Re: [PATCH v4 1/1] iio: mtk-auxadc: fix case IIO_CHAN_INFO_PROCESSED
From: Jonathan Cameron <jic23@kernel.org>
Date: 2021-09-26 11:28:02
On Sun, 26 Sep 2021 15:30:28 +0800 Hui-Liu Liu [off-list ref] wrote:
From: Hui Liu <redacted>
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 <redacted>Hi Hui Liu, Thanks for the updated description. Applied to the fixes-togreg branch of iio.git and marked for stable. Thanks, Jonathan
quoted hunk
--- drivers/iio/adc/mt6577_auxadc.c | 8 ++++++++ 1 file changed, 8 insertions(+)diff --git a/drivers/iio/adc/mt6577_auxadc.c b/drivers/iio/adc/mt6577_auxadc.c index 79c1dd68b909..d4fccd52ef08 100644 --- 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_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:
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