AM335X- GPIO interrupt

Joe Chen3

Dear Sir,

I want to implement the reset button(S2_GPIO2_8 from BBB_SCH) interrupt in the BBB EVB, but it couldn't generate the interrupt when I pressed the S2 button, my code add into the drivers/watchdog/omap_wdt.c as bleow,

static irqreturn_t rst_button_handle_irq(int irq, void *dev)
{

    printk("=============rst_button_handle_irq\n");
    return IRQ_HANDLED;
}

static void reset_button_gpio_init(void)
{
    int gpio_reset_button_pin = 72;//gpio2_8
    int status = gpio_request(gpio_reset_button_pin,"rstButton\n");
    if (status < 0)
        pr_err("Failed to request gpio for rstButton");
    else
        printk("rstButton request success\n");

    gpio_direction_input(gpio_reset_button_pin);

    status = request_irq(gpio_to_irq(gpio_reset_button_pin), rst_button_handle_irq, 0, "rst_Button", NULL);
    if (status < 0)
        printk("rstButton irq failed\n");
    else
        printk("rstButton request_irq success\n");
}

static int omap_wdt_probe(struct platform_device *pdev)
{
    struct omap_wd_timer_platform_data *pdata = dev_get_platdata(&pdev->dev);
    struct watchdog_device *omap_wdt;
    struct resource *res, *mem;
    struct omap_wdt_dev *wdev;
    u32 rs;
    int ret;

    reset_button_gpio_init();

Power on message:

[    1.275139] rstButton request success
[    1.284016] rstButton request_irq success
[    1.289229] omap_wdt: OMAP Watchdog Timer Rev 0x01: initial timeout 60 sec

The interrupt was created by cat /proc/interrupts

root@am335x-evm:~# cat /proc/interrupts
           CPU0
28:       1693      INTC 12 edma
30:          0      INTC 14 edma_error
44:         54      INTC 28 mmc1
56:          0      INTC 40 4a100000.ethernet
57:         22      INTC 41 4a100000.ethernet
58:          2      INTC 42 4a100000.ethernet
59:          0      INTC 43 4a100000.ethernet
80:       5296      INTC 64 mmc0
84:       4888      INTC 68 gp_timer
86:        730      INTC 70 44e0b000.i2c
87:          0      INTC 71 4802a000.i2c
88:        806      INTC 72 OMAP UART0
91:          0      INTC 75 rtc0
92:          0      INTC 76 rtc0
94:          0      INTC 78 wkup_m3_txev
125:          0      INTC 109 53100000.sham
127:          0      INTC 111 48310000.rng
150:          0 44e07000.gpio   6 mmc0
216:          0 481ac000.gpio   8 rst_Button
Err:          0
root@am335x-evm:~#

Please give me a favor for the question, thanks.

B.R.

Joe

over 10 years ago

0 Prabhakar Lad over 10 years ago

Guru 11260 points

Hi,

try out the below code:

#include <linux/module.h>
#include <linux/version.h>
#include <linux/delay.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/completion.h>
#include <mach/hardware.h>
#include <asm/gpio.h>

static int gpio_num;

DECLARE_COMPLETION(work);

static irqreturn_t handler (int irq, void * dev)
{
complete_all(&work);
return IRQ_HANDLED;
}

int init_module()
{
int status;
int irq;

init_completion(&work);

gpio_num = 72;

status = gpio_request(gpio_num, "gpio_test\n");
if (status < 0) {
printk("ERROR can not open GPIO %d\n", gpio_num);
return status;
}

gpio_export(gpio_num, true);

if(gpio_get_value(gpio_num) == 0)
printk("OFF. \n\tWaiting for the pin to be on..\n");
else
printk("ON. \n\tWaiting for the pin to be off..\n");

irq = gpio_to_irq(gpio_num);
status = request_irq(irq, handler, 0, "gpio_test", NULL);
if(status < 0) {
printk(KERN_ERR "error %d requesting GPIO IRQ %d\n", status, gpio_num);
return status;
}

set_irq_type(irq, IRQ_TYPE_EDGE_RISING);

wait_for_completion_interruptible(&work);

printk(".. done\n");

return 0;
}

void cleanup_module(void) {
free_irq(gpio_to_irq(gpio_num), NULL);
gpio_free(gpio_num);
}

MODULE_LICENSE("GPL");

Makefile:

obj-m += gpio_gpio_test.o
PWD := $(shell pwd)

KERNEL_DIR=<path to your linux source>
INSTALL_DIR=$(FINAL_DEST)/gpio

# Set KERNEL_DIR to your local kernel location

all:
$(MAKE) -C $(KERNEL_DIR) M=$(PWD) ARCH=arm CROSS_COMPILE=arm-cortex_a8-linux-gnueabi-

install:
mkdir -p $(INSTALL_DIR)
cp gpio_test.ko $(INSTALL_DIR)
clean:
rm -rf *.o *.ko *.mod.c .*.cmd .tmp_versions *.order *.symvers

Change the KERNEL_DIR to linux source directory.

Cheers,
--Prabhakar Lad

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AM335X- GPIO interrupt