[PATCH v5 0/3] platform/arm64: Lenovo Yoga Slim 7x Gen 11 embedded controller

[Oleg Keri <okerixx@gmail.com>]

The Lenovo Yoga Slim 7x Gen 11 is a Qualcomm Snapdragon X2 Elite (glymur)
laptop. It carries a Compal EF06 embedded controller on I2C at address
0x70, which is the only source on this machine for the board thermistors,
the fan tachometer, the keyboard backlight, Fn-lock, and the mic-mute
and airplane-mode keys.

Patch 1 documents the binding, patch 2 adds the driver, patch 3 adds the
node to the board.

Why one driver
--------------

The automated review of v2 asked for the hwmon part to become an
auxiliary driver under drivers/hwmon/. The hwmon channels, the LED and
the input device all sit behind one command mailbox and one interrupt,
so the driver stays in one file, like huawei-gaokun-ec,
lenovo-thinkpad-t14s and qcom-hamoa-ec next to it. It is documented
under Documentation/ABI only.

Notes
-----

Fan speed is reported but not controlled, deliberately - the EC enforces no
thermal floor over a manual setpoint. Patch 2 has the measurement.

Tested on a Lenovo Yoga Slim 7x Gen 11 (DMI 83QR, "Yoga Slim 7 14Q8Y11").

Changes in v5:
- Patch 2: drop the battery cell voltages. They live in an EC bank shared
  with other EC activity, and 43-79% of reads failed the signature check
  across runs; retries, a cache and a stale window only hid that.
- Patch 2: fn_lock had the polarity inverted: 1 left the multimedia keys
  primary and the Fn-lock LED off. SCUK bit 7 selects the multimedia keys
  and bit 5 turns the LED off, as the vendor ACPI FNUS method reports it;
  1 now means F1..F12, as documented and as in ideapad-laptop.
- Patch 2: FIELD_MODIFY() for the backlight level; notify fn_lock when
  the EC toggles it on Fn+Esc; Kconfig help updated; the ABI entry dated
  October 2026 for 7.5.
- Patch 3: pick up Reviewed-by from Konrad and Abel.
- Link to v4: https://lore.kernel.org/all/20260922165737.260443-1-okerixx@gmail.com/

Changes in v4:
- Patch 2, after Ilpo's review: the missing includes added where the
  symbols are used; the cache and stale periods defined in milliseconds
  with the unit in the name and converted to jiffies at the call;
  lockdep_assert_held() in the command path every EC access goes
  through; each EC read checked right after the call; ARRAY_SIZE() for
  the cell loop; MILLIDEGREE_PER_DEGREE from units.h; braces on the
  multi-line returns; the ABI entry dated September 2026 for 7.4.
- Patch 2: the i2c id was 20 characters, the size of i2c_device_id.name,
  leaving no room for the terminator; now "slim7x-gen11-ec".
- Patch 2: symbol prefix renamed from yoga_ec to slim7x11_ec, naming the
  machine like the driver does. No user-visible name changes.
- Link to v3: https://lore.kernel.org/all/20260921144953.15113-1-okerixx@gmail.com/

Changes in v3:
- Add the board DT node as patch 3. It was posted on its own [1], and a
  node cannot be merged before its binding (Konrad).
- Add the "Why one driver" section above.
- Patch 2: name the driver after the module, and the i2c id after the
  compatible.
- Patch 2: spell out both SCUK bits the Fn-lock toggle moves instead of
  the 0xa0/0x5f masks.
- Patch 2: return -ENODATA for a thermistor reading of 0, as probe already
  treats 0 as "not fitted".
- Patch 2: ten tries for a cell-voltage sample instead of thirty.
- Patch 2: include what is used directly, devm_mutex_init(), comment the
  mutex, fix the address in MODULE_AUTHOR, say in the commit message that
  results cannot be matched to commands.
- Link to v2: https://lore.kernel.org/all/20260908183403.2107-1-okerixx@gmail.com/

Changes in v2:
- Patch 2: drop #include <linux/mod_devicetable.h>; <linux/i2c.h> already
  provides both of_device_id (via linux/of.h) and i2c_device_id (via
  linux/device-id/i2c.h), and the header is on its way out.
  Reported-by: Uwe Kleine-Koenig <u.kleine-koenig@baylibre.com>
- Patch 2: add "depends on INPUT" to EC_LENOVO_YOGA_SLIM7X_GEN11; the driver
  registers an input device unconditionally, so a config with INPUT=n did
  not link.
- Patch 1: pick up Conor Dooley's Acked-by.
- Link to v1: https://lore.kernel.org/all/20260908091752.5508-1-okerixx@gmail.com/

[1] https://lore.kernel.org/all/20260914082950.9393-1-okerixx@gmail.com/

Oleg Keri (3):
  dt-bindings: embedded-controller: add Lenovo Yoga Slim 7x Gen 11 EC
  platform/arm64: add Lenovo Yoga Slim 7x Gen 11 EC driver
  arm64: dts: qcom: glymur-lenovo-yoga-slim7x: add the embedded
    controller

 .../sysfs-driver-lenovo-yoga-slim7x-gen11-ec  |  22 +
 .../lenovo,yoga-slim7x-gen11-ec.yaml          |  56 ++
 MAINTAINERS                                   |   8 +
 .../dts/qcom/glymur-lenovo-yoga-slim7x.dts    |  12 +-
 drivers/platform/arm64/Kconfig                |  23 +
 drivers/platform/arm64/Makefile               |   1 +
 .../arm64/lenovo-yoga-slim7x-gen11-ec.c       | 547 ++++++++++++++++++
 7 files changed, 667 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-driver-lenovo-yoga-slim7x-gen11-ec
 create mode 100644 Documentation/devicetree/bindings/embedded-controller/lenovo,yoga-slim7x-gen11-ec.yaml
 create mode 100644 drivers/platform/arm64/lenovo-yoga-slim7x-gen11-ec.c


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2.55.0