Re: [PATCH] HID: ayaneo-flip-kb: Add driver for keyboard backlight

[Antheas Kapenekakis]

On Sun, 8 Nov 2026 at 14:55, Hijae Song <hijae99@xxxxxxxxx> wrote:
>
> Hi Antheas,
>
> Thanks for the feedback.
>
> > If this is an actual keyboard product on the market and Ayaneo is
> > sourcing the part for their device, look-up similar devices and kernel
> > drivers.
>
> I checked. hid-sigmamicro only fixes the 0x0059 report descriptor, and
> I found no SiGma Micro backlight driver on lore.
>
> > The name of the driver cannot be -flip-kb. You need to make sure it is
> > generic enough to match most Ayaneo devices.
>
> 1c4f:007c also appears on the AYANEO Slide in hhd-dev/hwinfo, with the
> same vendor interface (report ID 0x41, 7-byte feature report). I only
> have a Flip KB, so I can only test the byte layout there.
>
> Matias's hid-ayaneo already claims 1c4f:0002 behind a DMI check for
> AYANEO 3. Would you prefer that I add 007c backlight support to
> hid-ayaneo once it is merged, or keep a separate driver named after
> the chip? I lean towards hid-ayaneo, since the Slide may work the same
> way, but I would like your view first.

Mmmm so Ayaneo does not have a vid and may trample the pid of another
device. That is not good. There is no guarantee this led profile is
used by a different vendor.

There are two options:
 - Adding the keyboard to the hid-ayaneo driver
     - This would happen after it merges
     - There is 0 common logic between the rgb device and the keyboard device
     - Driver registers a different led sysfs ABI and has convoluted
dmi handling
     - The driver would devolve
 - Adding a scoped driver for the keyboard
     - You can start now
     - Can tightly scope to keyboard device
     - name can be hid-ayaneo-kbd unless other vendor is found

I would tend towards the latter. hid-ayaneo has plenty of work to
merge. The controller firmware is quite unstable. Even my
implementation in userspace is buggy. But that's fine... Windows is
buggy too.

I have two comments for your current version:
  - remove all flip kbd references, name AYANEO_KBD
  - use brightness values of 0 and 1, no scaling. DEs know how to
handle these values by toggling.
     - another option is 0-3, which looks nicer, but let's not get too
deep into this
  - use devm to register the led structure, drop remove entry point.
Use devm prior to starting the device so that register code stays with
initialization
  - check if led subsystem is appropriate. I am not sure of the
correct place. If not, current location is fine
  - initialize host values to ff ff ff so on first write we get a nice
white color
  - if there is only one effect, brightness 0 is off. Do not add an
effect handler

With 2-3 revisions this should be good to go. While at it, try to find
a Slide user

Best,
Antheas

> I will also fix the two sashiko comments in v2.
>
> Thanks,
> Hijae
>