> >BTW, what does client->irq == 0 represent? > > This one I'm fairly confident on. Initially I had "client->irq < 0" > Which caused problems with an i2c mux that doesn't have irq's defined in the dt. > > This commit seems to confirm that. > commit dab472eb931b ("i2c / ACPI: Use 0 to indicate that device does not have interrupt assigned") In the Linux Kernel, 0 means no irq so one can write: if (!irq) ... There used to be NO_IRQ per arch but this is converted over, although it takes a lot of time... If there is a HW IRQ0, it needs to be remapped. But since we rely on irq_desc these days and not irq numbers, this is easy. At least this was the transition a few years ago, but I don't think something essential has changed. Please enlighten me, if so. Regards, Wolfram
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