2022年10月13日 | mini2440 简单touch screen驱动程序

模块加载后打印出水平和垂直方向的ad转换结果，没有做坐标的转换，只为学习一下touch screen接口的编程方法，代码记录如下：

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

static struct input_dev *ts_dev; //定时器用于处理长按和滑动

static struct ts_regs_t{

unsigned long adccon;

unsigned long adctsc;

unsigned long adcdly;

unsigned long adcdat0;

unsigned long adcdat1;

unsigned long adcupdn;

};

static volatile struct ts_regs_t *ts_regs;

static volatile unsigned long *clkcon;

static struct clk *adc_clk;

static struct timer_list ts_timer;

void enable_adc_clock(void){

(*clkcon) |= (1<<15);

}

void enter_wait4down_mode(void){

ts_regs->adctsc = 0xd3; //等待中断模式，检测触摸屏按下

}

void enter_wait4up_mode(void){

ts_regs->adctsc = 0x1d3; //等待中断模式，检测触摸屏松开

}

//进入测量xy坐标的工作模式

void enter_measure_xy_mode(void){

ts_regs->adctsc = (1<<3)|(1<<2);

}

//启动ac转换

void start_adc(void){

ts_regs->adccon |= (1<<0);

}

//adc中断处理函数

static irqreturn_t grh_handle_adc_irq(int irq, void *dev_id){

static int adc_count = 0;

static int xv=0, yv=0;

if(ts_regs->adcdat0 & (1<<15)){

enter_wait4down_mode();

adc_count = 0;

xv = yv = 0;

}

else{ //多次取值取平均值

if(adc_count == 4){

printk(KERN_EMERG"count=%d x=%d y=%dr", adc_count, xv>>2, yv>>2);

//上报事件

input_report_abs(ts_dev, ABS_X, xv>>2);

input_report_abs(ts_dev, ABS_Y, yv>>2);

input_report_abs(ts_dev, ABS_PRESSURE, 1);

input_report_key(ts_dev, BTN_TOUCH, 1);

input_sync(ts_dev);

adc_count = 0;

xv = yv = 0;

enter_wait4up_mode();

mod_timer(&ts_timer, jiffies+HZ/100); //10ms

}

else{

adc_count ++;

xv += (ts_regs->adcdat0)&0x3ff;

yv += (ts_regs->adcdat1)&0x3ff;

enter_measure_xy_mode();

start_adc();

}

}

return IRQ_HANDLED;

}

//tc中断处理函数

static irqreturn_t grh_handle_tc_irq(int irq, void *dev_id){

if(ts_regs->adcdat0 & (1<<15)){

//printk(KERN_EMERG"pen up!n");

enter_wait4down_mode();

}

else{

//printk(KERN_EMERG"pen downn");

//enter_wait4up_mode();

enter_measure_xy_mode();

start_adc();

}

return IRQ_HANDLED;

}

//定时器超时处理函数

static void grh_handle_timer_int(unsigned long num){

if(ts_regs->adcdat0 & (1<<15)){

//上报事件

input_report_abs(ts_dev, ABS_PRESSURE, 0);

input_report_key(ts_dev, BTN_TOUCH, 0);

input_sync(ts_dev);

enter_wait4down_mode();

}

else{

enter_measure_xy_mode();

start_adc();

}

}

static int ts_init(void){ 

ts_dev = input_allocate_device();

//设置能够产生哪些事件

set_bit(EV_KEY, ts_dev->evbit);

set_bit(EV_ABS, ts_dev->evbit);

set_bit(BTN_TOUCH, ts_dev->keybit); /*触摸屏按键事件*/

input_set_abs_params(ts_dev, ABS_X, 0, 0x3ff, 0, 0); /*设置绝对位移取值范围*/

input_set_abs_params(ts_dev, ABS_Y, 0, 0x3ff, 0, 0); /*设置绝对位移取值范围*/

input_set_abs_params(ts_dev, ABS_PRESSURE, 0, 1, 0, 0); /*设置压力的取值范围，只有0和1*/

/*注册*/

input_register_device(ts_dev);

//ioremap

ts_regs = ioremap(0x58000000, sizeof(struct ts_regs_t));

clkcon = ioremap(0x4C00000C, 4);

//使能时钟，使得adc可以正常工作

adc_clk = clk_get(NULL, "adc");

    if (!adc_clk) {  

        printk(KERN_ERR "failed to get adc clock sourcen");  

        return -ENOENT;  

    }  

    clk_enable(adc_clk);

/*

bit[14] PRESCEN=1 使能预分频

bit[13:6] PRESCVL=49 预分频数值为49(pclk=50.625M) adcclk = 50.625M/50=1.0125MHz

bit[2] STDBM=0 不进入等待模式

bit[1] READ_START=0

bit[0] ENABLE_START=0

*/

ts_regs->adccon = (1<<14)|(49<<6);

ts_regs->adcdly = 0xffff; //设定延时，保证数据的准确性

//注册中断

if( request_irq(IRQ_TC, grh_handle_tc_irq, IRQF_SAMPLE_RANDOM, "irq_tc", ts_dev) ){

printk(KERN_EMERG"allocate IRQ_TC error!n");

return -EIO;

}

if( request_irq(IRQ_ADC, grh_handle_adc_irq, IRQF_SHARED|IRQF_SAMPLE_RANDOM, "irq_adc", ts_dev) ){

printk(KERN_EMERG"allocate IRQ_ADC error!n");

return -EIO;

}

init_timer(&ts_timer);

ts_timer.function = grh_handle_timer_int;

add_timer(&ts_timer);

enter_wait4down_mode();//等待中断模式，检测触摸屏按下

return 0;

}

static void ts_exit(void){

iounmap(ts_regs);

iounmap(clkcon);

free_irq(IRQ_TC, ts_dev);

free_irq(IRQ_ADC, ts_dev);

input_unregister_device(ts_dev);

input_free_device(ts_dev);

del_timer(&ts_timer);

}

module_init(ts_init);

module_exit(ts_exit);

MODULE_AUTHOR("GRH");

MODULE_VERSION("1.0");

MODULE_DESCRIPTION("TOUCH SCREEN DRIVER");

MODULE_LICENSE("GPL");