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Diffstat (limited to 'drivers/misc/mpu3050/README')
| -rwxr-xr-x | drivers/misc/mpu3050/README | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/drivers/misc/mpu3050/README b/drivers/misc/mpu3050/README new file mode 100755 index 000000000000..8ff0c3009eca --- /dev/null +++ b/drivers/misc/mpu3050/README @@ -0,0 +1,138 @@ +Kernel driver mpu3050 +===================== + +Supported chips: + * Invensense IMU3050 + Prefix: 'mpu3050' + Datasheet: + PS-MPU-3000A-00.2.4b.pdf + +Author: Invensense <http://invensense.com> + +Description +----------- +The mpu3050 is a motion processor that controls the mpu3050 gyroscope, a slave +accelerometer and compass. This document describes how to install the driver +into a linux kernel and a small note about how to set up the file permissions +in an android file system. + +Sysfs entries +------------- +/dev/mpu +/dev/mpuirq + +General Remarks +--------------- + +Valid addresses for the MPU3050 is 0x68. +Accelerometer must be on the secondary I2C bus. + +Programming the chip using /dev/mpu +---------------------------------- +Programming of the MPU3050 is done by first opening the /dev/mpu file and +then performing a series of IOCTLS on the handle returned. The IOCTL codes can +be found in mpu3050.h. Typically this is done by the mllite library in user +space. + +Adding to a Kernel +================== + +The mpu3050 driver is designed to be inserted in the drivers/misc part of the +kernel. Copy the mpu3050 directory and the mpu3050 include file to: + + <kernel root dir>/drivers/misc/mpu3050 + <kernel root dir>/include/linux/mpu3050.h + +respectively. + +After this is done the drivers/misc/Kconfig must be edited to add the line: + + source "drivers/misc/mpu3050/Kconfig" + +Similarly drivers/misc/Makefile must be edited to add the line: + + obj-y += mpu3050/ + +Configuration can then be done as normal. + +Board and Platform Data +----------------------- + +In order for the driver to work, board and platform data specific to the device +needs to be added to the board file. A mpu3050_platform_data structure must +be created and populatd and set in the i2c_board_info_structure. For details of +each structure member see mpu3050.h. All values below are modified for the ventana +platform. You should add these lines into the +kernel/arch/arm/mach-tegra/board-generic.c file. + +#include <linux/mpu3050.h> + +static struct mpu3050_platform_data mpu3050_data = { + .int_config = 0x10, + .orientation = { 0, -1, 0, + -1, 0, 0, + 0, 0, -1 }, //Orientation matrix for MPU on ventana + .level_shifter = 0, + .accel = { + .get_slave_descr = kxtf9_get_slave_descr, + .adapt_num = 0, + .bus = EXT_SLAVE_BUS_SECONDARY, + .address = 0x0F, + .orientation = { 0, -1, 0, + -1, 0, 0, + 0, 0, -1 }, //Orientation matrix for Kionix on ventana + }, + + + .compass = { + .get_slave_descr = ak8975_get_slave_descr, + .adapt_num = 3, //bus number 3 on ventana + .bus = EXT_SLAVE_BUS_PRIMARY, + .address = 0x0C, + .orientation = { 1, 0, 0, + 0, -1, 0, + 0, 0, -1 }, //Orientation matrix for AKM on ventana + }, + +}; + +static struct i2c_board_info __initdata mpu3050_i2c0_boardinfo[] = { + { + I2C_BOARD_INFO("mpu3050", 0x68), + /*.irq = 299,*/ + .platform_data = &mpu3050_data, + }, +}; + +Note: If you are unsure where to add this code, look for other instances of "i2c_board_info" +and copy paste this code after one of them. + +After this is done, we must register the board upon initialization. This is done in the +i2c_device_setup function in the board-generic.c file. Look for this function and add these +lines of code: + +if (ARRAY_SIZE(mpu3050_i2c0_boardinfo)) + i2c_register_board_info(0, mpu3050_i2c0_boardinfo, + ARRAY_SIZE(mpu3050_i2c0_boardinfo)); + +Before you can build the kernel, you will need to remove the existing NVidia AK8975 driver for the compass. +In the board-generic.c file, rename the instance of CONFIG_SENSORS_AK8975 to NVIDIA_CONFIG_SENSORS_AK8975. +In kernel/drivers/hwmon/Makefile, rename that instance of CONFIG_SENSORS_AK8975 to NVIDIA_CONFIG_SENSORS_AK8975 as well. +This will prevent NVidia's driver for the compass from building. + +Now you can build the new kernel. First, we must configure the kernel. Take the tegra_ventana_android_defconfig +file from this package and replace the existing one in the kernel/arch/arm/configs directory. In the root kernel +directory, you can then run: + +export CCOMPILER=/<path to android environment>/prebuilt/linux-x86/toolchain/arm-eabi-4.4.0/bin/arm-eabi- +make ARCH=arm CROSS_COMPILE=$CCOMPILER mrproper +make ARCH=arm CROSS_COMPILE=$CCOMPILER tegra_ventana_android_defconfig +make ARCH=arm CROSS_COMPILE=$CCOMPILER + +This should build your zImage, which you will find in kernel/arch/arm/boot/zImage. You can use the mkbootimg utility to then +make a boot.img: + + ./mkbootimg --kernel <path to android system>/kernel/arch/arm/boot/zImage --ramdisk <path to android system>/out/target/product/ventana/ramdisk.img --output boot.img + +You can then flash this boot.img using the nvflash utility. + |