Android 平台上 使用 i2c-tools调试i2c
使用前提：
使用i2c-tools，的命令i2cdetect , i2cdump. i2cget. i2cset，本质上是在userspace操作i2c，这就需要内核的支持，即在/dev下有i2c-x 的字符设备节点存在。
编译内核的时候需要打开CONFIG_I2C_CHARDEV，
或者make menuconfig device drivers---> I2C support ---> I2C device interface
编译kernel/i2c/i2c-dev.c
内核文档：Documentation/i2c/dev-interface
参考链接：https://blog.csdn.net/AS520213211314/article/details/73105365
下载源码
在 https://launchpad.net/ubuntu/+source/i2c-tools 下载源码，我这里下载的是i2c-tools_3.1.1.orig.tar.bz2
将压缩包解压得到 i2c-tools-3.1.1,复制源码到 external 下
编译
在i2c-tools-3.1.1下新建Android.mk文件,内容如下
LOCAL_PATH:= $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE_TAGS := optional
LOCAL_C_INCLUDES += $(LOCAL_PATH)/include $(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 := optional
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)/include $(LOCAL_PATH) $(LOCAL_PATH)/$(KERNEL_DIR)/include
include $(BUILD_EXECUTABLE)
include $(CLEAR_VARS)
LOCAL_MODULE_TAGS := optional
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)/include $(LOCAL_PATH) $(LOCAL_PATH)/$(KERNEL_DIR)/include
include $(BUILD_EXECUTABLE)
include $(CLEAR_VARS)
LOCAL_MODULE_TAGS := optional
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)/include $(LOCAL_PATH) $(LOCAL_PATH)/$(KERNEL_DIR)/include
include $(BUILD_EXECUTABLE)
include $(CLEAR_VARS)
LOCAL_MODULE_TAGS := optional
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)/include $(LOCAL_PATH) $(LOCAL_PATH)/$(KERNEL_DIR)/include
include $(BUILD_EXECUTABLE)
执行 mmm external/i2c-tools-3.1.1/
会生成4个可执行文件 i2cdetect i2cdump i2cget i2cset
adb remount
adb sync
adb reboot
用法
i2cdetect
# i2cdetect -l
i2c-1 i2c 21a4000.i2c I2C adapter
i2c-2 i2c 21a8000.i2c I2C adapter
i2c-0 i2c 21a0000.i2c I2C adapter
列举i2c-2上的所有i2c设备
# i2cdetect -y 2
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- 19 -- UU -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: UU -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
发现I2C设备的位置显示为UU表示该设备的地址，UU表示该设备在driver中被使用
i2cdump
# i2cdump -y -f 2 0x1b w
0,8 1,9 2,a 3,b 4,c 5,d 6,e 7,f
00: 2100 0000 8888 0606 0000 0000 0000 0000
08: 0000 0000 0000 0000 0000 0083 0000 0606
10: 0808 0000 0000 0000 0000 0000 0000 0000
18: 0000 afaf afaf 000c afaf 2f2f 0000 0000
20: 0000 0000 0000 0000 0000 0000 0000 6078
......................................
需要注意的是高低位转换 如上所示0x27读到的为0x7860
i2cset
# i2cset
Usage: i2cset [-f] [-y] [-m MASK] [-r] I2CBUS CHIP-ADDRESS DATA-ADDRESS [VALUE] ... [MODE]
I2CBUS is an integer or an I2C bus name
ADDRESS is an integer (0x03 - 0x77)
MODE is one of:
c (byte, no value)
b (byte data, default)
w (word data)
i (I2C block data)
s (SMBus block data)
Append p for SMBus PEC
i2cget
# i2cget
Usage: i2cget [-f] [-y] I2CBUS CHIP-ADDRESS [DATA-ADDRESS [MODE]]
I2CBUS is an integer or an I2C bus name
ADDRESS is an integer (0x03 - 0x77)
MODE is one of:
b (read byte data, default)
w (read word data)
c (write byte/read byte)
Append p for SMBus PEC