gpio as interrupt - sysfs irq works - kernel irq fail

Hi Yordna,

I am using 2.6.37

GPIO 42 pinmux is configured as GPIO.

When working with sysfs the interrupt works OK.

On changing to kernel APIs it does not function correctly. I've been struglling with it for couple of hours, but still don't have any progress.

Best Regards,

Ran

Hi,

I've also tried the code in the attached file.

But It does not give me the printing from the interrupt routine.

4810.irq.c

Maybe gpio42 in DM8148 need some additional configuration which are done automatically when using sysfs entires ?

Regards,

Ran

Hi Titus,

Thank you very much for the feedback. It is helpful.
using /proc/interrupts I see the following:
- when using sysfs:
202: 4 GPIO gpiolib
- when using kernel APIs:
202: 0 GPIO gpiolib
I guess the 2nd column which indicates flag (I think) might point to the problem.

All APIs are successful (return 0), and gpio_to_irq return 202.
this is my code, I don't understand why it does not register the "raising" flag.
err=request_irq(ev->irq, drv_gpio_interrupt,IRQF_TRIGGER_RISING , "gpiolib", ev);
printk("return of request_irq is %d\n",err);

trying to change as foloowing:
err=request_irq(ev->irq, drv_gpio_interrupt,IRQF_TRIGGER_RISING , "gpiolib", ev);
printk("return of request_irq is %d\n",err);
err = irq_set_type(ev->irq, IRQF_TRIGGER_RISING);
printk("return of irq_set_type is %d\n",err);

And now I get compilation error:
error: implicit declaration of function 'irq_set_type'

Is it becuase kernel does not support irq_set_type ?

Hiow can I add it ? I see that CONFIG_GENERIC_HARDIRQS is no by default for this architecture.

Thank you!
Ran

using /proc/interrupts I see the following:
- when using sysfs:
202: 4 GPIO gpiolib

Hi,

I didn't yet receved the interrupts when using kernel APIs (only with sysfs it works).

root@dm814x:~# cat /proc/interrupts

          CPU0

 4:          0        INTC  omap2_elm

12:          0        INTC  edma

14:          0        INTC  edma_error

16:          0        INTC  ahci

17:          0        INTC  cppi41_dma

18:          0        INTC  musb-hdrc.0

19:          0        INTC  musb-hdrc.1

20:          0        INTC  gpmc

28:         13        INTC  mmc0

31:          0        INTC  omap_i2c

40:          0        INTC  cpsw.0

41:       8632        INTC  cpsw.0

42:      10109        INTC  cpsw.0

43:          0        INTC  cpsw.0

44:          0        INTC  serial idle

45:          0        INTC  serial idle

46:          0        INTC  serial idle

67:       1018        INTC  gp timer

70:        148        INTC  omap_i2c

72:        214        INTC  serial idle, OMAP UART0

73:          0        INTC  serial idle

74:          0        INTC  serial idle

75:          0        INTC  rtc0

76:          0        INTC  rtc0

77:          0        INTC  mailbox-dsp, mailbox-video, mailbox-vpss

116:         94        INTC  CDMA

122:          0        INTC  omap-iommu.1

123:          0        INTC  omap-iommu.0

202:          0        GPIO  gpiolib

Err:          0

I still can't use set_irq_type() .

Can it be all related to CONFIG_GENERIC_HARDIRQS (in my config it is "NO" and I can't change it) ?

Regards,

Ran

Hi Ran,

You can ignore those settings. That's for DM35x device.

I have attached the GPIO interrupt driver code which I have already worked with TI's OMAPL138 LCDK board, linux kernel version 3.2.

Have a try and let me know.

Just change the GPIO_INT for your GPIO no.

2063.gpio_irq.c

Hi Titus,

I just tried the code AS-IS (only changed the interrupt number from 37 to 42).
But I get no interrupt yet.
It is loaded successfuly, creates irq 202, and have no errors.

    root@dm814x:~# insmod gpio_irq.ko
    gpio_ctrl : GPIO NO: 42 Status -16
    IRQ is 202
    gpio_request_irq 202 status 0
    GPIO IRQ device is inserted sucessfully

But , I don't even see the printing from the interrupt handler "GPIO interrupt raised; IRQ No ..."

I really don't understand what I'm doing wrong.

Thank you very much for the help,
Ran

root@dm814x:~# insmod gpio_irq.ko
gpio_ctrl : GPIO NO: 42 Status -16
IRQ is 202
gpio_request_irq 202 status 0
GPIO IRQ device is inserted sucessfully

Hi Ran,

The attached driver (previous reply) is worked on my OMAPL138 LCDK board.

Also I've tried to change the request_irq function like below.

request_irq(irq_num,gpio_interrupt,IRQF_SHARED,"gpio_int",major);

It worked flawlessly for both methods of "request_irq" API.

Could you please tell me, how did you connect this GPIO in hardware ?

With pull up or pull down etc., ?

Custom board or EVM ?

Any switch or driving this GPIO from any uC etc., ??

How did you test the GPIO interrupt functionality with SYSFS commands and how did you confirm ?

Did you probe that GPIO pin while you drive or asserting the pin or pressing switch ?

Please make sure that you are using correct GPIO pin.

Hi Titus,

Since I already see the problem with PGIO41 output,

I read the pinmux register og GPIO41 (GP1[9] ) for both when using sysfs, and when using the kernel APIs version.

In both I see the same value :

dm814x login: root
root@dm814x:~# devmem2 0x481408fc
/dev/mem opened.
Memory mapped at address 0x4025b000.
Read at address 0x481408FC (0x4025b8fc): 0x00040080
root@dm814x:~# ./bit

So, I still don't undertsnad why the output of GPIO41 is not changed. It seems that the pinmux registers which contain the pullup/down value is correct (becuase this same value is used with the working sysfs)

Best Regards,

Ran

It seems that the sysfs usage was under flag in my application - which already initlized that register using sysfs ,  and I just did not noticed that initilization :( ... , i.e. sysfs AS-IS was not doing any additional magic , but what it initlized was the magic.