Re: dtschema: i2c: messy situation about timeouts

Wolfram Sang <[email protected]> Mon, 26 Feb 2024 22:16:58 +0100

Newsgroups	org.kernel.vger.devicetree-spec,org.kernel.vger.linux-i2c
Message-ID	<Zdz_ytwYd7A2sGsP@shikoro>

Hi Rob,

> > - "i2c-scl-clk-low-timeout-us"
> >
> > The description says "Number of microseconds the clock line needs to be
> > pulled down in order to force a waiting state." What does "forcing a
> > waiting state" mean here? I don't understand this description.
> 
> Does the commit msg or PR help?:
> https://github.com/devicetree-org/dt-schema/pull/103

I checked it beforehand. Sadly, it didn't help me.

> > It is used in the i2c-mpc driver. The use case is simply to put it into
> > the 'struct i2c_adapter.timeout' member. That timeout is used to
> > determine if a transfer failed. So, to me, "i2c-transfer-timeout-us"
> > makes a lot more sense to use here.
> >
> > Suggestion: let's remove this binding and conver i2c-mpc to
> > "i2c-transfer-timeout-us". Yes, not nice to have two deprecated
> > bindings, but things happened.
> 
> Maybe the core code should read it instead?

That's an interesting idea. I'll try to implement this tomorrow.

> I think we should mark as deprecated rather than remove unless we can
> just remove the properties from the kernel. The reason being that

You are right. I should have said "depreacte" instead of remove here.

All the best,

   Wolfram

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