Messages in this thread | | | From | Linus Walleij <> | Date | Sun, 27 Jun 2021 12:56:54 +0200 | Subject | Re: [RFC 04/11] dt-bindings: Add HTE bindings |
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Hi Dipen,
thanks a lot for this very interesting patch set!
I'm gonna try to review properly, just pointing out some conceptual things to begin with. Bindings is a good place to start.
On Sat, Jun 26, 2021 at 1:48 AM Dipen Patel <dipenp@nvidia.com> wrote:
> +description: | > + HTE properties should be named "htes". The exact meaning of each htes > + property must be documented in the device tree binding for each device. > + An optional property "hte-names" may contain a list of strings to label > + each of the HTE devices listed in the "htes" property.
I think this is a bit over-abbreviated. IIO has: io-channels =... io-channel-names =...
Given DT:s infatuation with using english plural I would opt for: hardware-timestamps = .. hardware-timestamp-names = ...
The "engine" part is a bit of an nVidia:ism I think and a too generic term. Could as well be "processor" or "automata" but nVidia just happened to name it an engine. (DMA engine would be a precedent though, so no hard preference from my side.)
When reading this it is pretty intuitively evident what is going on.
Other than that it looks really good!
> +++ b/Documentation/devicetree/bindings/hte/hte.yaml
I would name this hardware-timestamp-common.yamp or so.
> +title: HTE providers
Spell this out: Hardware timestamp providers
> +properties: > + $nodename: > + pattern: "^hte(@.*|-[0-9a-f])*$"
Likewise: hardware-timestamp@ ...
I think this is good because it is very unambiguous.
> +examples: > + - | > + tegra_hte_aon: hte@c1e0000 { > + compatible = "nvidia,tegra194-gte-aon"; > + reg = <0xc1e0000 0x10000>; > + interrupts = <0 13 0x4>; > + int-threshold = <1>; > + slices = <3>; > + #hte-cells = <1>; > + };
The examples can be kept to the tegra194 bindings I think, this generic binding doesn't need an example as such.
> +$id: http://devicetree.org/schemas/hte/nvidia,tegra194-hte.yaml#
This one should be named like this, that is great.
> +$schema: http://devicetree.org/meta-schemas/core.yaml# > + > +title: Tegra194 on chip generic hardware timestamping engine (HTE)
This is clear and nice.
> + int-threshold: > + description: > + HTE device generates its interrupt based on this u32 FIFO threshold > + value. The recommended value is 1. > + minimum: 1 > + maximum: 256
Does this mean a single timestamp in the FIFO will generate an IRQ? Then spell that out so it is clear.
> + slices: > + description: > + HTE lines are arranged in 32 bit slice where each bit represents different > + line/signal that it can enable/configure for the timestamp. It is u32 > + property and depends on the HTE instance in the chip. > + oneOf: > + - items: > + - const: 3 > + - items: > + - const: 11
Can't you just use enum: [3, 11] ?
> + '#hte-cells': > + const: 1
So IMO this would be something like #hardware-timestamp-cells
Other than this it overall looks very nice to me!
Yours, Linus Walleij
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