Re: [PATCH v3 1/1] i2c: add ACPI support for I2C mux ports

From: Mika Westerberg
Date: Wed Oct 21 2015 - 04:12:55 EST


On Tue, Oct 20, 2015 at 10:49:59AM -0700, Dustin Byford wrote:
> I considered it, but I thought a default that fairly closely matches the
> old behavior was more convenient.
>
> On the other hand, leaving it up to the controllers makes it all very
> explicit and perhaps simpler to reason about.
>
>
> I could be convinced either way. But, if we move it to the controller
> drivers, which ones need the change?
>
> grep -i acpi drivers/i2c/busses/i2c*
>
> shows 18 drivers that might care.

I'm quite confident the designware I2C is enough for now. Intel uses it
for all SoCs with LPSS and I think AMD has the same block for their I2C
solution.

> > adap->dev.parent = &pdev->dev;
> > adap->dev.of_node = pdev->dev.of_node;
> > ACPI_COMPANION_SET(&adap->dev, ACPI_COMPANION(&pdev->dev));
>
> Interesting, this code isn't in my tree. I wonder why it was added,
> what code looks at the acpi companion on the i2c dev? Before my change
> it was supposed to be NULL, and it is NULL on every other controller.

It is not in any tree. I meant that before b34bb1ee71158d5b it looked
something like that :-)
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