linuxSmartie/src/LCDDisplay.cpp

#include "LCDDisplay.hpp"

#include <fcntl.h>
#include <termios.h>
#include <unistd.h>

#include <array>
#include <cstdint>
#include <cstring>
#include <log.hpp>
#include <string>

/* lcd size hardcoded to 4x40 idgaf */
LCDDisplay::LCDDisplay(const std::string& dev, const uint32_t baud) {
    this->dev = dev;
    this->baud = baud;
}

LCDDisplay::~LCDDisplay() {
    this->close();
}

int LCDDisplay::Init() {
    if (const int ret = this->open(); ret < 0) {
        this->close();
        return -1;
    }

    struct termios term{};
    // Setup the serial port 8 data bits, no parity, 1 stopbit, no flow control
    term.c_cflag = baud | CS8 | CSTOPB | CLOCAL | CREAD;
    term.c_iflag = 0;
    term.c_oflag = 0;
    term.c_lflag = 0;
    tcflush(lcd, TCIFLUSH);
    tcsetattr(lcd, TCSANOW, &term);

    // init linebuf to spaces
    this->clearBuf();

    // disable underline and block cursor
    constexpr uint8_t cmdbuf[] = {254, 75, 254, 84};
    ::write(lcd, &cmdbuf, sizeof(cmdbuf));

    // clear display and set cursor home
    this->clear();
    return 0;
}

int LCDDisplay::open(const bool reopen) {
    applog(LOG::INF, "Opening serial port at \"{}\"", dev);
    if (lcd < 0 || reopen)
        lcd = ::open(dev.c_str(), O_RDWR | O_NOCTTY | O_NONBLOCK);  // ::open calls the global open() instead of LCDDisplay::open()
    if (lcd < 0) {
        applog(LOG::ERR, "Error opening serial port \"{}\"", dev);  // err
        return -1;
    }
    return 0;
}

void LCDDisplay::close() {
    if (lcd >= 0) {
        ::close(lcd);
        applog(LOG::INF, "LCD port closed");
    }
    lcd = -1;
}

void LCDDisplay::write(const uint8_t* cmdbuf, const uint8_t len) {
    if (::write(lcd, cmdbuf, len) != len) {
        applog(LOG::ERR, "failed to execute ::write, lost access to port?");
        this->open(true);
    }
}

void LCDDisplay::clear() {
    constexpr uint8_t cmdbuf[] = {254, 88};
    this->write(cmdbuf, sizeof(cmdbuf));
}

void LCDDisplay::setContrast(const uint8_t contrast) {
    applog(LOG::INF, "Set contrast to {}", contrast);
    const uint8_t cmdbuf[] = {254, 80, contrast};
    this->write(cmdbuf, sizeof(cmdbuf));
}

void LCDDisplay::setBacklight(const bool enabled) {
    applog(LOG::INF, "Set backlight to {}", enabled);
    const uint8_t cmdbuf[] = {254, static_cast<uint8_t>(enabled ? 66 : 70), 255};
    this->write(cmdbuf, enabled ? 3 : 2);
}

/* still doesnt work? */
void LCDDisplay::setBacklight(const uint8_t brightness) {
    applog(LOG::INF, "Set backlight brightness to {}", brightness);
    const uint8_t cmdbuf[] = {254, static_cast<uint8_t>(brightness ? 66 : 70), 255, brightness};  // 3rd char is timer, 4th is brightness
    this->write(cmdbuf, brightness ? 4 : 2);
}

void LCDDisplay::setCursor(const uint8_t row, const uint8_t col) {
    const uint8_t cmdbuf[] = {254, 71, static_cast<uint8_t>(col + 1), static_cast<uint8_t>(row + 1)};
    this->write(cmdbuf, sizeof(cmdbuf));
}

/* reconsider so im not writing every time. prepend custom chars to the write buffer? */
void LCDDisplay::setCustomChar(const uint8_t index, const std::array<uint8_t, 8> cchar) {
    uint8_t cmdbuf[] = {254, 78, index, 0, 0, 0, 0, 0, 0, 0, 0};
    std::memcpy(&cmdbuf[3], &cchar, sizeof(cchar));
    this->write(cmdbuf, sizeof(cmdbuf));
}

/* immediately writes string to the lcd at current cursor pos */
void LCDDisplay::writeStr(const std::string& str) {
    this->write(reinterpret_cast<const uint8_t*>(str.c_str()), str.size());
}

/* immediately writes string to the lcd at given cursor pos */
void LCDDisplay::writeStr(const uint8_t row, const uint8_t col, const std::string& str) {
    this->setCursor(row, col);
    this->write(reinterpret_cast<const uint8_t*>(str.c_str()), str.size());
}

/* writes string to write buffer at calculated pos */
void LCDDisplay::writeBuf(const uint8_t row, const uint8_t col, const std::string& str) {
    const size_t len = std::min(str.size(), writebuf.size() - col);
    uint8_t pos = 4 + col + (LCD_COLS * (row % 2));  // skip 4 bytes to leave room for set cursor command
    if (row >= 2) pos += 2 * LCD_COLS + 4;           // if we're writing to disp2, skip another 4 bytes for set cursor command and 2*40 bytes of disp 1
    std::memcpy(&writebuf[pos], str.c_str(), len);
}

/* initializes the write buffer to spaces */
void LCDDisplay::clearBuf() {
    std::memset(writebuf.data(), ' ', writebuf.size());
}

/* flushes writebuffer to lcd, hyperoptmized, flushes buffer and commands in a single write operation */
void LCDDisplay::flushBuf() {
    constexpr uint8_t setDisp[] = {254, 71, 1, 1};  // set cursor to char 1, line 1
    std::memcpy(&writebuf[0], setDisp, 4);
    std::memcpy(&writebuf[2 * LCD_COLS + 4], setDisp, 4);
    writebuf[2 * LCD_COLS + 7] = 3;  // overwrite set cursor c1 l1 to c1 l3
    this->write(reinterpret_cast<uint8_t*>(writebuf.data()), writebuf.size());
}

// i have a whole flushbuf func to avoid too many writes, but im writing on every bar, need to rethink this.
// we could have a separate pre-char buffer and put all the setCustomChar commands to that?
char LCDDisplay::bar(const uint8_t char_id, const double value) {
    std::array<uint8_t, 8> b{};
    b.fill(0b01110);
    for (uint8_t i = 0; i < (1.0 - value) * 8; i++)
        b[i] = 0;
    this->setCustomChar(char_id, b);
    return cc(char_id);
}