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

Thierry Reding
2023-04-04T10:30:52Z

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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.

Thierry

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