On Wednesday 10 April 2013 14:29:17 Stephen Warren wrote: > > > If the information is there, whether to convert from IRQ to GPIO > > or from GPIO to IRQ is a technicality and any order should be > > feasible in some way? > > There isn't always a unique 1:1 mapping between GPIOs and IRQs. Put > another way, a single GPIO would likely only ever trigger a single IRQ, > but a single IRQ might easily be triggered by any number of GPIOs. This > is exactly why the function irq_to_gpio() isn't something one should use > any more. More importantly, most irqs don't have any GPIO associated with them at all. The interface made some sense for simple platforms that had a linear range of GPIO IRQs, but that also isn't true these days, with arbitrary IRQ domains. > I think there was an effort to outright remove the API, > although it doesn't look like that's entirely complete yet. It's essentially complete. There are a few remnants in areas of the kernel that we don't like to look at: * The blackfin architecture provides the interface and uses it in the pata_rb532_cf driver. * MIPS provides it on a few older platforms, and it's used on the alchemy pcmcia driver. * avr32, m68k, sh and unicore32 provide the interface but don't use it. * On ARM, the interface is provided on iop, gemini, ixp4xx, ks8695 and w90x900. None of these use it, and they rarely see any patches at all these days. * ARM/davinci provides a stub but always return -ENOSYS. * One driver for PXA (tosa_battery) still uses this interface, but PXA stopped providing it long ago. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
