On Tue, Jan 09, 2018 at 06:43:47PM +0100, Andreas Kemnade wrote: > On Fri, 22 Dec 2017 13:44:27 +0100 > Johan Hovold <johan@xxxxxxxxxx> wrote: > > [...] > > I'd suggest reiterating the problem you're trying to solve and > > enumerating the previously discussed potential solutions in order to > > find a proper abstraction level for this (before getting lost in > > implementation details). > > > The main point here is in short words: Having a device powered on or off > when the uart it is attached to, is used or not used anymore, > so the already available userspace applications do not need to be changed. So we'd end up with something in-between a kernel driver and a user-space solution. What about devices that need to be (partially) powered also when the port isn't open? A pure user-space solution would be able to handle all variants. > I digged out a bit around: > alternative aproaches were: > adding hooks to the uart/tty layer: > https://marc.info/?l=linux-kernel&m=143333222014616&w=2 > https://marc.info/?l=devicetree&m=143130955414580&w=2 Thanks for the pointers, I remember those threads... > I do not find it right now in my archive: > adding a virtual gpio for dtr to the omap_serial driver. > The driver behind the virtual io would then handle pm. One reason it was > rejected was that the devicetree should only contain real hardware and > not virtual stuff. Oh, yeah, I think something like that made it in briefly before getting reverted again. I'll respond to Nikolaus mail as well. Johan -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
