[v2 5/9] iio: core: add thermocouple_type standard attribute

[Andrea Merello <andrea.merello@gmail.com>]

We have a couple of thermocouple IIO drivers, supporting several chips.
Some of them support only one specific thermocouple type (e.g. "K", "J"),
one of them can be configured to work with several different thermocouple
types.

In certain applications thermocouples could be externally connected to the
chip by the user.

This patch introduces a new IIO standard attribute to report the supported
thermocouple type and, where applicable, to allow it to be dynamically set
using sysfs.

Cc: Hartmut Knaack <knaack.h@gmx.de>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Patrick Havelange <patrick.havelange@essensium.com>
Cc: Paresh Chaudhary <paresh.chaudhary@rockwellcollins.com>
Cc: Matt Weber <matthew.weber@rockwellcollins.com>
Cc: Matt Ranostay <matt.ranostay@konsulko.com>
Cc: Chuhong Yuan <hslester96@gmail.com>
Cc: Daniel Gomez <dagmcr@gmail.com>
Cc: linux-iio@vger.kernel.org
Signed-off-by: Andrea Merello <andrea.merello@gmail.com>
---
 drivers/iio/industrialio-core.c | 1 +
 include/linux/iio/types.h       | 1 +
 2 files changed, 2 insertions(+)

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 958b5c48a86f..fa2c3b321bfd 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -161,6 +161,7 @@ static const char * const iio_chan_info_postfix[] = {
 	[IIO_CHAN_INFO_DEBOUNCE_TIME] = "debounce_time",
 	[IIO_CHAN_INFO_CALIBEMISSIVITY] = "calibemissivity",
 	[IIO_CHAN_INFO_OVERSAMPLING_RATIO] = "oversampling_ratio",
+	[IIO_CHAN_INFO_THERMOCOUPLE_TYPE] = "thermocouple_type",
 };
 
 /**
diff --git a/include/linux/iio/types.h b/include/linux/iio/types.h
index 8e0026da38c9..e6fd3645963c 100644
--- a/include/linux/iio/types.h
+++ b/include/linux/iio/types.h
@@ -58,6 +58,7 @@ enum iio_chan_info_enum {
 	IIO_CHAN_INFO_DEBOUNCE_TIME,
 	IIO_CHAN_INFO_CALIBEMISSIVITY,
 	IIO_CHAN_INFO_OVERSAMPLING_RATIO,
+	IIO_CHAN_INFO_THERMOCOUPLE_TYPE,
 };
 
 #endif /* _IIO_TYPES_H_ */
-- 
2.17.1