On Thu, Jan 8, 2015 at 1:37 PM, Linus Walleij <linus.walleij@xxxxxxxxxx> wrote: > On Tue, Dec 30, 2014 at 8:28 PM, Rob Herring <robherring2@xxxxxxxxx> wrote: > >> From: Rob Herring <robh@xxxxxxxxxx> >> >> Disable the Versatile PCI DT node when no PCI backplane is detected. This >> will prevent the Versatile PCI driver from probing when PCI is not >> populated. >> >> Signed-off-by: Rob Herring <robh@xxxxxxxxxx> >> Cc: Russell King <linux@xxxxxxxxxxxxxxxx> >> Cc: Linus Walleij <linus.walleij@xxxxxxxxxx> > > (...) >> + /* Check if PCI backplane is detected */ >> + val = __raw_readl(base + VERSATILE_SYS_PCICTL_OFFSET); > > I think this kind of random syscon register access should be handled > using the mfd/syscon.c hub and looked up in some way to be used > by the driver. Perhaps, but I've not figured out how much of VExpress syscon can be used for Versatile. I looked at it briefly, but it appeared to be more work that I have time for ATM. We still have other accesses to system registers in Versatile as well. So if we want to merge all this anytime soon, the options are: - this patch - Create a versatilepb-pci.dts which includes versatilepb.dts and enables PCI - Default to PCI enabled (for QEMU) in the dts and users have to disable in their dts if they don't have a PCI backplane. > I'm thinking along the pattern of adding code in drivers/* > by the pattern of e.g. > drivers/video/fbdev/amba-clcd-versatile.c > i.e. an add-on that gets compiled-in only for those platform > but still married to the main driver. One difference here is the PCI driver is pretty much only ever going to be for a single platform. Rob -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
