Re: [PATCH v4 3/7] can: rcar_canfd: Allow the CAN FD clock to be sourced from fck

[Marc Kleine-Budde <mkl@pengutronix.de>]

[-- Attachment #1: Type: text/plain, Size: 1687 bytes --]

On 19.10.2026 13:36:49, claudiu beznea wrote:
> > Based on the comment on this code "If not available fallback to CANFD clock"
> > I think the intention with IS_ERR() is to allow probing go forward,
> > falling back to CANFD clock, in case of any error of devm_clk_get().
> >
> > The device trees that I've checked sets the can_clk to a fixed clock
> > with rate = 0 or have the clock provided directly by the SoC clock
> > provider. I think the intention with IS_ERR() was not only for -ENOENT
> > but for any other kind of errors. We can return in case of
> > -EPROBE_DEFER, to ensure the expected clock is used, when it's available
> > and sane.
> >
> > I'll switch to something like:
> >
> >   gpriv->can_clk = devm_clk_get(&pdev->dev, "can_clk");
> > +if (ERR_PTR(gpriv->can_clk) == -EPROBE_DEFER)
> > +    return dev_err_ptr(dev, ...);
>
> On the other hand, returning -EPROBE_DEFER here means the driver may never
> probe if the can_clk provider fails to probe, even though the fallback clock
> is available. That would go against what I understand to be the intent of
> the IS_ERR() check: letting the probe continue when can_clk can't be
> obtained.
>
> Please let me know how you would like me to proceed.

If the clock continuously fails with the error -EPROBE_DEFER, your
.config/DT/system is broken. I don't think it's a good idea to ignore
these errors.

regards,
Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde          |
Embedded Linux                   | https://www.pengutronix.de |
Vertretung Nürnberg              | Phone: +49-5121-206917-129 |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-9   |

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]