topic Re: GPIO INTERRUPT in i.MX Processors

GPIO INTERRUPT

christophertele — Thu, 17 Dec 2015 07:16:33 GMT

Hy,

i´m working with an iMX6Q. I want to use a interrupt on a GPIO

I used gpio_to_irg() and request_irq() to set up my interrupt. it worked pretty well but its not that fast. Or not as fast as i want it to be.

Q1: Is there a way to use the GIC for GPIO interrupt?

i tried to configure the necessary GPIO registers(Direction, ICR , IMR).

i used the irq number listed in the processor manual to request the irq but that dosnt work so far.

Q2: what is the propper usage of request_irq() with the parameter IRQF_TRIGGER_???

(If i use NONE i will get an irq all the time)

Re: GPIO INTERRUPT

igorpadykov — Sat, 19 Dec 2015 02:52:38 GMT

Hi Christopher

GIC is used during interrupt procedures, details can be found in attached

document from SDK Chapter 4 Configuring the GIC Driver.

Seems more proper second question to send on kernel.org.

Best regards

igor

Re: GPIO INTERRUPT

christophertele — Tue, 22 Dec 2015 09:09:16 GMT

thanks so far!

cat /proc/interrupts

CPU0 CPU1 CPU2 CPU3

16: 2313 1658 2361 878 GIC 29 twd

17: 0 0 0 0 GIC 87 i.MX Timer Tick

18: 35 0 0 0 GIC 45 mxs-dma

19: 5 0 0 0 GIC 47 bch

22: 2 0 0 0 GIC 65 2010000.ecspi

23: 0 0 0 0 GIC 79 202c000.ssi

38: 0 0 0 0 gpio-mxc 6 2198000.usdhc cd

75: 69 0 0 0 gpio-mxc 9 da9063-irq

147: 6 0 0 0 gpio-mxc 13 PS_irq_handler

150: 193 0 0 0 gpio-mxc 16 CLK_irq_handler

the interrupts with the numbers 147 and 150 are my interrupts using gpio_to_irq() and request_irq().
is the 16 in the last line the interrupt ID? does it mean its a software generated irq?

Re: GPIO INTERRUPT

igorpadykov — Tue, 22 Dec 2015 09:19:31 GMT

right, first 32 interrupts are used for interrupts that are private to the CPUs interface.

Re: GPIO INTERRUPT

christophertele — Tue, 22 Dec 2015 12:59:47 GMT

ok.

according to "Table 3-1. ARM domain interrupt summary" of i.MX 6Dual/6Quad Applications Processor Reference Manual.

i want to use 104 but how do i get the interrupt number to request the interrupt line using request_irq()?

Re: GPIO INTERRUPT

igorpadykov — Tue, 22 Dec 2015 13:40:33 GMT

you can apply to linux documentation, like:

Registering an Interrupt Handler

http://www.oreilly.com/openbook/linuxdrive3/book/ch10.pdf

Re: GPIO INTERRUPT

christophertele — Wed, 23 Dec 2015 10:29:27 GMT

the problem is: in older versions /proc/interrupts looks like this:

root@freescale /proc/irq$ cat /proc/interrupts

CPU0 CPU1 CPU2 CPU3

34: 1 0 0 0 GIC sdma

35: 0 0 0 0 GIC VPU_JPG_IRQ

37: 0 0 0 0 GIC imx-ipuv3

38: 0 0 0 0 GIC imx-ipuv3

39: 0 0 0 0 GIC imx-ipuv3

40: 0 0 0 0 GIC imx-ipuv3

44: 0 0 0 0 GIC VPU_CODEC_IRQ

51: 0 0 0 0 GIC snvs_rtc

56: 48 0 0 0 GIC mmc1

57: 0 0 0 0 GIC mmc0

59: 1832 0 0 0 GIC IMX-uart

63: 4 0 0 0 GIC spi_imx

68: 468 0 0 0 GIC imx-i2c

69: 0 0 0 0 GIC imx-i2c

70: 1 0 0 0 GIC imx-i2c

72: 25 0 0 0 GIC usb_wakeup

75: 0 0 0 0 GIC usb_wakeup

82: 0 0 0 0 GIC asrc

87: 248984 0 0 0 GIC i.MX Timer Tick

121: 0 0 0 0 GIC dvfs

150: 12449 0 0 0 GIC fec

292: 0 0 0 0 GPIO itest

294: 0 0 0 0 GPIO mmc0

448: 0 0 0 0 GPIO mmc1

on my board it lokks like this:

cat /proc/interrupts

CPU0 CPU1 CPU2 CPU3

16: 2313 1658 2361 878 GIC 29 twd

17: 0 0 0 0 GIC 87 i.MX Timer Tick

18: 35 0 0 0 GIC 45 mxs-dma

19: 5 0 0 0 GIC 47 bch

22: 2 0 0 0 GIC 65 2010000.ecspi

23: 0 0 0 0 GIC 79 202c000.ssi

38: 0 0 0 0 gpio-mxc 6 2198000.usdhc cd

75: 69 0 0 0 gpio-mxc 9 da9063-irq

147: 6 0 0 0 gpio-mxc 13 PS_irq_handler

150: 193 0 0 0 gpio-mxc 16 CLK_irq_handler

^linux irq number ^irq number from the documentation

in the older version is the linux irq nuber the same as the number in the documentation. on my board its not. so the problem is i cant simply request the interrupt using request_irq(). are there any known changes between the kernel versions? an api the request the irq number?

Re: GPIO INTERRUPT

igorpadykov — Wed, 23 Dec 2015 12:41:26 GMT

you did not mention what version used, for example for NXP/FSL Linux

3.14.28 BSP one can look at attached Linux Manual sect.3.2.4 Interrupt Source Code Structure

Re: GPIO INTERRUPT

christophertele — Wed, 23 Dec 2015 12:44:00 GMT

linux 3.19.5

Re: GPIO INTERRUPT

igorpadykov — Wed, 23 Dec 2015 13:37:28 GMT

this kernel is not supported by NXP/FSL, I would suggest to

post this on kernel.org

Best regards

igor

Re: GPIO INTERRUPT

christophertele — Tue, 05 Jan 2016 08:17:59 GMT

there is a mapping between linux irq numbers and hwirqs. listed in irq_domain.

you can have a look at irq_domain via debugfs.

just enable debugfs and "irq subsystem ->expose hardware/virtual irq mapping..." in menuconfig.

the mapping is shown in file /sys/kernel/debug/irq_domain_mapping