触摸屏驱动－2.用input子系统报告事件

插入生成的ko文件后，会生成文件/dev/event0。

手指在触摸屏压下或抬起时，LED亮或灭，执行命令"read_ts /dev/event0"可在终端打印触摸屏的状态。

驱动代码如下：

#include <linux/module.h>
#include <linux/init.h>

#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/input.h>

#include <asm/io.h>
#include <asm/arch/regs-gpio.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("zhanglong");

struct touchscreen {
    unsigned long adccon,
                    adctsc,
                    adcdly,
                    adcdat0,
                    adcdat1,
                    adcupdn;
    struct clk *ts_clk;

    int down;

    void (*wait4irq)(struct touchscreen *, int); //set ts in wait-for-irq mode

    int (*isdown)(struct touchscreen *); //check stylus down or not

    
    struct input_dev dev;
};

unsigned long ts_virt;
struct touchscreen s3c2440_ts;

void s3c2440_ts_wait4irq(struct touchscreen *ts, int down)
{
    if (down) {
        iowrite32( 0x3 | ( 1 << 4) | ( 1 << 6) | (1 << 7) , ts->adctsc);
    } else {
        iowrite32( 0x3 | ( 1 << 4) | ( 1 << 6) | (1 << 7) | (1 << 8) , ts->adctsc);
    }
}

int s3c2440_ts_isdown(struct touchscreen *ts)
{
    int down;
    down = ioread32(ts->adcupdn);
    iowrite32(0, ts->adcupdn);

    return (down & 1);
}

irqreturn_t s3c2440_tstc_handle(int irq, struct touchscreen *ts)
{
    if(IRQ_TC == irq)
    {
        if(ts->isdown(ts))
        { //stylus down

            ts->wait4irq(ts, 0);
            input_report_abs(&ts->dev, ABS_PRESSURE, 1);
            s3c2410_gpio_setpin(S3C2410_GPF4, 0); //LED on

        }
        else
        { //stylus up

            ts->wait4irq(ts, 1);
            input_report_abs(&ts->dev, ABS_PRESSURE, 0);
            input_sync(&ts->dev);
            s3c2410_gpio_setpin(S3C2410_GPF4, 1); //LED off

        }
    }
    
    return IRQ_HANDLED;
}

int test_init(void)
{
    int ret;

    ret = request_mem_region(0x58000000, 0x1000, "s3c2440-ts");
    if(NULL == ret)
    {
        printk("request_mem_region failed .\n");
        ret = -EBUSY;
        goto err0;
    }

    ts_virt = ioremap(0x58000000, 0x1000);

    s3c2440_ts.down = 0;
    s3c2440_ts.adccon = ts_virt;
    s3c2440_ts.adctsc = ts_virt + 0x04;
    s3c2440_ts.adcdly = ts_virt + 0x08;
    s3c2440_ts.adcdat0 = ts_virt + 0x0c;
    s3c2440_ts.adcdat1 = ts_virt + 0x10;
    s3c2440_ts.adcupdn = ts_virt + 0x14;

    //---

    s3c2440_ts.wait4irq = s3c2440_ts_wait4irq;
    s3c2440_ts.isdown = s3c2440_ts_isdown;

    ret = request_irq(IRQ_TC, s3c2440_tstc_handle, 0, "s3c2440-ts", &s3c2440_ts);
    if(0 != ret)
    {
        printk("request irq[1] failed .\n");
        ret = -EBUSY;
        goto err1;
    }

    s3c2440_ts.ts_clk = clk_get(NULL, "adc");
    clk_use(s3c2440_ts.ts_clk);
    clk_enable(s3c2440_ts.ts_clk);

    s3c2440_ts.wait4irq(&s3c2440_ts, 1);

    s3c2440_ts.dev.evbit[0] = BIT(EV_ABS) | BIT(EV_SYN);
    input_set_abs_params(&s3c2440_ts.dev, ABS_PRESSURE, 0, 1, 0, 0);

    input_register_device(&s3c2440_ts.dev);


    return 0;

err1:
    iounmap(ts_virt);
    release_mem_region(0x58000000, 0x1000);
err0:
    return ret;
}

void test_exit(void)
{
    input_unregister_device(&s3c2440_ts.dev);
    free_irq(IRQ_TC, &s3c2440_ts);
    clk_disable(s3c2440_ts.ts_clk);
    clk_unuse(s3c2440_ts.ts_clk);
    clk_put(s3c2440_ts.ts_clk);
    iounmap(ts_virt);
    release_mem_region(0x58000000, 0x1000);
}

module_init(test_init);
module_exit(test_exit);

应用测试文件read_ts.c代码如下：

#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <linux/input.h>

int main(int argc, char **argv)
{
    int fd;
    struct input_event evt;

    if (argc < 2) {
        printf("Usage: %s \n", argv[0]);    
        return 0;
    }

    fd = open(argv[1], O_RDWR);
    if (fd < 0) {
        perror("open failed.\n");
        return 0;
    }
                
    while(1) {
        read(fd, &evt, sizeof(struct input_event));        

        switch(evt.type) {
            case EV_ABS:
            printf("touch screen: ");
            if (evt.code == ABS_X) {
                printf("X: %d\n", evt.value);
            } else if (evt.code == ABS_Y) {
                printf("Y: %d\n", evt.value);
            } else if (evt.code == ABS_PRESSURE) {
                char *s;
                s = evt.value == 0 ? "up\n" : "down\n";
                printf(s);
            }
            break;

            case EV_SYN:
            printf("-------------------------\n");
            break;
        }        
    }
    close(fd);
    return 0;
}