On 4/15/20 11:22 PM, Alexandre Belloni wrote:
The first received byte is the MSB, followed by the LSB so the value needs
to be byte swapped.
Also, the ADC actually has a delay of one clock on the SPI bus. Read three
bytes to get the last bit.
Fixes: 8dd2d7c0fed7 ("iio: adc: Add driver for the TI ADS8344 A/DC chips")
Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
---
drivers/iio/adc/ti-ads8344.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/iio/adc/ti-ads8344.c b/drivers/iio/adc/ti-ads8344.c
index 9a460807d46d..6da50ea35217 100644
--- a/drivers/iio/adc/ti-ads8344.c
+++ b/drivers/iio/adc/ti-ads8344.c
@@ -29,7 +29,6 @@ struct ads8344 {
struct mutex lock;
u8 tx_buf ____cacheline_aligned;
- u16 rx_buf;
};
#define ADS8344_VOLTAGE_CHANNEL(chan, si) \
@@ -76,6 +75,7 @@ static int ads8344_adc_conversion(struct ads8344 *adc, int channel,
{
struct spi_device *spi = adc->spi;
int ret;
+ u8 buf[3];
Same as with spi_write(), spi_read() transfer buffers should not be on
the stack in case the driver tries to use it for DMA.
adc->tx_buf = ADS8344_START;
if (!differential)
@@ -89,11 +89,11 @@ static int ads8344_adc_conversion(struct ads8344 *adc, int channel,
udelay(9);
- ret = spi_read(spi, &adc->rx_buf, 2);
+ ret = spi_read(spi, buf, sizeof(buf));
if (ret)
return ret;
- return adc->rx_buf;
+ return buf[0] << 9 | buf[1] << 1 | buf[2] >> 7;
}
static int ads8344_read_raw(struct iio_dev *iio,
