On Fri, 2013-11-01 at 15:22 +1100, Benjamin Herrenschmidt wrote: > On Fri, 2013-11-01 at 14:59 +1100, NeilBrown wrote: > > and I wonder how relevant it still is in this context. As platform devices > > are all in the root of the device-tree and hence are siblings, they must have > > unique names in the device-tree and so the platform devices created from > > them will also have unique names -- won't they? > > I agree about /sys/devices -> /sys/devices/platform, that makes more > sense > > The problem with names is that we don't *know* that your devices are > at the root and unique. They don't have to be. I have platforms that > have several "chips" each containing all the same devices. They need to > be de-duped. > > Maybe the right approach is to build the de-duplication in sysfs > itself ? BTW. How come you have devices at the root of the tree without "reg" ? It's fairly fishy ... The root of the tree is supposed to represent the processor address space, and has #address-cells/#size-cells set appropriately. Any MMIO mapped device shall thus have a "reg" property and a unit address. Only "container" nodes (such as /cpus or /chosen) or virtual devices (such as a node used to representing the collection of bits & pieces that makes the audio infrastructure) and are thus not per-se MMIO mapped entities can ommit the "reg" properties. In the case of pwm, it looks like there's another device providing a pwm capability, in which case your backlight would indeed be a "virtual device" (basically non-mmio device not hanging off any bus). Or it could have been represented as a child of pwm if that had been defined that way, I am not familiar with the pwm bindings. Cheers, Ben. > Cheers, > Ben. > > > Any help understanding and/or fixing this discrepancy greatly appreciated. > > > > The change of name is particularly annoying to me because one of my platform > > devices is a pwm_bl.c backlight. With a boardfile I > > get /sys/class/pwm_backlight. With devicetree the best I can get > > is /sys/class/pwm_backlight.23 (or similar). It would be really nice to have > > a more stable and sensible name here. > -- 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
