3

I'm pretty new to device tree programming, I'm trying to understand the interrupts line that shows up in the device tree for SAMA5D36 USART dts definition:

usart2: serial@f8020000 {
    compatible = "atmel,at91sam9260-usart";
    reg = <0xf8020000 0x100>;
    interrupts = <14 IRQ_TYPE_LEVEL_HIGH 5>;
    dmas = <&dma1 2 AT91_DMA_CFG_PER_ID(7)>, <&dma1 2 (AT91_DMA_CFG_PER_ID(8) | AT91_DMA_CFG_FIFOCFG_ASAP)>;
    dma-names = "tx", "rx";
    pinctrl-names = "default";
    pinctrl-0 = <&pinctrl_usart2>;
    clocks = <&usart2_clk>;
    clock-names = "usart";
    status = "disabled";
};

What I think it means is that the interrupt will be level-high triggered. The interrupt is registered as interrupt 14. And the 5... I'm guessing is a priority? I've looked around and one of the things that confuses me is that for some examples out there, the order of these 3 entries seems to vary. Sometimes the trigger type will be the third entry instead of the second. My purpose in trying to understand this, is that I would like to experiment with adjusting the priority of this interrupt (looking for better responsiveness), but I don't even know whether to increase or decrease the value.

(P.S. Is there a better exchange to ask this question in?)

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.