staging: iio: tsl2x7x: add error handling to tsl2x7x_prox_cal()

tsl2x7x_prox_cal() did not have any error checks. This patch adds
the missing error handling and ensures that any errors are reported to
user space via in_proximity0_calibrate_store().
Signed-off-by: Brian Masney <masneyb@onstation.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/staging/iio/light/tsl2x7x.c

@@ -807,10 +807,10 @@ static void tsl2x7x_prox_calculate(int *data, int length,
  * Calculates a standard deviation based on the samples,
  * and sets the threshold accordingly.
  */
-static void tsl2x7x_prox_cal(struct iio_dev *indio_dev)
+static int tsl2x7x_prox_cal(struct iio_dev *indio_dev)
 {
 	int prox_history[MAX_SAMPLES_CAL + 1];
-	int i;
+	int i, ret;
 	struct tsl2x7x_prox_stat prox_stat_data[2];
 	struct tsl2x7x_prox_stat *cal;
 	struct tsl2X7X_chip *chip = iio_priv(indio_dev);
@@ -825,25 +825,33 @@ static void tsl2x7x_prox_cal(struct iio_dev *indio_dev)
 	}
 
 	/* have to stop to change settings */
-	tsl2x7x_chip_off(indio_dev);
+	ret = tsl2x7x_chip_off(indio_dev);
+	if (ret < 0)
+		return ret;
 
 	/* Enable proximity detection save just in case prox not wanted yet*/
 	tmp_irq_settings = chip->settings.interrupts_en;
 	chip->settings.interrupts_en |= TSL2X7X_CNTL_PROX_INT_ENBL;
 
 	/*turn on device if not already on*/
-	tsl2x7x_chip_on(indio_dev);
+	ret = tsl2x7x_chip_on(indio_dev);
+	if (ret < 0)
+		return ret;
 
 	/*gather the samples*/
 	for (i = 0; i < chip->settings.prox_max_samples_cal; i++) {
 		usleep_range(15000, 17500);
-		tsl2x7x_get_prox(indio_dev);
+		ret = tsl2x7x_get_prox(indio_dev);
+		if (ret < 0)
+			return ret;
 		prox_history[i] = chip->prox_data;
 		dev_info(&chip->client->dev, "2 i=%d prox data= %d\n",
 			 i, chip->prox_data);
 	}
 
-	tsl2x7x_chip_off(indio_dev);
+	ret = tsl2x7x_chip_off(indio_dev);
+	if (ret < 0)
+		return ret;
 	cal = &prox_stat_data[PROX_STAT_CAL];
 	tsl2x7x_prox_calculate(prox_history,
 			       chip->settings.prox_max_samples_cal, cal);
@@ -857,8 +865,13 @@ static void tsl2x7x_prox_cal(struct iio_dev *indio_dev)
 
 	/* back to the way they were */
 	chip->settings.interrupts_en = tmp_irq_settings;
-	if (current_state == TSL2X7X_CHIP_WORKING)
-		tsl2x7x_chip_on(indio_dev);
+	if (current_state == TSL2X7X_CHIP_WORKING) {
+		ret = tsl2x7x_chip_on(indio_dev);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
 }
 
 static ssize_t
@@ -1018,8 +1031,11 @@ static ssize_t in_proximity0_calibrate_store(struct device *dev,
 	if (strtobool(buf, &value))
 		return -EINVAL;
 
-	if (value)
-		tsl2x7x_prox_cal(indio_dev);
+	if (value) {
+		ret = tsl2x7x_prox_cal(indio_dev);
+		if (ret < 0)
+			return ret;
+	}
 
 	ret = tsl2x7x_invoke_change(indio_dev);
 	if (ret < 0)