https://my.oschina.net/luoly/blog/368881
Android 平臺下使用 i2c-tools
Andorid 開發板爲 Freescale imx6 的 SabreSD Board
下載源碼
將 i2c-tools 代碼下載到 Android 源碼的 external 目錄下，我是使用 Subversion 直接從官方版本庫中檢出，當然使用別的方式下載到源代碼也是可以的。
～/mydroid $ svn checkout http://lm-sensors.org/svn/i2c-tools/branches/i2c-tools-3.1 external/i2c-tools
在 i2c-tools 目錄下新建 Android.mk 文件，內容如下：
# 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)
編譯
~/mydroid/external/i2c-tools $ mm
編譯後在 out/target/product/sabresd_6dq/system/bin目錄下生成4個可執行程序:
- i2cdetect
- i2cdump
- i2cget
- i2cset
安裝
製作新的 system image，然後重新燒錄 system.img
~/mydroid $ make snod
~/mydroid $ fastboot system out/target/product/sabresd_6dq/system.img
當然也可以通過 adb push 之間將編譯生成的4個文件複製到 Android 平臺的 /system/bin 目錄下。 在 abd pusll 之前，要先將 system 分區 remount 成可寫入模式。
i2c-tools 的用法
i2cdetect
列舉 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
列舉 I2C bus i2c-1 上面連接的所有設備
# 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: -- -- -- -- -- -- -- --
發現 I2C 設備的位置顯示爲UU或者表示設備地址的數值，UU表示該設備在 driver 中被使用。
i2cdump
dump I2C 設備大批量 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
讀取 I2C 設備某個 register 的值
# i2cget -y -f 1 0x3a 0x02
0x7f
i2cset
設置 I2C 設備某個 register 的值
# i2cset -y -f 1 0x3a 0x02 0x05