diff --git a/drivers/staging/iio/light/isl29028.c b/drivers/staging/iio/light/isl29028.c
index 8dc24c9478e84d0c971a72ac82432697ad8a84e3..177dceda0820e2e988f75fe5e4ee4a845da10a3e 100644
--- a/drivers/staging/iio/light/isl29028.c
+++ b/drivers/staging/iio/light/isl29028.c
@@ -63,6 +63,9 @@
 
 #define ISL29028_POWER_OFF_DELAY_MS		2000
 
+static const unsigned int isl29028_prox_sleep_time[] = {800, 400, 200, 100, 75,
+							50, 12, 0};
+
 enum isl29028_als_ir_mode {
 	ISL29028_MODE_NONE = 0,
 	ISL29028_MODE_ALS,
@@ -78,22 +81,29 @@ struct isl29028_chip {
 	enum isl29028_als_ir_mode	als_ir_mode;
 };
 
-static int isl29028_set_proxim_sampling(struct isl29028_chip *chip,
-					unsigned int sampling)
+static int isl29028_find_prox_sleep_time_index(int sampling)
 {
-	struct device *dev = regmap_get_device(chip->regmap);
-	static unsigned int prox_period[] = {800, 400, 200, 100, 75, 50, 12, 0};
 	unsigned int period = DIV_ROUND_UP(1000, sampling);
-	int sel, ret;
+	int i;
 
-	for (sel = 0; sel < ARRAY_SIZE(prox_period); ++sel) {
-		if (period >= prox_period[sel])
+	for (i = 0; i < ARRAY_SIZE(isl29028_prox_sleep_time); ++i) {
+		if (period >= isl29028_prox_sleep_time[i])
 			break;
 	}
 
+	return i;
+}
+
+static int isl29028_set_proxim_sampling(struct isl29028_chip *chip,
+					unsigned int sampling)
+{
+	struct device *dev = regmap_get_device(chip->regmap);
+	int sleep_index, ret;
+
+	sleep_index = isl29028_find_prox_sleep_time_index(sampling);
 	ret = regmap_update_bits(chip->regmap, ISL29028_REG_CONFIGURE,
 				 ISL29028_CONF_PROX_SLP_MASK,
-				 sel << ISL29028_CONF_PROX_SLP_SH);
+				 sleep_index << ISL29028_CONF_PROX_SLP_SH);
 
 	if (ret < 0) {
 		dev_err(dev, "%s(): Error %d setting the proximity sampling\n",
@@ -108,7 +118,7 @@ static int isl29028_set_proxim_sampling(struct isl29028_chip *chip,
 
 static int isl29028_enable_proximity(struct isl29028_chip *chip)
 {
-	int ret;
+	int sleep_index, ret;
 
 	ret = isl29028_set_proxim_sampling(chip, chip->prox_sampling);
 	if (ret < 0)
@@ -121,7 +131,8 @@ static int isl29028_enable_proximity(struct isl29028_chip *chip)
 		return ret;
 
 	/* Wait for conversion to be complete for first sample */
-	msleep(DIV_ROUND_UP(1000, chip->prox_sampling));
+	sleep_index = isl29028_find_prox_sleep_time_index(chip->prox_sampling);
+	msleep(isl29028_prox_sleep_time[sleep_index]);
 
 	return 0;
 }