AINCOM should actually be a supply. AINx inputs are referenced to AINCOM
in pseudo-differential operation mode. AINCOM voltage represents the
offset of corresponding channels.
Signed-off-by: Alisa-Dariana Roman <alisa.roman@xxxxxxxxxx>
---
drivers/iio/adc/ad7192.c | 50 ++++++++++++++++++++++++++++++++++++++--
1 file changed, 48 insertions(+), 2 deletions(-)
diff --git a/drivers/iio/adc/ad7192.c b/drivers/iio/adc/ad7192.c
index ace81e3817a1..7160929d32c9 100644
--- a/drivers/iio/adc/ad7192.c
+++ b/drivers/iio/adc/ad7192.c
@@ -20,6 +20,7 @@
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/property.h>
+#include <linux/units.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
@@ -186,6 +187,7 @@ struct ad7192_state {
struct regulator *vref;
struct clk *mclk;
u16 int_vref_mv;
+ u32 aincom_mv;
u32 fclk;
u32 mode;
u32 conf;
@@ -742,10 +744,24 @@ static int ad7192_read_raw(struct iio_dev *indio_dev,
*val = -(1 << (chan->scan_type.realbits - 1));
else
*val = 0;
+
+ switch (chan->type) {
+ case IIO_VOLTAGE:
+ /*
+ * Only applies to pseudo-differential inputs.
+ * AINCOM voltage has to be converted to "raw" units.
+ */
+ if (st->aincom_mv && !chan->differential)
+ *val += DIV_ROUND_CLOSEST_ULL((u64)st->aincom_mv * NANO,
+ st->scale_avail[gain][1]);
+ return IIO_VAL_INT;
/* Kelvin to Celsius */
- if (chan->type == IIO_TEMP)
+ case IIO_TEMP:
*val -= 273 * ad7192_get_temp_scale(unipolar);
- return IIO_VAL_INT;
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
case IIO_CHAN_INFO_SAMP_FREQ:
*val = DIV_ROUND_CLOSEST(ad7192_get_f_adc(st), 1024);
return IIO_VAL_INT;
@@ -1052,6 +1068,7 @@ static int ad7192_probe(struct spi_device *spi)
{
struct ad7192_state *st;
struct iio_dev *indio_dev;
+ struct regulator *aincom;
int ret;
if (!spi->irq) {
@@ -1067,6 +1084,35 @@ static int ad7192_probe(struct spi_device *spi)
mutex_init(&st->lock);
+ /*
+ * Regulator aincom is optional to maintain compatibility with older DT.
+ * Newer firmware should provide a zero volt fixed supply if wired to
+ * ground.
+ */
+ aincom = devm_regulator_get_optional(&spi->dev, "aincom");
+ if (IS_ERR(aincom)) {
+ if (PTR_ERR(aincom) != -ENODEV)
+ return dev_err_probe(&spi->dev, PTR_ERR(aincom),
+ "Failed to get AINCOM supply\n");
+
+ st->aincom_mv = 0;
+ } else {
+ ret = regulator_enable(aincom);
+ if (ret)
+ return dev_err_probe(&spi->dev, ret,
+ "Failed to enable specified AINCOM supply\n");
+
+ ret = devm_add_action_or_reset(&spi->dev, ad7192_reg_disable, aincom);
+ if (ret)
+ return ret;
+
+ ret = regulator_get_voltage(aincom);
+ if (ret < 0)
+ return dev_err_probe(&spi->dev, ret,
+ "Device tree error, AINCOM voltage undefined\n");
+ st->aincom_mv = ret / MILLI;
+ }
+
st->avdd = devm_regulator_get(&spi->dev, "avdd");
if (IS_ERR(st->avdd))
return PTR_ERR(st->avdd);
--
2.34.1
