iio: Add channel type for attention

Add a new channel type representing if the user's attention state to the
the system. This usually means if the user is looking at the screen or
not.

Signed-off-by: Ricardo Ribalda <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jonathan Cameron <[e-mail]>

Documentation/ABI/testing/sysfs-bus-iio

···
 Contact:	[e-mail]
 Description:
 		The value of current sense resistor in Ohms.
+
+What:		/sys/.../iio:deviceX/in_attention_input
+KernelVersion:	6.13
+Contact:	[e-mail]
+Description:
+		Value representing the user's attention to the system expressed
+		in units as percentage. This usually means if the user is
+		looking at the screen or not.

drivers/iio/industrialio-core.c

···
 	[IIO_DELTA_VELOCITY] = "deltavelocity",
 	[IIO_COLORTEMP] = "colortemp",
 	[IIO_CHROMATICITY] = "chromaticity",
+	[IIO_ATTENTION] = "attention",
 };
 
 static const char * const iio_modifier_names[] = {

include/uapi/linux/iio/types.h

···
 	IIO_DELTA_VELOCITY,
 	IIO_COLORTEMP,
 	IIO_CHROMATICITY,
+	IIO_ATTENTION,
 };
 
 enum iio_modifier {

tools/iio/iio_event_monitor.c

···
 	[IIO_DELTA_VELOCITY] = "deltavelocity",
 	[IIO_COLORTEMP] = "colortemp",
 	[IIO_CHROMATICITY] = "chromaticity",
+	[IIO_ATTENTION] = "attention",
 };
 
 static const char * const iio_ev_type_text[] = {
···
 	case IIO_DELTA_VELOCITY:
 	case IIO_COLORTEMP:
 	case IIO_CHROMATICITY:
+	case IIO_ATTENTION:
 		break;
 	default:
 		return false;