Re: [PATCH v2 1/2] ARM: DT: msm: Add Qualcomm's PRNG driver bindingdocument

[Stanimir Varbanov]

Hi Stephen,

Thanks for the review.

On 10/11/2013 11:46 PM, Stephen Boyd wrote:
> On 10/11, Stanimir Varbanov wrote:
>> This adds Qualcomm PRNG driver device tree binding documentation
>> to use as an example in dts trees.
>>
>> Signed-off-by: Stanimir Varbanov <svarbanov@xxxxxxxxxx>
>> ---
>>  Documentation/devicetree/bindings/rng/qcom,prng.txt | 17 +++++++++++++++++
>>  1 file changed, 17 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/rng/qcom,prng.txt
>>
>> diff --git a/Documentation/devicetree/bindings/rng/qcom,prng.txt b/Documentation/devicetree/bindings/rng/qcom,prng.txt
>> new file mode 100644
>> index 000000000000..92be00085ab1
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/rng/qcom,prng.txt
>> @@ -0,0 +1,17 @@
>> +Qualcomm MSM pseudo random number generator.
>> +
>> +Required properties:
>> +
>> +- compatible  : should be "qcom,prng"
>> +- reg         : specifies base physical address and size of the registers map
>> +- clocks      : phandle to clock-controller plus clock-specifier pair
>> +- clock-names : "prng" clocks all registers, FIFO and circuits in PRNG IP block
> 
> We're trying to keep to more generic names such as "core" for
> clocks like this. We've had problems in the past where hardware
> designers named the clock input after the name of the hardware
> and then the name of the hardware changed in the next version of
> the chip (although the hardware was mostly compatible with the
> previous version) and so they renamed the clock input. This
> leaked into the software drivers and we had horrible things like
> platform data for clock names. Sticking to "core" indicates what
> the clock does (i.e. it clocks the core PRNG hardware) while
> staying generic enough to prevent problems in the future if the
> block is renamed to something else. It might also help us in the
> future should our bus layer become smart enough to manage clocks
> for drivers without their knowing.

Thanks for the detailed explanation, I will rename the clock.

> 
>> +
>> +Example:
>> +
>> +	rng {
> 
> It's good practice to add the unit address here, so rng@f9bff000.

I will follow the good practice, thanks.

> 
>> +		compatible = "qcom,prng";
>> +		reg = <0xf9bff000 0x200>;
>> +		clocks = <&clock GCC_PRNG_AHB_CLK>;
>> +		clock-names = "prng";
>> +	};
> 

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