linux-kernel - Re: [PATCH V4 04/10] dt-bindings: timestamp: Add nvidia,gpio-controller

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Date:   Mon, 27 Mar 2023 09:58:19 -0700
From:   Dipen Patel <dipenp@...dia.com>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        thierry.reding@...il.com, jonathanh@...dia.com,
        linux-kernel@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-gpio@...r.kernel.org, linus.walleij@...aro.org,
        devicetree@...r.kernel.org, linux-doc@...r.kernel.org,
        robh+dt@...nel.org, timestamp@...ts.linux.dev,
        krzysztof.kozlowski+dt@...aro.org, brgl@...ev.pl, corbet@....net,
        gregkh@...uxfoundation.org
Subject: Re: [PATCH V4 04/10] dt-bindings: timestamp: Add
 nvidia,gpio-controller

On 3/25/23 4:07 AM, Krzysztof Kozlowski wrote:
> On 23/03/2023 02:29, Dipen Patel wrote:
>> Introducing nvidia,gpio-controller property from Tegra234 SoCs onwards.
>> This is done to help below case.
>>
>> Without this property code would look like:
>> if (of_device_is_compatible(dev->of_node, "nvidia,tegra194-gte-aon"))
>> 	hte_dev->c = gpiochip_find("tegra194-gpio-aon",
>> 				   tegra_get_gpiochip_from_name);
>> else if (of_device_is_compatible(dev->of_node, "nvidia,tegra234-gte-aon"))
>> 	hte_dev->c = gpiochip_find("tegra234-gpio-aon",
>> 				   tegra_get_gpiochip_from_name);
>> else
>> 	return -ENODEV;
>>
>> This means for every future addition of the compatible string, if else
>> condition statements have to be expanded.
>>
>> With the property:
>> gpio_ctrl = of_parse_phandle(dev->of_node, "nvidia,gpio-controller", 0);
>> ....
>> hte_dev->c = gpiochip_find(gpio_ctrl, tegra_get_gpiochip_from_of_node);
>>
>> This simplifies the code significantly. The introdunction of this
>> property/binding does not break existing Tegra194 provider driver.
>>
>> Signed-off-by: Dipen Patel <dipenp@...dia.com>
>> ---
>>  .../timestamp/nvidia,tegra194-hte.yaml        | 31 +++++++++++++++++--
>>  1 file changed, 29 insertions(+), 2 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/timestamp/nvidia,tegra194-hte.yaml b/Documentation/devicetree/bindings/timestamp/nvidia,tegra194-hte.yaml
>> index eafc33e9ae2e..841273a3d8ae 100644
>> --- a/Documentation/devicetree/bindings/timestamp/nvidia,tegra194-hte.yaml
>> +++ b/Documentation/devicetree/bindings/timestamp/nvidia,tegra194-hte.yaml
>> @@ -51,6 +51,12 @@ properties:
>>        LIC instance has 11 slices and Tegra234 LIC has 17 slices.
>>      enum: [3, 11, 17]
>>  
>> +  nvidia,gpio-controller:
>> +    $ref: /schemas/types.yaml#/definitions/phandle
>> +    description:
>> +      The phandle to AON gpio controller instance. This is required to handle
>> +      namespace conversion between GPIO and GTE.
>> +
>>    '#timestamp-cells':
>>      description:
>>        This represents number of line id arguments as specified by the
>> @@ -65,22 +71,43 @@ required:
>>    - interrupts
>>    - "#timestamp-cells"
>>  
>> +allOf:
>> +  - if:
>> +      properties:
>> +        compatible:
>> +          contains:
>> +            enum:
>> +              - nvidia,tegra234-gte-aon
>> +    then:
>> +      required:
>> +        - nvidia,gpio-controller
>> +
>>  additionalProperties: false
>>  
>>  examples:
>>    - |
>>      tegra_hte_aon: timestamp@...0000 {
>>                compatible = "nvidia,tegra194-gte-aon";
>> -              reg = <0xc1e0000 0x10000>;
>> +              reg = <0x0 0xc1e0000 0x0 0x10000>;
> 
> This is not really explained in commit msg... are you sure you tested it?
I have to revert this part back in next patch as when I upgraded dtsschema it gave me errors.
> 
> 
> Best regards,
> Krzysztof
>