[PATCH 5/5] iio/ti_am335x_adc: check if we found the value

[Sebastian Andrzej Siewior <bigeasy-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>]

Usually we get all the values we wanted but it is possible, that te ADC
unit is busy performing the conversation for the HW events. In that case
-EBUSY is returned and the user may re-call the function.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
---
 drivers/iio/adc/ti_am335x_adc.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
index df2de4c..6a00874 100644
--- a/drivers/iio/adc/ti_am335x_adc.c
+++ b/drivers/iio/adc/ti_am335x_adc.c
@@ -161,6 +161,7 @@ static int tiadc_read_raw(struct iio_dev *indio_dev,
 	int i;
 	unsigned int fifo1count, read;
 	u32 step = UINT_MAX;
+	bool found = false;
 
 	/*
 	 * When the sub-system is first enabled,
@@ -185,10 +186,14 @@ static int tiadc_read_raw(struct iio_dev *indio_dev,
 	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
 	for (i = 0; i < fifo1count; i++) {
 		read = tiadc_readl(adc_dev, REG_FIFO1);
-		if (read >> 16 == step)
+		if (read >> 16 == step) {
 			*val = read & 0xfff;
+			found = true;
+		}
 	}
 	tiadc_writel(adc_dev, REG_SE, STPENB_STEPENB);
+	if (found == false)
+		return -EBUSY;
 
 	return IIO_VAL_INT;
 }
-- 
1.7.10.4