[PATCH v3 0/5] platform/x86: asus-wmi: TUF keyboard shutdown naming and RGB readback

This series fixes the name of the fourth TUF keyboard power state and
makes the TUF keyboard RGB attributes readable.

The fourth flag of kbd_rgb_state was labelled "keyboard" and treated as
a no-op since it was introduced.  In hardware it gates the backlight
during the ACPI S5 power-off sequence: with the bit set the keyboard
lights up white while the machine powers off, with the bit clear the
machine powers off dark.  Patch 2 renames the field and carries a Fixes
tag for stable.

The remaining patches prepare and add readback.  DSTS device 0x0010005B
evaluates the DSDT method EC0.KBLS(), which returns a 16-byte snapshot
of the EC's keyboard state: lighting mode, red, green and blue levels,
animation speed, and the four power flags.  Both kbd_rgb_mode and
kbd_rgb_state become readable and report the write format with the
command word fixed at 1.

Responses to the v2 review:

Ilpo:
- Documentation: patch 5 adds the missing ABI entries.
- Errno: the helper already separates the cases.
  asus_wmi_evaluate_method_buf() returns -EIO for a failed evaluation
  and -ENODEV for an unsupported DEVID.  The readback keeps the
  err < 0 ? err : -ENODEV normalization for the positive ACPI integers
  that leak through, and the AML signature check returns -ENODEV as
  well.
- Named defines: patch 3 names the three speed codes and the four state
  bits, and the decoding comments are gone.
- Struct: patch 4 parses the status buffer through a packed struct.

Denis:
- DEVID naming: the write DEVID is now ASUS_WMI_DEVID_TUF_RGB_CMD
  (patch 1) and the read DEVID is ASUS_WMI_DEVID_TUF_RGB_READ_STATUS,
  as you suggested.
- -ENODATA: asus_wmi_evaluate_method_buf() already returns -ENODATA for
  empty buffers, so no extra handling was added.

Provenance: the KBLS buffer layout and the speed-code semantics were
recovered by static analysis of the EC firmware (ITE IT5570VG),
assisted by an LLM-driven toolchain; the readback patch carries an
Assisted-by tag.  Tested on a TUF Gaming A15 (FA507NV): the v2
readback on kernel 7.2.6, and the S5 behaviour of the shutdown flag by
A/B testing both values.

Changes in v3, relative to v2:
- split into five patches, one logical change each
- renamed the write DEVID to ASUS_WMI_DEVID_TUF_RGB_CMD and the new one
  to ASUS_WMI_DEVID_TUF_RGB_READ_STATUS, per Denis Benato
- named the speed codes and the power state bits and dropped the
  decoding comments
- parse the status buffer through a packed struct
- added the ABI documentation, with the attributes documented at their
  real location under /sys/class/leds/asus::kbd_backlight/ and worded
  for all laptops that expose the zonal RGB devices, not only TUF
  models
- added linux-api to Cc, which the earlier versions missed

v2: https://lore.kernel.org/all/20260926005625.171560-1-bartualev@gmail.com/ (local)
v1: https://lore.kernel.org/all/20260925200744.129714-1-bartualev@gmail.com/ (local)

Bartu Alev (5):
  platform/x86: asus-wmi: rename TUF RGB state DEVID to _CMD
  platform/x86: asus-wmi: fix TUF keyboard power state shutdown naming
  platform/x86: asus-wmi: name the TUF keyboard RGB state and speed
    codes
  platform/x86: asus-wmi: add TUF keyboard RGB readback support
  Documentation/ABI: asus-wmi: document TUF keyboard RGB attributes

 .../ABI/testing/sysfs-platform-asus-wmi       |  42 ++++++
 drivers/platform/x86/asus-wmi.c               | 123 +++++++++++++++---
 include/linux/platform_data/x86/asus-wmi.h    |   5 +-
 3 files changed, 153 insertions(+), 17 deletions(-)


base-commit: af32da41b0327b9c6a37856ba82b6760d6c8d10e
-- 
2.56.0