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

Dipen Patel
2023-04-04T17:21:16Z

On 4/4/23 3:30 AM, Thierry Reding wrote:
> On Mon, Mar 27, 2023 at 09:58:19AM -0700, Dipen Patel wrote:
>> 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@nvidia.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@c1e0000 {
>>>> 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.
>
> We need the 0x0 in the DTS files because we have #address-cells = <2>
> and #size-tells = <2>. For the examples, those default to just 1 cell,
> so this can't be an exact copy of what we have in the DTS files.
>
> Please make sure to always validate the bindings and examples.

Ack...
>
> Thierry