arm linux设备驱 2010-04-1016:03:45 阅读331 评论2 字号：大中小 订阅
//短短两百余行程序颇具玄机，在光标抬起后的处理中尤其值得推敲。
#include<linux/errno.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/init.h>
#include <linux/serio.h>
#include <linux/delay.h>
#include<linux/platform_device.h>
#include <linux/clk.h>
#include <asm/io.h>
#include <asm/irq.h>
#include<plat/regs-adc.h>
#include<mach/regs-gpio.h>
#define S3C2410TSVERSION 0x0101
//x为0时为等待按下中断，x为1是为等待抬起中断
#define WAIT4INT(x) (((x)<<8) | \
S3C2410_ADCTSC_YM_SEN | S3C2410_ADCTSC_YP_SEN |S3C2410_ADCTSC_XP_SEN | \
S3C2410_ADCTSC_XY_PST(3))
//自动连续测量X坐标和Y坐标
#defineAUTOPST (S3C2410_ADCTSC_YM_SEN | S3C2410_ADCTSC_YP_SEN |S3C2410_ADCTSC_XP_SEN | \
S3C2410_ADCTSC_AUTO_PST | S3C2410_ADCTSC_XY_PST(0))
//设备名
static char *tq2440ts_name = "TQ2440 TouchScreen";
static structinput_dev *dev;//
static long xp;
static long yp;
static int count;
extern structsemaphore ADC_LOCK;//申明一信号量该信号量在其他文件中定义
//该标志在按下中断处理函数中置1，抬起处理函数中置0，在AD转换结束中断处理函数中判断，
//如果为1则读取AD转换的数字，如果为0则什么也不做。
static int OwnADC = 0;
//寄存器基地址
static void __iomem *base_addr;
//管脚配置
static inline void tq2440_ts_connect(void)
{
s3c2410_gpio_cfgpin(S3C2410_GPG12,S3C2410_GPG12_XMON);
s3c2410_gpio_cfgpin(S3C2410_GPG13,S3C2410_GPG13_nXPON);
s3c2410_gpio_cfgpin(S3C2410_GPG14,S3C2410_GPG14_YMON);
s3c2410_gpio_cfgpin(S3C2410_GPG15,S3C2410_GPG15_nYPON);
}
//定时器定时时间到处理函数，该函数在按下抬起中断处理函数中直接调用，
//在AD转换结束中断处理函数中触发定时器经延时后被调用
static void touch_timer_fire(unsigned long data)
{
unsigned long data0;
unsigned long data1;
int updown;
data0 =ioread32(base_addr+S3C2410_ADCDAT0);
data1 =ioread32(base_addr+S3C2410_ADCDAT1);
//updown为1则被按下，为0则为抬起
updown = (!(data0 & S3C2410_ADCDAT0_UPDOWN))&& (!(data1 &S3C2410_ADCDAT0_UPDOWN));
if(updown) {//按下中断执行以下语句
if (count !=0)
{
longtmp;
tmp =xp;
xp =yp;
yp =tmp;
xp >>= 2;//四次AD转换求平均值
yp >>= 2;
input_report_abs(dev,ABS_X, xp);
input_report_abs(dev,ABS_Y, yp);//将x，y的值发向用户空间
input_report_key(dev,BTN_TOUCH, 1);//报告光标按下事件
input_report_abs(dev,ABS_PRESSURE, 1);
input_sync(dev);//表示报告结束
}
xp = 0;
yp = 0;
count =0;
//每次按下有四次AD转换，以下为在按下中断中触发的第一次AD转换，其余三次在AD转换中断处理函数中触发
iowrite32(S3C2410_ADCTSC_PULL_UP_DISABLE| AUTOPST, base_addr+S3C2410_ADCTSC);
iowrite32(ioread32(base_addr+S3C2410_ADCCON)| S3C2410_ADCCON_ENABLE_START, base_addr+S3C2410_ADCCON);
}
else
{
count =0;
input_report_key(dev,BTN_TOUCH, 0);//向用户空间报告光标抬起事件
input_report_abs(dev,ABS_PRESSURE, 0);
input_sync(dev);//报告结束
iowrite32(WAIT4INT(0),base_addr+S3C2410_ADCTSC);//置于按下中断等待状态
if(OwnADC)//如果抬起中断函数执行则此处不执行
{
OwnADC =0;
up(&ADC_LOCK);
}
}
}
static structtimer_list touch_timer =//定义一内核定时器
TIMER_INITIALIZER(touch_timer_fire,0, 0);//初始化定时器赋予处理函数touch_timer_fire
//光标按下抬起抬起中断处理函数
static irqreturn_t stylus_updown(int irq, void *dev_id)
{
unsigned long data0;
unsigned long data1;
int updown;
if(down_trylock(&ADC_LOCK) == 0)//获取信号量，在抬起处理函数中释放
{
OwnADC =1;//该标志置1表示处于光标按下状态中，在光标抬起处理函数中清零
data0 =ioread32(base_addr+S3C2410_ADCDAT0);
data1 =ioread32(base_addr+S3C2410_ADCDAT1);
updown= (!(data0 &S3C2410_ADCDAT0_UPDOWN)) &&(!(data1 &S3C2410_ADCDAT0_UPDOWN));
if(updown)
{
touch_timer_fire(0);//若为光标按下中断则调用该函数
}
else//光标抬起时执行的语句
{
OwnADC =0;//清零
up(&ADC_LOCK);//释放信号量
}
}
returnIRQ_HANDLED;//////
}
///AD转换结束中断处理函数
static irqreturn_t stylus_action(int irq, void *dev_id)
{
unsigned long data0;
unsigned long data1;
if(OwnADC)//OwnADC为1表示现在处于光标按下中断中
{
data0 =ioread32(base_addr+S3C2410_ADCDAT0);
data1 =ioread32(base_addr+S3C2410_ADCDAT1);
xp+= data0 &S3C2410_ADCDAT0_XPDATA_MASK;
yp += data1 &S3C2410_ADCDAT1_YPDATA_MASK;
count++;
if(count <(1<<2))//四次AD转换，将四次转换值相加求平均值
{//触发AD转换
iowrite32(S3C2410_ADCTSC_PULL_UP_DISABLE| AUTOPST, base_addr+S3C2410_ADCTSC);
iowrite32(ioread32(base_addr+S3C2410_ADCCON)| S3C2410_ADCCON_ENABLE_START, base_addr+S3C2410_ADCCON);
}
else
{
mod_timer(&touch_timer,jiffies+1);//触发内核定时器
iowrite32(WAIT4INT(1),base_addr+S3C2410_ADCTSC);//将设备置于等待抬起中断状态
}
}
returnIRQ_HANDLED;
}
static structclk *adc_clock;
static int__init tq2440ts_init(void)
{
struct input_dev *input_dev;
adc_clock= clk_get(NULL, "adc");//获取时钟"adc"
if (!adc_clock)
{
printk(KERN_ERR "failed to getadc clock source\n");
return -ENOENT;
}
clk_enable(adc_clock);//使能时钟
//以S3C2410_PA_ADC为起点映射一段IO内存
base_addr=ioremap(S3C2410_PA_ADC,0x20);
if (base_addr == NULL)
{
printk(KERN_ERR "Failed toremap register block\n");
return -ENOMEM;
}
tq2440_ts_connect();//配置管脚
iowrite32(S3C2410_ADCCON_PRSCEN| S3C2410_ADCCON_PRSCVL(0xFF),base_addr+S3C2410_ADCCON);
iowrite32(0xffff, base_addr+S3C2410_ADCDLY);
iowrite32(WAIT4INT(0),base_addr+S3C2410_ADCTSC);//将设备置于等待按下中断状态
input_dev =input_allocate_device();//为输入设备的结构体input_dev分配内存并做相应初始化
if(!input_dev)
{
printk(KERN_ERR "Unable toallocate the input device !!\n");
return -ENOMEM;
}
dev= input_dev;
dev->evbit[0] = BIT(EV_SYN) |BIT(EV_KEY) | BIT(EV_ABS);//设置其支持的事件
dev->keybit[BITS_TO_LONGS(BTN_TOUCH)]= BIT(BTN_TOUCH);//设置支持的keybit
input_set_abs_params(dev, ABS_X, 0, 0x3FF, 0,0);//设置其最大最小值
input_set_abs_params(dev, ABS_Y, 0, 0x3FF, 0,0);
input_set_abs_params(dev, ABS_PRESSURE, 0, 1, 0,0);
dev->name= tq2440ts_name;
dev->id.bustype = BUS_RS232;
dev->id.vendor = 0xDEAD;
dev->id.product = 0xBEEF;
dev->id.version =S3C2410TSVERSION;
//申请AD转换结束中断
if (request_irq(IRQ_ADC, stylus_action, IRQF_SHARED|IRQF_SAMPLE_RANDOM,tq2440ts_name, dev))
{
printk(KERN_ERR "tq2440_ts.c:Could not allocate ts IRQ_ADC !\n");
iounmap(base_addr);
return -EIO;
}//申请按下抬起中断
if (request_irq(IRQ_TC, stylus_updown,IRQF_SAMPLE_RANDOM, tq2440ts_name, dev))
{
printk(KERN_ERR "tq2440_ts.c:Could not allocate ts IRQ_ADC !\n");
iounmap(base_addr);
return -EIO;
}
printk(KERN_INFO"%s successfully loaded\n", tq2440ts_name);
//注册输入设备，在/dev下会产生一个eventn(n为0,1,2。。。。)的设备结点
input_register_device(dev);
return0;
}
static void__exit tq2440ts_exit(void)
{
disable_irq(IRQ_ADC);
disable_irq(IRQ_TC);
free_irq(IRQ_TC,dev);//先禁能中断再释放
free_irq(IRQ_ADC,dev);
if(adc_clock)
{
clk_disable(adc_clock);
clk_put(adc_clock);//先禁能时钟再释放
adc_clock = NULL;
}
input_unregister_device(dev);
iounmap(base_addr);
}
module_init(tq2440ts_init);
module_exit(tq2440ts_exit);
