Android 平台下使用 i2c-tools

下载源码

将 i2c-tools 代码下载到 Android 源码的 external 目录下，我是使用 Subversion 直接从官方版本库中检出，当然使用别的方式下载到源代码也是可以的。

～/mydroid $ svn checkout http://lm-sensors.org/svn/i2c-tools/branches/i2c-tools-3.1 external/i2c-tools

在 i2c-tools 目录下新建 Android.mk 文件，内容如下：

# external/i2c-tools/Android.mkLOCAL_PATH:= $(call my-dir)include $(CLEAR_VARS)LOCAL_MODULE_TAGS := engLOCAL_C_INCLUDES += $(LOCAL_PATH) $(LOCAL_PATH)/$(KERNEL_DIR)/includeLOCAL_SRC_FILES := tools/i2cbusses.c tools/util.cLOCAL_MODULE := i2c-toolsinclude $(BUILD_STATIC_LIBRARY)include $(CLEAR_VARS)LOCAL_MODULE_TAGS := engLOCAL_SRC_FILES:=tools/i2cdetect.cLOCAL_MODULE:=i2cdetectLOCAL_CPPFLAGS += -DANDROIDLOCAL_SHARED_LIBRARIES:=libcLOCAL_STATIC_LIBRARIES := i2c-toolsLOCAL_C_INCLUDES += $(LOCAL_PATH) $(LOCAL_PATH)/$(KERNEL_DIR)/includeinclude $(BUILD_EXECUTABLE)include $(CLEAR_VARS)LOCAL_MODULE_TAGS := engLOCAL_SRC_FILES:=tools/i2cget.cLOCAL_MODULE:=i2cgetLOCAL_CPPFLAGS += -DANDROIDLOCAL_SHARED_LIBRARIES:=libcLOCAL_STATIC_LIBRARIES := i2c-toolsLOCAL_C_INCLUDES += $(LOCAL_PATH) $(LOCAL_PATH)/$(KERNEL_DIR)/includeinclude $(BUILD_EXECUTABLE)include $(CLEAR_VARS)LOCAL_MODULE_TAGS := engLOCAL_SRC_FILES:=tools/i2cset.cLOCAL_MODULE:=i2csetLOCAL_CPPFLAGS += -DANDROIDLOCAL_SHARED_LIBRARIES:=libcLOCAL_STATIC_LIBRARIES := i2c-toolsLOCAL_C_INCLUDES += $(LOCAL_PATH) $(LOCAL_PATH)/$(KERNEL_DIR)/includeinclude $(BUILD_EXECUTABLE)include $(CLEAR_VARS)LOCAL_MODULE_TAGS := engLOCAL_SRC_FILES:=tools/i2cdump.cLOCAL_MODULE:=i2cdumpLOCAL_CPPFLAGS += -DANDROIDLOCAL_SHARED_LIBRARIES:=libcLOCAL_STATIC_LIBRARIES := i2c-toolsLOCAL_C_INCLUDES += $(LOCAL_PATH) $(LOCAL_PATH)/$(KERNEL_DIR)/includeinclude $(BUILD_EXECUTABLE)

编译

~/mydroid/external/i2c-tools $ mm

编译后在 out/target/product/sabresd_6dq/system/bin目录下生成4个可执行程序:

• i2cdetect
• i2cdump
• i2cget
• i2cset

安装

制作新的 system image，然后重新烧录 system.img

~/mydroid $ make snod~/mydroid $ fastboot system out/target/product/sabresd_6dq/system.img

当然也可以通过 adb push 之间将编译生成的4个文件复制到 Android 平台的 /system/bin 目录下。 
在 abd pusll 之前，要先将 system 分区 remount 成可写入模式。

i2c-tools 的用法

i2cdetect

列举 I2C bus

# i2cdetect -li2c-0   i2c             imx-i2c                                 I2C adapteri2c-1   i2c             imx-i2c                                 I2C adapteri2c-2   i2c             imx-i2c                                 I2C adapter

列举 I2C bus i2c-1 上面连接的所有设备

# i2cdetect -y 1     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f00:          -- -- -- -- -- UU -- -- -- -- -- -- -- 10: -- UU -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 30: -- -- -- -- -- -- -- -- -- -- 3a -- -- -- -- -- 40: -- -- -- -- -- -- -- -- UU -- -- -- -- -- -- -- 50: UU -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 70: -- -- -- -- -- -- -- --

发现 I2C 设备的位置显示为UU或者表示设备地址的数值，UU表示该设备在 driver 中被使用。

i2cdump

dump I2C 设备大批量 register 的值

# i2cdump -y -f 1 0x3aNo size specified (using byte-data access)     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef00: eb 00 7f 05 3d 00 00 00 08 06 00 00 00 00 00 00    ?.??=...??......10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................20: 01 23 45 67 89 ab cd ef fe dc ba 98 76 54 32 10    ?#Eg????????vT2?30: f0 e1 d2 c3 00 00 00 00 00 00 00 00 00 00 00 00    ????............40: 80 00 10 00 00 00 00 00 00 00 00 00 00 00 00 00    ?.?.............50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................f0: 00 00 00 00 00 00 00 00 00 00 00 30 00 00 00 00    ...........0....

i2cget

读取 I2C 设备某个 register 的值

# i2cget -y -f 1 0x3a 0x020x7f

i2cset

设置 I2C 设备某个 register 的值

# i2cset -y -f 1 0x3a 0x02 0x05