diff --git a/drivers/staging/iio/light/isl29028.c b/drivers/staging/iio/light/isl29028.c
index 5375e7a81205d..aeb50825acefc 100644
--- a/drivers/staging/iio/light/isl29028.c
+++ b/drivers/staging/iio/light/isl29028.c
@@ -64,8 +64,25 @@
 
 #define ISL29028_POWER_OFF_DELAY_MS		2000
 
-static const unsigned int isl29028_prox_sleep_time[] = {800, 400, 200, 100, 75,
-							50, 12, 0};
+struct isl29028_prox_data {
+	int sampling_int;
+	int sampling_fract;
+	int sleep_time;
+};
+
+static const struct isl29028_prox_data isl29028_prox_data[] = {
+	{   1, 250000, 800 },
+	{   2, 500000, 400 },
+	{   5,      0, 200 },
+	{  10,      0, 100 },
+	{  13, 300000,  75 },
+	{  20,      0,  50 },
+	{  80,      0,  13 }, /*
+			       * Note: Data sheet lists 12.5 ms sleep time.
+			       * Round up a half millisecond for msleep().
+			       */
+	{ 100,  0,   0 }
+};
 
 enum isl29028_als_ir_mode {
 	ISL29028_MODE_NONE = 0,
@@ -76,32 +93,37 @@ enum isl29028_als_ir_mode {
 struct isl29028_chip {
 	struct mutex			lock;
 	struct regmap			*regmap;
-	unsigned int			prox_sampling;
+	int				prox_sampling_int;
+	int				prox_sampling_frac;
 	bool				enable_prox;
 	int				lux_scale;
 	enum isl29028_als_ir_mode	als_ir_mode;
 };
 
-static int isl29028_find_prox_sleep_time_index(int sampling)
+static int isl29028_find_prox_sleep_index(int sampling_int, int sampling_fract)
 {
-	unsigned int period = DIV_ROUND_UP(1000, sampling);
 	int i;
 
-	for (i = 0; i < ARRAY_SIZE(isl29028_prox_sleep_time); ++i) {
-		if (period >= isl29028_prox_sleep_time[i])
-			break;
+	for (i = 0; i < ARRAY_SIZE(isl29028_prox_data); ++i) {
+		if (isl29028_prox_data[i].sampling_int == sampling_int &&
+		    isl29028_prox_data[i].sampling_fract == sampling_fract)
+			return i;
 	}
 
-	return i;
+	return -EINVAL;
 }
 
 static int isl29028_set_proxim_sampling(struct isl29028_chip *chip,
-					unsigned int sampling)
+					int sampling_int, int sampling_fract)
 {
 	struct device *dev = regmap_get_device(chip->regmap);
 	int sleep_index, ret;
 
-	sleep_index = isl29028_find_prox_sleep_time_index(sampling);
+	sleep_index = isl29028_find_prox_sleep_index(sampling_int,
+						     sampling_fract);
+	if (sleep_index < 0)
+		return sleep_index;
+
 	ret = regmap_update_bits(chip->regmap, ISL29028_REG_CONFIGURE,
 				 ISL29028_CONF_PROX_SLP_MASK,
 				 sleep_index << ISL29028_CONF_PROX_SLP_SH);
@@ -112,16 +134,18 @@ static int isl29028_set_proxim_sampling(struct isl29028_chip *chip,
 		return ret;
 	}
 
-	chip->prox_sampling = sampling;
+	chip->prox_sampling_int = sampling_int;
+	chip->prox_sampling_frac = sampling_fract;
 
 	return ret;
 }
 
 static int isl29028_enable_proximity(struct isl29028_chip *chip)
 {
-	int sleep_index, ret;
+	int prox_index, ret;
 
-	ret = isl29028_set_proxim_sampling(chip, chip->prox_sampling);
+	ret = isl29028_set_proxim_sampling(chip, chip->prox_sampling_int,
+					   chip->prox_sampling_frac);
 	if (ret < 0)
 		return ret;
 
@@ -132,8 +156,12 @@ static int isl29028_enable_proximity(struct isl29028_chip *chip)
 		return ret;
 
 	/* Wait for conversion to be complete for first sample */
-	sleep_index = isl29028_find_prox_sleep_time_index(chip->prox_sampling);
-	msleep(isl29028_prox_sleep_time[sleep_index]);
+	prox_index = isl29028_find_prox_sleep_index(chip->prox_sampling_int,
+						    chip->prox_sampling_frac);
+	if (prox_index < 0)
+		return prox_index;
+
+	msleep(isl29028_prox_data[prox_index].sleep_time);
 
 	return 0;
 }
@@ -361,7 +389,7 @@ static int isl29028_write_raw(struct iio_dev *indio_dev,
 			break;
 		}
 
-		ret = isl29028_set_proxim_sampling(chip, val);
+		ret = isl29028_set_proxim_sampling(chip, val, val2);
 		break;
 	case IIO_LIGHT:
 		if (mask != IIO_CHAN_INFO_SCALE) {
@@ -439,7 +467,8 @@ static int isl29028_read_raw(struct iio_dev *indio_dev,
 		if (chan->type != IIO_PROXIMITY)
 			break;
 
-		*val = chip->prox_sampling;
+		*val = chip->prox_sampling_int;
+		*val2 = chip->prox_sampling_frac;
 		ret = IIO_VAL_INT;
 		break;
 	case IIO_CHAN_INFO_SCALE:
@@ -472,7 +501,7 @@ static int isl29028_read_raw(struct iio_dev *indio_dev,
 }
 
 static IIO_CONST_ATTR(in_proximity_sampling_frequency_available,
-				"1 3 5 10 13 20 83 100");
+				"1.25 2.5 5 10 13.3 20 80 100");
 static IIO_CONST_ATTR(in_illuminance_scale_available, "125 2000");
 
 #define ISL29028_CONST_ATTR(name) (&iio_const_attr_##name.dev_attr.attr)
@@ -571,7 +600,8 @@ static int isl29028_probe(struct i2c_client *client,
 	}
 
 	chip->enable_prox  = false;
-	chip->prox_sampling = 20;
+	chip->prox_sampling_int = 20;
+	chip->prox_sampling_frac = 0;
 	chip->lux_scale = 2000;
 
 	ret = regmap_write(chip->regmap, ISL29028_REG_TEST1_MODE, 0x0);