Re: [PATCH v2 1/2] dt-bindings: Document the hi6220 thermal sensor bindings

[Xinwei Kong]

On 2015/4/6 22:03, Matt Porter wrote:
> On Tue, Mar 31, 2015 at 02:59:21PM +0800, Xinwei Kong wrote:
>> From: kongxinwei <kong.kongxinwei@xxxxxxxxxxxxx>
>>
>> This adds documentation of device tree bindings for the
>> thermal sensor controller of hi6220 SoC.
>>
>> Signed-off-by: Leo Yan <leo.yan@xxxxxxxxxx>
>> Signed-off-by: kongxinwei <kong.kongxinwei@xxxxxxxxxxxxx>
>> ---
>>  .../bindings/thermal/hisilicon-thermal.txt         | 45 ++++++++++++++++++++++
>>  1 file changed, 45 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/thermal/hisilicon-thermal.txt
>>
>> diff --git a/Documentation/devicetree/bindings/thermal/hisilicon-thermal.txt b/Documentation/devicetree/bindings/thermal/hisilicon-thermal.txt
>> new file mode 100644
>> index 0000000..ceb6e2e
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/thermal/hisilicon-thermal.txt
>> @@ -0,0 +1,45 @@
>> +* Hisilicon Thermal
>> +
>> +This driver is for hi6220 SoC which contain 4 thermal sensor.
>> +
>> +	1. sensor 0: local sensor;
>> +	2. sensor 1: remote sensor for ACPU cluster 1;
>> +	3. sensor 2: remote sensor for ACPU cluster 2;
>> +	4. sensor 3: remote sensor for GPU.
>> +
>> +Every sensor use one child node to represent it, so thermal sensor include
>> +parent node and four child node. The parent node describe common feature and
>> +child node describe private feature for thermal sensor;
>> +
>> +** Required properties :
>> +
>> +- compatible: "hisilicon,tsensor".
>> +- reg: physical base address of thermal sensor and length of memory mapped
>> +  region.
>> +- interrupt: The interrupt number to the cpu. Defines the interrupt used
>> +  by SOCTHERM.
>> +- clock-names: Input clock name, should be 'thermal_clk'.
>> +- clocks: phandles for clock specified in "clock-names" property.
>> +- #thermal-sensor-cells: Should be 1. See ./thermal.txt for a description.
>> +
>> +** Required properties for child nodes :
>> +
>> +- hisilicon,tsensor-id: the index of thermal sensor and use it to distinguish
>> +  thermal sensor. For example: <0> stands for local sensor; <1> stands for
>> +  acpu1 sensor;
> 
> Please show an example illustrating why this property is needed. The
> example below doesn't show any per sensor properties aside from the
> sensor id. Other bindings with a similar sub-sensor hardware design like
> tegra-soctherm and rockchip-thermal don't have a need for a vendor
> specific property like this. Their drivers simply iterate over an id
> index during thermal sensor registration.
> 
> -Matt
> 
Thermal Ip of hisilicon SoC can get four module temperature--local sensor, ACPU0
sensor, ACPU1 sensor and gpu sensor. In order to use these sensors, this driver
will make use of sensor id to distinguish sensor in using process.

These four sensors only get one sensor temperature at the same times. Because
these sensor commonly use the same register by setting diff value to enable one
sensor. howerver, sensor id is key flag for these diff sensor modules.

If deleting sensor id, this driver will define some value which set diff sensor
regitser and it difficult to understand sensor register operation.

Thanks
Xinwei

>> +
>> +Example :
>> +
>> +	tsensor: tsensor@0,f7030700 {
>> +		compatible = "hisilicon,tsensor";
>> +		reg = <0x0 0xf7030700 0x0 0x1000>;
>> +		interrupts = <0 7 0x4>;
>> +		clocks = <&clock_sys HI6220_TSENSOR_CLK>;
>> +		clock-names = "thermal_clk";
>> +		#thermal-sensor-cells = <1>;
>> +
>> +		local_sensor {
>> +			hisilicon,tsensor-id = <0>;
>> +		}
>> +		.......
>> +	}
>> -- 
>> 1.9.1
>>
>>
>>
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> 
> .
> 

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