P2040: How to configure GPIO as an interrupt

[gouravjain]

Hi,

In my custom board, based on P2040rdb, tired to configure GPIO22/IRQ04 as an interrupt.

Kept RCW bit[373]= 0 and GPICR = 0x00000200 and EIVPR2 = 0x80080002 (it must rigger on high to low).

While inserting module im getting error,

genirq: Setting trigger mode 0 for irq22 failed ((mpc8xxx_irq_set_type+0x0/0xec)).

And not able to catch interrupt.

root@hmd-modem::~# cat /proc/interrupts
CPU0 CPU1 CPU2 CPU3
16: 0 0 0 0 OpenPIC Edge mpic-error-int
22: 0 0 0 0 mpc8xxx-gpio Edge CYCLONE_GPIO_IRQ22

Pls let me know if i'm missing anything here.

Thanks in advance.

--

Gourav

[ufedor]

You wrote:

> configure GPIO22/IRQ04 as an interrupt.

GPIO interrupts are jointly connected to the MPIC as internal interrupt 39 - refer to the QorIQ P2040 Reference Manual, Table 24-1. P2040 Internal Interrupt Assignments.

This means that you have to configure IIVPR39.

[gouravjain]

Hi ufedor,

Thanks for your response.

Can you pls explain how to configure i.e. which all registers need to be changed??

[ufedor]

From hardware point of view you have to configure GPIMR = 0x00000200 and IIVPR39.

Consider that you have to properly declare the IRQ in the DTS.

Refer to /Documentation/powerpc/booting-without-of.txt for details. The value of the "interrupt" property is calculated by the following formula:
   
   [DTS_interrupt_number] = ([EIVPR/IIVPR_addr] - [Interrupt_Source_Configuration_Registers_Base]) / 0x20

where [EIVPR/IIVPR_addr] is the address of the interrupt configuration registers of the IRQ being declared, [Interrupt_Source_Configuration_Registers_Base] is 0x5000 for P2040.

[gouravjain]

Hi,

Interrupt is getting triggered on GPIO-22, after doing following settings,

bit -22 is for GPIO-22

1) GPIER : 0x00000000

2) GPIMR : 0x00000200        bit-22=1 i.e. gpio-22 is non-masked, enabled 

3) GPICR : 0x00011015         bit-22=0 i.e. interrupt can be triggered in high to low and low to high

4) IIVPR39(0xFE0506E0): 0x7261703D bit 8 =0, As per ref manual all internal interrupts will be active high.

But im getting interrupts in both the edges. Pls have a look in register settings.

Thanks,

Gourav

[ufedor]

> 3) GPICR : 0x00011015         bit-22=0 i.e. interrupt can be triggered in high to low and low to high

Set the bit 22 to 1 - i.e.:

GPICR = 0x00011215

[gouravjain]

"1" menas interrupt will be triggered on high to low transaction but  "IIVPR30" register tells all internal interrupts will be active high. What does it mean??

Anyways, I made bit 22 as 1 but still interrupts are triggering on both the edges.

[gouravjain]

Hi ufedor,

Waiting for your reply....

[ufedor]

1) Use a debug mode to ensure that when GPICR[22]=1, the GPIER[22] is set only by high-to-low change on the port.

2) Ensure that GPIER[22] is cleared (by writing 1) in the interrupt handler.