Background simplified, I need to generate a kernel signal when pin-X drops low. The CPU documentation identifies this as IRQ-1 (zero based), and searching the kernel code shows me that IPIC_EXT1 = 17... except that when I try to register my callback function I get an error that IRQ17 is already in use with ttyS1. Clearly I am missing something. It doesn't help that the legacy code snipit I am trying to merge in was from an old 2.x kernel (before device trees).
So... can anyone recommend a set of tutorials on hwirq/irq mapping and maybe also the device tree? Better yet, does anyone know of a good free webinar or online collage course covering these subjects and/or linux kernel driver development in general?
My starting point is 'user space c/c++ expert', but my only prior kernel work is to recompile with different #define config options.
So... can anyone recommend a set of tutorials on hwirq/irq mapping and maybe also the device tree? Better yet, does anyone know of a good free webinar or online collage course covering these subjects and/or linux kernel driver development in general?
My starting point is 'user space c/c++ expert', but my only prior kernel work is to recompile with different #define config options.