On Thu, Sep 15, 2016 at 03:20:58PM +0200, Bartosz Golaszewski wrote:

2016-09-15 14:41 GMT+02:00 Linus Walleij [off-list ref]:

quoted

quoted

So can't you walk up that and see if you encounter the exact same driver
again?

Something like:

        for (nr = 0, parent = dev->parent; parent; parent = parent->parent) {
                if (parent->device_driver == &pca953x_driver.driver)
                        nr++;
        }

Oh clever. Of course.

Bartosz can you try out this approach?

I think it may be more complicated than that, depending on the hw
topology, but the general idea seems reasonable. I'll try this.

Yeah, I figured there might be more to it.

In any case, if this fails, we can always punt and simply count the
total number of instances of this driver on the system and go with that.