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IRQ Flags for NNMI interrupt (EXTINTn pin)

marlon@kaertech.com
Prodigy 210 points
Other Parts Discussed in Thread: AM3352

Hi all,

I am trying to handle the NNMI interrupt (EXTINTn pin, AM3352 board) in linux as an irq button. I modified gpio_keys.c and I was able to hook the interrupt but I noticed that it seems the processor stops as soon as I hook up the interrupt and continues whenever I press the button connected to the EXTINTn pin. Here's a sample log:

[ 2.264022] Inside gpio_keys_get_devtree_pdata.
[ 2.290336] gpio-keys gpio_buttons.6: gpio_keys_setup_key: Setting up button button0 as IRQ button no.: 23
[ 2.309258] gpio-keys gpio_buttons.6: gpio_keys_setup_key: now calling request_any_context_irq: irq[23] irqflags[0x4]  <-- here the processor stops
[ 8.875182] gpio-keys gpio_buttons.6: gpio_keys_setup_key: done calling request_any_context_irq. <-- processor continues from here on when I press the button 
[ 8.884556] [sched_delayed] sched: RT throttling activated
[ 8.898326] gpio-keys gpio_buttons.6: gpio_keys_setup_key: IRQ[23] for button[button0] has been claimed
[ 8.909148] input: gpio_buttons.6 as /devices/gpio_buttons.6/input/input0
[ 8.917840] omap_rtc 44e3e000.rtc: setting system clock to 2000-01-01 00:00:08 UTC (946684808)

So it seems I was able to setup the interrupt hook but I am not passing the correct irq flags. I tried every combination but the output is the same.

Regards,

Marlon

  • 0
    TI__Guru**** 161600 points

    Hi Marlon,

    Marlon Hacla said:
    So it seems I was able to setup the interrupt hook but I am not passing the correct irq flags. I tried every combination but the output is the same

    Can you share the changes you've made? gpio_keys, dts, etc. 

    As per device TRM, NMI irq number is 7, see Table 6-1. ARM Cortex-A8 Interrupts. 

    Best Regards, 

    Yordan

  • 0 in reply to Yordan Kovachev
    Prodigy 210 points

    See attached zip file below. Basically I applied the patch from this link and I modified the DTS by adding the button:

    gpio_buttons: gpio_buttons@0 {
    compatible = "gpio-keys";
    #address-cells = <1>;
    #size-cells = <0>;

    switch@1 {
    label = "button0";
    linux,code = <0x100>;
    interrupt-parent = <&intc>;
    interrupts = <7>; // interrupt number of NNMI
    };

    };

    I also added a quick printf and return statements in the irq handlers just to see if the handler is being called. I tried harcdoding irq no.7 in gpio_keys.c but that doesn't work but the irq number (23) returned by irq_of_parse_and_map for interrupt number 7 seems to work.

    button-tests.zip

  • 0 in reply to Yordan Kovachev
    Prodigy 210 points

    I found I modified the wrong interrupt handler function. So I edited gpio_keys_irq_isr by doing a quick printkn and return and I found that the I receive the interrupt every time and it only stops when I press the button. I saw on this thread that I might need to change the polarity, but how do I do that in the software?