This patch adds pressure compensation to the scd4x driver. The pressure can
be written to the sensor in hPa. The pressure will be compensated
internally by the sensor.
Signed-off-by: Roan van Dijk <roan@xxxxxxxxxxx>
---
drivers/iio/chemical/scd4x.c | 41 +++++++++++++++++++++++++++++++++---
1 file changed, 38 insertions(+), 3 deletions(-)
diff --git a/drivers/iio/chemical/scd4x.c b/drivers/iio/chemical/scd4x.c
index a4f22d926400..fe6b3f3f7186 100644
--- a/drivers/iio/chemical/scd4x.c
+++ b/drivers/iio/chemical/scd4x.c
@@ -36,6 +36,8 @@
#define SCD4X_WRITE_BUF_SIZE 5
#define SCD4X_FRC_MIN_PPM 0
#define SCD4X_FRC_MAX_PPM 2000
+#define SCD4X_AMB_PRESSURE_MIN 700
+#define SCD4X_AMB_PRESSURE_MAX 1200
#define SCD4X_READY_MASK 0x01
/*Commands SCD4X*/
@@ -45,6 +47,8 @@ enum scd4x_cmd {
CMD_STOP_MEAS = 0x3f86,
CMD_SET_TEMP_OFFSET = 0x241d,
CMD_GET_TEMP_OFFSET = 0x2318,
+ CMD_SET_AMB_PRESSURE = 0xe000,
+ CMD_GET_AMB_PRESSURE = 0xe000,
CMD_FRC = 0x362f,
CMD_SET_ASC = 0x2416,
CMD_GET_ASC = 0x2313,
@@ -373,7 +377,10 @@ static int scd4x_read_raw(struct iio_dev *indio_dev,
return IIO_VAL_INT_PLUS_MICRO;
case IIO_CHAN_INFO_CALIBBIAS:
mutex_lock(&state->lock);
- ret = scd4x_read(state, CMD_GET_TEMP_OFFSET, &tmp, sizeof(tmp));
+ if (chan->type == IIO_TEMP)
+ ret = scd4x_read(state, CMD_GET_TEMP_OFFSET, &tmp, sizeof(tmp));
+ else if (chan->type == IIO_PRESSURE)
+ ret = scd4x_read(state, CMD_GET_AMB_PRESSURE, &tmp, sizeof(tmp));
mutex_unlock(&state->lock);
if (ret)
return ret;
@@ -386,6 +393,25 @@ static int scd4x_read_raw(struct iio_dev *indio_dev,
}
}
+static const int scd4x_pressure_calibbias_available[] = {
+ SCD4X_AMB_PRESSURE_MIN, 1, SCD4X_AMB_PRESSURE_MAX,
+};
+
+static int scd4x_read_avail(struct iio_dev *indio_dev, struct iio_chan_spec const *chan,
+ const int **vals, int *type, int *length, long mask)
+{
+ switch (mask) {
+ case IIO_CHAN_INFO_CALIBBIAS:
+ *vals = scd4x_pressure_calibbias_available;
+ *type = IIO_VAL_INT;
+
+ return IIO_AVAIL_RANGE;
+ }
+
+ return -EINVAL;
+}
+
+
static int scd4x_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
@@ -395,9 +421,11 @@ static int scd4x_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec const
switch (mask) {
case IIO_CHAN_INFO_CALIBBIAS:
mutex_lock(&state->lock);
- ret = scd4x_write(state, CMD_SET_TEMP_OFFSET, val);
+ if (chan->type == IIO_TEMP)
+ ret = scd4x_write(state, CMD_SET_TEMP_OFFSET, val);
+ else if (chan->type == IIO_PRESSURE)
+ ret = scd4x_write(state, CMD_SET_AMB_PRESSURE, val);
mutex_unlock(&state->lock);
-
return ret;
default:
return -EINVAL;
@@ -503,9 +531,16 @@ static const struct iio_info scd4x_info = {
.attrs = &scd4x_attr_group,
.read_raw = scd4x_read_raw,
.write_raw = scd4x_write_raw,
+ .read_avail = scd4x_read_avail,
};
static const struct iio_chan_spec scd4x_channels[] = {
+ {
+ .type = IIO_PRESSURE,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_CALIBBIAS),
+ .info_mask_separate_available = BIT(IIO_CHAN_INFO_CALIBBIAS),
+ .scan_index = -1,
+ },
{
.type = IIO_CONCENTRATION,
.channel2 = IIO_MOD_CO2,
--
2.39.2
