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iio: mtk-auxadc: fix case IIO_CHAN_INFO_PROCESSED

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commit c2980c64c7 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: ace4cdfe67 ("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>
This commit is contained in:
Hui Liu 2021-09-26 15:30:28 +08:00 • committed by Greg Kroah-Hartman
commit e811506f60
1 changed files with 8 additions and 0 deletions
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8
drivers/iio/adc/mt6577_auxadc.c
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@ -82,6 +82,10 @@ static const struct iio_chan_spec mt6577_auxadc_iio_channels[] = {
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 iio_dev *indio_dev,
}
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: