OK6410之ADC驅動程序

參考
mini6410 實現 linux adc驅動詳解--muge0913版 http://www.linuxidc.com/Linux/2011-12/49243.htm

/*之前自己根據裸機程序改的，給ADC寄存器地址，不行
*調試了幾天，原因是" Unable to handle kernel paging request at virtual address 0x7E00B000 "
* 後來，還是按照人家的來吧!結果成功了*/

平台：Ubuntu 10.04 arm內核linux2.6.28

驅動程序

1. #include <linux/kernel.h>
2. #include <linux/module.h>
3. #include <linux/slab.h>
4. #include <linux/input.h>
5. #include <linux/init.h>
6. #include <linux/errno.h>
7. #include <linux/serio.h>
8. #include <linux/delay.h>
9. #include <linux/clk.h>
10. #include <linux/sched.h>
11. #include <linux/cdev.h>
12. #include <linux/miscdevice.h>
15. #include <asm/io.h>
16. #include <asm/irq.h>
17. #include <asm/uaccess.h>
19. #include <plat/regs-adc.h>
20. #include <mach/map.h>
22. static void __iomem * base_addr;
23. static struct clk *adc_clock;
25. /*#define ADCCON_BASE (0x7E00B000)
26. #define ADCCON (*(volatile unsigned *)(ADCCON_BASE+0x00)) // ADC control
27. #define ADCTSC (*(volatile unsigned *)(ADCCON_BASE+0x04)) // ADC touch screen control
28. #define ADCDLY (*(volatile unsigned *)(ADCCON_BASE+0x08)) // ADC start or Interval Delay
29. #define ADCDAT0 (*(volatile unsigned *)(ADCCON_BASE+0x0C)) // ADC conversion data 0
30. #define ADCDAT1 (*(volatile unsigned *)(ADCCON_BASE+0x10)) // ADC conversion data 1
31. #define ADCUPDN (*(volatile unsigned *)(ADCCON_BASE+0x14)) // Stylus Up/Down interrupt status
32. #define PRESCALE_DIS (0 << 14)
33. #define PRESCALE_EN (1 << 14)
34. #define PRSCVL(x) ((x) << 6)
35. #define ADC_INPUT(x) ((x) << 3)
36. #define ADC_START (1 << 0)
37. #define ADC_ENDCVT (1 << 15) */
39. /*ADC寄存器地址*/
40. #define __ADCREG(name) (*(volatile unsigned long *)(base_addr + name))
41. #define ADCCON __ADCREG(S3C_ADCCON) // ADC control
42. #define ADCTSC __ADCREG(S3C_ADCTSC) // ADC touch screen control
43. #define ADCDLY __ADCREG(S3C_ADCDLY) // ADC start or Interval Delay
44. #define ADCDAT0 __ADCREG(S3C_ADCDAT0) // ADC conversion data 0
45. #define ADCDAT1 __ADCREG(S3C_ADCDAT1) // ADC conversion data 1
46. #define ADCUPDN __ADCREG(S3C_ADCUPDN) // Stylus Up/Down interrupt status
49. /*根據s3c6410的文檔，設置相應的ADC控制器位*/
50. #define PRESCALE_DIS (0 << 14)
51. #define PRESCALE_EN (1 << 14)
52. #define PRSCVL(x) ((x) << 6)
53. #define ADC_INPUT(x) ((x) << 3)
54. #define ADC_START (1 << 0)
55. #define ADC_ENDCVT (1 << 15)
57. #define DEVICE_NAME "adc_dev"
59. static int adc_init()
60. {
61. printk("<0>adc_init sucessed!\n");
62. unsigned int preScaler = 0XFF;
63. printk("<0>111111111!\n");
64. ADCCON = (1<<14)|(preScaler<<6)|(0<<3)|(0<<2);
65. ADCCON |= ADC_START;
66. printk("<0>2222222222!\n");
67. return 0;
69. }
70. static int adc_open(struct inode *inode ,struct file *filp)
71. {
72. printk("adc_open!\n");
73. adc_init();
74. return 0;
75. }
76. static int adc_release(struct inode *inode,struct file *filp)
77. {
78. return 0;
79. }
80. static ssize_t adc_read(struct file *filp,char __user *buff,size_t size,loff_t *ppos)
81. {
82. printk("<0>adc_read!\n");
83. int ret=0;
84. ADCCON |= ADC_START;
85. while(ADCCON & 0x01);//check if Enable_start is low
86. while(!(ADCCON &0x8000));/*檢查轉換是否結束*/
87. ret = ADCDAT0 & 0x3ff; //重點，與參考的不同，我覺得這樣才是正確的
88. copy_to_user(buff,(char *)&ret,sizeof(ret));
90. return sizeof(ret);
91. }
93. static struct file_operations dev_fops =
94. {
95. .owner = THIS_MODULE,
96. .open = adc_open,
97. .release = adc_release,
98. .read = adc_read,
99. };
101. static struct miscdevice misc =
102. {
103. .minor = MISC_DYNAMIC_MINOR,
104. .name = DEVICE_NAME,
105. .fops = &dev_fops,
106. };
108. static int __init dev_init()
109. {
110. int ret;
113. base_addr =ioremap(0x7E00B000,0X20);//地址映射
114. printk("<0>ioremap sucessed!\n");
115. if(base_addr == NULL)
116. {
117. printk(KERN_ERR"failed to remap\n");
118. return -ENOMEM;
119. }
121. adc_clock = clk_get(NULL,"adc");//激活adc時鐘模塊
122. printk("<0>clk_get sucessed!\n");
123. if(!adc_clock)
124. {
125. printk(KERN_ERR"failed to get adc clock\n");
126. return -ENOENT;
127. }
128. clk_enable(adc_clock);
131. ret = misc_register(&misc);//混雜設備注冊
132. printk("dev_init return ret:%d\n",ret);
133. return ret;
134. }
135. static void __exit dev_exit()
136. {
137. iounmap(base_addr);//取消映射
139. if(adc_clock)//disable adc clock取消adc時鐘
140. {
141. clk_disable(adc_clock);
142. clk_put(adc_clock);
143. adc_clock =NULL;
144. }
145. misc_deregister(&misc);//注銷混雜設備
147. }
148. module_init(dev_init);
149. module_exit(dev_exit);
151. MODULE_LICENSE("GPL");
152. MODULE_AUTHOR("MUGE0913");

應用程序：

1. #include <stdio.h>
2. #include <fcntl.h>
3. #include <unistd.h>
5. int main()
6. {
7. int fp,adc_data,i;
8. int ret;
9. fp = open("/dev/adc_dev",O_RDWR);
10. if(fp<0)
11. printf("open failed!\n");
12. printf("open sucessed!\n");
14. for(i=0;i<100;i++)
15. {
16. ret = read(fp,&adc_data,sizeof(adc_data));
17. printf("read sucessed!\n");
18. if(ret<0)
19. {
20. printf("read ADC failed!\n");
21. return -1;
22. }
23. else
24. printf("Read ADC value is: %d\n",adc_data);
25. sleep(1);
26. }
27. close(fp);
28. return 0;
29. }

運行結果：