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");