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TQ2440觸摸屏驅動程序的移植

日期：2017/3/1 9:38:42 编辑：Linux編程

按照天嵌官方的《Linux移植之step by step》手冊上的方法，做linux2.6.30.4觸摸屏驅動程序的移植沒有成功，經過一番摸索發現是2.6.30.4沒有合適的ADC驅動，所以就著手自己做ADC和觸摸屏驅動的移植。

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

或者

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免費下載地址在 http://linux.linuxidc.com/

用戶名與密碼都是www.linuxidc.com

具體下載目錄在 /2014年資料/10月/13日/TQ2440觸摸屏驅動程序的移植

下載方法見 http://www.linuxidc.com/Linux/2013-07/87684.htm

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下面是我解決問題的詳細過程：

1.找到天嵌給的linux2.6.30.4的源碼，進入drivers/char 目錄，把ADC驅動程序的源碼摳出來，注意還有那個ADC驅動程序要調用的頭文件，我的是直接把頭文件加到ADC驅動程序的源碼裡面，下面是加入頭文件修改後的ADC驅動程序的源代碼（我把他命名為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");