加载TS驱动2里面的驱动后,发现同一点的x轴和y轴坐标变化太大,需要优化
主要有以下几种优化方法:
1.设置ADCDLY寄存器的bit0-15为最大值, 是延时最长,这使得电压稳定后再发出IRQ_PENDN中断
2.在ADC中断服务函数中,如果ADC完成时, 发现触摸笔已经松开, 则丢弃此次结果
3.多次测量求平均值
4.软件过滤
代码如下
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/input.h>
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#include <linux/init.h>
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#include <linux/serio.h>
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#include <linux/delay.h>
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#include <linux/platform_device.h>
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#include <linux/clk.h>
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#include <asm/io.h>
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#include <asm/irq.h>
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#include <mach/hardware.h>
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#include <plat/regs-adc.h>
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#include <mach/ts.h>
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#include <mach/irqs.h>
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struct ts_regs{
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unsigned long adccon;
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unsigned long adctsc;
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unsigned long adcdly;
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unsigned long adcdat0;
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unsigned long adcdat1;
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unsigned long adcupdn;
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unsigned long adcclrint;
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unsigned long reserverd;
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unsigned long adcclrintpndnup;
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};
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static volatile struct ts_regs *ts_regs;
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static struct input_dev *ts_dev;
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static void enter_wait_pen_down_mode(void)//等待中断模式
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{
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ts_regs->adctsc = 0xd3;//adctsc寄存器的bit-8为0时,Detect Stylus Down Interrupt Signal
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}
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static void enter_wait_pen_up_mode(void)//等待中断模式
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{
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ts_regs->adctsc = 0x1d3;//adctsc寄存器的bit-8为1时,Detect Stylus Up Interrupt Signal
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}
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static void enter_measure_xy_mode(void)//自动测量x/y座标模式
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{
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ts_regs->adctsc = (1<<3)|(1<<2);
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}
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static void start_adc(void)//启动ADC
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{
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ts_regs->adccon |= (1<<0);
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}
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static int s3c_filter_ts(int x[], int y[])/* 优化措施4: 软件过滤函数 */
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{
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#define ERR_LIMIT 70
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int avr_x, avr_y;
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int det_x, det_y;
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avr_x = (x[0] + x[1])/2;
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avr_y = (y[0] + y[1])/2;
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det_x = (x[2] > avr_x) ? (x[2] - avr_x) : (avr_x - x[2]);
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det_y = (y[2] > avr_y) ? (y[2] - avr_y) : (avr_y - y[2]);
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if ((det_x > ERR_LIMIT) || (det_y > ERR_LIMIT))
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return 0;
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avr_x = (x[1] + x[2])/2;
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avr_y = (y[1] + y[2])/2;
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det_x = (x[3] > avr_x) ? (x[3] - avr_x) : (avr_x - x[3]);
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det_y = (y[3] > avr_y) ? (y[3] - avr_y) : (avr_y - y[3]);
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if ((det_x > ERR_LIMIT) || (det_y > ERR_LIMIT))
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return 0;
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return 1;
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}
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static irqreturn_t pen_down_up_irq(int irq, void *dev_id)
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{
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if (ts_regs->adcdat0 & (1<<15))//如果寄存器adcdat0的bit-15值为1,说明触摸笔松开
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{
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printk("pen up\n");
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enter_wait_pen_down_mode();//Detect Stylus Down Interrupt Signal,检查触笔落下中断
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}
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else
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{
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printk("pen down\n");
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//enter_wait_pen_up_mode();//Detect Stylus Up Interrupt Signal,检查触笔松开中断
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enter_measure_xy_mode();/* 进入"自动测量x/y座标模式" */
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start_adc();/* 启动ADC */
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}
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ts_regs->adcupdn = 0;//Stylus Up/Down Interrupt history. (After check, this bit should be cleared manually)
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ts_regs->adcclrint = 1;// 产生adc中断后要清除adc中断,给寄存器adcclrint赋任意值都能清除adc中断
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ts_regs->adcclrintpndnup = 1;// 产生up/down中断后要清除up/down中断,给寄存器adcclrintpndnup赋任意值都能清除up/down中断
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return IRQ_HANDLED;
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}
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static irqreturn_t adc_irq(int irq, void *dev_id)
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{
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static int cnt = 0;
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static int x[4], y[4];
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int adcdat0,adcdat1;
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adcdat0 = ts_regs->adcdat0;
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adcdat1 = ts_regs->adcdat1;
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/* 优化措施2: 如果ADC完成时, 发现触摸笔已经松开, 则丢弃此次结果 */
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if (ts_regs->adcdat0 & (1<<15))//如果触摸笔松开
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{
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enter_wait_pen_down_mode();//丢弃结果,等待触摸笔按下
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}
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else
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{
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/* 优化措施3: 多次测量求平均值 */
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x[cnt] = adcdat0 & 0xfff;
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y[cnt] = adcdat1 & 0xfff;
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++cnt;
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if (cnt == 4)//测量到四次结果后,打印出平均值
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{
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if (s3c_filter_ts(x, y))/* 优化措施4: 软件过滤 */
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printk("x = %d, y = %d\n", (x[0]+x[1]+x[2]+x[3])/4, (y[0]+y[1]+y[2]+y[3])/4);
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cnt = 0;
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enter_wait_pen_up_mode();//Detect Stylus Up Interrupt Signal,检查触笔松开中断
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}
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else//没有测量到四次结果,再次启动ADC继续测量
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{
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enter_measure_xy_mode();/* 进入"自动测量x/y座标模式" */
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start_adc();/* 启动ADC */
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}
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}
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ts_regs->adcupdn = 0;//Stylus Up/Down Interrupt history. (After check, this bit should be cleared manually)
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ts_regs->adcclrint = 1 ;// 产生adc中断后要清除adc中断,给寄存器adcclrint赋任意值都能清除adc中断
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ts_regs->adcclrintpndnup = 1;// 产生up/down中断后要清除up/down中断,给寄存器adcclrintpndnup赋任意值都能清除up/down中断
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return IRQ_HANDLED;
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}
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static int ts_init(void)
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{
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struct clk *clk;
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/* 1. 分配input_dev */
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ts_dev = input_allocate_device();
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/* 2. 设置 */
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/* 2.1 能产生哪类事件 */
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set_bit(EV_KEY, ts_dev->evbit);//能产生按键类事件
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set_bit(EV_ABS, ts_dev->evbit);//能产生绝对位移事件
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/* 2.2 能产生这类事件里的哪些事件 */
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set_bit(BTN_TOUCH, ts_dev->keybit);//能产生按键类里面的触摸屏事件
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input_set_abs_params(ts_dev, ABS_X, 0, 0xFFF, 0, 0);
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input_set_abs_params(ts_dev, ABS_Y, 0, 0xFFF, 0, 0);
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input_set_abs_params(ts_dev, ABS_PRESSURE, 0, 1, 0, 0);
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/* 3. 注册 */
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if( input_register_device(ts_dev) )
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return -EFAULT;
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/* 4.硬件相关操作 */
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//4.1使能时钟
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clk = clk_get(NULL, "adc");
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clk_enable(clk);/* PCLK_GATE[12]设为1 */
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//4.2设置s3c6410的ADC/TS寄存器
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ts_regs = ioremap(0x7E00B000, sizeof(struct ts_regs));
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/* bit[16] : 1 = 12-bit A/D conversion
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* bit[14] : 1-A/D converter prescaler enable
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* bit[13:6]: A/D converter prescaler value,
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* 13, ADCCLK=PCLK/(13+1)=66MHz/(13+1)=4.75MHz,最高支持5Mhz
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* bit[2]: 设为0
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* bit[0]: A/D conversion starts by enable. 先设为0
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*/
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ts_regs->adccon =(1<<16) | (1<<14) | (13<<6);
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ts_regs->adcclrintpndnup = 1;//Clear Pen Down/Up Interrupt,给寄存器adcclrintpndnup赋任意值都能清除up/down中断
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if ( request_irq(IRQ_PENDN, pen_down_up_irq, IRQF_SAMPLE_RANDOM, "ts_pen", NULL) )
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return -EFAULT;
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if ( request_irq(IRQ_ADC, adc_irq, IRQF_SAMPLE_RANDOM, "adc", NULL) )
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return -EFAULT;
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/* 优化措施1:
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* 设置ADCDLY为最大值, 这使得电压稳定后再发出IRQ_PENDN中断
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*/
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ts_regs->adcdly = 0xffff;
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/* 进入"wait for interrupt mode", 等待触摸笔按下或松开的模式 */
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enter_wait_pen_down_mode();
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return 0;
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}
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static void ts_exit(void)
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{
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free_irq(IRQ_PENDN, NULL);
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free_irq(IRQ_ADC, NULL);
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iounmap(ts_regs);
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input_unregister_device(ts_dev);
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input_free_device(ts_dev);
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}
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module_init(ts_init);
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module_exit(ts_exit);
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MODULE_LICENSE("GPL");
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