[PATCH 2/4] iio: Introduce IIO_CHAN_INFO_RANGE

[Roberta Dobrescu <roberta.dobrescu@gmail.com>]

Some ambient light sensors have hardware dependent ranges and
resolutions. In this case user won't be able to calculate illuminance
(lux) using only scale attribute.

For instance, a device that uses a Full Scale Range is the
light sensor ISL29018. In this case, IIO_CHAN_INFO_RANGE is
needed since the number of ADC bits can be 4, 8, 12 or 16 and
using just scales would result in too similar values for different
ranges and resolutions.

Signed-off-by: Roberta Dobrescu <roberta.dobrescu@gmail.com>
---
 Documentation/ABI/testing/sysfs-bus-iio | 13 +++++++++++++
 drivers/iio/industrialio-core.c         |  1 +
 include/linux/iio/iio.h                 |  1 +
 3 files changed, 15 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
index 9a70c31..ad1541f 100644
--- a/Documentation/ABI/testing/sysfs-bus-iio
+++ b/Documentation/ABI/testing/sysfs-bus-iio
@@ -1249,3 +1249,16 @@ Contact:	linux-iio@vger.kernel.org
 Description:
 		Specifies number of seconds in which we compute the steps
 		that occur in order to decide if the consumer is making steps.
+
+What:		/sys/bus/iio/devices/deviceX/in_illuminance0_range
+KernelVersion:	3.21
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Hardware dependent ADC Full Scale Range used for some ambient
+		light sensors in calculating lux.
+
+What:		/sys/bus/iio/devices/deviceX/in_illuminance_range_available
+KernelVersion:	3.21
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Hardware dependent supported values for ADC Full Scale Range.
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index aaba9d3..4138042 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -128,6 +128,7 @@ static const char * const iio_chan_info_postfix[] = {
 	[IIO_CHAN_INFO_CALIBWEIGHT] = "calibweight",
 	[IIO_CHAN_INFO_DEBOUNCE_COUNT] = "debounce_count",
 	[IIO_CHAN_INFO_DEBOUNCE_TIME] = "debounce_time",
+	[IIO_CHAN_INFO_RANGE] = "range",
 };
 
 /**
diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index 80d8550..fbdd434 100644
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -43,6 +43,7 @@ enum iio_chan_info_enum {
 	IIO_CHAN_INFO_CALIBWEIGHT,
 	IIO_CHAN_INFO_DEBOUNCE_COUNT,
 	IIO_CHAN_INFO_DEBOUNCE_TIME,
+	IIO_CHAN_INFO_RANGE,
 };
 
 enum iio_shared_by {
-- 
1.9.1