On Thu, Jan 28, 2021 at 12:31:36PM +0000, Andre Przywara wrote: > Mark Brown <broonie@xxxxxxxxxx> wrote: > > It sounds like you're trying to register an IRQ chip with a somehow > > bogus configuration? > I patched the AXP MFD driver [1] to skip the regmap-irq creation when no > interrupts DT property was found, but this NULL pointer now > understandably confuses the -pek driver, and leads to this crash: > http://lists.infradead.org/pipermail/linux-arm-kernel/2021-January/634969.html > Hence I wanted to plug this hole, which seems useful regardless of this > particular issue. The driver code here looks pretty confused. It appears to be looking up the interrupt to use from a resource (which is what I'd expect for a MFD child) then for reasons I can't fathom trying to pass that resource into regmap_irq_get_virq() which is at best going to just return the value that was passed in but may potentially end up just returning a random interrupt other than the one that was asked for since we're passing in a global interrupt number rather than a controller relative one. I really can't tell what's supposed to be going on there. A driver should either use resources or it should use regmap_irq_get_virq(), using both is a bug. The MFD for this device is also just plain buggy in that it is providing IRQ resources to the children when there is in fact no support for the interrupts on the device in the system. This means that the MFD core sees that it has no interrupt domain, assumes that those interrupt resources are in fact absolute interrupt numbers and passes them straight through to the children. This means that the children will just be requesting random interrupts in the system which may actually exist and be requestable which probably isn't going to end well. When there is no interrupt controller the parent should not be trying to supply interrupt resources to the children at all.
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