linux adc驅(qū)動(基于三星通用adc api)

linux adc驅(qū)動(基于三星通用adc api)

硬件平臺: 基于訊為開發(fā)板itop4412 scp 1G

驅(qū)動說明：

本驅(qū)動基于三星提供的通用api函數(shù)來實(shí)現(xiàn)的,具體adc寄存器操作有三星公司實(shí) 現(xiàn)，我們要做的是調(diào)用三星公司提供的api來實(shí)現(xiàn)我們自己的功能。下面對相關(guān)的結(jié)構(gòu)體和api函數(shù)進(jìn)行解析

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struct?s3c_adc_client?{??

struct?platform_device??*pdev;??

struct?list_head?????pend;??

wait_queue_head_t???*wait;??

unsigned?int?????????nr_samples;??

int??????????result;??

unsigned?char????????is_ts;??

unsigned?char????????channel;??

void????(*select_cb)(struct?s3c_adc_client?*c,?unsigned?selected);??

void????(*convert_cb)(struct?s3c_adc_client?*c,??

unsigned?val1,?unsigned?val2,??

unsigned?*samples_left);??

};??

一個具體s3c_adc_client結(jié)構(gòu)體來描述一個具體的客戶(一個具體的驅(qū)動)

2.我們需要在驅(qū)動中構(gòu)建這個驅(qū)動，并且注冊到linux的內(nèi)核

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struct?s3c_adc_client?*s3c_adc_register(struct?platform_device?*pdev,??

void?(*select)(struct?s3c_adc_client?*client,??

unsigned?int?selected),??

void?(*conv)(struct?s3c_adc_client?*client,??

unsigned?d0,?unsigned?d1,??

unsigned?*samples_left),??

unsigned?int?is_ts)??

例子:

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adcdev.client?=?s3c_adc_register(dev,?NULL,?NULL,?0);??

3.adc開始和停止轉(zhuǎn)換函數(shù)?

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int?s3c_adc_start(struct?s3c_adc_client?*client,??

unsigned?int?channel,?unsigned?int?nr_samples)??

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static?void?s3c_adc_stop(struct?s3c_adc_client?*client)??

4.讀取adc轉(zhuǎn)換數(shù)據(jù)

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int?s3c_adc_read(struct?s3c_adc_client?*client,?unsigned?int?ch)??

5.adc配置相關(guān)的函數(shù)
? ?具體的講解可以讀取博客http://blog.csdn.net/liuhaoyutz/article/details/7461268

平臺文件adc設(shè)備注冊

方法一:在配置文件/home/topeet/Android4.0/iTop4412_Kernel_3.0/arch/arm/mach-exynos中的mach-iTop4412.添加

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struct?platform_device?s3c_device_adc_ctl?=?{??

.name???????????????????=?"adc_ll",??

.id?????????????????????????????=?-1,??

};??

方法二:以模塊的方式注冊到內(nèi)核

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#include???

#include???

#include???

#include???

#include???

#include???

#include???

#include???

#include???

#include???

#include???

static?struct?platform_device?adc_dev?=?{??

.name?????????=?"adc_ll",??

.id???????=?-1,??

};??

static?int?__init?adc_dev_init(void)??

{??

platform_device_register(&adc_dev);??

return?0;??

}??

static?void?__exit?adc_dev_exit(void)??

{??

platform_device_unregister(&adc_dev);??

}??

module_init(adc_dev_init);??

module_exit(adc_dev_exit);??

MODULE_LICENSE("GPL");??

第二部分:基于雜項(xiàng)設(shè)備方式的設(shè)備驅(qū)動

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/*?

*?This?program?is?free?software;?you?can?redistribute?it?and/or?modify?

*?it?under?the?terms?of?the?GNU?General?Public?License?version?2?as?

*?published?by?the?Free?Software?Foundation.?

*/??

#include???

#include???

#include???

#include???

#include???

#include???

#include???

#include???

#include???

#include???

#include???

#define?DEVICE_NAME?????"adc"??

#define?DRIVER_NAME?????"adc_ll"??

typedef?struct?{??

struct?mutex?lock;??

struct?s3c_adc_client?*client;??

int?channel;??

}?ADC_DEV;??

static?ADC_DEV?adcdev;??

static?inline?int?exynos_adc_read_ch(void)?{??

int?ret;??

ret?=?mutex_lock_interruptible(&adcdev.lock);??

if?(ret?

return?ret;??

ret?=?s3c_adc_read(adcdev.client,?adcdev.channel);??

mutex_unlock(&adcdev.lock);??

return?ret;??

}??

static?inline?void?exynos_adc_set_channel(int?channel)?{??

if?(channel??3)??

return;??

adcdev.channel?=?channel;??

}??

static?ssize_t?exynos_adc_read(struct?file?*filp,?char?*buffer,??

size_t?count,?loff_t?*ppos)??

{??

char?str[20];??

int?value;??

size_t?len;??

value?=?exynos_adc_read_ch();??

printk("value?=?0x%x ",?value);??

len?=?sprintf(str,?"%d ",?value);??

if?(count?>=?len)?{??

int?r?=?copy_to_user(buffer,?str,?len);??

return?r???r?:?len;??

}?else?{??

return?-EINVAL;??

}??

}??

static?long?exynos_adc_ioctl(struct?file?*file,??

unsigned?int?cmd,?unsigned?long?arg)??

{??

#define?ADC_SET_CHANNEL?????0xc000fa01??

#define?ADC_SET_ADCTSC??????0xc000fa02??

switch?(cmd)?{??

case?ADC_SET_CHANNEL:??

exynos_adc_set_channel(arg);??

break;??

case?ADC_SET_ADCTSC:??

/*?do?nothing?*/??

break;??

default:??

return?-EINVAL;??

}??

return?0;??

}??

static?int?exynos_adc_open(struct?inode?*inode,?struct?file?*filp)??

{??

exynos_adc_set_channel(0);??

printk("adc?opened ");??

return?0;??

}??

static?int?exynos_adc_release(struct?inode?*inode,?struct?file?*filp)??

{??

printk("adc?closed ");??

return?0;??

}??

static?struct?file_operations?adc_dev_fops?=?{??

owner:??THIS_MODULE,??

open:???exynos_adc_open,??

read:???exynos_adc_read,??????

unlocked_ioctl:?exynos_adc_ioctl,??

release:????exynos_adc_release,??

};??

static?struct?miscdevice?misc?=?{??

.minor??=?MISC_DYNAMIC_MINOR,??

.name???=?DEVICE_NAME,??

.fops???=?&adc_dev_fops,??

};??

static?int?__devinit?exynos_adc_probe(struct?platform_device?*dev)??

{??

int?ret;??

mutex_init(&adcdev.lock);??

printk("%s,?%d ",?__FUNCTION__,?__LINE__);??

/*?Register?with?the?core?ADC?driver.?*/??

#if?1??

adcdev.client?=?s3c_adc_register(dev,?NULL,?NULL,?0);??

if?(IS_ERR(adcdev.client))?{??

printk("itop4412_adc:?cannot?register?adc ");??

ret?=?PTR_ERR(adcdev.client);??

goto?err_mem;??

}??

#endif??

printk("%s,?%d ",?__FUNCTION__,?__LINE__);??

ret?=?misc_register(&misc);??

printk("%s,?%d ",?__FUNCTION__,?__LINE__);??

printk(DEVICE_NAME" initialized ");??

err_mem:??

return?ret;??

}??

static?int?__devexit?exynos_adc_remove(struct?platform_device?*dev)??

{??

misc_deregister(&misc);??

s3c_adc_release(adcdev.client);??

return?0;??

}??

static?int?itop4412_adc_ctl_suspend?(struct?platform_device?*pdev,?pm_message_t?state)??

{??

printk("itop4412_led_ctl?suspend:power?off! ");??

return?0;??

}??

static?int?itop4412_adc_ctl_resume?(struct?platform_device?*pdev)??

{??

printk("itop4412_led_ctl?resume:power?on! ");??

return?0;??

}??

static?struct?platform_driver?exynos_adc_driver?=?{??

.probe??????=?exynos_adc_probe,??

.remove?????=?exynos_adc_remove,??

.suspend?=?itop4412_adc_ctl_suspend,??

.resume?=?itop4412_adc_ctl_resume,??

.driver?=?{??

.name???????=?DRIVER_NAME,??

.owner??????=?THIS_MODULE,??

},??

};??

static?int?__init?exynos_adc_init(void)??

{??

return?platform_driver_register(&exynos_adc_driver);??

}??

static?void?__exit?exynos_adc_exit(void)??

{??

platform_driver_unregister(&exynos_adc_driver);??

}??

module_init(exynos_adc_init);??

module_exit(exynos_adc_exit);??

MODULE_LICENSE("GPL");??

MODULE_AUTHOR("TOPEET?Inc.");??

測試代碼

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#include???

#include???

#include???

#include???

#include???

#include???

#include???

#include???

#include???

#include???

//#include???

//#include???

int?main(void){??

int?fd;??

char?*adc?=?"/dev/adc";??

char?buffer[512];??

int?len=0,?r=0;??

memset(buffer,0,sizeof(buffer));??

printf("adc?ready! ");??

if((fd?=?open(adc,?O_RDWR|O_NOCTTY|O_NDELAY))<0)??

printf("open?adc?err! ");??

else{??

printf("open?adc?success! ");??

len=read(fd,buffer,10);???

if(len?==?0)??

printf("return?null ");??

else{??

r?=?atoi(buffer);??

r?=?(int)(r*10000/4095);????//Datas??transition?to?Res??

printf("res?value?is?%d ",r);??

}?????????????

}??

}??

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