iio: chemical: Add IIO_CONCENTRATION channel type

There are air quality sensors that report data back in parts per million
of VOC (Volatile Organic Compounds) which are usually indexed from CO2
or another common pollutant.

This patchset adds an IIO_CONCENTRATION type that returns a percentage
of substance because no other channels types fit this use case.
Modifiers for IIO_MOD_CO2 and IIO_MOD_VOC gas types are defined.

Signed-off-by: Matt Ranostay <mranostay@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
index 20312a0e81979789a60ce1f295cf0931e0c0850a..08903b940957d6dce8c9b489d99e84743b40dad3 100644 (file)
--- a/Documentation/ABI/testing/sysfs-bus-iio
+++ b/Documentation/ABI/testing/sysfs-bus-iio
@@ -1460,3 +1460,14 @@ Description:
                measurements and return the average value as output data. Each
                value resulted from <type>[_name]_oversampling_ratio measurements
                is considered as one sample for <type>[_name]_sampling_frequency.
+
+What:          /sys/bus/iio/devices/iio:deviceX/in_concentration_raw
+What:          /sys/bus/iio/devices/iio:deviceX/in_concentrationX_raw
+What:          /sys/bus/iio/devices/iio:deviceX/in_concentration_co2_raw
+What:          /sys/bus/iio/devices/iio:deviceX/in_concentrationX_co2_raw
+What:          /sys/bus/iio/devices/iio:deviceX/in_concentration_voc_raw
+What:          /sys/bus/iio/devices/iio:deviceX/in_concentrationX_voc_raw
+KernelVersion: 4.3
+Contact:       linux-iio@vger.kernel.org
+Description:
+               Raw (unscaled no offset etc.) percentage reading of a substance.

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index bef690ed048031e6fbb4f5fa1ef4bbdc72bb5a52..ee09a945a2c7abb5f5593b8fec1a58dba501f5e8 100644 (file)
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -75,6 +75,7 @@ static const char * const iio_chan_type_name_spec[] = {
        [IIO_ENERGY] = "energy",
        [IIO_DISTANCE] = "distance",
        [IIO_VELOCITY] = "velocity",
+       [IIO_CONCENTRATION] = "concentration",
 };
 
 static const char * const iio_modifier_names[] = {
@@ -111,6 +112,8 @@ static const char * const iio_modifier_names[] = {
        [IIO_MOD_ROOT_SUM_SQUARED_X_Y_Z] = "sqrt(x^2+y^2+z^2)",
        [IIO_MOD_I] = "i",
        [IIO_MOD_Q] = "q",
+       [IIO_MOD_CO2] = "co2",
+       [IIO_MOD_VOC] = "voc",
 };
 
 /* relies on pairs of these shared then separate */

diff --git a/include/uapi/linux/iio/types.h b/include/uapi/linux/iio/types.h
index 2f8b11722204dcc6528dfab601961ef6834f3e13..1e4c4e346ffbadd18453d5910f57d2ff95c2c4c4 100644 (file)
--- a/include/uapi/linux/iio/types.h
+++ b/include/uapi/linux/iio/types.h
@@ -35,6 +35,7 @@ enum iio_chan_type {
        IIO_ENERGY,
        IIO_DISTANCE,
        IIO_VELOCITY,
+       IIO_CONCENTRATION,
 };
 
 enum iio_modifier {
@@ -72,6 +73,8 @@ enum iio_modifier {
        IIO_MOD_ROOT_SUM_SQUARED_X_Y_Z,
        IIO_MOD_I,
        IIO_MOD_Q,
+       IIO_MOD_CO2,
+       IIO_MOD_VOC,
 };
 
 enum iio_event_type {