[PATCH 2/5] iio: adc: stm32-dfsdm: fix data type

From: Olivier Moysan
Date: Wed Jun 19 2019 - 09:09:43 EST


Fix the data type as DFSDM raw output is complements 2,
24bits left aligned in a 32-bit register.
This change does not affect AUDIO path
- Set data as signed for IIO (as for AUDIO)
- Set 8 bit right shift for IIO.
The 8 LSBs bits of data contains channel info and are masked.

Fixes: e2e6771c6462 ("IIO: ADC: add STM32 DFSDM sigma delta ADC support")

Signed-off-by: Olivier Moysan <olivier.moysan@xxxxxx>
---
drivers/iio/adc/stm32-dfsdm-adc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/adc/stm32-dfsdm-adc.c b/drivers/iio/adc/stm32-dfsdm-adc.c
index cb596f104919..6b90a40882f2 100644
--- a/drivers/iio/adc/stm32-dfsdm-adc.c
+++ b/drivers/iio/adc/stm32-dfsdm-adc.c
@@ -1365,11 +1365,11 @@ static int stm32_dfsdm_adc_chan_init_one(struct iio_dev *indio_dev,
BIT(IIO_CHAN_INFO_SAMP_FREQ);

if (adc->dev_data->type == DFSDM_AUDIO) {
- ch->scan_type.sign = 's';
ch->ext_info = dfsdm_adc_audio_ext_info;
} else {
- ch->scan_type.sign = 'u';
+ ch->scan_type.shift = 8;
}
+ ch->scan_type.sign = 's';
ch->scan_type.realbits = 24;
ch->scan_type.storagebits = 32;

--
2.7.4