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

Stephen Warren swarren at wwwdotorg.org
Fri Feb 14 11:43:04 EST 2014


On 02/14/2014 03:35 AM, Mark Rutland wrote:
> On Fri, Feb 14, 2014 at 06:16:52AM +0000, Stephen Warren wrote:
>> 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:-/

> 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?

> 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.



More information about the linux-arm-kernel mailing list