (i2c_master_write(0x0 /* command byte follows */)) {
        print("failed to write control byte\n");

        goto done;
    }

    if (i2c_master_write(cmd)) {
        xprintf("failed to write command %d\n", cmd);
        goto done;
    }
    res = true;
done:
    i2c_master_stop();
    return res;
}

// Write 2-byte command sequence.
// Returns true on success
static inline bool _send_cmd2(uint8_t cmd, uint8_t opr) {
    if (!_send_cmd1(cmd)) {
        return false;
    }
    return _send_cmd1(opr);
}

// Write 3-byte command sequence.
// Returns true on success
static inline bool _send_cmd3(uint8_t cmd, uint8_t opr1, uint8_t opr2) {
    if (!_send_cmd1(cmd)) {
        return false;
    }
    if (!_send_cmd1(opr1)) {
        return false;
    }
    return _send_cmd1(opr2);
}

#    define send_cmd1(c)      \
        if (!_send_cmd1(c)) { \
            goto done;        \
        }
#    define send_cmd2(c, o)      \
        if (!_send_cmd2(c, o)) { \
            goto done;           \
        }
#    define send_cmd3(c, o1, o2)      \
        if (!_send_cmd3(c, o1, o2)) { \
            goto done;                \
        }

static void clear_display(void) {
    matrix_clear(&display);

    // Clear all of the display bits (there can be random noise
    // in the RAM on startup)
    send_cmd3(PageAddr, 0, (DisplayHeight / 8) - 1);
    send_cmd3(ColumnAddr, 0, DisplayWidth - 1);

    if (i2c_start_write(SSD1306_ADDRESS)) {
        goto done;
    }
    if (i2c_master_write(0x40)) {
        // Data mode
        goto done;
    }
    for (uint8_t row = 0; row < MatrixRows; ++row) {
        for (uint8_t col = 0; col < DisplayWidth; ++col) {
            i2c_master_write(0);
        }
    }

    display.dirty = false;

done:
    i2c_master_stop();
}

#    if DEBUG_TO_SCREEN
#        undef sendchar
static int8_t capture_sendchar(uint8_t c) {
    sendchar(c);
    iota_gfx_write_char(c);

    if (!displaying) {
        iota_gfx_flush();
    }
    return 0;
}
#    endif

bool iota_gfx_init(void) {
    bool success = false;

    send_cmd1(DisplayOff);
    send_cmd2(SetDisplayClockDiv, 0x80);
    send_cmd2(SetMultiPlex, DisplayHeight - 1);

    send_cmd2(SetDisplayOffset, 0);

    send_cmd1(SetStartLine | 0x0);
    send_cmd2(SetChargePump, 0x14 /* Enable */);
    send_cmd2(SetMemoryMode, 0 /* horizontal addressing */);

#    ifdef OLED_ROTATE180
    // the following Flip the display orientation 180 degrees
    send_cmd1(SegRemap);
    send_cmd1(ComScanInc);
#    endif
#    ifndef OLED_ROTATE180
    // Flips the display orientation 0 degrees
    send_cmd1(SegRemap | 0x1);
    send_cmd1(ComScanDec);
#    endif

    send_cmd2(SetComPins, 0x2);
    send_cmd2(SetContrast, 0x8f);
    send_cmd2(SetPreCharge, 0xf1);
    send_cmd2(SetVComDetect, 0x40);
    send_cmd1(DisplayAllOnResume);
    send_cmd1(NormalDisplay);
    send_cmd1(DeActivateScroll);
    send_cmd1(DisplayOn);

    send_cmd2(SetContrast, 0);  // Dim

    clear_display();

    success = true;

    iota_gfx_flush();

#    if DEBUG_TO_SCREEN
    print_set_sendchar(capture_sendchar);
#    endif

done:
    return success;
}

bool iota_gfx_off(void) {
    bool success = false;

    send_cmd1(DisplayOff);
    success = true;

done:
    return success;
}

bool iota_gfx_on(void) {
    bool success = false;

    send_cmd1(DisplayOn);
    success = true;

done:
    return success;
}

void matrix_write_char_inner(struct CharacterMatrix *matrix, uint8_t c) {
    *matrix->cursor = c;
    ++matrix->cursor;

    if (matrix->cursor - &matrix->display[0][0] == sizeof(matrix->display)) {
        // We went off the end; scroll the display upwards by one line
        memmove(&matrix->display[0], &matrix->display[1], MatrixCols * (MatrixRows - 1));
        matrix->cursor = &matrix->display[MatrixRows - 1][0];
        memset(matrix->cursor, ' ', MatrixCols);
    }
}

void matrix_write_char(struct CharacterMatrix *matrix, uint8_t c) {
    matrix->dirty = true;

    if (c == '\n') {
        // Clear to end of line from the cursor and then move to the
        // start of the next line
        uint8_t cursor_col = (matrix->cursor - &matrix->display[0][0]) % MatrixCols;

        while (cursor_col++ < MatrixCols) {
            matrix_write_char_inner(matrix, ' ');
        }
        return;
    }

    matrix_write_char_inner(matrix, c);
}

void iota_gfx_write_char(uint8_t c) { matrix_write_char(&display, c); }

void matrix_write(struct CharacterMatrix *matrix, const char *data) {
    const char *end = data + strlen(data);
    while (data < end) {
        matrix_write_char(matrix, *data);
        ++data;
    }
}

void iota_gfx_write(const char *data) { matrix_write(&display, data); }

void matrix_write_P(struct CharacterMatrix *matrix, const char *data) {
    while (true) {
        uint8_t c = pgm_read_byte(data);
        if (c == 0) {
            return;
        }
        matrix_write_char(matrix, c);
        ++data;
    }
}

void iota_gfx_write_P(const char *data) { matrix_write_P(&display, data); }

void matrix_clear(struct CharacterMatrix *matrix) {
    memset(matrix->display, ' ', sizeof(matrix->display));
    matrix->cursor = &matrix->display[0][0];
    matrix->dirty  = true;
}

void iota_gfx_clear_screen(void) { matrix_clear(&display); }

void matrix_render(struct CharacterMatrix *matrix) {
    last_flush = timer_read();
    iota_gfx_on();
#    if DEBUG_TO_SCREEN
    ++displaying;
#    endif

    // Move to the home position
    send_cmd3(PageAddr, 0, MatrixRows - 1);
    send_cmd3(ColumnAddr, 0, (MatrixCols * FontWidth) - 1);

    if (i2c_start_write(SSD1306_ADDRESS)) {
        goto done;
    }
    if (i2c_master_write(0x40)) {
        // Data mode
        goto done;
    }

    for (uint8_t row = 0; row < MatrixRows; ++row) {
        for (uint8_t col = 0; col < MatrixCols; ++col) {
            const uint8_t *glyph = font + (matrix->display[row][col] * (FontWidth - 1));

            for (uint8_t glyphCol = 0; glyphCol < FontWidth - 1; ++glyphCol) {
                uint8_t colBits = pgm_read_byte(glyph + glyphCol);
                i2c_master_write(colBits);
            }

            // 1 column of space between chars (it's not included in the glyph)
            i2c_master_write(0);
        }
    }

    matrix->dirty = false;

done:
    i2c_master_stop();
#    if DEBUG_TO_SCREEN
    --displaying;
#    endif
}

void iota_gfx_flush(void) { matrix_render(&display); }

__attribute__((weak)) void iota_gfx_task_user(void) {}

void iota_gfx_task(void) {
    iota_gfx_task_user();

    if (display.dirty) {
        iota_gfx_flush();
    }

    if (timer_elapsed(last_flush) > ScreenOffInterval) {
        iota_gfx_off();
    }
}
#endif