On Wed, 21 May 2014 09:53:57 +0900, Grant Likely <[email protected]>
wrote:
> On Tue, 20 May 2014 13:30:02 -0500, Rob Herring <[email protected]> wrote:
> > On Tue, May 20, 2014 at 1:50 AM, Grant Likely <[email protected]>
> > wrote:
> > > On Sun, 18 May 2014 18:11:07 -0500, Rob Herring <[email protected]>
> > > wrote:
> > >> On Sun, May 18, 2014 at 12:01 PM, Ezequiel Garcia
> > >> <[email protected]> wrote:
> > >> > When creating a device object for a devicetree node, the device name
> > >> > is created by using the node name and the 'reg' property, to make a
> > >> > name
> > >> > such as "a000.foo_device".
> > >> >
> > >> > For certain devices without an associated address, and hence no 'reg'
> > >> > property,
> > >> > the current code attempts to make a unique name, by using a global
> > >> > integer.
> > >> > Names look like "foo_device.1", "bar_device.2", and so on.
> > >> > Examples of such devices are: gpio-keys', backlights and
> > >> > rotary-encoders.
> > >> >
> > >> > The system cannot know such devices name before hand, given they are
> > >> > determined
> > >> > by the kernel probe order and by the nodes present in the devicetree.
> > >> > This can
> > >> > be problematic, on systems that are tied to the device's name, e.g.
> > >> > when
> > >> > catching hotplug events.
> > >
> > > The device's uevent file in sysfs contains both the ->name and
> > > ->full_name values for a node. Does that help you?
> > >
> > > The big problem is not the structure under /sys/devices, but rather the
> > > symlinks to devices that appear under /sys/bus/*/devices. If two leaf
> > > nodes have the same name, then they will conflict when they get added to
> > > a bus_type's array of devices.
> > >
> > > Another way to handle it is to only add the suffix when a conflict
> > > actually occurs. That requires checking first whether or not a name will
> > > conflict and ammending it only when that happens. I don't know if that
> > > can be done nicely. I'll take a look.
> >
> > That was my idea as well and to move to a local number so you have
> > something like deviceA, deviceA.1, deviceB, deviceB.1 (maybe the
> > number is always appended). Perhaps a random number instead so no one
> > expects the names to be an ABI. ;)
>
> Another idea: how about fix the name to alwasy be the final component of
> the path name, followed by phandle. Anything that doesn't have a phandle
> can be assigned one at boot. That would guarantee uniqueness without the
> cost of trying to find duplicates.
>
> for example:
> uart@10043000:0012
The following actually works. I don't like it because it results in very
long names, but it does work.
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 9c121819e813..6e11c70b0616 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -74,60 +74,7 @@ EXPORT_SYMBOL(of_find_device_by_node);
*/
void of_device_make_bus_id(struct device *dev)
{
- static atomic_t bus_no_reg_magic;
- struct device_node *node = dev->of_node;
- const __be32 *reg;
- u64 addr;
- const __be32 *addrp;
- int magic;
-
-#ifdef CONFIG_PPC_DCR
- /*
- * If it's a DCR based device, use 'd' for native DCRs
- * and 'D' for MMIO DCRs.
- */
- reg = of_get_property(node, "dcr-reg", NULL);
- if (reg) {
-#ifdef CONFIG_PPC_DCR_NATIVE
- dev_set_name(dev, "d%x.%s", *reg, node->name);
-#else /* CONFIG_PPC_DCR_NATIVE */
- u64 addr = of_translate_dcr_address(node, *reg, NULL);
- if (addr != OF_BAD_ADDR) {
- dev_set_name(dev, "D%llx.%s",
- (unsigned long long)addr, node->name);
- return;
- }
-#endif /* !CONFIG_PPC_DCR_NATIVE */
- }
-#endif /* CONFIG_PPC_DCR */
-
- /*
- * For MMIO, get the physical address
- */
- reg = of_get_property(node, "reg", NULL);
- if (reg) {
- if (of_can_translate_address(node)) {
- addr = of_translate_address(node, reg);
- } else {
- addrp = of_get_address(node, 0, NULL, NULL);
- if (addrp)
- addr = of_read_number(addrp, 1);
- else
- addr = OF_BAD_ADDR;
- }
- if (addr != OF_BAD_ADDR) {
- dev_set_name(dev, "%llx.%s",
- (unsigned long long)addr, node->name);
- return;
- }
- }
-
- /*
- * No BusID, use the node name and add a globally incremented
- * counter (and pray...)
- */
- magic = atomic_add_return(1, &bus_no_reg_magic);
- dev_set_name(dev, "%s.%d", node->name, magic - 1);
+ dev_set_name(dev, dev->of_node->full_name);
}
/**
>
> g.
>
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