2010-04-10 16:03:45 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 #define AUTOPST (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 struct input_dev *dev;// static long xp; static long yp; static int count;
extern struct semaphore 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) { long tmp; 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 struct timer_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 } }
return IRQ_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 } }
return IRQ_HANDLED; }
static struct clk *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 get adc 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 to remap 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 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);
return 0; }
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);