> > > + hub->cfg.power_off_in_suspend = > of_property_read_bool(dev->of_node, "power-off-in-suspend"); > > > + hub->cfg.wakeup_source = of_property_read_bool(dev->of_node, > > > +"wakeup-source"); > > > > Do you really need these two properties? If the device (and its > > children if existed) has wakeup enabled, you keep power in suspend, > > otherwise, you could close it, any exceptions? > > That would work for my use case, but I'm not sure it's a universally good > configuration. > > I don't have a specific USB device in mind, but you could have a device that > shouldn't lose it's context during suspend or keep operating autonomously (e.g. > a sensor with a large buffer collecting samples). Not sure if something like this > exists in the real though. > > I'm not an expert, but it seems there are USB controllers with wakeup support > which is always enabled. A board with such a controller then couldn't have a > policy to power down the hub regardless of wakeup capable devices being > connected. > Whether or not it is a wakeup_source, it could get through its or its children's /sys/../power/wakeup value, you have already used usb_wakeup_enabled_descendants to know it. If the onboard HUB needs to reflect wakeup signal, it should not power off its regulator. For another property power-off-in-suspend, I think it is also a user option, but not a hardware feature. If (wakeup-source || ! power-off-in-suspend) power off; else keep power; Peter
