移植ads7846驱动到tiny6410（tiny6410）

 转自：http://www.cnblogs.com/liu_xf/archive/2011/06/23/2088417.html

摘要：

目前，市面上很多6410开发板都存在触摸屏抖动的问题，tiny6410也不例外，友善的解决方法是采用一线触摸，即在LCD板上，用一个单片机控制ADS7846芯片AD转换，再将数据通过单总线的方式与6410通讯。可是，我这里没有一线触摸板，于是就开始移植ADS7846驱动到tiny6410。

介绍：

 可能有人会问，6410的触摸屏为什么会抖动呢，是不是滤波没做好，或者是硬件走线的原因？是不是硬件的原因，我无法验证。我尝试过通过滤波来改善，但效果一般。不说别的，我在单独测试AD的时候，发现在输入不变的情况下，AD采样的跳幅最大达到25（0～1024范围），可见，跳动还是很大的，这样的情况下，即使再滤波也只是浪费时间。

先说说我的硬件：

TS_PEN ----- GPN9 EINT9

TS_MISO ---- GPC0 MISO0

TS_MOSI ---- GPC2 MOSI0

TS_SCK ----- GPC1 SCK0

TS_CS ----- GPC3 CS0

这些端子在核心板的CON1上可以找到，我这里是用的IO模拟的SPI。

下面的开始介绍移植的过程，代码，我在下面会全部帖出来，里面注释也很详细，一般都能看明白。

1、复制/opt/FriendlyARM/mini6410/linux-2.6.38/drivers/input/touchscreen/mini6410-ts.c为mini6410-ads7846.c。

修改后，如下：

/* linux/drivers/input/touchscreen/s3c-ts.c  002  *  003  * This program is free software; you can redistribute it and/or modify  004  * it under the terms of the GNU General Public License as published by  005  * the Free Software Foundation; either version 2 of the License, or  006  * (at your option) any later version.  007  *  008  * This program is distributed in the hope that it will be useful,  009  * but WITHOUT ANY WARRANTY; without even the implied warranty of  010  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the  011  * GNU General Public License for more details.  012  *  013  * You should have received a copy of the GNU General Public License  014  * along with this program; if not, write to the Free Software  015  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA  016  *  017  * a misc driver for mini6410 touch screen  018  *  by FriendlyARM 2010  019  *  020  * Based on following software:  021  *  022  ** Copyright (c) 2004 Arnaud Patard <[e-mail]>  023  ** iPAQ H1940 touchscreen support  024  **  025  ** ChangeLog  026  **  027  ** 2004-09-05: Herbert Potzl <[e-mail]>  028  ** - added clock (de-)allocation code  029  **  030  ** 2005-03-06: Arnaud Patard <[e-mail]>  031  **      - h1940_ -> s3c24xx (this driver is now also used on the n30  032  **        machines :P)  033  **      - Debug messages are now enabled with the config option  034  **        TOUCHSCREEN_S3C_DEBUG  035  **      - Changed the way the value are read  036  **      - Input subsystem should now work  037  **      - Use ioremap and readl/writel  038  **  039  ** 2005-03-23: Arnaud Patard <[e-mail]>  040  **      - Make use of some undocumented features of the touchscreen  041  **        controller  042  **  043  ** 2006-09-05: Ryu Euiyoul <[e-mail]>  044  **      - added power management suspend and resume code  045  *  046  * 2011-6-23: ADS7846触摸屏驱动程序 by liu_xf  047  *           http://www.cnblogs.com/liu_xf  048  *   049  * 2011-6-29 改进滤波，并将AD连续转换8次的间隔缩小了  050  */ 051    052 #include <linux/errno.h>  053 #include <linux/kernel.h>  054 #include <linux/module.h>  055 #include <linux/slab.h>  056 #include <linux/input.h>  057 #include <linux/init.h>  058 #include <linux/serio.h>  059 #include <linux/delay.h>  060 #include <linux/platform_device.h>  061 #include <linux/clk.h>  062 #include <linux/fs.h>  063 #include <linux/poll.h>  064 #include <linux/irq.h>  065 #include <linux/interrupt.h>  066 #include <linux/cdev.h>  067 #include <linux/miscdevice.h>  068    069 #include <asm/uaccess.h>  070 #include <asm/io.h>  071 #include <asm/irq.h>  072 #include <mach/hardware.h>  073    074    075 //#include <mach/irqs.h>  076 #include <mach/map.h>  077 #include <mach/regs-clock.h>  078 #include <mach/regs-gpio.h>  079 #include <plat/gpio-cfg.h>  080 #include <mach/gpio-bank-n.h>  081 #include <mach/gpio-bank-c.h>  082    083    084 #define CONFIG_TOUCHSCREEN_ADS7846_DEBUG  085 #undef CONFIG_TOUCHSCREEN_ADS7846_DEBUG  086 #define DEBUG_LVL       KERN_DEBUG  087    088    089 /*  090  * Definitions & global arrays.  091  */ 092 #define DEVICE_NAME     "touchscreen"  093 static DECLARE_WAIT_QUEUE_HEAD(ts_waitq); //定义并初始化一个等待队列  094    095 typedef unsigned        TS_EVENT;  096 #define NR_EVENTS       64     //触摸屏fifo大小  097    098    099 static TS_EVENT         events[NR_EVENTS];  100 static int              evt_head, evt_tail; //fifo的头的尾  101                                                             //驱动写fifo时evt_head++，应用读fifo时 evt_tail++  102    103 #define ts_evt_pending()    ((volatile u8)(evt_head != evt_tail))   //相等就表示满了  104 #define ts_evt_get()        (events + evt_tail)  105 #define ts_evt_pull()       (evt_tail = (evt_tail + 1) & (NR_EVENTS - 1))  106 #define ts_evt_clear()      (evt_head = evt_tail = 0)  107    108 #define ADS7846_CNV_NBR  8  //ADC连续转换的次数  109 struct ads7846_ts_info {  110    111     struct input_dev *dev;  112    113     unsigned int xp; //x方向位置  114     unsigned int yp; //y方向位置  115     unsigned int count; //adc转换次数  116     unsigned int cnv_nbr;  117     unsigned int x_buf[ADS7846_CNV_NBR];  //ad转换buf   118     unsigned int y_buf[ADS7846_CNV_NBR];  119        120 };  121    122 static struct ads7846_ts_info   *ts;  123    124    125    126    127 //ADS7846底层操作========================================================================  128 #define ADS7846_GPIO_MISO   0   //gpc0  129 #define ADS7846_GPIO_MOSI   2     //gpc2  130 #define ADS7846_GPIO_CLK   1       //gpc1  131 #define ADS7846_GPIO_CS   3       //gpc3  132    133 // ADS7846 Control Byte bit defines  134 #define ADS7846_CMD_START   0x0080  135 #define ADS7846_ADDR_BIT    4  136 #define ADS7846_ADDR_MASK   (0x7<<ADS7846_ADDR_BIT)  137 #define ADS7846_MEASURE_X   (0x5<<ADS7846_ADDR_BIT)  138 #define ADS7846_MEASURE_Y   (0x1<<ADS7846_ADDR_BIT)  139 #define ADS7846_MEASURE_Z1  (0x3<<ADS7846_ADDR_BIT)  140 #define ADS7846_MEASURE_Z2  (0x4<<ADS7846_ADDR_BIT)  141 #define ADS7846_8BITS       (1<<3)  142 #define ADS7846_12BITS      0  143 #define ADS7846_SER         (1<<2)  144 #define ADS7846_DFR         0  145 #define ADS7846_PWR_BIT     0  146 #define ADS7846_PD          0  147 #define ADS7846_ADC_ON      (0x1<<ADS7846_PWR_BIT)  148 #define ADS7846_REF_ON      (0x2<<ADS7846_PWR_BIT)  149 #define ADS7846_REF_ADC_ON  (0x3<<ADS7846_PWR_BIT)  150    151 #define MEASURE_8BIT_X\  152     (unsigned short)(ADS7846_CMD_START | ADS7846_MEASURE_X | ADS7846_8BITS | ADS7846_DFR | ADS7846_PD)  153 #define MEASURE_8BIT_Y\  154     (unsigned short)(ADS7846_CMD_START | ADS7846_MEASURE_Y | ADS7846_8BITS | ADS7846_DFR | ADS7846_PD)  155    156 #define MEASURE_12BIT_X \  157     (unsigned short)(ADS7846_CMD_START | ADS7846_MEASURE_X | ADS7846_12BITS | ADS7846_DFR | ADS7846_PD)  158 #define MEASURE_12BIT_Y \  159     (unsigned short)(ADS7846_CMD_START | ADS7846_MEASURE_Y | ADS7846_12BITS | ADS7846_DFR | ADS7846_PD)  160 #define MEASURE_12BIT_Z1 \  161     (unsigned char)(ADS7846_MEASURE_Z1 | ADS7846_12BITS | ADS7846_DFR | ADS7846_PD)  162 #define MEASURE_12BIT_Z2 \  163     (unsigned char)(ADS7846_MEASURE_Z2 | ADS7846_12BITS | ADS7846_DFR | ADS7846_PD)  164        165 // Pin access  166 //  167 static inline void set_miso_as_up(void)//gpc0  168 {  169     unsigned long tmp;  170     tmp = readl(S3C64XX_GPCPUD);  171     tmp &= ~(3U <<0);  172     tmp |= (2U << 0);  173     writel(tmp, S3C64XX_GPCPUD);  174 }  175    176 static inline void set_miso_as_input(void)//gpc0  177 {  178     unsigned long tmp;  179     tmp = readl(S3C64XX_GPCCON);  180     tmp &= ~(0xf << 0);  181     writel(tmp, S3C64XX_GPCCON);  182 }  183    184 static inline void set_cs_mosi_clk_as_output(void)//gpc1 2 3  185 {  186     unsigned long tmp;  187     tmp = readl(S3C64XX_GPCCON);  188     tmp = (tmp & ~0xfff0) | (0x1110);  189     writel(tmp, S3C64XX_GPCCON);  190 }  191    192 static inline void set_cs_mosi_clk_as_up(void)//gpc1 2 3  193 {  194     unsigned long tmp;  195     tmp = readl(S3C64XX_GPCPUD);  196     tmp &= ~((3U <<2)|(3U <<4)|(3U <<6));  197     tmp |= (2U << 2) | (2U << 4) | (2U << 6);  198     writel(tmp, S3C64XX_GPCPUD);  199 }  200    201    202 static inline void set_gpcx_value(int pinx ,int v)  203 {  204     unsigned long tmp;  205     tmp = readl(S3C64XX_GPCDAT);  206     if (v) {  207         tmp |= (1 << pinx);  208     } else {  209         tmp &= ~(1<<pinx);  210     }  211     writel(tmp, S3C64XX_GPCDAT);  212 }  213    214 static inline int get_gpcx_value(int pinx)  215 {  216     int v;  217     unsigned long tmp;  218     tmp = readl(S3C64XX_GPCDAT);  219     v = !!(tmp & (1<<pinx));  220     return v;  221 }  222    223 //读12bit  224 static unsigned int ads7846_Read_Data(void)  225 {  226  unsigned int i,temp=0x00;  227    for(i=0;i<12;i++)  228    {  229        temp <<=1;  230        set_gpcx_value(ADS7846_GPIO_CLK, 1); udelay(10);  231        set_gpcx_value(ADS7846_GPIO_CLK, 0); udelay(10);  232        if(get_gpcx_value(ADS7846_GPIO_MISO) != 0)temp++;  233    }  234    return (temp);  235 }  236 //写8bit  237 static void ads7846_Write_Data(unsigned int n)  238 {  239    unsigned char i;  240   set_gpcx_value(ADS7846_GPIO_CLK, 0);  241   for(i=0;i<8;i++)  242    {  243     if((n&0x80)==0x80)  244       set_gpcx_value(ADS7846_GPIO_MOSI, 1);  245      else 246       set_gpcx_value(ADS7846_GPIO_MOSI, 0);  247        248     n <<= 1;  249     set_gpcx_value(ADS7846_GPIO_CLK, 1);  udelay(10);  250     set_gpcx_value(ADS7846_GPIO_CLK, 0); udelay(10);  251     }  252 }  253    254    255 //ADS7846转换==  256 //保存在ts->buf 当中  257 static void ads7846_conver_start(void)  258 {  259     int i;  260     unsigned int cmd[2];  261     unsigned int data[2];  262            263     set_gpcx_value(ADS7846_GPIO_CS, 0);  264         //开读  265     cmd[0] = MEASURE_12BIT_X;  266     cmd[1] = MEASURE_12BIT_Y;  267    268     /* CS# Low */ 269     set_gpcx_value(ADS7846_GPIO_CS, 0);  270        271     //连续转换  272     for(ts->count=0; ts->count<ts->cnv_nbr;)   273     {  274         //分别读出x y坐标＝＝  275         for(i=0; i<2; i++){  276           ads7846_Write_Data(cmd[i]);  277           udelay(40);  278           data[i] = ads7846_Read_Data();  279         }  280            281            282    283         //保存转换结果  284         ts->x_buf[ts->count]= data[0];  285         ts->y_buf[ts->count]= data[1];  286         ts->count++;  287     }  288     /* CS# High */ 289     set_gpcx_value(ADS7846_GPIO_CS, 1);  290    291 #ifdef CONFIG_TOUCHSCREEN_ADS7846_DEBUG   292     //printk("ts read pos: x = %d, y = %d\n", data[0], data[1]);  293 #endif  294        295 }  296    297    298 //-----------------------------------------------------------------------------  299    300 //触摸屏数据滤波算法  301 //触摸屏AD连续转换N次后，按升序排列，再取中间几位值求平均  302 #define  TS_AD_NBR_PJ    4       //取中间4位求平均值   303 #define  TS_AD_NBR_MAX_CZ    10       //最大与最小的差值  304 static inline bool touch_ad_data_filter(unsigned int *buf0, unsigned int *buf1)  305 {  306    unsigned int i,j,k,temp,temp1,nbr=(ADS7846_CNV_NBR);  307    //将转换结果升序排列  308    //buf0  309     for (j= 0; j< nbr; j++)  310     for (i = 0; i < nbr; i++)   311     {             312         if(buf0[i]>buf0[i+1])//升序排列  313     {  314         temp=buf0[i+1];  315         buf0[i+1]=buf0[i];  316         buf0[i]=temp;  317     }    318     }  319      320     //buf1  321     for (j= 0; j< nbr; j++)  322     for (i = 0; i < nbr; i++)   323     {             324         if(buf1[i]>buf1[i+1])//升序排列  325     {  326         temp=buf1[i+1];  327         buf1[i+1]=buf1[i];  328         buf1[i]=temp;  329     }    330     }   331     332     //串口调试查看结果  333     //for (j= 0; j< nbr; j++)  334      // printk("buf0[%2d]=%4d, buf1[%2d]=%4d,\r\n",j,buf0[j],j,buf1[j]);  335    //取中间值求平均==  336    k=((nbr-TS_AD_NBR_PJ)>>1);  337    temp = 0;temp1 = 0;  338    //检查值是否有效==  339    if((buf0[k+TS_AD_NBR_PJ-1]-buf0[k]>TS_AD_NBR_MAX_CZ)||(buf1[k+TS_AD_NBR_PJ-1]-buf1[k]>TS_AD_NBR_MAX_CZ)) //无效值  340     {  341    342       return 0;   343     }  344    //--  345    //将中间指定位数累加  346    for(i=0;i<TS_AD_NBR_PJ;i++)  347    {    348       temp += buf0[k+i];  349       temp1 += buf1[k+i];  350    }  351    //求平均值,将结果保存在最低位  352    buf0[0]=temp/TS_AD_NBR_PJ;     353    buf1[0] = temp1/TS_AD_NBR_PJ;   354    //--  355    return 1;   356       357 }  358    359    360 //将AD转换的值放入FIFO  361 //这里是一个先进先出的fifo  362 //只要有数据被添加进来，就会唤醒ts_waitq进程  363 static void ts_evt_add(unsigned x, unsigned y, unsigned down) {  364     unsigned ts_event;  365     int next_head;  366    367     ts_event = ((x << 16) | (y)) | (down << 31);  368     next_head = (evt_head + 1) & (NR_EVENTS - 1);  369         //没满就装入  370     if (next_head != evt_tail) {  371         events[evt_head] = ts_event;  372         evt_head = next_head;  373 #ifdef CONFIG_TOUCHSCREEN_ADS7846_DEBUG   374         printk("====>Add ... [ %4d,  %4d ]%s\n", x, y, down ? "":" ~~~");  375 #endif  376         /* wake up any read call */ 377         if (waitqueue_active(&ts_waitq)) { //判斷等待隊列是否有進程睡眠  378             wake_up_interruptible(&ts_waitq);  //唤醒ts_waitq等待队列中所有interruptible类型的进程  379         }  380     } else {  381         /* drop the event and try to wakeup readers */ 382         printk(KERN_WARNING "mini6410-ads7846: touch event buffer full");  383         wake_up_interruptible(&ts_waitq);  384     }  385 }  386    387 static unsigned int ads7846_ts_poll( struct file *file, struct poll_table_struct *wait)  388 {  389     unsigned int mask = 0;  390    391     //将ts_waitq等待队列添加到poll_table里去  392     poll_wait(file, &ts_waitq, wait);   393     //返回掩码                                    394     if (ts_evt_pending())  395         mask |= POLLIN | POLLRDNORM;  //返回设备可读  396    397     return mask;  398 }  399    400 //读 系统调用==  401 static int ads7846_ts_read(struct file *filp, char __user *buff, size_t count, loff_t *offp)  402 {  403     DECLARE_WAITQUEUE(wait, current); //把当前进程加到定义的等待队列头wait中   404     char *ptr = buff;  405     int err = 0;  406    407     add_wait_queue(&ts_waitq, &wait); //把wait入到等待队列头中。该队列会在进程等待的条件满足时唤醒它。  408                                       //我们必须在其他地方写相关代码，在事件发生时，对等的队列执行wake_up()操作。  409                                       //这里是在ts_evt_add里wake_up  410     while (count >= sizeof(TS_EVENT)) {  411         err = -ERESTARTSYS;  412         if (signal_pending(current)) //如果是信号唤醒    参考http://www.360doc.com/content/10/1009/17/1317564_59632874.shtml  413             break;  414    415         if (ts_evt_pending()) {  416             TS_EVENT *evt = ts_evt_get();  417    418             err = copy_to_user(ptr, evt, sizeof(TS_EVENT));  419             ts_evt_pull();  420    421             if (err)  422                 break;  423    424             ptr += sizeof(TS_EVENT);  425             count -= sizeof(TS_EVENT);  426             continue;  427         }  428    429         set_current_state(TASK_INTERRUPTIBLE); //改变进程状态为可中断的睡眠  430         err = -EAGAIN;  431         if (filp->f_flags & O_NONBLOCK) //如果上层调用是非阻塞方式，则不阻塞该进程，直接返回EAGAIN  432             break;  433         schedule();  //本进程在此处交出CPU控制权，等待被唤醒  434                       //进程调度的意思侧重于把当前任务从CPU拿掉，再从就绪队列中按照调度算法取一就绪进程占用CPU  435     }  436     current->state = TASK_RUNNING;  437     remove_wait_queue(&ts_waitq, &wait);  438    439     return ptr == buff ? err : ptr - buff;  440 }  441 //--  442    443 static int ads7846_ts_open(struct inode *inode, struct file *filp) {  444     /* flush event queue */ 445     ts_evt_clear();  446    447     return 0;  448 }  449    450 //当应用程序操作设备文件时调用的open read等函数，最终会调用这个结构体中对应的函数  451 static struct file_operations dev_fops = {  452     .owner              = THIS_MODULE,  453     .read               = ads7846_ts_read,  454     .poll               = ads7846_ts_poll,  //select系统调用  455     .open               = ads7846_ts_open,  456 };  457    458 //设备号，设备名，注册的时候用到这个数组  459 //混杂设备主设备号为10  460 static struct miscdevice misc = {  461         .minor              = MISC_DYNAMIC_MINOR, //自动分配次设置号  462     //.minor                = 180,   463     .name               = DEVICE_NAME,  464     .fops               = &dev_fops,  465 };  466    467    468    469    470    471    472 /**  473  * get_down - return the down state of the pen  474  * 获取pen引脚状态，为0表示down  475  * GPN9 EINT9 TS_PEN  476  */ 477 static inline bool get_down(void)  478 {  479    int tmp,down;  480    tmp = readl(S3C64XX_GPNDAT);  481    down = !(tmp & (1<<9));  482     return (down);    483 }  484    485    486 /*===========================================================================================  487     touch_timer_get_value这个函数的调用：  488        489     1、  触摸笔开始点击的时候， 在中断函数touch_down里面被调用，不是直接调用，而是设置定时器超时后调用  490          这样是为了去抖动  491             492     2、  touch_timer_get_value被调用一次后，如果pendown信号有效，则touch_timer_get_value会被持续调用  493          也是通过定时器实现的  494             495     touch_timer_get_value这个函数的功能：  496       启动7846转换，直到连续转换8次后，再滤波处理，获得有效值，并向上报告触摸屏事件  497    498 ============================================================================================*/ 499 static void touch_timer_get_value(unsigned long data);   500    501 static DEFINE_TIMER(touch_timer, touch_timer_get_value, 0, 0);  502    503 static void touch_timer_get_value(unsigned long data) {  504    505     int pendown;  506           507     pendown = get_down();  508    509 #ifdef CONFIG_TOUCHSCREEN_ADS7846_DEBUG   510 //  if(pendown)  511 //  {    512 //    printk("touch is down!\n");  513 //  }  514 //  else  515 //    printk("touch is up!\n");  516 #endif  517        518     if (pendown) {  519    520             //关中断===  521            disable_irq(IRQ_EINT(9));  522            //--  523            //启动ADS7846转换==  524             ads7846_conver_start();  525          //开中断==  526              enable_irq(IRQ_EINT(9));  527              //--  528         //如果转换了8次，就写入FIFO保存  529         //if (ts->count == ( ts->cnv_nbr)) {    530             if(touch_ad_data_filter(ts->x_buf,ts->y_buf)) //滤波处理  531                        {  532                    533             ts->xp = ts->x_buf[0];  534             ts->yp = ts->y_buf[0];  535                536             ts_evt_add(ts->xp, ts->yp, 1);  //向上报告触摸屏事件  537                }  538                   539    540             ts->xp = 0;  541             ts->yp = 0;  542             ts->count = 0;  543         //}  544                 //--  545                   546         mod_timer(&touch_timer, jiffies + 2);   //重新设置系统定时器，超时后，又会调用touch_timer_get_value  547                                                  //jiffies变量记录了系统启动以来，系统定时器已经触发的次数。内核每秒钟将jiffies变量增加HZ次。  548                                                 //因此，对于HZ值为100的系统，1个jiffy等于10ms，而对于HZ为1000的系统，1个jiffy仅为1ms  549                                                 //这里系统配置提HZ是100  550            551     } else {  //如果是松开，报告其触摸笔状态  552         ts->xp = 0;  553         ts->yp = 0;  554         ts->count = 0;  555    556         ts_evt_add(0, 0, 0);  557    558    559     }  560        561 }  562    563    564    565 //触摸屏按下中断服务==  566 //双边沿中断  567 static irqreturn_t touch_down(int irqno, void *param)  568 {  569           570          571     /* Clear  interrupt */ 572     //__raw_writel(0x0, ts_base + S3C_ADCCLRWK);  573     //__raw_writel(0x0, ts_base + S3C_ADCCLRINT);  574    575         //稍后调用touch_timer_get_value，去抖动  576     mod_timer(&touch_timer, jiffies + 2);  //等ADS7846转换完成了再读  577                                             //同时还可以防抖动，如果定时器没有超时的这段时间里，发生了抬起和按下中断，则定时器的值会被重设，不会超时  578                                             //内核配置时HZ值设为100，即1个jiffy等于10ms，  579     //touch_timer_get_value(1);  //直接调用会有抖动  580    581     return IRQ_RETVAL(IRQ_HANDLED);  582 }  583    584    585    586    587 //-------------------------------------------  588    589    590 /*  591  * The functions for inserting/removing us as a module.  592  */ 593 static int __init ads7846_ts_probe(struct platform_device *pdev)  594 {  595     struct device *dev;  596     int ret = 0;  597        598     dev = &pdev->dev;  599 #ifdef CONFIG_TOUCHSCREEN_ADS7846_DEBUG   600     printk("ads7846_ts_probe start!\n");  601 #endif      602     //给ads7846_ts_info指针分配内存==  603     ts = kzalloc(sizeof(struct ads7846_ts_info), GFP_KERNEL);  604     ts->cnv_nbr = ADS7846_CNV_NBR;  605     ts->xp = 0;  606     ts->yp = 0;  607     ts->count = 0;  608      609        610     //申请中断==  611     //TS_PEN双边沿触发 EINT9  GPN9  612     ret = request_irq(IRQ_EINT(9), touch_down,IRQ_TYPE_EDGE_BOTH,   613                           "ads7864_touch", ts);  614    615     if (ret != 0) {  616         dev_err(dev,"ads7846_ts.c: Could not allocate ts IRQ_EINT !\n");  617         ret = -EIO;  618         goto fail;  619     }  620           621         622    623        624      ret = misc_register(&misc);  //注册这混杂字符设备  625     if (ret) {  626         dev_err(dev, "ads7846_ts.c: Could not register device(mini6410 touchscreen)!\n");  627         ret = -EIO;  628         goto fail;  629     }  630     //初始化GPIO==  631     set_miso_as_up();   632     set_miso_as_input();   633     set_cs_mosi_clk_as_up();  634     set_cs_mosi_clk_as_output();   635     set_gpcx_value(ADS7846_GPIO_MOSI ,1);     636     set_gpcx_value(ADS7846_GPIO_CS ,1);  637     set_gpcx_value(ADS7846_GPIO_CLK ,1);  638     //--  639    640 #ifdef CONFIG_TOUCHSCREEN_ADS7846_DEBUG   641     printk("ads7846_ts_probe end!\n");  642 #endif      643        644     return 0;  645    646 fail:  647     disable_irq(IRQ_EINT(9));  648         free_irq(IRQ_EINT(9), ts);  649    650     return ret;  651    652 }  653    654 static int ads7846_ts_remove(struct platform_device *dev)  655 {  656     printk(KERN_INFO "ads7846_ts_remove() of TS called !\n");  657            658     disable_irq(IRQ_EINT(9));  659         free_irq(IRQ_EINT(9), ts);  660     return 0;  661 }  662    663 #ifdef CONFIG_PM  664 static unsigned int adccon, adctsc, adcdly;  665    666 static int ads7846_ts_suspend(struct platform_device *dev, pm_message_t state)  667 {  668    669     return 0;  670 }  671    672 static int ads7846_ts_resume(struct platform_device *pdev)  673 {  674     return 0;  675 }  676 #else  677 #define ads7846_ts_suspend  NULL  678 #define ads7846_ts_resume   NULL  679 #endif  680    681 static struct platform_driver ads7846_ts_driver = {  682     .probe          = ads7846_ts_probe,  683     .remove         = ads7846_ts_remove,  684     .suspend        = ads7846_ts_suspend,  685     .resume         = ads7846_ts_resume,  686     .driver         = {  687         .owner          = THIS_MODULE,  688         .name           = "ads7846-ts",  689     },  690 };  691    692 static char banner[] __initdata = KERN_INFO "mini6410 ads7846 Touchscreen driver,by liu_xf 20110622,\n";  693    694 static int __init ads7846_ts_init(void)  695 {  696     printk(banner);  697     return platform_driver_register(&ads7846_ts_driver);  698 }  699    700 static void __exit ads7846_ts_exit(void)  701 {  702     platform_driver_unregister(&ads7846_ts_driver);  703 }  704    705 module_init(ads7846_ts_init);  706 module_exit(ads7846_ts_exit);  707    708 MODULE_AUTHOR("Hunan Create Inc.");  709 MODULE_LICENSE("GPL"); 

 2、修改当前目录下的Kconfig和makefile，让它在menuconfig里可见，并能被编译。

在 Kconfig里添加：

config TOUCHSCREEN_MINI6410_ADS7846  02     tristate "ADS7846 touchscreen driver for Mini6410" 03     depends on MACH_MINI6410  04     default y  05     help  06       Say Y here to enable the driver for the ADS7846 touchscreen on the  07       FriendlyARM Mini6410 development board.  08    09       If unsure, say N.  10    11       To compile this driver as a module, choose M here: the  12       module will be called mini6410-ads7846. 

Makefile里添加

obj-$(CONFIG_TOUCHSCREEN_MINI6410_ADS7846)  += mini6410-ads7846.o

3、 ads7846_device_ts设备定义

复制 /opt/FriendlyARM/mini6410/linux-2.6.38/arch/arm/mach-s3c64xx/dev-ts-mini6410.c为dev-ads7846-mini6410.c，更改代码为

01 /* linux/arch/arm/mach-s3c64xx/dev-ts-mini6410.c  02  *  03  * Copyright (c) 2008 Simtec Electronics  04  *  Ben Dooks <[e-mail]>  05  *  http://armlinux.simtec.co.uk/  06  *  07  * S3C series device definition for touchscreen devices  08  *  09  * This program is free software; you can redistribute it and/or modify  10  * it under the terms of the GNU General Public License version 2 as  11  * published by the Free Software Foundation.  12 */ 13    14 #include <linux/kernel.h>  15 #include <linux/platform_device.h>  16    17 #include <mach/map.h>  18 #include <mach/irqs.h>  19 #include <plat/devs.h>  20 #include <plat/cpu.h>  21 #include <mach/ts.h>  22    23 /* Touch srcreen */ 24 //resource没有用，先留在这，不管它  25 static struct resource ads7846_ts_resource[] = {  26     [0] = {  27         .start = SAMSUNG_PA_ADC,  28         .end   = SAMSUNG_PA_ADC + SZ_256 - 1,  29         .flags = IORESOURCE_MEM,  30     },  31     [1] = {  32         .start = IRQ_PENDN,  33         .end   = IRQ_PENDN,  34         .flags = IORESOURCE_IRQ,  35     },  36     [2] = {  37         .start = IRQ_ADC,  38         .end   = IRQ_ADC,  39         .flags = IORESOURCE_IRQ,  40     }  41 };  42    43 struct platform_device ads7846_device_ts = {  44     .name         = "ads7846-ts",  45     .id       = -1,  46     .num_resources    = ARRAY_SIZE(ads7846_ts_resource),  47     .resource     = ads7846_ts_resource,  48 };  49 /*  50 void __init ads7846_ts_set_platdata(struct s3c_ts_mach_info *pd)  51 {  52         printk(KERN_ERR "%s: no platform data\n", __func__);  53        54 }  55 */ 

4、在/opt/FriendlyARM/mini6410/linux-2.6.38/arch/arm/mach-s3c64xx/mach-mini6410.c的platform_device添加ads7846_device_ts设备（s3c_device_ts附近），注册设备时要用到它

#ifdef CONFIG_TOUCHSCREEN_MINI6410_ADS7846      &ads7846_device_ts,  #endif 

5、添加设备声明

mach-mini6410里注册ads7846_device_ts设备，但在哪里mach-mini6410并不知道，需要在devs.h里声明，打开当前目录下的devs.h，添加如下代码：

extern struct platform_device ads7846_device_ts;<BR>

6、然后再make，放到SD卡里运行

make menuconfig，在device drives－> input device support -> touch screens选择ADS7846 touchscreen driver for Mini6410 ,然后再make zImage。

完成后，再放到SD卡里运行，怎么样，一点也不抖动了吧！

结语：

 这个驱动是由mini6410-ts.c修改而来的，那些系统调用的函数都没有改，只是将获取触摸屏数据的方式变了，可以直接用原来的tslib。经测试，效果良好。但是在移植的过程中，有一个问题还是没搞明白，之前，我是将TS_PEN接在EINT6上在的，但一接上去，就一直中断，把系统都弄死了，要按下触摸屏才能停止中断，不知道是什么原因，可能是EINT6被其它地方设置了，还是怎么回事，后来换成EINT9就好了，正好两个端子相邻。知道的大侠还请告诉我一声。

源代码下载（下载后将后缀改为tar.gz）

http://files.cnblogs.com/liu_xf/mini6410-ads7846.rar