kobox ： key_waitqueue.c -v1 如何内核线程，如何使用等待队列

平台：TQ2440 按键驱动

（1）在init中创建一个内核线程作为等待队列的处理函数，该内核线程是一个while(1)死循环，一直检測等待队列的触发条件

DECLARE_WAIT_QUEUE_HEAD(key_driver_wq);

/* create a kernel thread */
kthread_run(key_wait_queue_handler, "thread_key_waitqueue", "[key_wait_queue]");

static int key_wait_queue_handler(void *name)
{
	int i = 0;
	int ret;
	unsigned int pin;

	printk("thread name:[%s]\n", name);

	while(1)
	{
		wait_event(key_driver_wq, condition == 1);

		if(condition == 1)
		{
			...
		}

		msleep(100);

		if(condition == 1)
		{
			condition = 0;
		}
	}

	return;
}

（2）中断中调度等待队列

static irqreturn_t kobox_gpio_irq_handle(int irq, void *dev_id)
{
	int key;

	disable_irq_nosync(irq);

	printk("irq = %d\n", irq);

	if(dev_id)
		printk("dev_id:%s\n", dev_id);

	switch(irq)
	{
		case IRQ_EINT1:
			key = 0;
			break;
		case IRQ_EINT4:
			key = 1;
			break;
		case IRQ_EINT2:
			key = 2;
			break;
		case IRQ_EINT0:
			key = 3;
			break;
		default:
			printk("invalid irq:%d\n", irq);
 			return IRQ_HANDLED;
 	}

	/* 去抖:延时100ms后，在buttons_timer中读取按键状态，假设还是按下的，就说明是被正常按下的
		使用timer是一种方式，后面再採用工作队列、tasklet中的方式来处理	*/
	condition = 1;
	wake_up(&key_driver_wq);

	enable_irq(irq);

	return IRQ_RETVAL(IRQ_HANDLED);
}

（3）驱动源代码：

#include "key.h"

#define S3C_ADDR_BASE	0xF6000000
#define S3C_ADDR(x)	(S3C_ADDR_BASE + (x))
#define S3C2410_PA_UART		(0x50000000)
#define S3C2410_PA_GPIO		(0x56000000)
#define S3C_VA_UART	S3C_ADDR(0x01000000)	/* UART */
#define S3C24XX_PA_UART		S3C2410_PA_UART
#define S3C24XX_VA_UART		S3C_VA_UART
#define S3C24XX_PA_GPIO		S3C2410_PA_GPIO
#define S3C24XX_VA_GPIO		((S3C24XX_PA_GPIO - S3C24XX_PA_UART) + S3C24XX_VA_UART)

#define S3C2410_GPIOREG(x) ((x) + S3C24XX_VA_GPIO)

#define S3C2410_GPBCON	   S3C2410_GPIOREG(0x10)
#define S3C2410_GPBDAT	   S3C2410_GPIOREG(0x14)
#define S3C2410_GPBUP	   S3C2410_GPIOREG(0x18)

#define S3C2410_GPFCON	   S3C2410_GPIOREG(0x50)
#define S3C2410_GPFDAT	   S3C2410_GPIOREG(0x54)
#define S3C2410_GPFUP	   S3C2410_GPIOREG(0x58)

#define S3C2410_EXTINT0	   S3C2410_GPIOREG(0x88)
#define S3C2410_EXTINT1	   S3C2410_GPIOREG(0x8C)
#define S3C2410_EXTINT2	   S3C2410_GPIOREG(0x90)

#define S3C2410_CPUIRQ_OFFSET	 (16)
#define S3C2410_IRQ(x) ((x) + S3C2410_CPUIRQ_OFFSET)
/* main cpu interrupts */
#define IRQ_EINT0      S3C2410_IRQ(0)	    /* 16 */
#define IRQ_EINT1      S3C2410_IRQ(1)		/* 17 */
#define IRQ_EINT2      S3C2410_IRQ(2)		/* 18 */
#define IRQ_EINT4t7    S3C2410_IRQ(4)	    /* 20 */
#define IRQ_EINT4      S3C2410_IRQ(36)	   /* 52 */

#define IRQF_DISABLED		0x00000020
#define IRQF_SHARED		0x00000080
#define IRQF_PROBE_SHARED	0x00000100
#define __IRQF_TIMER		0x00000200
#define IRQF_PERCPU		0x00000400
#define IRQF_NOBALANCING	0x00000800
#define IRQF_IRQPOLL		0x00001000
#define IRQF_ONESHOT		0x00002000
#define IRQF_NO_SUSPEND	0x00004000
#define IRQF_FORCE_RESUME	0x00008000
#define IRQF_NO_THREAD		0x00010000
#define IRQF_EARLY_RESUME	0x00020000

typedef struct gpioRes
{
	int irqNum;		/* 中断号 */
	unsigned int ctrlReg;	/* 控制寄存器,用于设置复用为GPIO */
	unsigned int ctrlBit; 	/* 控制寄存器的哪一位，用于复用为GPIO */
	unsigned int trigReg;	/* 中断方式寄存器，设置中断的触发方式 */
	unsigned int trigBit;	/* 中断方式寄存器哪一位，设置中断的触发方式 */
	unsigned int irqFlag;	/* 共享还是不共享，注冊中断的flag */
	char irqName[32];		/* 中断名称 */
	unsigned int gpfPin;	/* GPF的第几个pin */
	char Reserved[10];		/* 保留 */
}gpioRes;

unsigned int pressCnt[4] = {0, 0, 0, 0};

#define ARRAY_SIZE(arr) (sizeof(arr)/sizeof((arr)[0]))

static int kobox_key_open(struct inode *inode, struct file *file)
{
	return 0;
}

static int kobox_key_release(struct inode *inode, struct file *file)
{
	return 0;
}

static long kobox_key_ioctl(struct file *file, unsigned int cmd,
			   unsigned long arg)
{
	return 0;
}

static int kobox_key_read(struct file *file, char __user *buff, size_t count, loff_t *pos)
{
	printk("Enter [%s][%d]\n", __FUNCTION__,__LINE__);
	copy_to_user(buff, &pressCnt[0], sizeof(pressCnt));

	return 0;
}

/*
GPF相关寄存器:

GPFCON 0x56000050 R/W Configures the pins of port F 0x0
GPFDAT 0x56000054 R/W The data register for port F Undef.
GPFUP  0x56000058 R/W Pull-up disable register for port F 0x000

K1: GPF1 -EINT1: GPF1 [3:2] 00 = Input	01 = Output 10 = EINT[1]  11 = Reserved
K2: GPF4 -EINT4: GPF4 [9:8] 00 = Input	01 = Output 10 = EINT[4]  11 = Reserved
K3: GPF2 -EINT2: GPF2 [5:4] 00 = Input	01 = Output 10 = EINT2]  11 = Reserved
K4: GPF0 -EINT0: GPF0 [1:0] 00 = Input	01 = Output 10 = EINT[0]  11 = Reserved
*/

gpioRes key_gpio_res[4] =
{
	{IRQ_EINT1, S3C2410_GPFCON, 2, S3C2410_EXTINT0, 5, NULL, "key1", 1},	/* key1 */
	{IRQ_EINT4, S3C2410_GPFCON, 8, S3C2410_EXTINT0, 17, IRQF_SHARED, "key2", 4},	/* key2 */
	{IRQ_EINT2, S3C2410_GPFCON, 4, S3C2410_EXTINT0, 9, NULL, "key3", 2},	/* key3 */
	{IRQ_EINT0, S3C2410_GPFCON, 0, S3C2410_EXTINT0, 1, NULL, "key4", 0},	/* key4 */
};

#define KEY_TIMER_DELAY1    (HZ/50)             //按键按下去抖延时20毫秒
#define KEY_TIMER_DELAY2    (HZ/10)             //按键抬起去抖延时100毫秒
#define KEY_COUNT 4
//static struct timer_list key_timers[KEY_COUNT];  //定义4个按键去抖动定时器
//static DECLARE_WAIT_QUEUE_HEAD(button_waitq);    //定义并初始化等待队列
static int condition = 0;
DECLARE_WAIT_QUEUE_HEAD(key_driver_wq);
static int key_wait_queue_handler(void *name);

static void set_gpio_as_eint(void)
{
	int i;
	unsigned uiVal = 0;

	for(i=0; i<	ARRAY_SIZE(key_gpio_res); i++)
	{
		uiVal = readl(key_gpio_res[i].ctrlReg);
		uiVal &= ~(0x01 << key_gpio_res[i].ctrlBit);
		uiVal |= (0x01 << (key_gpio_res[i].ctrlBit + 1));
		writel(uiVal, key_gpio_res[i].ctrlReg);
	}

	return;
}

static void set_gpio_as_gpio(void)
{
	int i;
	unsigned uiVal = 0;

	for(i=0; i<	ARRAY_SIZE(key_gpio_res); i++)
	{
		uiVal = readl(key_gpio_res[i].ctrlReg);
		uiVal &= ~(0x01 << key_gpio_res[i].ctrlBit);
		uiVal &= ~(0x01 << (key_gpio_res[i].ctrlBit + 1));
		writel(uiVal, key_gpio_res[i].ctrlReg);
	}

	return;
}

static irqreturn_t kobox_gpio_irq_handle(int irq, void *dev_id)
{
	int key;

	disable_irq_nosync(irq);

	printk("irq = %d\n", irq);

	if(dev_id)
		printk("dev_id:%s\n", dev_id);

	switch(irq)
	{
		case IRQ_EINT1:
			key = 0;
			break;
		case IRQ_EINT4:
			key = 1;
			break;
		case IRQ_EINT2:
			key = 2;
			break;
		case IRQ_EINT0:
			key = 3;
			break;
		default:
			printk("invalid irq:%d\n", irq);
 			return IRQ_HANDLED;
 	}

	/* 去抖:延时100ms后，在buttons_timer中读取按键状态，假设还是按下的，就说明是被正常按下的
		使用timer是一种方式，后面再採用工作队列、tasklet中的方式来处理	*/
	condition = 1;
	wake_up(&key_driver_wq);

	enable_irq(irq);

	return IRQ_RETVAL(IRQ_HANDLED);
}

/*
GPF相关寄存器:

GPFCON 0x56000050 R/W Configures the pins of port F 0x0
GPFDAT 0x56000054 R/W The data register for port F Undef.
GPFUP  0x56000058 R/W Pull-up disable register for port F 0x000

K1: GPF1 -EINT1: GPF1 [3:2] 00 = Input	01 = Output 10 = EINT[1]  11 = Reserved
K2: GPF4 -EINT4: GPF4 [9:8] 00 = Input	01 = Output 10 = EINT[4]  11 = Reserved
K3: GPF2 -EINT2: GPF2 [5:4] 00 = Input	01 = Output 10 = EINT2]  11 = Reserved
K4: GPF0 -EINT0: GPF0 [1:0] 00 = Input	01 = Output 10 = EINT[0]  11 = Reserved
*/
/* 该函数返回0表示按键被按下，返回非0表示没有再被按下，觉得这是电平毛刺导致的，是噪声信号
	所以，该函数返回0，表示有按键被按下，返回非0表示是抖动	*/
static int get_gpio_portf_value(unsigned int pin)
{
	int ret;
	unsigned int uiVal = 0;

	printk("I AM @ [%s][%d], pin:%d\n", __FUNCTION__,__LINE__, pin);	

	uiVal = readl(S3C2410_GPFDAT);
	ret = (0x1 << pin) & uiVal;

	printk("I AM @ [%s][%d], ret:%d\n", __FUNCTION__,__LINE__, ret);	

	return ret;
}

static int request_irq_for_gpio(void)
{
	int i;
	int ret;
	unsigned uiVal;
	int nouse;

	for(i=0; i<ARRAY_SIZE(key_gpio_res);i++)
	{
		/* 设置中断触发方式:下降沿有效，触发中断，以便依据GPIO的值来推断是否仍在按下 */
		uiVal = readl(key_gpio_res[i].trigReg);
		uiVal |= (0x1 << (key_gpio_res[i].trigBit));
		uiVal &= ~(0x1 << (key_gpio_res[i].trigBit + 1));
		writel(uiVal, key_gpio_res[i].trigReg);

		/* 注冊中断 */
		ret = request_irq(key_gpio_res[i].irqNum,
						   kobox_gpio_irq_handle,
						   key_gpio_res[i].irqFlag,
						   key_gpio_res[i].irqName,
						   (void *)key_gpio_res[i].irqName);
		if(ret)
			printk("[func:%s][line:%d] request_irq failed, ret:%d!\n", __FUNCTION__,__LINE__,ret);
		else
			printk("[func:%s][line:%d] request_irq ok, irq:%d!\n", __FUNCTION__,__LINE__, key_gpio_res[i].irqNum);
	}

	return 0;
}

static int key_wait_queue_handler(void *name)
{
	int i = 0;
	int ret;
	unsigned int pin;

	printk("thread name:[%s]\n", name);

	while(1)
	{
		wait_event(key_driver_wq, condition == 1);

		if(condition == 1)
		{
			/* 将引脚由EINTX设置会GPIO */
			set_gpio_as_gpio();

			for(i=0; i<ARRAY_SIZE(key_gpio_res); i++)
			{
				pin = key_gpio_res[i].gpfPin;

				/* 读取相应引脚GPIO的值，返回0表示按键真正被按下，返回1表示抖动 */
				ret = get_gpio_portf_value(pin);
				if(0 == ret)
				{
					pressCnt[i]++;
					printk("key pressed: pressCnt[%d]:%d\n", i, pressCnt[i]);
				}
			}
			/* 将引脚设置回EINTX */
			set_gpio_as_eint();

			condition = 0;
		}

		msleep(1000);
	}

	return;
}

struct file_operations kobox_key_operations = {
	.owner          = THIS_MODULE,
	.open           = kobox_key_open,
	.read 			= kobox_key_read,
	.release        = kobox_key_release,
	.unlocked_ioctl = kobox_key_ioctl,
};

//GPB0
int major;
int minor;
struct cdev cdev;
struct class *kobox_key_class;
struct device *pstdev = NULL;
#define GPIO_KEY_NAME "kobox_key"

int __init key_drv_init(void)
{
	int error;
	dev_t dev;

	printk("#####enter key_drv_init!\n");

	major = register_chrdev(0, GPIO_KEY_NAME, &kobox_key_operations);
	if (major < 0)
	{
		printk(" can't register major number\n");
		return major;
	}

	/* create class */
	kobox_key_class = class_create(THIS_MODULE, GPIO_KEY_NAME);
	if(IS_ERR(kobox_key_class))
	{
		printk("class_create failed!\n");
		goto fail;
	}

	/* create /dev/kobox_gpio */
	pstdev = device_create(kobox_key_class, NULL, MKDEV(major, 0), NULL, GPIO_KEY_NAME);
	if(!pstdev)
	{
		printk("device_create failed!\n");
		goto fail1;
	}

	/* set gpf0/1/2/4 as extern interrupt pins */
	set_gpio_as_eint();

	request_irq_for_gpio();

	/* create a kernel thread */
	kthread_run(key_wait_queue_handler, "thread_key_waitqueue", "[key_wait_queue]");

	printk("#####key_drv_init ok!\n");

	return 0;
fail1:
	class_destroy(kobox_key_class);
fail:
	unregister_chrdev(major, GPIO_KEY_NAME);
	return -1;
}

void __exit key_drv_exit(void)
{
	printk("exit gpio drv!\n");	

	device_destroy(kobox_key_class, MKDEV(major, 0));
	class_destroy(kobox_key_class);
	unregister_chrdev(major, GPIO_KEY_NAME);

	return;
}

module_init(key_drv_init);
module_exit(key_drv_exit);
MODULE_LICENSE("GPL");