iio: Add support for humidity sensors

There are already humidity sensors in the hwmon subsystem,
so we use their unit (milli percent) here as well.

Signed-off-by: Harald Geyer <harald@ccbib.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

3 files changed, 15 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
index b20e829d350f..6e02c5029152 100644
--- a/Documentation/ABI/testing/sysfs-bus-iio
+++ b/Documentation/ABI/testing/sysfs-bus-iio
@@ -197,6 +197,19 @@ Description:
                 Raw pressure measurement from channel Y. Units after
                 application of scale and offset are kilopascal.
 
+What:           /sys/bus/iio/devices/iio:deviceX/in_humidityrelative_raw
+KernelVersion:  3.14
+Contact:        linux-iio@vger.kernel.org
+Description:
+                Raw humidity measurement of air. Units after application of
+                scale and offset are milli percent.
+
+What:           /sys/bus/iio/devices/iio:deviceX/in_humidityrelative_input
+KernelVersion:  3.14
+Contact:        linux-iio@vger.kernel.org
+Description:
+                Scaled humidity measurement in milli percent.
+
 What:           /sys/bus/iio/devices/iio:deviceX/in_accel_offset
 What:           /sys/bus/iio/devices/iio:deviceX/in_accel_x_offset
 What:           /sys/bus/iio/devices/iio:deviceX/in_accel_y_offset
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 2fe88c189f74..acc911a836ca 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -69,6 +69,7 @@ static const char * const iio_chan_type_name_spec[] = {
         [IIO_ALTVOLTAGE] = "altvoltage",
         [IIO_CCT] = "cct",
         [IIO_PRESSURE] = "pressure",
+        [IIO_HUMIDITYRELATIVE] = "humidityrelative",
 };
 
 static const char * const iio_modifier_names[] = {
diff --git a/include/linux/iio/types.h b/include/linux/iio/types.h
index 4ac928ee31c5..084d882fe01b 100644
--- a/include/linux/iio/types.h
+++ b/include/linux/iio/types.h
@@ -29,6 +29,7 @@ enum iio_chan_type {
         IIO_ALTVOLTAGE,
         IIO_CCT,
         IIO_PRESSURE,
+        IIO_HUMIDITYRELATIVE,
 };
 
 enum iio_modifier {