pca953x: Probing too early

[Andrew Lunn]

On Tue, Aug 20, 2024 at 05:47:27PM -0300, Fabio Estevam wrote:
> Adding the i2c-folks on Cc.
> 
> On Tue, Aug 20, 2024 at 5:02 PM Fabio Estevam <festevam at gmail.com> wrote:
> >
> > Hi,
> >
> > I am seeing an issue with the PCA935X driver in 6.6.41 and
> > 6.11.0-rc4-next-20240820.
> >
> > The pca953x is getting probed before its I2C parent (i2c-2):
> >
> > [    1.872917] pca953x 2-0020: supply vcc not found, using dummy regulator
> > [    1.889195] pca953x 2-0020: using no AI
> > [    1.893260] pca953x 2-0020: failed writing register
> > [    1.898258] pca953x 2-0020: probe with driver pca953x failed with error -11

-11 is EAGAIN, which is a bit odd. Given your description, i would of
expected ENODEV. My guess is, it needs another resource, a GPIO,
regulator, or interrupt controller. That resources might not of probed
yet. If that is true, you want the pca953x_probe() to return
-EPROBE_DEFER. The driver core will then try the probe again sometime
later, hopefully when all the needed resources are available.

Track down where the EAGAIN is coming from.

      Andrew