It’s likely that most TOHs providing some sort of complex functionality will contain a microcontroller or an FPGA. Given that these could be programmed specifically for the TOH, I’m wondering if it would make sense to design an interface for them on top of I3C?
I’m thinking of something that allows the TOH to expose multiple “services” and exchange command-like messages with the phone. Maybe it could be similar to D-Bus in some way.
As a bonus, standard “services” could be integrated directly into Sailfish OS, e.g. for battery level indication. Allowing the phone to expose “services” to the TOH in the other direction might also offer some interesting opportunities.
A lot of this could also be solved by having a separate privileged app or daemon for each TOH, which is more flexible. On the other hand, standardizing TOH communication could strengthen collaboration between developers. What do you think? Is there any interest in this?