Hi Tony, On 2/20/2019 10:06 PM, Tony Lindgren wrote: > Hi, > > Some more info on chained irq vs mux below that might > help. > > * Tony Lindgren <tony@xxxxxxxxxxx> [190219 15:36]: >> * Lokesh Vutla <lokeshvutla@xxxxxx> [190219 08:51]: >>> With this can you tell me how can we not have a device-tree and still support >>> irq allocation? >> >> Using standard dts reg property to differentiate the interrupt >> router instances. And if the interrupt router is a mux, you should >> treat it as a mux rather than a chained interrupt controller. >> >> We do have drivers/mux nowadays, not sure if it helps in this case >> as at least timer interrupts need to be configured very early. > > Adding Linus Walleij to Cc since he posted a good test to > consider if something should use chained (or nested) irq: > > "individual masking and ACKing bits and can all be used at the > same time" [0] Interrupt Router just routes M inputs to N outputs. One input can only be mapped to one output. This is a clear case of a hierarchical domain and the driver is implementing it. Thanks and regards, Lokesh > > Not sure if we have that documented somewhere? > > But seems like the interrupt router should be set up as > a separate mux driver talking with firmware that the > interrupt controller driver calls on request_irq(> > Cheers, > > Tony > > > [0] https://marc.info/?l=linux-omap&m=155065629529311&w=2 >
