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");