[PATCH v4 7/9] platform/chrome: of_hw_prober: Add delay for hana trackpads

[Chen-Yu Tsai]

On Thu, Aug 13, 2026 at 11:14 AM Tzung-Bi Shih <tzungbi at kernel.org> wrote:
>
> On Tue, Aug 11, 2026 at 08:20:07PM +0800, Chen-Yu Tsai wrote:
> > Up until now, the MT8173 elm/hana device tree has set the dedicated
> > regulator supplying the trackpad as always-on, simply because the Elan
> > driver was missing proper delays. As a result the delay for the
> > Synaptics trackpad was also omitted, as it was not strictly required
> > under such a model and delayed the availability of the trackpad to the
> > user.
> >
> > The Elan driver recently gained proper delays after power-up, with
> > adaptive skipping of the delay if the regulator was originally
> > on. The I2C HID driver and I2C OF component prober library gained
> > similar adaptive delay skipping. The device tree will be fixed to have
> > the regulator not be always on, and proper post-power-on delay time
> > added to the I2C HID device.
> >
> > Also add the post-power-on delay to the ChromeOS OF component prober,
> > so that if the regulator is off at the time of probing, the prober knows
> > to wait for the hardware to initialize.
>
> > [...]
>
> This looks harmless even without the aforementioned patches.

As mentioned in the cover letter, it is harmless, but will delay the
probing and subsequent enablement of the trackpad.


> Applied to
>
>     https://git.kernel.org/pub/scm/linux/kernel/git/chrome-platform/linux.git for-next
>
> [7/9] platform/chrome: of_hw_prober: Add delay for hana trackpads
>       commit: 81c1c0cb68a13d14dd1bbffcf4c49e26f9a6478c
>
> Thanks!

Thanks!

ChenYu