Re: [PATCH 1/4] amba: Export amba_bustype

[Russell King - ARM Linux <linux@armlinux.org.uk>]

On Wed, May 16, 2018 at 12:16:28PM +0300, Andy Shevchenko wrote:
> On Tue, May 8, 2018 at 10:06 PM, Kim Phillips <kim.phillips@arm.com> wrote:
> > This patch is provided in the context of allowing the Coresight driver
> > subsystem to be loaded as modules.  Coresight uses amba_bus in its call
> > to bus_find_device() in of_coresight_get_endpoint_device() when
> > searching for a configurable endpoint device.  This patch allows
> > Coresight to reference amba_bustype when built as a module.
> 
> > --- a/drivers/amba/bus.c
> > +++ b/drivers/amba/bus.c
> > @@ -197,6 +197,7 @@ struct bus_type amba_bustype = {
> >         .pm             = &amba_pm,
> >         .force_dma      = true,
> >  };
> > +EXPORT_SYMBOL_GPL(amba_bustype);
> 
> Oh,
> 
> What wrong with the approach let's say similar to PCI bus?
> 
> Whenever you have a struct device you may use two helpers:
> 
> dev_is_pci() -> is the device of PCI bus type?
> to_pci_dev() -> get's container of struct device for PCI bus case

How does that help with bus_find_device() which requires the bus_type
structure for the type of devices to be searched?

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