[Bug 221993] New: [ideapad-laptop] Missing driver support for IDEA2008 / Ambient Light Sensor on Yoga Slim 7 14AKP9

[bugzilla-daemon@kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=221993

            Bug ID: 221993
           Summary: [ideapad-laptop] Missing driver support for IDEA2008 /
                    Ambient Light Sensor on Yoga Slim 7 14AKP9
           Product: Drivers
           Version: 2.5
          Hardware: AMD
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P3
         Component: Platform_x86
          Assignee: drivers_platform_x86@kernel-bugs.osdl.org
          Reporter: dadodasyra.pro@gmail.com
        Regression: No

Created attachment 310826
  --> https://bugzilla.kernel.org/attachment.cgi?id=310826&action=edit
Decompiled ACPI table

Created attachment: SSDT2.dsl (Decompiled ACPI table)

Hardware: Lenovo Yoga Slim 7 14AKP9 (MT: 83JY)
OS: Fedora (Kernel 7.1.x)

The Ambient Light Sensor (ALS) on this laptop model is currently completely
non-functional on Linux. The sensor is not exposed via standard ACPI (_ALI)
methods, nor is it routed through the AMD Sensor Fusion Hub / amd_pmf. (The
amd-pmf TA session initializes cleanly with the correct firmware, but registers
no IIO devices).

ACPI dumping reveals the sensor is gated behind proprietary Lenovo ACPI devices
that currently lack driver bindings in `ideapad-laptop`:

- IDEA2008 (ITSD - Integrated Thermal/Sensor Device): _STA returns 0x0F.
- IDEA2002 (LISD): _STA returns 0x00.

In the attached `SSDT2.dsl`, IDEA2008 defines an interface directly to the
Embedded Controller:

    Device (ITSD)
    {
        Name (_HID, "IDEA2008") 
        Method (_STA, 0, NotSerialized) { Return (0x0F) }
    }
    // ...
    OperationRegion (ECF2, EmbeddedControl, Zero, 0xFF)
    Field (ECF2, ByteAcc, Lock, Preserve)
    {
        Offset (0x00), 
        VCMD,   8, 
        VDAT,   8, 
        VSTA,   8
    }

Steps to reproduce:
1. Boot Linux on Lenovo Yoga Slim 7 14AKP9.
2. Observe that no ALS appears in /sys/bus/iio/devices/.
3. Check /sys/bus/acpi/devices/IDEA2008:00/status (returns 15).
4. No driver claims the device.

Expected behavior:
`ideapad-laptop` (or a dedicated sensor driver) should bind to IDEA2008,
interface with the EC (VCMD/VDAT), and expose the ambient light readings to the
`iio` subsystem so userspace tools like iio-sensor-proxy can manage automatic
screen brightness.

I don't know much about drivers and new to linux environment on physical
devices. This was mainly AI generated after many back and forth.
I am available to test any patches or probe EC registers if maintainers can
provide instructions.

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