[PATCH] i3c: master: Add WO sysfs option to re-DDA bus.
David Nyström
david.nystrom at est.tech
Thu Jan 22 07:47:39 PST 2026
On Thu, 22 Jan 2026, Wolfram Sang wrote:
> On Thu, Jan 22, 2026 at 12:36:30PM +0100, David Nyström wrote:
>> Add ability to rescan the i3c bus from userspace, i.e. provoke a DDA.
>
> Your are describing what you do but what is missing is why you want the
> change. What is the use case?
The usecase would be an i3cdev userspace driver for a device with
broken hotjoin support.
The device requires FW loading(userspace framework) before it will respond
to DAA, and is thus not registered during initial bus probe.
I guess a similiar problem would apply if hot-join is bus disabled
via sysfs, and resume hook DDA runs before i3c devices are powered up properly.
A bit of a niche usecase, I know.
I found it to be usable though, but perhaps this is better placed in
debugfs in case its too much of an eyesore for the stable ABI.
More information about the linux-i3c
mailing list