From: Hui Liu hui.liu@mediatek.com
commit c2980c64c7fd4585d684574c92d1624d44961edd upstream.
The previous driver does't apply the necessary scaling to take the voltage range into account. We change readback value from raw data to input voltage to fix case IIO_CHAN_INFO_PROCESSED.
Fixes: ace4cdfe67be ("iio: adc: mt2701: Add Mediatek auxadc driver for mt2701.") Signed-off-by: Hui Liu hui.liu@mediatek.com Link: https://lore.kernel.org/r/20210926073028.11045-2-hui.liu@mediatek.com Cc: Stable@vger.kernel.org Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/iio/adc/mt6577_auxadc.c | 8 ++++++++ 1 file changed, 8 insertions(+)
--- a/drivers/iio/adc/mt6577_auxadc.c +++ b/drivers/iio/adc/mt6577_auxadc.c @@ -82,6 +82,10 @@ static const struct iio_chan_spec mt6577 MT6577_AUXADC_CHANNEL(15), };
+/* For Voltage calculation */ +#define VOLTAGE_FULL_RANGE 1500 /* VA voltage */ +#define AUXADC_PRECISE 4096 /* 12 bits */ + static int mt_auxadc_get_cali_data(int rawdata, bool enable_cali) { return rawdata; @@ -191,6 +195,10 @@ static int mt6577_auxadc_read_raw(struct } if (adc_dev->dev_comp->sample_data_cali) *val = mt_auxadc_get_cali_data(*val, true); + + /* Convert adc raw data to voltage: 0 - 1500 mV */ + *val = *val * VOLTAGE_FULL_RANGE / AUXADC_PRECISE; + return IIO_VAL_INT;
default: