“I2C overview”的版本间的差异

2020年11月6日 (五) 17:53的最新版本

本文提供有关I2C系统以及如何插入I2C STM32驱动程序的基本信息。

1 Framework purpose
2 System overview
- 2.1 Component description
- 2.2 API description
3 Configuration
- 3.1 Kernel configuration
- 3.2 Device tree configuration
4 How to use the framework
5 How to trace and debug the framework
- 5.1 How to trace
  - 5.1.1 Dynamic trace
  - 5.1.2 Bus snooping
- 5.2 How to debug
6 Source code location
7 To go further
8 References

Framework purpose

本文旨在解释如何更准确地使用I2C：

如何在 Linux^® BSP 上激活I2C接口
如何从内核空间访问I2C
如何从用户空间访问I2C。

本文介绍了在master 和 slave模式下的 Linux^® I²C^[1]接口。

通过该外部资源，提出了I²C^[2] 的简介。

有关 slave 接口的说明，请参见slave-interface^[3].

System overview

I²C 是“ IC间总线”的缩写，“ Inter-IC”总线是一种简单的总线协议，广泛用于低数据速率通信就足够了。
I2C是微处理器 I²C 外围设备接口的缩写。

在微处理器设备周围，用户可以添加许多 I²C 外部设备来创建定制板。可以通过I2C从用户空间或内核空间访问每个外部设备。

Implementation architecture

Component description

Board external I²C devices

从设备X是相对于STM32表现为从设备的物理设备(通过 I²C 总线连接到STM32)。

STM32仍是 I²C 总线上的主机。

主设备X是相对于STM32充当主设备的物理设备 (通过 I²C 总线连接到STM32) 。

在这种情况下，STM32充当 I²C 总线上的从设备。

STM32 I2C internal peripheral controller

它对应于STM32 I2C适配器，该适配器处理与同一总线上连接的任何外部设备的通信。
它管理从设备（如果有的话），并且如果连接了外部主设备，则可以充当从设备。 STM32微处理器设备通常嵌入 I2C internal peripheral 的多个实例，以管理多个I2C总线。提供了一个驱动程序，用于控制硬件。

i2c-stm32

内部STM32 I2C控制器驱动程序向基于i2c-core-base的ST I2C内部外围控制器抽象层提供了支持。
它定义了I2C核心基础要使用的所有I2C传输方法算法，其中包括I2C和SMBus^[4] 传输API ，注册/注销从属API和功能检查。
即使I2C Core可以在整个标准I2C消息中模拟SMBus协议，所有SMBus功能都在驱动程序中实现。

i2c-core

这是通信的大脑：它实例化和管理所有总线和外围设备。

如其名称所述，为i2c-core ，它是I2C核心引擎，但它也负责解析适配器和/或设备的设备树条目
i2c-core-smbus处理所有与SMBus相关的API。
i2c-core-slave 管理充当STM32中的从设备的I2C设备。
i2c-smbus处理特定的协议SMBus警报。 (由I2C核心库处理的SMBus主机通知)

Board peripheral drivers

该层表示与物理外围设备关联的所有驱动程序。
外围设备驱动程序可以编译为内核模块，也可以直接编译为内核(也称为内置).

i2c-dev

i2c-dev是用户与外围设备之间的接口。它是一个内核驱动程序，它使用此dev-interface API提供对用户空间应用程序的I2C总线访问。请参见示例API Description.

i2c-tools

I2C Tools软件包提供了：

shell命令通过i2c-dev通过SMBus协议访问I2C
library 将SMBus函数用于用户空间应用程序，所有这些函数都在这个SMBus协议API中进行了描述。

Note : 某些外围设备无需SMBus协议即可工作。

Application

应用程序可以使用 I2C Tools, libI2C (I2C Tools), i2c-dev.

API description

libi2c

I2C工具^[5] 软件包提供了一组Shell命令，这些命令主要使用SMBus协议访问I2C和API，开发一个应用程序（libi2c）。
所有工具和libi2c均依赖SMBus API，但 i2ctransfer不是，因为它依赖于标准I2C协议。
工具和libi2c通过devfs读/写/ ioctl调用访问SMBus和I2C API。

SMBus协议构成 I²C 规范中定义的数据传输格式的子集。
SMBus规范中定义的标准方法无法访问不符合这些协议的I2C外设。
有关 I²C^[6] 和SMBus协议^[7]的更多详细信息，请参见外部参考。

libi2c API模拟“SMBus协议”^[7] ，但在用户空间级别。
此库中的API与 SMBus protocol^[7]中的API相同。除了特定的SMBus协议API（例如SMBus Host Notify和SMBus Alert）外，所有SMBus API均在此处重复。

User space application

User space application 正在使用内核驱动程序（i2c-dev），该驱动程序通过devfs提供I2C访问。
支持的系统调用: open(), close(), read(), write(), ioctl(), llseek(), release().

Supported ioctls commands
Constant	Description
I2C_SLAVE/I2C_SLAVE_FORCE	Sets slave address for read/write operations
I2C_FUNCS	Gets bus functionalities
I2C_TENBIT	10bits address support
I2C_RDWR	Combined R/W transfer (one STOP only)
I2C_SMBUS	Perform an SMBus transfer instead of standard I²C

以上命令是主要命令(框架中定义了更多命令)：请参见dev-interface API^[8] 获取完整列表。

Kernel space peripheral driver

Kernel space peripheral driver 同时访问 I²C 和SMBus设备，并使用以下 I2C核心API^[9]

Configuration

Kernel configuration

使用Linux Menuconfig工具在内核配置中激活I2C： Menuconfig or how to configure kernel.

[x] Device Drivers
    [x] I2C support
        [x] I2C device interface
        [ ] I2C Hardware Bus support
            [x] STMicroelectronics STM32F7 I2C support

这可以在您的内核中手动完成：

CONFIG_I2C=y
CONFIG_I2C_CHARDEV=y
CONFIG_I2C_STM32F7=y

如果软件需要SMBus特定协议，例如SMBus Alert协议和SMBus Host Notify协议，则添加：

[x] Device Drivers
    [x] I2C support
        [x] I2C device interface
        [ ] Autoselect pertinent helper modules
        [x] SMBus-specific protocols
        [ ] I2C Hardware Bus support
            [x] STMicroelectronics STM32F7 I2C support

这可以在您的内核中手动完成：

CONFIG_I2C_SMBUS=y

Device tree configuration

请参考I2C device tree configuration.

How to use the framework

本节介绍如何使用框架访问I2C外设。

i2c-tools package

在用户空间中将 I2C Tools 与基于SMBus API协议^[7] 的shell命令配合使用，可以轻松快速地访问I2C，而无需编写任何代码。
用例许多外壳命令允许检测I2C总线并通过SMBus协议访问I2C外设。该软件包包括一个库，以便在C程序中使用SMBus协议。
有关详细说明，请访问 link。

User space application

允许在用户空间中使用带有此 device interface的i2c-dev内核驱动程序来开发应用程序。^[8].
用例：通过加载i2c-dev模块，用户可以通过/dev接口访问I2C。通过函数open()、ioctl()、read()、write()和lose()可以非常轻松地访问I2C。如果外围设备兼容，则也可以使用 I2C Tools 库。

Kernel space driver

允许使用I2C core API开发已编译到内核或作为模块插入的驱动程序^[9]
Linux内核提供了有关如何编写I2C客户端驱动程序的示例 ^[10]
用例 : 使用内核空间内的特定驱动程序控制I2C外设。例如，驱动程序在系统引导时初始化所有参数，并通过sysfs创建对外围数据的访问。

Board description

要实例化外围设备，存在几种方法：更多细节，请参见 实例化设备^[11] 。

下列资料主要介绍 device tree, sysfs 和 Application Code.

Device tree

设备树是对内核用来了解连接哪些设备的硬件的描述。为了在I2C总线上添加从设备，请使用与新设备相关的信息来完成设备树。

例子： 带有EEPROM

 1 &i2c4 {
 2     status = "okay";
 3     i2c-scl-rising-time-ns = <185>;
 4     i2c-scl-falling-time-ns = <20>;
 5 
 6     dmas = <&mdma1 36 0x0 0x40008 0x0 0x0 0>,
 7            <&mdma1 37 0x0 0x40002 0x0 0x0 0>;
 8     dma-names = "rx", "tx";
 9     
10     eeprom@50 {
11     compatible = "at,24c256";
12         pagesize = <64>;
13         reg = <0x50>;
14     };
15 };

EEPROM现在在地址为0x50的总线i2c-X上实例化（X取决于运行时探测的适配器数量），并且它与使用相同属性注册的驱动程序兼容。
请注意，驱动程序指定SCL上升/下降时间作为输入。

有关正确的配置和说明，请参考 I2C device tree configuration。

请注意，I2C规范为特殊目的保留了一系列地址，请参阅 slave addressing^[12].
下图显示了设备树及其用法之间的关系：

sysfs

通过sysfs，i2c-core提供了实例化和删除外围设备的可能性：

在地址0xAA上添加附加到总线x的外围设备“ myPeripheralName”
注意字段 "myPeripheralName" 应该与兼容的驱动程序字符串具有相同的名称，以便它们彼此匹配。

echo myPeripheralName 0xAA > i2c-x/new_device

卸下连接到总线x的地址0xAA的外围设备

echo 0xAA > i2c-x/delete_device

进入每个驱动程序目录(/sys/bus/i2c/drivers/at24/ for the EEPROM peripheral example), it is possible to:
将外围设备与驱动器绑定

echo 3-0050 > bind

取消外围设备与驱动程序的绑定

echo 3-0050 > unbind

Application code

这是用于在不使用设备树的情况下将新的从设备注册到I2C适配器的极简代码。

 1 #include <linux/i2c.h>
 2 
 3 /* 创建具有从属地址的设备 <0x42> */
 4 static struct i2c_board_info stm32_i2c_test_board_info = {
 5     I2C_BOARD_INFO("i2c_test07", 0x42);
 6 };
 7 
 8 /* 
 9   跳过模块定义创建
10 */
11 
12 static int __init i2c_test_probe(void)
13 {
14     struct i2c_adapter *adap;
15     struct i2c_client *client;
16 
17     /* Get I2C controller */
18     adap = i2c_get_adapter(i);
19     /* Build new devices */
20     client = i2c_new_device(adap,&stm32_i2c_test_board_info);
21 }

How to trace and debug the framework

在 Linux^® 内核中，有调试和监视I2C的标准方法。调试可以在不同的级别进行：硬件和软件。

How to trace

Dynamic trace

此处提供了详细的动态跟踪 How to use the kernel dynamic debug

 Board $> echo  "file i2c-* +p" > /sys/kernel/debug/dynamic_debug/control

此命令在运行时启用与I2C内核和驱动程序有关的所有跟踪。

尽管如此，在 Linux® Kernel menu configuration 级，它提供了调试的粒度：核心和/或总线。

Device Drivers -> 
    [*] I2C support ->
        [*] I2C Core debugging messages
        [*] I2C Bus debugging messages

I2C核心调试消息 (CONFIG_I2C_DEBUG_CORE)
使用DEBUG标志编译I2C引擎。
I2C总线调试消息（CONFIG_I2C_DEBUG_BUS)
用DEBUG标志编译I2C驱动程序。

同时具有 I2C Core 和 I2C Bus调试消息等同于使用上述动态调试命令：dmesg输出将相同。

Bus snooping

总线侦听对于查看I2C协议以及查看STM32和设备之间交换的内容非常方便。
由于此调试功能使用 Ftrace，因此请参考Ftrace 文章以启用它。

为了访问事件以进行I2C总线侦听，必须进行以下内核配置：

Kernel hacking -> 
    [*] Tracers ->
        [*] Trace process context switches and events

根据所使用的协议，有必要启用i2c和/或smbus跟踪器，如下所示：

echo 1 > /sys/kernel/debug/tracing/events/i2c/enable
echo 1 > /sys/kernel/debug/tracing/events/smbus/enable

然后使用以下命令启用跟踪：

echo 1 > /sys/kernel/debug/tracing/tracing_on

After a transaction, trace can be read by looking at the trace file:

cat /sys/kernel/debug/tracing/trace

这是输出的一部分，以及在i2c-0总线上使用“ i2cdetect”命令时的外观：

... smbus_write: i2c-0 a=003 f=0000 c=0 QUICK l=0 []
... smbus_result: i2c-0 a=003 f=0000 c=0 QUICK wr res=-6
... smbus_write: i2c-0 a=004 f=0000 c=0 QUICK l=0 []
... smbus_result: i2c-0 a=004 f=0000 c=0 QUICK wr res=-6

请注意，i2cdetect，i2cget / i2cput，i2cdump正在执行基于smbus协议的事务.

相反，以下输出显示了以I2C协议模式完成的事务的结果:

... i2c_write: i2c-1 #0 a=042 f=0000 l=1 [45]
... i2c_result: i2c-1 n=1 ret=1
... i2c_write: i2c-2 #0 a=020 f=0000 l=1 [45]
... i2c_result: i2c-2 n=1 ret=1

I2C总线走线的使用在此处进行了很好的描述 I2C 总线监听^[13].

How to debug

Detect I2C configuration

sysfs

实例化外围设备后，i2c-core和内核会通过sysfs导出不同的文件：
/sys/class/i2c-adapter/i2c-x 显示所有实例化的I2C总线，其中“ x”为I2C总线号。
/sys/bus/i2c/devices列出所有实例化的外围设备。例如，有一个名为3-0050的目录，它对应于总线号3上地址0x50的EEPROM外设。
/sys/bus/i2c/drivers 列出所有实例化的驱动程序。名为at24 /的目录是EEPROM的驱动程序。

/sys/bus/i2c/devices/3-0050/
            /       /
            /       /i2c-3/3-0050/
            /
            /drivers/at24/3-0050/

/sys/class/i2c-adapter/i2c-0/
                      /i2c-1/
                      /i2c-2/
                      /i2c-3/3-0050/
                      /i2c-4/
                      /i2c-5/

devfs

如果将i2c-dev驱动程序编译到内核中，则目录dev包含所有编号为i2c-0至i2c-n的I2C总线名称。

/dev/i2c-0
    /i2c-1
    /i2c-2
    /i2c-3
    /i2c-4
    /i2c-n

i2c-tools

检查所有I2C实例化的适配器：

Board $>i2cdetect -l

有关完整说明，请参阅 i2c-tools。

Source code location

I2C框架驱动程序位于drivers/i2c drivers/i2c| |}} drivers/i2c drivers/i2c
I2C STM32驱动程序位于drivers/i2c/busses/i2c-stm32f7.c| |}} drivers/i2c/busses/i2c-stm32f7.c
2C总线用户接口在 include/uapi/linux/i2c.h| |}} include/uapi/linux/i2c.h ，I2C dev在 include/uapi/linux/i2c-dev.h| |}} include/uapi/linux/i2c-dev.h .

To go further

Bootlin写了一篇很好的演练文章： 为STM32MP1构建Linux系统：连接I2C传感器^[14]

References

↑ http://www.i2c-bus.org/
↑ https://bootlin.com/doc/training/linux-kernel/
↑ Documentation/i2c/slave-interface| |}} Documentation/i2c/slave-interface slave interface description
↑ https://www.i2c-bus.org/smbus/
↑ https://i2c.wiki.kernel.org/index.php/I2C_Tools
↑ Documentation/i2c/summary| |}} Documentation/i2c/summary I2C and SMBus summary
↑ ^7.0^7.1^7.2^7.3 Documentation/i2c/smbus-protocol| |}} Documentation/i2c/smbus-protocol SMBus protocol summary
↑ ^8.0^8.1 Documentation/i2c/dev-interface| |}} Documentation/i2c/dev-interface dev-interface API
↑ ^9.0^9.1 https://www.kernel.org/doc/html/latest/driver-api/i2c.html
↑ https://www.kernel.org/doc/html/latest/i2c/writing-clients.html
↑ Documentation/i2c/instantiating-devices| |}} Documentation/i2c/instantiating-devices How to instantiate I2C devices
↑ http://www.totalphase.com/support/articles/200349176-7-bit-8-bit-and-10-bit-I2C-Slave-Addressing Slave addressing
↑ https://linuxtv.org/wiki/index.php/Bus_snooping/sniffing#i2c I2C Bus Snooping
↑ https://bootlin.com/blog/building-a-linux-system-for-the-stm32mp1-connecting-an-i2c-sensor/

[More_about_I2C-1] ttp://www.i2c-bus.org/

[I2C_introduction-2] ttps://bootlin.com/doc/training/linux-kernel/

[3] Documentation/i2c/slave-interface| |}} Documentation/i2c/slave-interface slave interface description

[More_about_SMBus-4] ttps://www.i2c-bus.org/smbus/

[I2C_tools-5] ttps://i2c.wiki.kernel.org/index.php/I2C_Tools

[I2C_summary-6] Documentation/i2c/summary| |}} Documentation/i2c/summary I2C and SMBus summary

[SMBus_protocol-7] 7.0^7.1^7.2^7.3 Documentation/i2c/smbus-protocol| |}} Documentation/i2c/smbus-protocol SMBus protocol summary

[dev-interface_API-8] 8.0^8.1 Documentation/i2c/dev-interface| |}} Documentation/i2c/dev-interface dev-interface API

[I2C_core_API-9] 9.0^9.1 https://www.kernel.org/doc/html/latest/driver-api/i2c.html

[10] ttps://www.kernel.org/doc/html/latest/i2c/writing-clients.html

[11] Documentation/i2c/instantiating-devices| |}} Documentation/i2c/instantiating-devices How to instantiate I2C devices

[slave_addressing-12] ttp://www.totalphase.com/support/articles/200349176-7-bit-8-bit-and-10-bit-I2C-Slave-Addressing Slave addressing

[I2C_bus_snooping-13] ttps://linuxtv.org/wiki/index.php/Bus_snooping/sniffing#i2c I2C Bus Snooping

[Building_a_Linux_system_for_the_STM32MP1:_connecting_an_I2C_sensor-14] ttps://bootlin.com/blog/building-a-linux-system-for-the-stm32mp1-connecting-an-i2c-sensor/

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@@ 第1行： / 第1行： @@
-This article provides basic information on I2C system and how I2C STM32 drivers is plugged upon.
+本文提供有关I2C系统以及如何插入I2C STM32驱动程序的基本信息。
 ==Framework purpose==
-This article aims to explain how to use I2C and more accurately:
+本文旨在解释如何更准确地使用I2C：
-* how to activate I2C interface on a Linux® BSP
+* 如何在 Linux<sup>&reg;</sup> BSP 上激活I2C接口
-* how to access I2C from kernel space
+* 如何从内核空间访问I2C
-* how to access I2C from user space.
+* 如何从用户空间访问I2C。
-This article describes Linux<sup>&reg;</sup> I<sup>2</sup>C<ref name="More about I2C">http://www.i2c-bus.org/</ref> interface in '''master''' and '''slave''' modes.
+本文介绍了在'''master''' 和 '''slave'''模式下的 Linux<sup>&reg;</sup> I<sup>2</sup>C<ref name="More about I2C">http://www.i2c-bus.org/</ref>接口。
-An introduction to I<sup>2</sup>C<ref name="I2C introduction">https://bootlin.com/doc/training/linux-kernel/</ref> is proposed through this external resource.
+通过该外部资源，提出了I<sup>2</sup>C<ref name="I2C introduction">https://bootlin.com/doc/training/linux-kernel/</ref> 的简介。
-For a '''slave''' interface description, see '''slave-interface'''<ref>{{CodeSource | Linux kernel | Documentation/i2c/slave-interface}} slave interface description</ref>.<br />
+有关 '''slave''' 接口的说明，请参见'''slave-interface'''<ref>{{CodeSource | Linux kernel | Documentation/i2c/slave-interface}} slave interface description</ref>.<br />
 ==System overview==
-I<sup>2</sup>C is an acronym for the “Inter-IC” bus, a simple bus protocol which is widely used where low data rate communications suffice.<br />
+I<sup>2</sup>C 是“ IC间总线”的缩写，“ Inter-IC”总线是一种简单的总线协议，广泛用于低数据速率通信就足够了。<br />
-I2C is the acronym for the microprocessor I<sup>2</sup>C peripheral interface.
+I2C是微处理器 I<sup>2</sup>C 外围设备接口的缩写。
-Around the microprocessor device, the user can add many I<sup>2</sup>C external devices to create a custom board. Each external device can be accessed through the I2C from the user space or the kernel space.
+在微处理器设备周围，用户可以添加许多 I<sup>2</sup>C 外部设备来创建定制板。 可以通过I2C从用户空间或内核空间访问每个外部设备。
 {{ImageMap|
@@ 第43行： / 第43行： @@
 ===Component description===
 ====Board external I<sup>2</sup>C devices====
-* Slave devices X are physical devices (connected to STM32 via I<sup>2</sup>C bus) that behave as Slave with respect to STM32. <br/> STM32 remains the master on the I<sup>2</sup>C bus.
+* 从设备X是相对于STM32表现为从设备的物理设备(通过 I<sup>2</sup>C 总线连接到STM32)。<br/>
-* Master devices X are physical devices (connected to STM32 via I<sup>2</sup>C bus) that behave as Master with respect to STM32. <br/>STM32 behaves as a Slave in this case on the I<sup>2</sup>C bus.
+ STM32仍是 I<sup>2</sup>C 总线上的主机。
+* 主设备X是相对于STM32充当主设备的物理设备 (通过 I<sup>2</sup>C 总线连接到STM32) 。<br/>
+在这种情况下，STM32充当 I<sup>2</sup>C 总线上的从设备。
 ====STM32 I2C internal peripheral controller====
-It corresponds to STM32 I2C adapter that handles communications with any external device connected on the same bus. <br/>It manages Slave devices (if any) and behaves as Slave if an external Master is connected.
+它对应于STM32 I2C适配器，该适配器处理与同一总线上连接的任何外部设备的通信。 <br/>它管理从设备（如果有的话），并且如果连接了外部主设备，则可以充当从设备。
+STM32微处理器设备通常嵌入 [[I2C internal peripheral]] 的多个实例，以管理多个I2C总线。 提供了一个驱动程序，用于控制硬件。
-STM32 microprocessor devices usually embed several instances of the [[I2C internal peripheral]] allowing to manage multiple I2C buses. A driver is provided that pilots the hardware.
 ====i2c-stm32====
-The internal STM32 I2C controller driver offers ST I2C internal peripheral controller abstraction layer to i2c-core-base.<br/> It defines all I2C transfer method algorithms to be used by I2C Core base, this includes I2C and SMBus<ref name="More about SMBus">https://www.i2c-bus.org/smbus/</ref> transfers API, Register/Unregister slave API and functionality check.<br/> Even if I2C Core can emulate SMBus protocol throughout standard I2C messages, all SMBus functions are implemented within the driver.
+内部STM32 I2C控制器驱动程序向基于i2c-core-base的ST I2C内部外围控制器抽象层提供了支持。<br/> 它定义了I2C核心基础要使用的所有I2C传输方法算法，其中包括I2C和SMBus<ref name="More about SMBus">https://www.i2c-bus.org/smbus/</ref> 传输API ，注册/注销从属API和功能检查。<br/> 即使I2C Core可以在整个标准I2C消息中模拟SMBus协议，所有SMBus功能都在驱动程序中实现。
 ====i2c-core====
-This is the brain of the communication: it instantiates and manages all buses and peripherals.
+这是通信的大脑：它实例化和管理所有总线和外围设备。
-* '''{{Highlight|i2c-core}}''' as stated by its name, this is the I2C core engine but it is also in charge of parsing device tree entries for both adapter and/or devices
+* 如其名称所述，为'''{{Highlight|i2c-core}}''' ，它是I2C核心引擎，但它也负责解析适配器和/或设备的设备树条目
-* '''{{Highlight|i2c-core-smbus}}''' deals with all SMBus related API.
+* '''{{Highlight|i2c-core-smbus}}'''处理所有与SMBus相关的API。
-* '''{{Highlight|i2c-core-slave}}''' manages I2C devices acting as slaves running in STM32.
+* '''{{Highlight|i2c-core-slave}}''' 管理充当STM32中的从设备的I2C设备。
-* '''{{Highlight|i2c-smbus}}''' handles specific protocol SMBus Alert. (SMBus host notification handled by I2C core base)
+* '''{{Highlight|i2c-smbus}}'''处理特定的协议SMBus警报。 (由I2C核心库处理的SMBus主机通知)
 ====Board peripheral drivers====
-This layer represents all drivers associated to physical peripherals.<br/>
+该层表示与物理外围设备关联的所有驱动程序。<br/>
-A peripheral driver can be compiled as a kernel module or directly into the kernel (aka built-in).
+外围设备驱动程序可以编译为内核模块，也可以直接编译为内核(也称为内置).
 ====i2c-dev====
-i2c-dev is the interface between the user and the peripheral.
+i2c-dev是用户与外围设备之间的接口。
-It is a kernel driver offering I2C bus access to user space application using this dev-interface API.
+它是一个内核驱动程序，它使用此dev-interface API提供对用户空间应用程序的I2C总线访问。
-See examples [[I2C overview#API_description|API Description]].
+请参见示例[[I2C overview#API_description|API Description]].
 ====i2c-tools====
-[[I2C_i2c-tools | I2C Tools]] package provides:
+[[I2C_i2c-tools | I2C Tools]]软件包提供了：
-* shell commands to access I2C with SMBus protocol via i2c-dev
+* shell命令通过i2c-dev通过SMBus协议访问I2C
-* library to use SMBus functions into a user space application
+* library 将SMBus函数用于用户空间应用程序，所有这些函数都在这个SMBus协议API中进行了描述。<br/>
-All those functions are described in this smbus-protocol API.<br/>
+'''Note''' : 某些外围设备无需SMBus协议即可工作。
-'''Note''' : some peripherals can work without SMBus protocol.
 ====Application====
-An application can control all peripherals using different methods offered by [[I2C_i2c-tools | I2C Tools]], libI2C ([[I2C_i2c-tools|I2C Tools]]), i2c-dev.
+应用程序可以使用 [[I2C_i2c-tools | I2C Tools]], libI2C ([[I2C_i2c-tools|I2C Tools]]), i2c-dev.
 ===API description===
 ====libi2c====
-I2C tools<ref name="I2C tools">https://i2c.wiki.kernel.org/index.php/I2C_Tools</ref> package offers a set of shell commands using mostly SMBus protocols to access I2C and an API to develop an application (libi2c).<br/>
+I2C工具<ref name="I2C tools">https://i2c.wiki.kernel.org/index.php/I2C_Tools</ref> 软件包提供了一组Shell命令，这些命令主要使用SMBus协议访问I2C和API， 开发一个应用程序（libi2c）。<br/>
-All tools and libi2c rely on SMBus API but [[I2C_i2c-tools#I2C_Transfer| i2ctransfer]] does not since it relies on standard I2C protocol.<br/>
+所有工具和libi2c均依赖SMBus API，但[[I2C_i2c-tools#I2C_Transfer| i2ctransfer]]不是，因为它依赖于标准I2C协议。<br/>
-Tools and libi2c access SMBus and I2C API through out '''devfs''' read/write/ioctl call.<br/><br/>
+工具和libi2c通过'''devfs'''读/写/ ioctl调用访问SMBus和I2C API。<br/><br/>
-The SMBus protocols constitute a subset of the data transfer formats defined in the I<sup>2</sup>C specification. <br/>
+SMBus协议构成 I<sup>2</sup>C 规范中定义的数据传输格式的子集。 <br/>
-I2C peripherals that do not comply to these protocols cannot be accessed by standard methods as defined in the SMBus specification. <br/>
+SMBus规范中定义的标准方法无法访问不符合这些协议的I2C外设。 <br/>
-See external references for further details on '''I<sup>2</sup>C'''<ref name="I2C summary">{{CodeSource | Linux kernel | Documentation/i2c/summary}} I2C and SMBus summary</ref> and '''SMBus protocol'''<ref name="SMBus protocol">{{CodeSource | Linux kernel | Documentation/i2c/smbus-protocol}} SMBus protocol summary</ref>.
+有关 '''I<sup>2</sup>C'''<ref name="I2C summary">{{CodeSource | Linux kernel | Documentation/i2c/summary}} I2C and SMBus summary</ref> 和'''SMBus协议'''<ref name="SMBus protocol">{{CodeSource | Linux kernel | Documentation/i2c/smbus-protocol}} SMBus protocol summary</ref>的更多详细信息，请参见外部参考。
-libi2c API mimics ''SMBus protocol''<ref name="SMBus protocol">{{CodeSource | Linux kernel | Documentation/i2c/smbus-protocol}} SMBus protocol summary</ref> but at user space level. <br/>
+libi2c API模拟“SMBus协议”<ref name="SMBus protocol">{{CodeSource | Linux kernel | Documentation/i2c/smbus-protocol}} SMBus protocol summary</ref> ，但在用户空间级别。<br/>
-Same API can be found in this library as in ''SMBus protocol''<ref name="SMBus protocol">{{CodeSource | Linux kernel | Documentation/i2c/smbus-protocol}} SMBus protocol summary</ref>. All SMBus API are duplicated here with the exception of specific SMBus protocol API like SMBus Host Notify and SMBus Alert.
+此库中的API与 ''SMBus protocol''<ref name="SMBus protocol">{{CodeSource | Linux kernel | Documentation/i2c/smbus-protocol}} SMBus protocol summary</ref>中的API相同。除了特定的SMBus协议API（例如SMBus Host Notify和SMBus Alert）外，所有SMBus API均在此处重复。
 ====User space application====
-[[#user_space_application| User space application]] is using a kernel driver (i2c-dev) which offers I2C access through devfs.<br />
+[[#user_space_application| User space application]] 正在使用内核驱动程序（i2c-dev），该驱动程序通过devfs提供I2C访问。<br />
-'''Supported system calls : '''open(), close(), read(), write(), ioctl(), llseek(), release().<br />
+'''支持的系统调用: '''open(), close(), read(), write(), ioctl(), llseek(), release().<br />
 {|
 |+ Supported ioctls commands
@@ 第119行： / 第119行： @@
 |Perform an SMBus transfer instead of standard I<sup>2</sup>C
 |}
-The above commands are the main ones (more are defined in the framework):
+以上命令是主要命令(框架中定义了更多命令)：
-see '''dev-interface API'''<ref name="dev-interface API">{{CodeSource | Linux kernel | Documentation/i2c/dev-interface}} dev-interface API</ref> for complete list.
+请参见'''dev-interface API'''<ref name="dev-interface API">{{CodeSource | Linux kernel | Documentation/i2c/dev-interface}} dev-interface API</ref> 获取完整列表。
 ====Kernel space peripheral driver====
-[[#Kernel_space_driver| Kernel space peripheral driver]] accesses both I<sup>2</sup>C and SMBus devices and uses following '''I2C core API'''<ref name="I2C core API">https://www.kernel.org/doc/html/latest/driver-api/i2c.html</ref>
+[[#Kernel_space_driver| Kernel space peripheral driver]] 同时访问 I<sup>2</sup>C 和SMBus设备，并使用以下 '''I2C核心API'''<ref name="I2C core API">https://www.kernel.org/doc/html/latest/driver-api/i2c.html</ref>
 ==Configuration==
 ===Kernel configuration===
-Activate I2C in kernel configuration with Linux Menuconfig tool: [[Menuconfig or how to configure kernel]].
+使用Linux Menuconfig工具在内核配置中激活I2C： [[Menuconfig or how to configure kernel]].
   [x] Device Drivers
@@ 第135行： / 第134行： @@
               [x] STMicroelectronics STM32F7 I2C support
-This can be done manually in your kernel:
+这可以在您的内核中手动完成：
   CONFIG_I2C=y
   CONFIG_I2C_CHARDEV=y
   CONFIG_I2C_STM32F7=y
-If software needs SMBus specific protocols like SMBus Alert protocol and the SMBus Host Notify protocol, then add:
+如果软件需要SMBus特定协议，例如SMBus Alert协议和SMBus Host Notify协议，则添加：
   [x] Device Drivers
       [x] I2C support
@@ 第149行： / 第148行： @@
               [x] STMicroelectronics STM32F7 I2C support
-This can be done manually in your kernel:
+这可以在您的内核中手动完成：
   CONFIG_I2C_SMBUS=y
 ===Device tree configuration===
-Please refer to [[I2C device tree configuration]].
+请参考[[I2C device tree configuration]].
 ==How to use the framework==
-This section describes how to use the framework to access I2C peripherals.
+本节介绍如何使用框架访问I2C外设。
 ===i2c-tools package===
-Using [[I2C_i2c-tools | I2C Tools]] in user space with shell commands based on the '''SMBus API protocol'''<ref name="SMBus protocol">{{CodeSource | Linux kernel | Documentation/i2c/smbus-protocol}} SMBus protocol summary</ref> makes it easy to access I2C quickly without the need to write any code.<br />
+在用户空间中将[[I2C_i2c-tools | I2C Tools]] 与基于'''SMBus API协议'''<ref name="SMBus protocol">{{CodeSource | Linux kernel | Documentation/i2c/smbus-protocol}} SMBus protocol summary</ref> 的shell命令配合使用，可以轻松快速地访问I2C，而无需编写任何代码。<br />
-'''Use case :''' a lot of shell commands allow detection of I2C bus and access to I2C peripherals by SMBus protocol. The package includes a library in order to use SMBus protocol into a C program.<br />
+'''用例''' 许多外壳命令允许检测I2C总线并通过SMBus协议访问I2C外设。 该软件包包括一个库，以便在C程序中使用SMBus协议。<br />
-Full explanation is available via this [[I2C_i2c-tools| link]].
+有关详细说明，请访问[[I2C_i2c-tools| link]]。
 [[File:i2c-tools-overview.png|800px|center|link=|Using i2c-tools overview]]
 === User space application ===
-Allows to develop an application using the i2c-dev kernel driver in user space with this '''device interface'''<ref name="dev-interface API">{{CodeSource | Linux kernel | Documentation/i2c/dev-interface}} dev-interface API</ref>.<br />
+允许在用户空间中使用带有此 '''device interface'''的i2c-dev内核驱动程序来开发应用程序。<ref name="dev-interface API">{{CodeSource | Linux kernel | Documentation/i2c/dev-interface}} dev-interface API</ref>.<br />
-'''Use case :''' by loading i2c-dev module, user can access I2C through the '''/dev''' interface. Access to I2C can be done very easily with functions open(), ioctl(), read(), write() and close(). If the peripheral is compatible, SMBus protocol access is also possible using the [[I2C_i2c-tools | I2C Tools]] library.<br />
+'''用例：'''通过加载i2c-dev模块，用户可以通过'''/dev'''接口访问I2C。 通过函数open()、ioctl()、read()、write()和lose()可以非常轻松地访问I2C。 如果外围设备兼容，则也可以使用 [[I2C_i2c-tools | I2C Tools]] 库。<br />
 [[File:i2c-dev-overview.png|800px|center|link=|Using i2c-dev overview]]
 === Kernel space driver ===
-Allows to develop a driver compiled into the kernel or inserted as a module using this '''I2C core API'''<ref name="I2C core API"/><br />
+允许使用'''I2C core API'''开发已编译到内核或作为模块插入的驱动程序<ref name="I2C core API"/><br />
-The Linux kernel provides example about how to write an I2C client driver.<ref>https://www.kernel.org/doc/html/latest/i2c/writing-clients.html</ref><br />
+Linux内核提供了有关如何编写I2C客户端驱动程序的示例
-'''Use case''' : control I2C peripheral with a specific driver inside the kernel space. The driver initializes all parameters while system is booting and creates an access to the peripheral data through sysfs for example.<br />
+<ref>https://www.kernel.org/doc/html/latest/i2c/writing-clients.html</ref><br />
+'''用例''' : 使用内核空间内的特定驱动程序控制I2C外设。 例如，驱动程序在系统引导时初始化所有参数，并通过sysfs创建对外围数据的访问。<br />
 [[File:i2c-driver-overview.png|800 px|center|link=|Using driver i2c overview]]
 ===Board description===
-To instantiate a peripheral, several methods exist: see '''instantiating devices'''<ref ="instantiating-devices">{{CodeSource | Linux kernel | Documentation/i2c/instantiating-devices}} How to instantiate I2C devices</ref> for more details. <br/>
+要实例化外围设备，存在几种方法：更多细节，请参见 '''实例化设备'''<ref ="instantiating-devices">{{CodeSource | Linux kernel | Documentation/i2c/instantiating-devices}} How to instantiate I2C devices</ref> 。 <br/>
-The below information focuses on '''device tree''', '''sysfs''' and '''Application Code'''.
+下列资料主要介绍 '''device tree''', '''sysfs''' 和 '''Application Code'''.
 ==== Device tree ====
-The device tree is a description of the hardware that is used by the kernel to know which devices are connected. In order to add a slave device on an I2C bus, complete the device tree with the information related to the new device.<br />
+设备树是对内核用来了解连接哪些设备的硬件的描述。为了在I2C总线上添加从设备，请使用与新设备相关的信息来完成设备树。<br />
-'''Example :''' with an EEPROM
+'''例子：''' 带有EEPROM
 <syntaxhighlight lang="c" line highlight="10-14">
@@ 第201行： / 第201行： @@
 </syntaxhighlight>
-The EEPROM is now instantiated on the bus i2c-X (X depends on how many adapters are probed at runtime) at address 0x50 and it is compatible with the driver registered with the same property.<br/>
+EEPROM现在在地址为0x50的总线i2c-X上实例化（X取决于运行时探测的适配器数量），并且它与使用相同属性注册的驱动程序兼容。<br/>
-Please note the driver specifies a SCL rising/falling time as input.<br/>
+请注意，驱动程序指定SCL上升/下降时间作为输入。<br/>
-Please refer to [[I2C device tree configuration]] for proper configuration and explanation.
+有关正确的配置和说明，请参考 [[I2C device tree configuration]]。
-Be aware the I2C specification reserves a range of addresses for special purposes, see '''slave addressing'''<ref name="slave addressing">http://www.totalphase.com/support/articles/200349176-7-bit-8-bit-and-10-bit-I2C-Slave-Addressing Slave addressing</ref>.<br />
+请注意，I2C规范为特殊目的保留了一系列地址，请参阅 '''slave addressing'''<ref name="slave addressing">http://www.totalphase.com/support/articles/200349176-7-bit-8-bit-and-10-bit-I2C-Slave-Addressing Slave addressing</ref>.<br />
-The below figure shows the relation between the device tree and how it is used :<br />
+下图显示了设备树及其用法之间的关系：<br />
 [[File:i2c-overview-dt.png|840 px|center|link=|relation between device tree and kernel]]
 ====sysfs====
-Through sysfs, i2c-core offers the possibility to instantiate and remove a peripheral: <br /><br />
+通过sysfs，i2c-core提供了实例化和删除外围设备的可能性：<br /><br />
-Add a peripheral "myPeripheralName" attached to the bus x at the address 0xAA<br />
+在地址0xAA上添加附加到总线x的外围设备“ myPeripheralName”<br />
-'''Note''' that the field "myPeripheralName" should have the same name as the compatible driver string so that they match one another.
+'''注意''' 字段 "myPeripheralName" 应该与兼容的驱动程序字符串具有相同的名称，以便它们彼此匹配。
 <pre>
 echo myPeripheralName 0xAA > i2c-x/new_device
 </pre>
-Remove a peripheral attached to the bus x at the address 0xAA
+卸下连接到总线x的地址0xAA的外围设备
 <pre>
 echo 0xAA > i2c-x/delete_device
 </pre>
-Into each driver directory ('''/sys/bus/i2c/drivers/at24/''' for the EEPROM peripheral example), it is possible to:<br />
+进入每个驱动程序目录('''/sys/bus/i2c/drivers/at24/''' for the EEPROM peripheral example), it is possible to:<br />
-bind a peripheral with a driver
+将外围设备与驱动器绑定
 <pre>
 echo 3-0050 > bind
 </pre>
-unbind a peripheral with a driver
+取消外围设备与驱动程序的绑定
 <pre>
 echo 3-0050 > unbind
@@ 第237行： / 第237行： @@
 ==== Application code ====
-Here is a minimalist code to register a new slave device onto I2C adapter without Device Tree usage.
+这是用于在不使用设备树的情况下将新的从设备注册到I2C适配器的极简代码。
 <syntaxhighlight lang="c" line highlight="4-6,18,20">
 #include <linux/i2c.h>
-/* Create a device with slave address <0x42> */
+/* 创建具有从属地址的设备 <0x42> */
 static struct i2c_board_info stm32_i2c_test_board_info = {
      I2C_BOARD_INFO("i2c_test07", 0x42);
@@ 第248行： / 第247行： @@
 /*
-   Module define creation skipped
+  跳过模块定义创建
 */
@@ 第264行： / 第263行： @@
 ==How to trace and debug the framework ==
-In Linux<sup>&reg;</sup> kernel, there are standard ways to debug and monitor I2C. The debug can take place at different levels: hardware and software.
+在 Linux<sup>&reg;</sup> 内核中，有调试和监视I2C的标准方法。调试可以在不同的级别进行：硬件和软件。
 ===How to trace===
 ====Dynamic trace====
-Detailed dynamic trace is available here [[How to use the kernel dynamic debug]]<br/>
+此处提供了详细的动态跟踪 [[How to use the kernel dynamic debug]]<br/>
    {{Board$}} echo  "file i2c-* +p" > /sys/kernel/debug/dynamic_debug/control
-This command enables all traces related to I2C core and drivers at runtime.<br/><br/>
+此命令在运行时启用与I2C内核和驱动程序有关的所有跟踪。<br/><br/>
-Nonetheless at [[Menuconfig or how to configure kernel | Linux® Kernel menu configuration]] level, it provides the granularity for debugging: Core and/or Bus.<br/>
+尽管如此，在 [[Menuconfig or how to configure kernel | Linux® Kernel menu configuration]] 级，它提供了调试的粒度：核心和/或总线。<br/>
   Device Drivers ->
       [*] I2C support ->
@@ 第277行： / 第276行： @@
           [*] I2C Bus debugging messages
-* I2C Core debugging messages (CONFIG_I2C_DEBUG_CORE)<br> Compile I2C engine with DEBUG flag.
+* I2C核心调试消息 (CONFIG_I2C_DEBUG_CORE)<br> 使用DEBUG标志编译I2C引擎。
-* I2C Bus debugging messages (CONFIG_I2C_DEBUG_BUS)<br> Compile I2C drivers with DEBUG flag.
+* I2C总线调试消息（CONFIG_I2C_DEBUG_BUS)<br> 用DEBUG标志编译I2C驱动程序。
-Having both '''I2C Core''' and '''I2C Bus''' debugging messages is equivalent to using the above dynamic debug command: the dmesg output will be the same.
+同时具有 '''I2C Core''' 和 '''I2C Bus'''调试消息等同于使用上述动态调试命令：dmesg输出将相同。
 ====Bus snooping====
-Bus snooping is really convenient for viewing I2C protocol and see what has been exchanged between the STM32 and the devices.<br/>
+总线侦听对于查看I2C协议以及查看STM32和设备之间交换的内容非常方便。<br/>
-As this debug feature uses [[Ftrace]], please refer to the [[Ftrace]] article for enabling it.
+由于此调试功能使用 [[Ftrace]]，因此请参考[[Ftrace]] 文章以启用它。
-In order to access to events for I2C bus snooping, the following kernel configuration is necessary:
+为了访问事件以进行I2C总线侦听，必须进行以下内核配置：
   Kernel hacking ->
@@ 第292行： / 第291行： @@
           [*] Trace process context switches and events
-Depending on the protocol being used, it is necessary to enable i2c and/or smbus tracers as follow:
+根据所使用的协议，有必要启用i2c和/或smbus跟踪器，如下所示：
   echo 1 > /sys/kernel/debug/tracing/events/i2c/enable
   echo 1 > /sys/kernel/debug/tracing/events/smbus/enable
-Then tracing is enabled using the following command:
+然后使用以下命令启用跟踪：
   echo 1 > /sys/kernel/debug/tracing/tracing_on
@@ 第302行： / 第301行： @@
   cat /sys/kernel/debug/tracing/trace
-Here is part of the output, and how it looks like when using ''i2cdetect'' command on the i2c-0 bus:
+这是输出的一部分，以及在i2c-0总线上使用“ i2cdetect”命令时的外观：
   ... smbus_write: i2c-0 a=003 f=0000 c=0 QUICK l=0 []
   ... smbus_result: i2c-0 a=003 f=0000 c=0 QUICK wr res=-6
@@ 第308行： / 第307行： @@
   ... smbus_result: i2c-0 a=004 f=0000 c=0 QUICK wr res=-6
-{{Info|Notice that i2cdetect, i2cget/i2cput, i2cdump are doing smbus protocol based transactions.}}
+{{Info|请注意，i2cdetect，i2cget / i2cput，i2cdump正在执行基于smbus协议的事务.}}
-On the contrary, below output shows the result of a transaction done in I2C protocol mode:
+相反，以下输出显示了以I2C协议模式完成的事务的结果:
   ... i2c_write: i2c-1 #0 a=042 f=0000 l=1 [45]
   ... i2c_result: i2c-1 n=1 ret=1
@@ 第316行： / 第315行： @@
   ... i2c_result: i2c-2 n=1 ret=1
-The utilization of traces of I2C bus is well described here '''I2C bus snooping'''<ref name="I2C bus snooping">https://linuxtv.org/wiki/index.php/Bus_snooping/sniffing#i2c I2C Bus Snooping</ref>.
+I2C总线走线的使用在此处进行了很好的描述 '''I2C 总线监听'''<ref name="I2C bus snooping">https://linuxtv.org/wiki/index.php/Bus_snooping/sniffing#i2c I2C Bus Snooping</ref>.
 ===How to debug===
 ====Detect I2C configuration====
 =====sysfs=====
-When a peripheral is instantiated, i2c-core and the kernel export different files through sysfs :<br />
+实例化外围设备后，i2c-core和内核会通过sysfs导出不同的文件：<br />
-'''/sys/class/i2c-adapter/i2c-x''' shows all instantiated I2C buses with 'x' being the I2C bus number.<br />
+'''/sys/class/i2c-adapter/i2c-x''' 显示所有实例化的I2C总线，其中“ x”为I2C总线号。<br />
-'''/sys/bus/i2c/devices''' lists all instantiated peripherals. For example, there is a directory named '''3-0050''' that corresponds to the EEPROM peripheral at address 0x50 on bus number 3.<br />
+'''/sys/bus/i2c/devices'''列出所有实例化的外围设备。例如，有一个名为'''3-0050'''的目录，它对应于总线号3上地址0x50的EEPROM外设。<br />
-'''/sys/bus/i2c/drivers''' lists all instantiated drivers. Directory named '''at24/''' is the driver of EEPROM.<br />
+'''/sys/bus/i2c/drivers''' 列出所有实例化的驱动程序。 名为'''at24 /'''的目录是EEPROM的驱动程序。<br />
 <pre>
@@ 第344行： / 第343行： @@
 ====devfs====
-If i2c-dev driver is compiled into the kernel, the directory '''dev''' contains all I2C bus names numbered i2c-0 to i2c-n.
+如果将i2c-dev驱动程序编译到内核中，则目录'''dev'''包含所有编号为i2c-0至i2c-n的I2C总线名称。
 <pre>
 /dev/i2c-0
@@ 第355行： / 第354行： @@
 ====i2c-tools====
-Check all I2C instantiated adapters:
+检查所有I2C实例化的适配器：
   {{Board$}}i2cdetect -l
-See [[I2C_i2c-tools| i2c-tools]] for full description.
+有关完整说明，请参阅[[I2C_i2c-tools| i2c-tools]]。
 ==Source code location==
-* I2C Framework driver is in {{CodeSource | Linux kernel | drivers/i2c drivers/i2c}}
+* I2C框架驱动程序位于{{CodeSource | Linux kernel | drivers/i2c drivers/i2c}}
-* I2C STM32 Driver is in {{CodeSource | Linux kernel | drivers/i2c/busses/i2c-stm32f7.c}}
+* I2C STM32驱动程序位于{{CodeSource | Linux kernel | drivers/i2c/busses/i2c-stm32f7.c}}
-* User API for I2C bus is in {{CodeSource | Linux kernel | include/uapi/linux/i2c.h}} and I2C dev is {{CodeSource | Linux kernel | include/uapi/linux/i2c-dev.h}}.
+* 2C总线用户接口在 {{CodeSource | Linux kernel | include/uapi/linux/i2c.h}} ，I2C dev在 {{CodeSource | Linux kernel | include/uapi/linux/i2c-dev.h}}.
 ==To go further==
-Bootlin has written a nice walkthrough article:
+Bootlin写了一篇很好的演练文章：
-''Building a Linux system for the STM32MP1: connecting an I2C sensor''<ref name="Building a Linux system for the STM32MP1: connecting an I2C sensor">https://bootlin.com/blog/building-a-linux-system-for-the-stm32mp1-connecting-an-i2c-sensor/</ref>
+''为STM32MP1构建Linux系统：连接I2C传感器''<ref name="Building a Linux system for the STM32MP1: connecting an I2C sensor">https://bootlin.com/blog/building-a-linux-system-for-the-stm32mp1-connecting-an-i2c-sensor/</ref>
 ==References==
 <references />

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“I2C overview”的版本间的差异

2020年11月6日 (五) 17:53的最新版本

目录

Framework purpose

System overview

Component description

Board external I2C devices

STM32 I2C internal peripheral controller

i2c-stm32

i2c-core

Board peripheral drivers

i2c-dev

i2c-tools

Application

API description

libi2c

User space application

Kernel space peripheral driver

Configuration

Kernel configuration

Device tree configuration

How to use the framework

i2c-tools package

User space application

Kernel space driver

Board description

Device tree

sysfs

Application code

How to trace and debug the framework

How to trace

Dynamic trace

Bus snooping

How to debug

Detect I2C configuration

sysfs

devfs

i2c-tools

Source code location

To go further

References

导航

Wiki工具

页面工具

Board external I²C devices