当前位置:网站首页>IIC bus realizes client device
IIC bus realizes client device
2022-07-05 22:10:00 【wwwlyj123321】
One 、Linux I2C Introduction to drive frame
I2C Bus and platform Bus is similar , It's just platform Bus is a virtual bus , and I2C The bus actually exists .
Linux Medium l2C It is also designed according to the platform bus model , Since it is also designed according to the platform bus model , Is it also divided into one device And a driver Well ? however I2C there device Don't cry device, But is called client.
among I2C Bus driver is SOC Of I2C Controller drive , Generally speaking, it is SOC The manufacturer has achieved good . and I2C The device driver is the user according to their own different devices actualized . The drive of each device is different , But the writing process is one . Let's analyze it in detail .
Two 、 Device side code writing
1、 Do not use device tree files
When you start writing I2C When the device is driven , First, add device information . First, let's take a look at not using the device tree , When using platform files , How to add I2C Equipment information . Pass in the platform file i2c_board_info Structure to describe a specific I2C equipment .
struct i2c_board_info
{
char type[I2C_NAME_SIZE]; /* I2C Device name */
unsigned short flags; /* sign */
unsigned short addr; /* I2C Device address */
void *platform_data;
struct dev_archdata *archdata;
struct device_node *of_node;
struct fwnode_handle *fwnode;
int irq;
};
static struct i2c_board_info mx27_3ds_i2c_camera =
{
I2C_BOARD_INFO("ov2640", 0x30),
};
Example :
#include <linux/init.h>
#include <linux/module.h>
#include <linux/i2c.h>
struct i2c adapter*i2c_ada;
// Allocate one I2C_client The pointer
struct i2c_cllent*i2c_client;
// Supported by I2C Device list for
struct i2c board_info ft5x06_info[]=
{
// Each item represents a I2C equipment , This sentence means that the name of this device is ft5×06_test, The device address is 0×38
{I2C_BOARD_INFO("ft5×06_test",0x38)},
}
static int ft5x06_client_init(void)
{
// call i2c_get_adapter To obtain a I2C Bus . because t5x06 It is attached to I2C2 On ,
// So this parameter is 1, from 0 Numbered starting
i2c_ada=i2c_get_adapter(1);
// hold I2C CLIENT and I2C Devices are associated
i2c_client=i2c_new_device(i2c_ada,ft5x06_info);
i2c_put_adapter(i2c_ada);// Release I2q
return e;
}
static void ft5x06_client_exit(void)
{
i2c_unregister_device(i2c_client);
}
module_init(ft5x06_client_init);
module_exit(ft5x06_client_exit);
MODULE_LICENSE("GPL");
2、 Use the device tree file
After loading the device tree , stay sys/bus/i2c/devices You can see it under the directory iic Equipment
In the device tree reg It's settings IIC The address of the device , therefore ,edt-ft5x06 The device address of is 0x38
3、 ... and 、driver Side code writing
The basic flow :
- i2c_driver Structure initialization
- After the initialization is completed, the i2c_driver Register into the kernel ,i2c_add_driver
- When the device and driver match successfully , Will execute probe function ,probe Function is to execute a set of processes driven by character devices .
#include <linux/init.h>
#include <linux/module.h>
#include <linux/i2c.h>
static const struct i2c_device_id ft5x06_id_ts[]={
{"xxx",0},
{}
};
static const struct of_device_id ft5x06_id[]=
{
{.compatible="edt,edt-ft5306",0,},
{.compatible="edt,edt-ft5x06",0,},
{.compatible="edt,edt-ft5406",0,},
{}
};
static struct i2c_driver ft5x06_driver={
.driver={
.owner=THIS_MODULE,
.name="ft5×06 test",
.of_match_table=ft5×06_id,// and device Match to use
},
.probe=ft5x06_probe,
.remove=ft5x06_remove,
.idtable=ft5x06_id_ts// It is also used for matching , Usually use of_match_table.
};
int(*probe)(struct l2c_client *i2c_cllent, const struct 12c_device_id * id)
{
// You can register one here misc Equipment or char Equipment
}
static int ft5x06_driver_init(void)
{
int ret;
ret=i2c_add_driver(&ft5x06_driver);
if(ret<0){
printk("i2c_add_ driver is error\n");
return ret;
}
}
static void ft5x06_driver_exit(void)
{
i2c_del_driver(&ft5xo6_driver);
}
module_init(ft5x06_driver_init);
module_exit(ft5x06_driver_exit);
MODULE_LICENSE("GPL");
边栏推荐
- 数博会精彩回顾 | 彰显科研实力,中创算力荣获数字化影响力企业奖
- Cobaltstrike builds an intranet tunnel
- A long's perception
- Web3为互联网带来了哪些改变?
- 【愚公系列】2022年7月 Go教学课程 004-Go代码注释
- Alternating merging strings of leetcode simple questions
- poj 3237 Tree(樹鏈拆分)
- MySQL连接断开报错MySQLdb._exceptions.OperationalError 4031, The client was disconnected by the server
- What if win11 is missing a DLL file? Win11 system cannot find DLL file repair method
- PyGame practical project: write Snake games with 300 lines of code
猜你喜欢
Leetcode simple question: check whether each row and column contain all integers
Unique occurrence times of leetcode simple questions
The simple problem of leetcode is to split a string into several groups of length K
Huawei game multimedia service calls the method of shielding the voice of the specified player, and the error code 3010 is returned
Pl/sql basic syntax
What if the files on the USB flash disk cannot be deleted? Win11 unable to delete U disk file solution tutorial
[Yugong series] go teaching course 003-ide installation and basic use in July 2022
Leetcode simple question ring and rod
Decorator learning 01
Oracle checkpoint queue - Analysis of the principle of instance crash recovery
随机推荐
Pl/sql basic syntax
大约SQL现场“这包括”与“包括在”字符串的写法
Implementing Lmax disruptor queue from scratch (IV) principle analysis of multithreaded producer multiproducersequencer
Database recovery strategy
Oracle hint understanding
Database tuning solution
Summarize the reasons for 2XX, 3xx, 4xx, 5xx status codes
Web3为互联网带来了哪些改变?
Matlab draws a cute fat doll
Tips for using SecureCRT
Oracle views the data size of a table
AD637 usage notes
Drawing HSV color wheel with MATLAB
微服务入门(RestTemplate、Eureka、Nacos、Feign、Gateway)
Understand the basic concept of datastore in Android kotlin and why SharedPreferences should be stopped in Android
Lightweight dynamic monitorable thread pool based on configuration center - dynamictp
Cobaltstrike builds an intranet tunnel
How to view Apache log4j 2 remote code execution vulnerability?
Blocking of concurrency control
Evolution of large website architecture and knowledge system