[PATCH 1/2] clk: fixed-rate: use full DT node name

On Fri, Feb 14, 2014 at 04:43:04PM +0000, Stephen Warren wrote:

On 02/14/2014 03:35 AM, Mark Rutland wrote:

quoted

On Fri, Feb 14, 2014 at 06:16:52AM +0000, Stephen Warren wrote:

quoted

clk-fixed-rate currently names clocks according to a node's name without
the unit address. When faced with the legal and technically correct DT
structure below, this causes rgistration attempts for 3 clocks with the
same name, 2 of which fail.

	clocks {
		compatible = "simple-bus";
		#address-cells = <1>;
		#size-cells = <0>;

		clk_mmc: clock at 0 {
			compatible = "fixed-clock";
			reg = <0>;
...
		clk_i2c: clock at 1 {
			compatible = "fixed-clock";
			reg = <1>;
...
		clk_spi: clock at 2 {
			compatible = "fixed-clock";
			reg = <2>;
...

I'd argue that this case isn't valid.

Well, it's very widely used, and was the result of numerous discussions
of how this kind of thing should be represented:-/

Maybe we have to live with it then. :/

quoted

The fixed-clock binding doesn't define a reg, yet simple bus binding
implies that the reg property of child nodes should be interpretted as
the same address space as their parent (MMIO in this case?). The
fixed-clock nodes reg proeprties clearly aren't MMIO addresses.

Additionally, the _requred_ ranges property is missing.

Perhaps we need to invent a simple-container instead then?

As you mention in your other reply, it makes some sense to omit ranges
if the address space is disjoint. My concern is that the address space
is meaningless and arbitrary. If we had a real disjoint address space
we'd have another kind of bus node as the container.

quoted

It's just nonsensical; rename them to clock_{0,1,..} instead and get rid
of the reg properties. Then they're named uniquely.

That's not legal either. DT node names are supposed to represent the
type of device/object (i.e. just "clock"), not the identity of the
device/object (i.e. not include IDs etc.). Hence, the node name needs to
be "clock" for all of them, and the unit address must be used to
differentiate them.

As far as I can see from ePAPR, the only requriement is:

  The node-name shall start with a lower or uppercase character and
  should describe the general class of device.

IMO clock_1 describes the general class of device as well as clock at 1,
while also not filling a unexpected property with a meaningless value.

Thanks,
Mark.