On Thu, 04 Apr 2019, Andy Shevchenko wrote:
> On Thu, Apr 04, 2019 at 10:03:14AM +0100, Lee Jones wrote:
> > On Thu, 04 Apr 2019, Andy Shevchenko wrote:
> > > On Thu, Apr 04, 2019 at 08:03:57AM +0100, Lee Jones wrote:
> > > > On Thu, 04 Apr 2019, Lee Jones wrote:
> > > > > On Tue, 02 Apr 2019, Andy Shevchenko wrote:
> > > > > > On Tue, Apr 02, 2019 at 06:12:11AM +0100, Lee Jones wrote:
> > > > > > > On Mon, 18 Mar 2019, Andy Shevchenko wrote:
>
> > > > > > > Although succinct, dragging values from one platform device into
> > > > > > > another doesn't sound that neat.
> > > > > >
> > > > > > So, how to split resources given in one _physical_ multi-functional
> > > > > > device to
> > > > > > several of them? Isn't it what MFD framework for?
> > > > > >
> > > > > > Any other approach here? I'm all ears!
> > > > >
> > > > > From the child:
> > > > >
> > > > > platform_get_irq(dev->parent, CLIENT_ID);
> > >
> > > So, instead of keeping a fragile approach in one driver, we will spread
> > > this
> > > to all of them.
> >
> > No, the fragileness goes away with implicit definitions of IDs.
>
> Did you mean "explicit"?
Yes. Thank you for correcting my English. :)
> Something like we need to have a shared map of those indices?
Defining the IDs of the devices would lead to a more robust
implementation, yes.
> > > > > > > Also, since the ordering of the
> > > > > > > devices is critical in this implementation, it also comes across
> > > > > > > as
> > > > > > > fragile.
> > > > > >
> > > > > > How fragile? In ACPI we don't have IRQ labeling scheme. Index is
> > > > > > used for that.
> > > > > >
> > > > > > > Any reason why ACPI can't register all of the child devices, or
> > > > > > > for
> > > > > > > the child devices to obtain their IRQ directly from the tables?
> > > > > >
> > > > > > And how are we supposed to enumerated them taking into
> > > > > > consideration single
> > > > > > ACPI ID given?
> > > > >
> > > > > This question was a little whimsical, since I have no idea how the
> > > > > ACPI tables you're working with are laid out.
> > >
> > > There is one device node with several IRQ and other resources.
> > > In pseudo code:
> > >
> > > device node {
> > > device ID,
> > > IRQ 0,
> > > IRQ 1,
> > > ...
> > > MMIO 0,
> > > ...
> > > }
> >
> > Sure. Thanks for the explanation.
> >
> > Very well. I guess it's not too bad as it is.
>
> It represent real hardware 1:1.
> Just out of curiosity how this case can be described in DT?
In DT you can have a sub-node for each child which can contain the
IRQ. Without a sub-node you would define the IRQs in this file. If
these IRQs do not change, that option is still available to you.
I can't think of an example where all of the children's IRQs have been
listed in the parent's DT node in this way.
--
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
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