mirror of
https://github.com/sysprog21/lkmpg.git
synced 2024-11-22 10:28:13 +08:00
150 lines
3.6 KiB
C
150 lines
3.6 KiB
C
/*
|
|
* bh_thread.c - Top and bottom half interrupt handling
|
|
*
|
|
* Based upon the RPi example by Stefan Wendler (devnull@kaltpost.de)
|
|
* from:
|
|
* https://github.com/wendlers/rpi-kmod-samples
|
|
*
|
|
* Press one button to turn on a LED and another to turn it off
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/gpio.h>
|
|
#include <linux/delay.h>
|
|
#include <linux/interrupt.h>
|
|
|
|
static int button_irqs[] = { -1, -1 };
|
|
|
|
/* Define GPIOs for LEDs.
|
|
* FIXME: Change the numbers for the GPIO on your board.
|
|
*/
|
|
static struct gpio leds[] = { { 4, GPIOF_OUT_INIT_LOW, "LED 1" } };
|
|
|
|
/* Define GPIOs for BUTTONS
|
|
* FIXME: Change the numbers for the GPIO on your board.
|
|
*/
|
|
static struct gpio buttons[] = {
|
|
{ 17, GPIOF_IN, "LED 1 ON BUTTON" },
|
|
{ 18, GPIOF_IN, "LED 1 OFF BUTTON" },
|
|
};
|
|
|
|
/* This happens immediately, when the IRQ is triggered */
|
|
static irqreturn_t button_top_half(int irq, void *ident)
|
|
{
|
|
return IRQ_WAKE_THREAD;
|
|
}
|
|
|
|
/* This can happen at leisure, freeing up IRQs for other high priority task */
|
|
static irqreturn_t button_bottom_half(int irq, void *ident)
|
|
{
|
|
pr_info("Bottom half task starts\n");
|
|
mdelay(500); /* do something which takes a while */
|
|
pr_info("Bottom half task ends\n");
|
|
return IRQ_HANDLED;
|
|
}
|
|
|
|
static int __init bottomhalf_init(void)
|
|
{
|
|
int ret = 0;
|
|
|
|
pr_info("%s\n", __func__);
|
|
|
|
/* register LED gpios */
|
|
ret = gpio_request_array(leds, ARRAY_SIZE(leds));
|
|
|
|
if (ret) {
|
|
pr_err("Unable to request GPIOs for LEDs: %d\n", ret);
|
|
return ret;
|
|
}
|
|
|
|
/* register BUTTON gpios */
|
|
ret = gpio_request_array(buttons, ARRAY_SIZE(buttons));
|
|
|
|
if (ret) {
|
|
pr_err("Unable to request GPIOs for BUTTONs: %d\n", ret);
|
|
goto fail1;
|
|
}
|
|
|
|
pr_info("Current button1 value: %d\n", gpio_get_value(buttons[0].gpio));
|
|
|
|
ret = gpio_to_irq(buttons[0].gpio);
|
|
|
|
if (ret < 0) {
|
|
pr_err("Unable to request IRQ: %d\n", ret);
|
|
goto fail2;
|
|
}
|
|
|
|
button_irqs[0] = ret;
|
|
|
|
pr_info("Successfully requested BUTTON1 IRQ # %d\n", button_irqs[0]);
|
|
|
|
ret = request_threaded_irq(
|
|
gpio_to_irq(button_irqs[0]), button_top_half, button_bottom_half,
|
|
IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING, "gpiomod#button1", NULL);
|
|
|
|
if (ret) {
|
|
pr_err("Unable to request IRQ: %d\n", ret);
|
|
goto fail2;
|
|
}
|
|
|
|
ret = gpio_to_irq(buttons[1].gpio);
|
|
|
|
if (ret < 0) {
|
|
pr_err("Unable to request IRQ: %d\n", ret);
|
|
goto fail2;
|
|
}
|
|
|
|
button_irqs[1] = ret;
|
|
|
|
pr_info("Successfully requested BUTTON2 IRQ # %d\n", button_irqs[1]);
|
|
|
|
ret = request_threaded_irq(
|
|
gpio_to_irq(button_irqs[1]), button_top_half, button_bottom_half,
|
|
IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING, "gpiomod#button2", NULL);
|
|
|
|
if (ret) {
|
|
pr_err("Unable to request IRQ: %d\n", ret);
|
|
goto fail3;
|
|
}
|
|
|
|
return 0;
|
|
|
|
/* cleanup what has been setup so far */
|
|
fail3:
|
|
free_irq(button_irqs[0], NULL);
|
|
|
|
fail2:
|
|
gpio_free_array(buttons, ARRAY_SIZE(leds));
|
|
|
|
fail1:
|
|
gpio_free_array(leds, ARRAY_SIZE(leds));
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void __exit bottomhalf_exit(void)
|
|
{
|
|
int i;
|
|
|
|
pr_info("%s\n", __func__);
|
|
|
|
/* free irqs */
|
|
free_irq(button_irqs[0], NULL);
|
|
free_irq(button_irqs[1], NULL);
|
|
|
|
/* turn all LEDs off */
|
|
for (i = 0; i < ARRAY_SIZE(leds); i++)
|
|
gpio_set_value(leds[i].gpio, 0);
|
|
|
|
/* unregister */
|
|
gpio_free_array(leds, ARRAY_SIZE(leds));
|
|
gpio_free_array(buttons, ARRAY_SIZE(buttons));
|
|
}
|
|
|
|
module_init(bottomhalf_init);
|
|
module_exit(bottomhalf_exit);
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_DESCRIPTION("Interrupt with top and bottom half");
|