+/* Convert linear sensor value to milli-units */
+static long zl6100_l2d(s16 l)
+{
+ s16 exponent;
+ s32 mantissa;
+ long val;
+
+ exponent = l >> 11;
+ mantissa = ((s16)((l & 0x7ff) << 5)) >> 5;
+
+ val = mantissa;
+
+ /* scale result to milli-units */
+ val = val * 1000L;
+
+ if (exponent >= 0)
+ val <<= exponent;
+ else
+ val >>= -exponent;
+
+ return val;
+}
+
+#define MAX_MANTISSA (1023 * 1000)
+#define MIN_MANTISSA (511 * 1000)
+
+static u16 zl6100_d2l(long val)
+{
+ s16 exponent = 0, mantissa;
+ bool negative = false;
+
+ /* simple case */
+ if (val == 0)
+ return 0;
+
+ if (val < 0) {
+ negative = true;
+ val = -val;
+ }
+
+ /* Reduce large mantissa until it fits into 10 bit */
+ while (val >= MAX_MANTISSA && exponent < 15) {
+ exponent++;
+ val >>= 1;
+ }
+ /* Increase small mantissa to improve precision */
+ while (val < MIN_MANTISSA && exponent > -15) {
+ exponent--;
+ val <<= 1;
+ }
+
+ /* Convert mantissa from milli-units to units */
+ mantissa = DIV_ROUND_CLOSEST(val, 1000);
+
+ /* Ensure that resulting number is within range */
+ if (mantissa > 0x3ff)
+ mantissa = 0x3ff;
+
+ /* restore sign */
+ if (negative)
+ mantissa = -mantissa;
+
+ /* Convert to 5 bit exponent, 11 bit mantissa */
+ return (mantissa & 0x7ff) | ((exponent << 11) & 0xf800);
+}
+