一、触摸屏驱动分析
- static int __init tq2440ts_init(void)
- {
- struct input_dev *input_dev;
-
- adc_clock = clk_get(NULL, "adc");
- if (!adc_clock)
- {
- printk(KERN_ERR "failed to get adc clock source\n");
- return -ENOENT;
- }
- clk_enable(adc_clock); //使能ADC时钟
-
- base_addr=ioremap(S3C2410_PA_ADC,0x20); //将物理基地址转化成虚拟地址
- if (base_addr == NULL)
- {
- printk(KERN_ERR "Failed to remap register block\n");
- return -ENOMEM;
- }
-
- /* Configure GPIOs */
- // tq2440_ts_connect();
-
- iowrite32(S3C2410_ADCCON_PRSCEN | S3C2410_ADCCON_PRSCVL(0xFF),base_addr+S3C2410_ADCCON); //设置寄存器
- iowrite32(0xffff, base_addr+S3C2410_ADCDLY);
- iowrite32(WAIT4INT(0), base_addr+S3C2410_ADCTSC);
-
- /* Initialise input stuff */
- input_dev = input_allocate_device(); //分配输入设备
-
- if (!input_dev)
- {
- printk(KERN_ERR "Unable to allocate the input device !!\n");
- return -ENOMEM;
- }
-
- dev = input_dev;
- dev->evbit[0] = BIT(EV_SYN) | BIT(EV_KEY) | BIT(EV_ABS); //设置可能的上报事件（同步信息）（按键信息）（abs是坐标）
- dev->keybit[BITS_TO_LONGS(BTN_TOUCH)] = BIT(BTN_TOUCH);
- input_set_abs_params(dev, ABS_X, 0, 0x3FF, 0, 0);
- 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; //填充一些设备信息
- dev->id.bustype = BUS_RS232;
- dev->id.vendor = 0xDEAD;
- dev->id.product = 0xBEEF;
- dev->id.version = S3C2410TSVERSION;
-
- if (request_irq(IRQ_ADC, stylus_action, IRQF_SHARED|IRQF_SAMPLE_RANDOM, tq2440ts_name, dev)) //注册ADC中断处理程序
- {
- printk(KERN_ERR "tq2440_ts.c: Could not allocate ts IRQ_ADC !\n");
- iounmap(base_addr);
- return -EIO;
- }
- if (request_irq(IRQ_TC, stylus_updown, IRQF_SAMPLE_RANDOM, tq2440ts_name, dev)) //注册TOUCH_SCREEN中断
- {
- 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);
-
- input_register_device(dev); //注册输入型设备
-
- return 0;
- }
在手按下触摸屏时，会触发TC中断，stylus_updown:
- static irqreturn_t stylus_updown(int irq, void *dev_id)
- {
- unsigned long data0;
- unsigned long data1;
- int updown;
-
- if (down_trylock(&ADC_LOCK) == 0) //通过锁保护起来
- {
- OwnADC = 1;
- data0 = ioread32(base_addr+S3C2410_ADCDAT0); //读取寄存器
- data1 = ioread32(base_addr+S3C2410_ADCDAT1);
-
- updown = (!(data0 & S3C2410_ADCDAT0_UPDOWN)) && (!(data1 & S3C2410_ADCDAT0_UPDOWN)); //判断按下还是弹起
-
- if (updown) //按下
- {
- touch_timer_fire(0); //采样
- }
- else
- {
- OwnADC = 0;
- up(&ADC_LOCK); //释放锁
- }
- }
-
- return IRQ_HANDLED;
- }
touch_timer_fire():
- 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 = (!(data0 & S3C2410_ADCDAT0_UPDOWN)) && (!(data1 & S3C2410_ADCDAT0_UPDOWN));
-
- if (updown) {
- if (count != 0) //如果count不是0，4次AD转换后进入
- {
- long tmp;
-
- tmp = xp;
- xp = yp;
- yp = tmp;
-
- xp >>= 2; //这是取平均值
- yp >>= 2;
-
- input_report_abs(dev, ABS_X, xp); //可以上报XY坐标了
- input_report_abs(dev, ABS_Y, yp);
-
- input_report_key(dev, BTN_TOUCH, 1); //上报按键
- input_report_abs(dev, ABS_PRESSURE, 1); //上报ABS按下
- input_sync(dev); //上报结束
- }
-
- xp = 0;
- yp = 0;
- count = 0;
-
- iowrite32(S3C2410_ADCTSC_PULL_UP_DISABLE | AUTOPST, base_addr+S3C2410_ADCTSC); //启动xy转换
- iowrite32(ioread32(base_addr+S3C2410_ADCCON) | S3C2410_ADCCON_ENABLE_START, base_addr+S3C2410_ADCCON);
- }
- else
- {
- count = 0;
-
- input_report_key(dev, BTN_TOUCH, 0);
- input_report_abs(dev, ABS_PRESSURE, 0);
- input_sync(dev);
-
- iowrite32(WAIT4INT(0), base_addr+S3C2410_ADCTSC);
- if (OwnADC)
- {
- OwnADC = 0;
- up(&ADC_LOCK);
- }
- }
- }
调用adc中断(stylus_action)：
- static irqreturn_t stylus_action(int irq, void *dev_id)
- {
- unsigned long data0;
- unsigned long data1;
-
- if (OwnADC)
- {
- data0 = ioread32(base_addr+S3C2410_ADCDAT0);
- data1 = ioread32(base_addr+S3C2410_ADCDAT1);
-
- xp += data0 & S3C2410_ADCDAT0_XPDATA_MASK; //获取X、Y坐标
- yp += data1 & S3C2410_ADCDAT1_YPDATA_MASK;
- count++;
-
- if (count < (1<<2)) //count<4,意味着获取了4次
- {
- 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); //启动内核定时器，1个时间就调用touch_timer
- iowrite32(WAIT4INT(1), base_addr+S3C2410_ADCTSC);
- }
- }
-
- return IRQ_HANDLED;
- }
touch_timer:
- static struct timer_list touch_timer =
- TIMER_INITIALIZER(touch_timer_fire, 0, 0); //又调用了touch_timer_fire,不过此时count是4了
二、触摸屏驱动编程 - 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 = (!(data0 & S3C2410_ADCDAT0_UPDOWN)) && (!(data1 & S3C2410_ADCDAT0_UPDOWN));
-
- if (updown) {
- if(count != 0)
- {
- long tmp;
- /*交换XY坐标*/
- tmp = xp;
- xp = yp;
- yp = tmp;
- /*除以4*/
- xp >>= 2;
- yp >>= 2;
- /*上报XY坐标*/
- input_report_abs(dev, ABS_X, xp);
- input_report_abs(dev, ABS_Y, yp);
-
- input_report_key(dev, BTN_TOUCH, 1);
- input_report_abs(dev, ABS_PRESSURE, 1);
- input_sync(dev);
-
- printk("x=%d,y=%d\n",xp,yp);
- }
-
- xp = 0;
- yp = 0;
-
- count = 0;
- /*1.启动自动转换*/
- iowrite32(1<<2, base_addr+S3C2410_ADCTSC);
- iowrite32((ioread32(base_addr+S3C2410_ADCCON)|1<<0), base_addr+S3C2410_ADCCON);
-
- }
- else
- {
- count = 0;
-
- input_report_key(dev, BTN_TOUCH, 0);
- input_report_abs(dev, ABS_PRESSURE, 0);
- input_sync(dev);
-
- iowrite32(WAIT4INT(0), base_addr+S3C2410_ADCTSC);
- if (OwnADC)
- {
- OwnADC = 0;
- up(&ADC_LOCK);
- }
- }
- }