docs: iio-sensor-proxy: document current state of compass in Pinephone

hosts/common/programs/iio-sensor-proxy.nix

@@ -1,9 +1,10 @@
+# chat (Matrix): #iio-sensor-proxy:dylanvanassche.be
 # src: <https://gitlab.freedesktop.org/hadess/iio-sensor-proxy>
 # IIO = "Industrial I/O": <https://www.kernel.org/doc/html/v4.12/driver-api/iio/index.html>
 # iio-sensor-proxy reads IIO data reported by the kernel at /sys/bus/iio/* and makes it available to dbus applications.
 # this includes:
 # - ambient light sensor
-# - compass/magnetometer
+# - compass/magnetometer  (LIMITED)
 # - accelerometer (rotation)
 #
 # use:
@@ -11,6 +12,18 @@
 # - read sensors: `sudo -u geoclue monitor-sensor --compass`
 #   - default dbus policy only allows geoclue to use the compass
 #   - `sudo monitor-sensor` for light/rotation
+#
+# HARDWARE SUPPORT: PINEPHONE (2024/07/01)
+# - accelerometer and light sensor seem to work
+# - magnetometer IS NOT SUPPORTED
+#   - <https://gitlab.freedesktop.org/hadess/iio-sensor-proxy/-/issues/310>
+#   - exists in sysfs and can be viewed with
+#     `cat /sys/devices/platform/soc/1c2b000.i2c/i2c-1/1-001c/iio:device2/in_magn_x_raw`
+#   - nothing in iio-sensor-proxy reads anything related to "magn".
+#   - my sensor is af8133j -- different but similar to lis3mdl listed in issue report,
+#   - seems i could add a new "polling" iio-sensor-proxy driver which reads the data from sysfs pretty easily.
+#     not sure how much post-processing needs to happen on that data, but i doubt it's too much?
+#   - TODO: try using this implementation that's out for PR: <https://gitlab.freedesktop.org/hadess/iio-sensor-proxy/-/merge_requests/316>
 { config, lib, ... }:
 let
   cfg = config.sane.programs.iio-sensor-proxy;