On 2/14/20 10:40 PM, Greg KH wrote: > On Fri, Feb 14, 2020 at 05:05:07PM +0100, Linus Walleij wrote: >> On Fri, Jan 31, 2020 at 10:06 AM Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: >> >>> Why do people want to abuse the platform bus so much? If a device is on >>> a bus that can have such a controller, then it is on a real bus, use it! >> I'm not saying it is a good thing, but the reason why it is (ab)used so >> much can be found in: >> drivers/of/platform.c >> >> TL;DR: struct platform_device is the Device McDeviceFace and >> platform bus the Bus McBusFace used by the device tree parser since >> it is slightly to completely unaware of what devices it is actually >> spawning. > <snip> > > Yeah, great explaination, and I understand. DT stuff really is ok to be > on a platform bus, as that's what almost all of them are. > > But, when you try to start messing around with things like this > "firewall" says it is doing, it's then obvious that this really isn't a > DT like thing, but rather you do have a bus involved with a controller > so that should be used instead. Ok but how put in place a new bus while keeping the devices on platform bus to avoid changing all the drivers ? > > Or just filter away the DT stuff so that the kernel never even sees > those devices, which might just be simplest :) yes but we lost the possibility to change the firewall configuration at run time. I do expect to be able to describe in the DT firewall configuration and to use them at run time. That could allow, for example, to handover a HW block to the coprocessor when the main core is going to be suspended to save power. Benjamin > > thanks, > > greg k-h
