On Sun, 2021-02-28 at 14:45 +0000, Jonathan Cameron wrote:

On Sat, 27 Feb 2021 17:26:40 -0800
Ronald Tschalär [off-list ref] wrote:

quoted

Recent MacBook Pro's specify the usage of the change sensitivity
field
as illuminance (with a change sensitivity modifier) rather than as
light.

Signed-off-by: Ronald Tschalär <redacted>

This looks fine to me though it the hid sensors spec never fails to
surprise
me in the different slight variants of the same thing that come up.

Illuminance is at least fairly well defined, but who knows what for
the DATA_LIGHT
version takes?

The current implementations are deploying using
"HID_USAGE_SENSOR_LIGHT_ILLUM" usage id 0xD1 for input. So this is
natural to use the same usage id for sensitivity. So patch looks good
to me.

But most implementation choose to use DATA_LIGHT for the sensitivity.
probably referring to change in quantity of light without referring to
area. There are no obvious units specified for DATA_LIGHT in the spec.

Thanks,
Srinivas

Anyhow, lets give time for Srinivas to sanity check this as he's much
more familiar
with that spec than I am.

Jonathan

quoted

---
 drivers/iio/light/hid-sensor-als.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/iio/light/hid-sensor-als.c

b/drivers/iio/light/hid-sensor-als.c
index a21c827e4953d..849ee37dcd866 100644

--- a/drivers/iio/light/hid-sensor-als.c
+++ b/drivers/iio/light/hid-sensor-als.c

@@ -252,6 +252,14 @@ static int als_parse_report(struct

platform_device *pdev,
 			HID_USAGE_SENSOR_DATA_MOD_CHANGE_SENSITIVITY_AB
S |
 			HID_USAGE_SENSOR_DATA_LIGHT,
 			&st->common_attributes.sensitivity);
+
+		if (st->common_attributes.sensitivity.index < 0)
+			sensor_hub_input_get_attribute_info(hsdev,
+				HID_FEATURE_REPORT, usage_id,
+				HID_USAGE_SENSOR_DATA_MOD_CHANGE_SENSIT
IVITY_ABS |
+				HID_USAGE_SENSOR_LIGHT_ILLUM,
+				&st->common_attributes.sensitivity);
+
 		dev_dbg(&pdev->dev, "Sensitivity index:report %d:%d\n",
 			st->common_attributes.sensitivity.index,
 			st->common_attributes.sensitivity.report_id);