gpio模拟i2c驱动

前段时间做项目，需要gpio模拟i2c通信，最后参考了一些资料，然后编写了一个程序。现在发出来，以免以后忘记，也为一些需要的朋友提供参考。不喜勿喷哈。

/* 说明：该程序是基于atmel公司的sama5d35 MCU 用其中两个GPIO引脚模拟i2c通信。
* 其中两个引脚连接到了hd1650上面。然后检测按键扫描的驱动
* */

该程序可以作为gpio模拟i2c程序的参考。不同的平台，函数实现不同，但是i2c通信的时序和原理是相同的。希望对一些朋友有帮助。

 #include<linux/init.h>
 #include<linux/module.h>
 #include<linux/kernel.h>
 #include<linux/sched.h>
 #include<linux/init.h>
 #include<linux/sched.h>
 #include<linux/completion.h>
 #include <asm/system.h>
 #include <linux/param.h>
 #include<linux/gpio.h>
 #include<linux/cdev.h>
 #include<linux/fs.h>
 #include<linux/device.h>
 #include<linux/slab.h>
 #include<asm/uaccess.h>
 #include<linux/delay.h>
 #include<linux/miscdevice.h>

 /* 定义GPIO引脚值，这个在内核里面有定义 */
 #define GPIO_PC30 94
 #define GPIO_PC31 95

 /* 定义GPIO引脚结构体，用于和上层进行通信 */
 typedef struct gpio_ctrl_blk{
     int pin;
     int value;
 }gpio_cblk_t;

 #define HD1650_DEV_ID 'k'
 #define GET_KEY             _IOWR (HD1650_DEV_ID,0x34,int)

 /* 定义延时函数，用于i2c通信 */
 #define DELAY_BUILD()    udelay(10)
 #define DELAY()            udelay(10)

 /* this define copy from datasheet */
 #define CMD_SYSOFF    0x4800
 #define CMD_SYSON    0x4801
 #define CMD_SLEEPOFF    0x4800
 #define CMD_SLEEPON    0x4804
 #define CMD_7SEGON    0x4809
 #define CMD_8SEGON    0x4801

 #define CMD_7SEGON1    0x4819
 #define CMD_7SEGON2    0x4829
 #define CMD_7SEGON3    0x4839
 #define CMD_7SEGON4    0x4849
 #define CMD_7SEGON5    0x4859
 #define CMD_7SEGON6    0x4869
 #define CMD_7SEGON7    0x4879
 #define CMD_7SEGON8    0x4809

 #define CMD_8SEGON1    0x4811
 #define CMD_8SEGON2    0x4821
 #define CMD_8SEGON3    0x4831
 #define CMD_8SEGON4    0x4841
 #define CMD_8SEGON5    0x4851
 #define CMD_8SEGON6    0x4861
 #define CMD_8SEGON7    0x4871
 #define CMD_8SEGON8    0x4801

 #define CMD_DIG0(x)    0x6800 | (x)
 #define CMD_DIG1(x)    0x6A00 | (x)
 #define CMD_DIG2(x)    0x6C00 | (x)
 #define CMD_DIG3(x)    0x6E00 | (x)
 #define CMD_GETKEY    0x4F00

 /*show define*/
 /******************************************************************
   a
   __
 f|__|b
 e|__|c .dop  中间那段为g
 d
 *******************************************************************/

 //数码管末一段的值
 #define BA        0x1
 #define BB        0x1<<1
 #define BC        0x1<<2
 #define BD        0x1<<3
 #define BE        0x1<<4
 #define BF        0x1<<5
 #define BG        0x1<<6
 #define BP        0x1<<7

 //数码管显示的字符的值
 #define TM_A        BF | BA | BB | BG | BE | BC
 #define TM_B        BF | BE | BG | BD | BC
 #define TM_C        BG | BE | BD
 #define TM_D        BB | BC | BD | BE | BG
 #define TM_E        BA | BF | BG | BE | BD
 #define TM_G        BA | BF | BE | BD | BC
 #define TM_F        BA | BF | BG | BE
 #define TM_H        BF | BE | BG | BC
 #define TM_I        BB | BC
 #define TM_J        BB | BC | BD | BE
 #define TM_K        BF | BG | BE | BC | BB
 #define TM_L        BF | BE | BD
 #define TM_M        0
 #define TM_N        BE | BG | BC
 #define TM_O        BG | BC | BD | BE
 #define TM_P        BA | BB |BG | BF |BE
 #define TM_Q        BF | BA | BB | BG | BC
 #define TM_R        BE | BG
 #define TM_S        BA | BF | BG | BC | BD
 #define TM_T        BF | BG | BE | BD
 #define TM_U        BF | BE | BD | BC | BB
 #define TM_V        BE | BD | BC
 #define TM_W        0
 #define TM_X        0
 #define TM_Y        0
 #define TM_Z        0

 #define TM_0        BA | BB | BC | BD | BE | BF
 #define TM_1        BB | BC
 #define TM_2        BA | BB | BG | BE | BD
 #define TM_3        BA | BB | BC | BD | BG
 #define TM_4        BF | BG | BB | BC
 #define TM_5        BA | BF | BG | BC | BD
 #define TM_6        BA | BF | BG | BE | BD | BC
 #define TM_7        BF | BA | BB | BC
 #define TM_8        BA | BB | BC | BD | BE | BF | BG
 #define TM_9        BA | BB | BC | BD | BG | BF

 unsigned char TM_NUM[] = {TM_0, TM_1, TM_2, TM_3, TM_4,
 TM_5, TM_6, TM_7, TM_8, TM_9}; //定义键值

 unsigned char TM_CHAR[] = {TM_A, TM_B, TM_C, TM_D, TM_E, TM_F, TM_G,
 TM_H, TM_I, TM_J, TM_K, TM_L, TM_M, TM_N,
 TM_O, TM_P, TM_Q, TM_R, TM_S, TM_T, TM_U,
 TM_V, TM_W, TM_X, TM_Y, TM_Z};

 /*对i2c操作函数*/
 static void i2c_start(void);
 static void i2c_stop(void);
 static void i2c_send(unsigned char data);
 static unsigned char i2c_recv(unsigned char *data);
 static int i2c_get_ack(void);
 static int i2c_get_ack_getkey(void);

 static void CLK_OUT(void);
 static void SDA_IN(void);
 static void SDA_OUT(void);
 static int GET_SDA(void);
 static void CLK_H(void);
 static void CLK_L(void);
 static void SDA_H(void);
 static void SDA_L(void);

 static unsigned char hd1650_sendcmd(unsigned short cmd);

 /*************函数实现******************/

 /* 设置时钟引脚为输出引脚 */
 static void CLK_OUT(void)
 {
     gpio_cblk_t gpio_dev;
     gpio_dev.pin = GPIO_PC31;
     gpio_dev.value = ;

     at91_set_gpio_output(gpio_dev.pin,gpio_dev.value);
 }

 /* 设置数据引脚为输出引脚 */
 static void SDA_OUT(void)
 {
     gpio_cblk_t gpio_dev;

     gpio_dev.pin = GPIO_PC30;
     gpio_dev.value = ;

     at91_set_gpio_output(gpio_dev.pin,gpio_dev.value);
 }

 /* 设置数据引脚为输入引脚 */
 static void SDA_IN(void)
 {
     gpio_cblk_t gpio_dev;

     gpio_dev.pin = GPIO_PC30;
     gpio_dev.value = ;

     at91_set_gpio_input(gpio_dev.pin,gpio_dev.value);
 }

 /* 取数据引脚的值 */
 static int GET_SDA(void)
 {
     gpio_cblk_t gpio_dev;

     gpio_dev.pin = GPIO_PC30;
     gpio_dev.value = at91_get_gpio_value(gpio_dev.pin);

     return gpio_dev.value;
 }

 /* 设置时钟引脚为高 */
 static void CLK_H(void)
 {
     gpio_cblk_t gpio_dev;
     gpio_dev.pin = GPIO_PC31;
     gpio_dev.value = ;

     at91_set_gpio_value(gpio_dev.pin,gpio_dev.value);
 }

 /* 设置时钟引脚为低*/
 static void CLK_L(void)
 {
     gpio_cblk_t gpio_dev;
     gpio_dev.pin = GPIO_PC31;
     gpio_dev.value = ;

     at91_set_gpio_value(gpio_dev.pin,gpio_dev.value);
 }

 /* 设置数据引脚为高 */
 static void SDA_H(void)
 {
     gpio_cblk_t gpio_dev;
     gpio_dev.pin = GPIO_PC30;
     gpio_dev.value = ;

     at91_set_gpio_value(gpio_dev.pin,gpio_dev.value);
 }

 /* 设置数据引脚为低 */
 static void SDA_L(void)
 {
     gpio_cblk_t gpio_dev;
     gpio_dev.pin = GPIO_PC30;
     gpio_dev.value = ;

     at91_set_gpio_value(gpio_dev.pin,gpio_dev.value);
 }

 /*****************************global function *********************************/
 void hd1650_init(void)
 {
     hd1650_sendcmd(CMD_8SEGON);

     /* clear 4 segment */
     hd1650_sendcmd(CMD_DIG0(0x00));
     hd1650_sendcmd(CMD_DIG1(0x00));
     hd1650_sendcmd(CMD_DIG2(0x00));
     hd1650_sendcmd(CMD_DIG3(0x00));
 }

 unsigned char asc2code(unsigned char src)
 {

     if(src <= )
         return TM_NUM[src];
     else if(src >= '' && src <= '')
         return TM_NUM[src - ''];
     else if(src >= 'a' && src <= 'z')
         return TM_CHAR[src - 'a'];
     else if(src >= 'A' && src <= 'Z')
         return TM_CHAR[src - 'A'];
     else
         return ;

 }

 /*data : 0-6
  * pos: 2
  * dot_flag:数码管的点的亮灭*/
 void hd1650_show_each(unsigned char data, unsigned char pos,unsigned char dot_flag)
 {
     unsigned char tmpData;
     //tmpData = asc2code(data);
     switch(pos)
     {
         case :
             hd1650_sendcmd(CMD_DIG0(tmpData));
             break;
         case :
             if(dot_flag)
                 hd1650_sendcmd(CMD_DIG1(tmpData|0x80));
             else
                 //hd1650_sendcmd(CMD_DIG1(tmpData&0x7f));
                 hd1650_sendcmd(CMD_DIG1(data));
             break;
         case :
             hd1650_sendcmd(CMD_DIG2(tmpData));
             break;
         case :
             hd1650_sendcmd(CMD_DIG3(tmpData));
             break;
     }
 }

 unsigned char hd1650_getkey(unsigned char *key)
 {
     unsigned char tmp = ;

     tmp = hd1650_sendcmd( CMD_GETKEY );

     if((tmp & 0x40)== )
         tmp = 0x2e;

     if( key )
         *key = tmp;

     return tmp;
 }

 /*****************************local function implemention*********************************/
 /*****************************DO NOT MODIFY*********************************/
 static void i2c_start(void)
 {
     CLK_OUT();
     SDA_OUT();

     SDA_H();
     DELAY();
     CLK_H();
     DELAY_BUILD();
     SDA_L();
     DELAY();
 }

 static void i2c_stop(void)
 {
     SDA_OUT();
     SDA_L();
     DELAY();

     CLK_H();
     DELAY_BUILD();
     SDA_H();
     DELAY();

 }

 /* MSB */
 static void i2c_send(unsigned char data)
 {
     unsigned char i = ;
     for(; i <  ; i++)
     {
         CLK_L();
         DELAY_BUILD();
         if( data & 0x80 )
             SDA_H();
         else
             SDA_L();
         data <<= ;
         DELAY();
         CLK_H();
         DELAY();
     }
 }

 static unsigned char i2c_recv(unsigned char *data)
 {
     unsigned char i = , tmp=;
     SDA_IN();
     for(; i <  ; i++)
     {
         CLK_L();
         DELAY();
         CLK_H();
         DELAY_BUILD();
         tmp <<= ;
         tmp |= GET_SDA();

         DELAY();
     }
     SDA_OUT();

     if( data )
         *data = tmp;
     return tmp;
 }

 static int i2c_get_ack(void)
 {
     int i = ;

     CLK_L();
     SDA_IN();
     DELAY_BUILD();

     CLK_H();
     DELAY();
     while(GET_SDA() && i-- );
     CLK_L();
     SDA_OUT();

     return ;/*!!!Fixme. this should return the right value, but sometimes the ack cannot get */
 }

 static int i2c_get_ack_getkey(void)
 {
     int i = ;

     CLK_L();
     SDA_IN();
     DELAY_BUILD();

     CLK_H();
     DELAY();
     while(!GET_SDA() && i-- );
     CLK_L();
     SDA_OUT();

     return ;/*!!!Fixme. this should return the right value, but sometimes the ack cannot get */
 }

 static unsigned char hd1650_sendcmd(unsigned short cmd)
 {
     unsigned char tmp_data = cmd>>;

     i2c_start();
     i2c_send(tmp_data);
     if( != i2c_get_ack() )
     {
         /* printk some error
         * hd1650 didnot send the ack
         */
     }

     if( cmd == CMD_GETKEY )
     {
         i2c_recv(&tmp_data);
         if( != i2c_get_ack_getkey())
         {
             /* printk some error
             * hd1650 didnot send the ack
             */
         }
     }else{
         tmp_data = cmd&0x0ff;
         i2c_send(tmp_data);
         if( != i2c_get_ack())
         {
             /* printk some error
             * hd1650 didnot send the ack
             */
         }
     }

     i2c_stop();

     return tmp_data;/* just valid for the CMD_GETKEY */
 }

 /*******END OF THE FILE *********/

 static int hd1650_ctrl_drv_open(struct node *node, struct file *file )
 {
     return ;
 }

 static int hd1650_ctrl_drv_release(struct node *node, struct file *file )
 {
     return ;
 }

 static long hd1650_ctrl_drv_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
     unsigned char key = ;

     int ret = ;

     switch (cmd) {
     case GET_KEY:
             hd1650_getkey(&key);
             ret = put_user(key,(int *)arg);
             break;
     default:
         return -EINVAL;

     }

     return ;
 }

 static struct file_operations hd1650_ctl_drv_fileops = {
     .owner = THIS_MODULE,
     .open = hd1650_ctrl_drv_open,
     .unlocked_ioctl = hd1650_ctrl_drv_unlocked_ioctl,
     .release = hd1650_ctrl_drv_release
 };

 static struct miscdevice hd1650_dev = {
     MISC_DYNAMIC_MINOR,
     "hd1650_dev",
     &hd1650_ctl_drv_fileops,
 };
 int gpio_ctrl_drv_module_init(void)
 {
     int ret = ;

     ret = misc_register(&hd1650_dev);
     if(ret != )
     {
         ret = -EFAULT;
         return ret;
     }
     hd1650_init();
     hd1650_show_each(0x40 ,,);
     printk("hd1650_drv_init ok\n");
     return ;
 }

 void gpio_ctrl_drv_module_exit(void)
 {

     misc_deregister(&hd1650_dev);
     printk("gpio_drv_exit ok\n");
 }

 module_init(gpio_ctrl_drv_module_init);
 module_exit(gpio_ctrl_drv_module_exit);
 MODULE_LICENSE("GPL");