iio: temperature: mlx90632: Interface to change object ambient temperature

Since object temperature might be different than the sensor temperature
the infrared sensors should provide an interface to inject ambient
temperature. This was in past done via write to ambient temperature
interface (in_temp_ambient_raw), but I think most people did not know
about it. This solution introduces a new iio type of the CALIBAMBIENT
which is hopefully more descriptive and more explicit about the purpose
and capabilities of the sensors.

Signed-off-by: Crt Mori <cmo@melexis.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20200906210231.383976-1-cmo@melexis.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
index c203344..a9d5181 100644 (file)
--- a/Documentation/ABI/testing/sysfs-bus-iio
+++ b/Documentation/ABI/testing/sysfs-bus-iio
@@ -1758,6 +1758,14 @@ Contact: linux-iio@vger.kernel.org
 Description:
                One of the following thermocouple types: B, E, J, K, N, R, S, T.
 
+What:          /sys/bus/iio/devices/iio:deviceX/in_temp_object_calibambient
+What:          /sys/bus/iio/devices/iio:deviceX/in_tempX_object_calibambient
+KernelVersion: 5.10
+Contact:       linux-iio@vger.kernel.org
+Description:
+               Calibrated ambient temperature for object temperature
+               calculation in milli degrees Celsius.
+
 What:          /sys/bus/iio/devices/iio:deviceX/in_intensity_x_raw
 What:          /sys/bus/iio/devices/iio:deviceX/in_intensity_y_raw
 What:          /sys/bus/iio/devices/iio:deviceX/in_intensity_z_raw

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 59003dc..8ddc6df 100644 (file)
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -166,6 +166,7 @@ static const char * const iio_chan_info_postfix[] = {
        [IIO_CHAN_INFO_CALIBEMISSIVITY] = "calibemissivity",
        [IIO_CHAN_INFO_OVERSAMPLING_RATIO] = "oversampling_ratio",
        [IIO_CHAN_INFO_THERMOCOUPLE_TYPE] = "thermocouple_type",
+       [IIO_CHAN_INFO_CALIBAMBIENT] = "calibambient",
 };
 
 #if defined(CONFIG_DEBUG_FS)

diff --git a/drivers/iio/temperature/mlx90632.c b/drivers/iio/temperature/mlx90632.c
index 472a7fb..503fe54 100644 (file)
--- a/drivers/iio/temperature/mlx90632.c
+++ b/drivers/iio/temperature/mlx90632.c
@@ -761,7 +761,9 @@ static int mlx90632_read_raw(struct iio_dev *indio_dev,
                        *val2 = data->emissivity * 1000;
                }
                return IIO_VAL_INT_PLUS_MICRO;
-
+       case IIO_CHAN_INFO_CALIBAMBIENT:
+               *val = data->object_ambient_temperature;
+               return IIO_VAL_INT;
        default:
                return -EINVAL;
        }
@@ -781,6 +783,9 @@ static int mlx90632_write_raw(struct iio_dev *indio_dev,
                        return -EINVAL;
                data->emissivity = val * 1000 + val2 / 1000;
                return 0;
+       case IIO_CHAN_INFO_CALIBAMBIENT:
+               data->object_ambient_temperature = val;
+               return 0;
        default:
                return -EINVAL;
        }
@@ -798,7 +803,7 @@ static const struct iio_chan_spec mlx90632_channels[] = {
                .modified = 1,
                .channel2 = IIO_MOD_TEMP_OBJECT,
                .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
-                       BIT(IIO_CHAN_INFO_CALIBEMISSIVITY),
+                       BIT(IIO_CHAN_INFO_CALIBEMISSIVITY) | BIT(IIO_CHAN_INFO_CALIBAMBIENT),
        },
 };
 

diff --git a/include/linux/iio/types.h b/include/linux/iio/types.h
index e6fd364..1e3ed6f 100644 (file)
--- a/include/linux/iio/types.h
+++ b/include/linux/iio/types.h
@@ -59,6 +59,7 @@ enum iio_chan_info_enum {
        IIO_CHAN_INFO_CALIBEMISSIVITY,
        IIO_CHAN_INFO_OVERSAMPLING_RATIO,
        IIO_CHAN_INFO_THERMOCOUPLE_TYPE,
+       IIO_CHAN_INFO_CALIBAMBIENT,
 };
 
 #endif /* _IIO_TYPES_H_ */