The function ntc_adc_iio_read assumes both a 12 bit ADC and that
pullup_uv is the same as the ADC reference voltage. If either
assumption is false, then the result is incorrect.
For iio channels supporting either IIO_CHAN_INFO_PROCESSED or
IIO_CHAN_INFO_SCALE, a new function, ntc_adc_iio_read_processed,
will be used. That function gets microvolts directly with a call to
iio_read_channel_processed.
Signed-off-by: Chris Lesiak <chris.lesiak@xxxxxxxxx>
---
drivers/hwmon/ntc_thermistor.c | 21 ++++++++++++++++++++-
1 file changed, 20 insertions(+), 1 deletion(-)
diff --git a/drivers/hwmon/ntc_thermistor.c b/drivers/hwmon/ntc_thermistor.c
index 6880011..311df86 100644
--- a/drivers/hwmon/ntc_thermistor.c
+++ b/drivers/hwmon/ntc_thermistor.c
@@ -206,6 +206,20 @@ static int ntc_adc_iio_read(struct ntc_thermistor_platform_data *pdata)
return (int)result;
}
+static int ntc_adc_iio_read_processed(struct ntc_thermistor_platform_data *pdata)
+{
+ struct iio_channel *channel = pdata->chan;
+ int val, ret;
+
+ ret = iio_read_channel_processed(channel, &val);
+ if (ret < 0) {
+ pr_err("read channel() error: %d\n", ret);
+ return ret;
+ }
+
+ return val;
+}
+
static const struct of_device_id ntc_match[] = {
{ .compatible = "murata,ncp15wb473",
.data = &ntc_thermistor_id[0] },
@@ -275,7 +289,12 @@ ntc_thermistor_parse_dt(struct platform_device *pdev)
pdata->connect = NTC_CONNECTED_GROUND;
pdata->chan = chan;
- pdata->read_uv = ntc_adc_iio_read;
+
+ if (iio_channel_has_info(chan->channel, IIO_CHAN_INFO_PROCESSED)
+ || iio_channel_has_info(chan->channel, IIO_CHAN_INFO_SCALE))
+ pdata->read_uv = ntc_adc_iio_read_processed;
+ else
+ pdata->read_uv = ntc_adc_iio_read;
return pdata;
}
--
1.9.3
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