TQ2440触摸屏驱动程序的移植

按照天嵌官方的《Linux移植之step by step》手册上的方法，做linux2.6.30.4触摸屏驱动程序的移植没有成功，经过一番摸索发现是2.6.30.4没有合适的ADC驱动，所以就着手自己做ADC和触摸屏驱动的移植。

Linux移植之step by step PDF 版下载：http://pan.baidu.com/s/1mgFUvg8

或者

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具体下载目录在 /2014年资料/10月/13日/TQ2440触摸屏驱动程序的移植

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下面是我解决问题的详细过程：

1.找到天嵌给的linux2.6.30.4的源码，进入drivers/char 目录，把ADC驱动程序的源码抠出来，注意还有那个ADC驱动程序要调用的头文件，我的是直接把头文件加到ADC驱动程序的源码里面，下面是加入头文件修改后的ADC驱动程序的源代码（我把他命名为my_adc.c）：

#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/clk.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
#include <mach/regs-clock.h>
#include <plat/regs-timer.h>
     
#include <plat/regs-adc.h>
#include <mach/regs-gpio.h>
#include <linux/cdev.h>
#include <linux/miscdevice.h>
 
#ifndef _S3C2410_ADC_H_
#define _S3C2410_ADC_H_
 
#define ADC_WRITE(ch, prescale)  ((ch)<<16|(prescale))
 
#define ADC_WRITE_GETCH(data)  (((data)>>16)&0x7)
#define ADC_WRITE_GETPRE(data) ((data)&0xff)
 
#endif /* _S3C2410_ADC_H_ */
 
 
#undef DEBUG
//#define DEBUG
#ifdef DEBUG
#define DPRINTK(x...) {printk("EmbedSky_adc: " x);}
#else
#define DPRINTK(x...) (void)(0)
#endif
 
#define DEVICE_NAME    "adc"
 
#define ch_0 0
#define ch_1 1
#define ch_2 2
#define ch_3 3
 
static void __iomem *base_addr;
 
typedef struct
{
    wait_queue_head_t wait;
    int channel;
    int prescale;
}ADC_DEV;
 
DECLARE_MUTEX(ADC_LOCK);
static int ADC_enable = 0;
 
static ADC_DEV adcdev;
static volatile int ev_adc = 0;
static int adc_data;
 
static struct clk *adc_clock;
 
#define ADCCON        (*(volatile unsigned long *)(base_addr + S3C2410_ADCCON))  //ADC control
#define ADCTSC        (*(volatile unsigned long *)(base_addr + S3C2410_ADCTSC))  //ADC touch screen control
#define ADCDLY        (*(volatile unsigned long *)(base_addr + S3C2410_ADCDLY))  //ADC start or Interval Delay
#define ADCDAT0        (*(volatile unsigned long *)(base_addr + S3C2410_ADCDAT0)) //ADC conversion data 0
#define ADCDAT1        (*(volatile unsigned long *)(base_addr + S3C2410_ADCDAT1)) //ADC conversion data 1
#define ADCUPDN        (*(volatile unsigned long *)(base_addr + 0x14))            //Stylus Up/Down interrupt status
 
#define PRESCALE_DIS  (0 << 14)
#define PRESCALE_EN    (1 << 14)
#define PRSCVL(x)      ((x) << 6)
#define ADC_INPUT(x)  ((x) << 3)
#define ADC_START      (1 << 0)
#define ADC_ENDCVT    (1 << 15)
 
#define START_ADC_AIN(ch, prescale) \
    do{    ADCCON = PRESCALE_EN | PRSCVL(prescale) | ADC_INPUT((ch)) ; \
        ADCCON |= ADC_START; \
    }while(0)
 
int iSaveADCTSC=0;
 
static int tq2440_adc_ioctl(
    struct inode *inode,
    struct file *file,
    unsigned int cmd,
    unsigned long arg)
{
    if (arg > 4)
    {
        return -EINVAL;
    }
 
    switch(cmd)
    {
        case ch_0:
           
            adcdev.channel=0;
            return 0;
 
        case ch_1:
           
            adcdev.channel=1;
            return 0;
        case ch_2:
           
            adcdev.channel=2;
            return 0;
        case ch_3:
           
            adcdev.channel=3;
            return 0;
 
        default:
            return -EINVAL;
    }
}
 
static ssize_t tq2440_adc_read(struct file *filp, char *buffer, size_t count, loff_t *ppos)
{
    char str[20];
    int value;
    size_t len;
    if (down_trylock(&ADC_LOCK) == 0)
    {
        ADC_enable = 1;
        START_ADC_AIN(adcdev.channel, adcdev.prescale);
 
        iSaveADCTSC=ADCTSC;
        ADCTSC=ADCTSC&(~0x1<<2);
        ADCCON|=0x01;
        while(ADCCON&0x1);
        while(!ADCCON&(0x1<<15));
        adc_data = ADCDAT0 & 0x3ff;
        ADCTSC=iSaveADCTSC;
        ev_adc = 0;
 
        DPRINTK("AIN[%d] = 0x%04x, %d\n", adcdev.channel, adc_data, ((ADCCON & 0x80) ? 1:0));
 
        value = adc_data;
        sprintf(str,"%5d", adc_data);
        copy_to_user(buffer, (char *)&adc_data, sizeof(adc_data));
 
        ADC_enable = 0;
        up(&ADC_LOCK);
       
        len = sprintf(str, "%d\n", value);
        if (count >= len)
        {
            int r = copy_to_user(buffer, str, len);
            return r ? r : len;
        }
        else
        {
            return -1;
        }
    }
    else
    {
        return -1;
        //value = -1;
    }
}
 
static int tq2440_adc_open(struct inode *inode, struct file *filp)
{
    init_waitqueue_head(&(adcdev.wait));
 
    adcdev.channel=2; 
    adcdev.prescale=0xff;
 
    DPRINTK( "ADC opened\n");
 
    return 0;
}
 
static int tq2440_adc_release(struct inode *inode, struct file *filp)
{
    DPRINTK( "ADC closed\n");
    return 0;
}
 
 
static struct file_operations dev_fops = {
    .owner      = THIS_MODULE,
    .open      = tq2440_adc_open,
    .ioctl      = tq2440_adc_ioctl,
    .read      = tq2440_adc_read,
    .release    = tq2440_adc_release,
};
 
static struct miscdevice misc = {
    .minor = MISC_DYNAMIC_MINOR,
    .name = DEVICE_NAME,
    .fops = &dev_fops,
};
 
static int __init dev_init(void)
{
    int ret;
 
    base_addr=ioremap(S3C2410_PA_ADC,0x20);
    if (base_addr == NULL)
    {
        printk(KERN_ERR "failed to remap register block\n");
        return -ENOMEM;
    }
 
    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);
   
    ADCTSC = 0;
 
    ret = misc_register(&misc);
 
    printk (DEVICE_NAME" initialized\n");
    return ret;
}
 
static void __exit dev_exit(void)
{
 
    if (adc_clock)
    {
        clk_disable(adc_clock);
        clk_put(adc_clock);
        adc_clock = NULL;
    }
 
    misc_deregister(&misc);
}
 
EXPORT_SYMBOL(ADC_LOCK);
module_init(dev_init);
module_exit(dev_exit);
MODULE_LICENSE("GPL");

上述程序的源码以后再作分析。