topic Re: I.MX 8M MINI Interrupt in i.MX Processors

I.MX 8M MINI Interrupt

dan_hilgert — Fri, 18 Dec 2020 20:47:09 GMT

I want to make the GPIO pin assigned to my RTC a falling edge interrupt.

This is what I have done so far:

Defined the pin node

Defined I2C node for the RTC and designated interrupt info

Compile new .dtb and scp the file to the board

Finally, when I execute a ' cat /proc/interrupts' the interrupt always shows up as a level interrupt and never and edge like I defined it to be.

Looking at the datasheet, it appears each pin can be assigned as a high or low level as well as falling or rising edge interrupt.

When I test the interrupt functionality this is what I see:

Line pulled high no interrupts generated
Line pulled low, continuous interrupts generated

Can someone point me in the right direction to identify what I am doing wrong or missing here?

Thanks,

Dan

Re: I.MX 8M MINI Interrupt

Zhiming_Liu — Mon, 21 Dec 2020 02:36:19 GMT

You can use our gpio config tool to generate dts code https://www.nxp.com/design/designs/pins-tool-for-i-mx-application-processors:PINS-TOOL-IMX

Zhiming

Re: I.MX 8M MINI Interrupt

dan_hilgert — Sun, 03 Jan 2021 15:57:27 GMT

I think I figured out what's going on. I believe the device tree interrupt configuration be overwritten by the device driver.

I am fairly new to embedded Linux applications, but I assume a device driver can overwrite the info the device tree is telling the kernel. Can you confirm?

Re: I.MX 8M MINI Interrupt

Zhiming_Liu — Mon, 04 Jan 2021 01:47:17 GMT

NO, device tree can not be changed by driver.The code you show just judge the trigger type to handle irq.For example, if you define the gpio irq is type of low trigger.The driver find current irq is low and it will call m4lt80_handle_irq.

Zhiming