[PATCH] [hwmon] mc13783-adc: handle failure of mc13783_adc_do_conversion ...

[Uwe Kleine-König]

If reading the result of a channel fails pass the failure to userspace.

res is renamed to val to prevent confusion with the new variable ret.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig at pengutronix.de>
---
 drivers/hwmon/mc13783-adc.c |   36 +++++++++++++++++++++++++-----------
 1 files changed, 25 insertions(+), 11 deletions(-)

diff --git a/drivers/hwmon/mc13783-adc.c b/drivers/hwmon/mc13783-adc.c
index fafb193..ed0453d 100644
--- a/drivers/hwmon/mc13783-adc.c
+++ b/drivers/hwmon/mc13783-adc.c
@@ -40,49 +40,63 @@ static ssize_t mc13783_adc_show_name(struct device *dev, struct device_attribute
 	return sprintf(buf, "mc13783_adc\n");
 }
 
-static unsigned int mc13783_adc_read(struct device *dev,
-		struct device_attribute *devattr)
+static int mc13783_adc_read(struct device *dev,
+		struct device_attribute *devattr, unsigned int *val)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct mc13783_adc_priv *priv = platform_get_drvdata(pdev);
 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
 	unsigned int channel = attr->index;
 	unsigned int sample[4];
+	int ret;
 
-	mc13783_adc_do_conversion(priv->mc13783, MC13783_ADC_MODE_MULT_CHAN,
+	ret = mc13783_adc_do_conversion(priv->mc13783,
+			MC13783_ADC_MODE_MULT_CHAN,
 			channel, sample);
+	if (ret)
+		return ret;
 
 	channel &= 0x7;
 
-	return (sample[channel % 4] >> (channel > 3 ? 14 : 2)) & 0x3ff;
+	*val = (sample[channel % 4] >> (channel > 3 ? 14 : 2)) & 0x3ff;
+
+	return 0;
 }
 
 static ssize_t mc13783_adc_read_bp(struct device *dev,
 		struct device_attribute *devattr, char *buf)
 {
-	unsigned res = mc13783_adc_read(dev, devattr);
+	unsigned val;
+	int ret = mc13783_adc_read(dev, devattr, &val);
+
+	if (ret)
+		return ret;
 
 	/*
 	 * BP (channel 2) reports with offset 2.4V to the actual value to fit
 	 * the input range of the ADC.  unit = 2.25mV = 9/4 mV.
 	 */
-	res = DIV_ROUND_CLOSEST(res * 9, 4) + 2400;
+	val = DIV_ROUND_CLOSEST(val * 9, 4) + 2400;
 
-	return sprintf(buf, "%u\n", res);
+	return sprintf(buf, "%u\n", val);
 }
 
 static ssize_t mc13783_adc_read_gp(struct device *dev,
 		struct device_attribute *devattr, char *buf)
 {
-	unsigned res = mc13783_adc_read(dev, devattr);
+	unsigned val;
+	int ret = mc13783_adc_read(dev, devattr, &val);
+
+	if (ret)
+		return ret;
 
 	/*
-	 * input range is [0, 2.3V], res has 10 bits, so each bit
+	 * input range is [0, 2.3V], val has 10 bits, so each bit
 	 * is worth 9/4 mV.
 	 */
-	res = DIV_ROUND_CLOSEST(res * 9, 4);
+	val = DIV_ROUND_CLOSEST(val * 9, 4);
 
-	return sprintf(buf, "%u\n", res);
+	return sprintf(buf, "%u\n", val);
 }
 
 static DEVICE_ATTR(name, S_IRUGO, mc13783_adc_show_name, NULL);
-- 
1.6.5.2


-- 
Pengutronix e.K.                              | Uwe Kleine-König            |
Industrial Linux Solutions                    | http://www.pengutronix.de/  |