A functon to round a float number to particular float multiple.

RoundToPrecisionMultiple.php

 /**
     * Function to round a number to a precision multiple
     *
     * @param float $number original number
     * @param float $pointMultiple the point multiple to which it needs to be rounded
     * @param bool $roundDown whether to round up or down
     * @param int $precision precision for rounding
     * @return float rounded float number
     */
    function roundToPrecisionMultiple(float $number,
                                      float $pointMultiple = 0.25,
                                      bool  $roundDown = true,
                                      int   $precision = 2): float
    {
        $lowerBound = floor($number);
        $roundedNum = $lowerBound;
        while ($roundedNum <= round($number, $precision)) {
            $roundedNum += $pointMultiple;
        }
        return $roundDown ? ($roundedNum - $pointMultiple) : $roundedNum;
    }

echo roundToPrecisionMultiple(0.126, 0.12, true, 2); // prints 0.12
echo roundToPrecisionMultiple(0.126, 0.12, false, 2); // prints 0.24