Try following code, it works for me.

static const QString PROC_ENTRY = "/sys/class/i2c-adapter/i2c-3/3-001d/coord";


QFile f(PROC_ENTRY);
if (!f.exists() or !f.open(QIODevice::ReadOnly | QIODevice::Text)) {
qDebug() << "could not read motion data";
}
else {
QByteArray line = f.readLine();
QRegExp rx("([0-9-]+) ([0-9-]+) ([0-9-]+)");

rx.indexIn(line);
qreal x = rx.cap(1).toInt();
qreal y = rx.cap(2).toInt();
qreal z = rx.cap(3).toInt();

mCurrentPos.setX(x);
mCurrentPos.setY(y);

f.close();
}