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@xxxxxxxxxx> 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
