Dear Thierry Reding, On Tue, 18 Jun 2013 13:26:04 +0200, Thierry Reding wrote: > > As I replied to Grant, of_find_device_by_node() returns NULL, I believe > > because the all IRQ controller driver initialization is done pretty > > early, before the of_platform_populate() call is made, so there is no > > platform_device associated with the IRQ controller node at the time the > > armada_370_xp_mpic_of_init() function is called. > > > > Do you see another approach, especially in relation to your comment on > > PATCH 2/8 ? > > Hmmm, that's too bad. The only other possibility that I see is that you > could associate the struct device at a later point when it becomes > available, but looking at the irqchip driver it doesn't look like you > get notification of that either. I suppose you could add a > platform_driver to it and hook things up in its .probe() callback, but > I'm not sure if that's in line with how the irqchip was designed. Adding > Grant Likely and Thomas Gleixner on Cc, maybe they have better advice. If we do hook the MSI stuff in a ->probe() callback, then we'd have a dependency between the ->probe() of the PCIe driver and the ->probe() of the IRQ controller driver. In order for the PCIe ->probe() to succeed, it needs the MSI controller to be registered, which wouldn't appear until the ->probe() of the IRQ controller driver gets called. A typical case of platform device dependency where the two platform devices don't have a bus -> child dependency. Could be handled by a -EPROBE_DEFER trick, though. > Looking at other irqchip drivers I find it a bit odd to see how they're > structured, though. We've been preaching for years that drivers should > be well-encapsulated and told everybody it was bad to use globals and > they should be associating driver-specific data with each instance of a > device. Then comes along irqchip and all of a sudden it's okay to use > globals again. It feels a bit fragile. Yes, I've seen this as well, and I'm thinking of doing some improvements in this area if there's some interest. But I believe this is fairly separate from the specific discussion of this patch set. Best regards, Thomas -- Thomas Petazzoni, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
