Re: [PATCH 1/2] dt: bindings: add new dt entry to indentify external FEM

[bperumal-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org]

On 2018-10-16 00:54, Rob Herring wrote:
> On Thu, Oct 04, 2018 at 05:12:43PM +0530, Bhagavathi Perumal S wrote:
>> This adds new dt entry ext-fem-name, it is used by ath10k driver
>> to select correct timing parameters and configure it in target wifi 
>> hardware.
>> The Front End Module(FEM) normally includes tx power amplifier(PA) and
>> rx low noise amplifier(LNA). The default timing parameters like tx end 
>> to
>> PA off timing values were fine tuned for internal FEM used in 
>> reference
>> design. And these timing values can not be same if ODM modifies 
>> hardware
>> design with different external FEM. This DT entry helps to choose 
>> correct
>> timing values in driver if different external FEM hardware used.
> 
> 'dt-bindings: net: ath10k: ...' for the subject please.
Sure, I will change and send v2 patch.

> 
>> 
>> Signed-off-by: Bhagavathi Perumal S <bperumal-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
>> ---
>>  .../bindings/net/wireless/qcom,ath10k.txt          | 22 
>> ++++++++++++++++++++++
>>  1 file changed, 22 insertions(+)
>> 
>> diff --git 
>> a/Documentation/devicetree/bindings/net/wireless/qcom,ath10k.txt 
>> b/Documentation/devicetree/bindings/net/wireless/qcom,ath10k.txt
>> index 7fd4e8c..fbaf309 100644
>> --- a/Documentation/devicetree/bindings/net/wireless/qcom,ath10k.txt
>> +++ b/Documentation/devicetree/bindings/net/wireless/qcom,ath10k.txt
>> @@ -56,6 +56,7 @@ Optional properties:
>>  				     the length can vary between hw versions.
>>  - <supply-name>-supply: handle to the regulator device tree node
>>  			   optional "supply-name" is "vdd-0.8-cx-mx".
>> +- ext-fem-name: name of external front end module used.
> 
> What are valid names? What if the OS doesn't recognize the name? 
> Perhaps
Some valid FEM devices are "microsemi-lx5586", "sky85703-11" and 
"sky85803" etc.
Currently driver accepts only "microsemi-lx5586", Since this FEM 
requires different timing settings,
And it can be extended for other FEM devices in future.
If OS doesn't recognize the name, it uses predefined default timing 
settings.

> this should be a compatible string for the particular module instead?
> Then it could cover any differences, not just the FEM.
> 
No, it is specific to FEM device.

>> 
>>  Example (to supply the calibration data alone):
>> 
>> @@ -150,3 +151,24 @@ wifi@18000000 {
>>  			   <0 141 0 /* CE11 */ >;
>>  		vdd-0.8-cx-mx-supply = <&pm8998_l5>;
>>  };
>> +
>> +Example (to supply the external front end module name):
>> +
>> +In this example, the front end module is defined as a property of the 
>> ath10k
>> +device node.
> 
> Really need a whole new example for 1 property?
Will add this property in existing example.

> 
>> +
>> +pci {
>> +	pcie@0 {
>> +		reg = <0 0 0 0 0>;
>> +		#interrupt-cells = <1>;
>> +		#size-cells = <2>;
>> +		#address-cells = <3>;
>> +		device_type = "pci";
>> +
>> +		ath10k@0,0 {
> 
> wifi@0,0
Added in ath10k@0,0 to make consistent with existing property 
"qcom,ath10k-calibration-data" below,
"
pci {
         pcie@0 {
                 reg = <0 0 0 0 0>;
                 #interrupt-cells = <1>;
                 #size-cells = <2>;
                 #address-cells = <3>;
                 device_type = "pci";

                 ath10k@0,0 {
                         reg = <0 0 0 0 0>;
                         device_type = "pci";
                         qcom,ath10k-calibration-data = [ 01 02 03 ... ];
                 };
         };
};
"

If wifi@0,0 is preferable, then I will add new entry "wifi@0,0" and add 
ext-fem-name into it.

> 
>> +			reg = <0 0 0 0 0>;
>> +			device_type = "pci";
>> +			ext-fem-name = "microsemi-lx5586";
>> +		};
>> +	};
>> +};
>> --
>> 1.9.1
>> 

Thanks, Sorry for the delayed response,
Bhagavathi Perumal S.