i2c tools

将 i2c-tools 代码下载到 Android 源码的 external 目录下，我是在下面的网址上下载的:

https://sourcecodebrowser.com/i2c-tools/

在 i2c-tools 目录下新建 Android.mk 文件，内容如下：

# external/i2c-tools/Android.mk LOCAL_PATH:= $(call my-dir) include $(CLEAR_VARS) LOCAL_MODULE_TAGS := eng LOCAL_C_INCLUDES += $(LOCAL_PATH) $(LOCAL_PATH)/$(KERNEL_DIR)/include LOCAL_SRC_FILES := tools/i2cbusses.c tools/util.c LOCAL_MODULE := i2c-tools
include $(BUILD_STATIC_LIBRARY)

include $(CLEAR_VARS) LOCAL_MODULE_TAGS := eng LOCAL_SRC_FILES:=tools/i2cdetect.c LOCAL_MODULE:=i2cdetect LOCAL_CPPFLAGS += -DANDROID LOCAL_SHARED_LIBRARIES:=libc LOCAL_STATIC_LIBRARIES := i2c-tools LOCAL_C_INCLUDES += $(LOCAL_PATH) $(LOCAL_PATH)/$(KERNEL_DIR)/include
include $(BUILD_EXECUTABLE)

include $(CLEAR_VARS) LOCAL_MODULE_TAGS := eng LOCAL_SRC_FILES:=tools/i2cget.c LOCAL_MODULE:=i2cget LOCAL_CPPFLAGS += -DANDROID LOCAL_SHARED_LIBRARIES:=libc LOCAL_STATIC_LIBRARIES := i2c-tools LOCAL_C_INCLUDES += $(LOCAL_PATH) $(LOCAL_PATH)/$(KERNEL_DIR)/include
include $(BUILD_EXECUTABLE)

include $(CLEAR_VARS) LOCAL_MODULE_TAGS := eng LOCAL_SRC_FILES:=tools/i2cset.c LOCAL_MODULE:=i2cset LOCAL_CPPFLAGS += -DANDROID LOCAL_SHARED_LIBRARIES:=libc LOCAL_STATIC_LIBRARIES := i2c-tools LOCAL_C_INCLUDES += $(LOCAL_PATH) $(LOCAL_PATH)/$(KERNEL_DIR)/include
include $(BUILD_EXECUTABLE)

include $(CLEAR_VARS) LOCAL_MODULE_TAGS := eng LOCAL_SRC_FILES:=tools/i2cdump.c LOCAL_MODULE:=i2cdump LOCAL_CPPFLAGS += -DANDROID LOCAL_SHARED_LIBRARIES:=libc LOCAL_STATIC_LIBRARIES := i2c-tools LOCAL_C_INCLUDES += $(LOCAL_PATH) $(LOCAL_PATH)/$(KERNEL_DIR)/include
include $(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 -l i2c-0 i2c             imx-i2c                                 I2C adapter
i2c-1 i2c             imx-i2c                                 I2C adapter
i2c-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 f 00: -- -- -- -- -- 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 0x3a No size specified (using byte-data access) 0 1 2 3 4 5 6 7 8 9 a  b  c  d  e  f 0123456789abcdef 00: 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 0x02 0x7f 

i2cset

设置 I2C 设备某个 register 的值

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