- General Description
- License
- System Configuration
- Linux driver files
- Linux driver principle
- The sysfs interface attributes
- Input Event
- Interrupt support
- Other configurations
This document introduces the usage of SMI130 Linux driver
See LICENSE file
Table 1: System Configuration
| System Configuration | Settings |
|---|---|
| Linux Kernel configuration | CONFIG_SYSFS=y |
| I2C interface configuration | CONFIG_I2C=y |
| SPI interface configuration | CONFIG_SPI_MASTER=y |
Table 2: Driver Description
| Files name | Description |
|---|---|
| bs_log.c bs_log.h |
This file implements Bosch sensor log driver |
| Kconfig | Kconfig |
| Makefile | Makefile |
| LICENSE | License |
| README.md | Brief info of SMI130 Linux driver |
| smi130_i2c_driver.c smi130_spi_driver.c |
This file implements i2c/spi interface function of SMI130 |
| smi130_acc_driver.c smi130_acc_driver.h |
This file implements the Linux input level driver of SMI130 ACC |
| smi130_acc.c smi130_acc.h |
This file implements the low level API of SMI130 ACC |
| smi130_gyro_driver.c smi130_gyro_driver.h |
This file implements the Linux input level driver of SMI130 GYRO |
| smi130_gyro.c smi130_gyro.h |
This file implements the low level API of SMI130 GYRO |
| smi130_defs.h | This file implements the common definition of SMI130 |
By sysfs interface, application enables sensor to launch a delay task on work queue. The task delay value can be configured by sysfs interface. The default delay value is 200ms. The delay task will get the sensor values and update them as input event on input device. If compiled with interrupt support, the interrupt service routine will launch an IRQ task on work queue.The IRQ task will identify the interrupt type and send the interrupt event on input device. Application will block read the input device to get the input events. The input event will carry the sensor values or the interrupt type data.
User space
----------------------------------------------
| |
sysfs dev
\ /
input-subsystem
|
i2c/spi bus <-- smi130_driver --> sensor_API
|
----------------------------------------------
Hardware
SMI130_ACC driver is registered as input class. In /sys/devices/virtual/input/inputX(X indicates the sensor number) on sysfs, the registered name is “smi130_acc”.
Table 3: sysfs interface attributes
| Name | Descriptions | RW | Usage |
|---|---|---|---|
| Range | Set and get sensor G-range | RW | Write: 3------ +/- 2G 5 ------ +/- 4G 8 ------ +/- 8G 12 ------ +/- 16G Read: 3------ +/- 2G 5 ------ +/- 4G 8 ------ +/- 8G 12 ------ +/- 16G Default : 3 |
| bandwidth | Set and get sensor bandwidth | RW | Write: 8 ------ 7.81 Hz 9 ------ 15.63 H 10 ------ 31.25 Hz 11 ------ 62.5 Hz 12 ------ 125 Hz 13 ------ 250 Hz 14 ------ 500 Hz 15 ------ 1000 Hz Read: 8 ------ 7.81 Hz 9 ------ 15.63 Hz 10 ------ 31.25 Hz 11 ------ 62.5 Hz 12 ------ 125 Hz 13 ------ 250 Hz 14 ------ 500 Hz 15 ------ 1000 Hz Default : 12 |
| op_mode | Set and get sensor mode | RW | Write : 0 ------ normal Mode 3 ------ deep suspend 4 ------ low power 2 5 ------ standby Read: 0 ------ normal Mode 3 ------ deep suspend 4 ------ low power 2 5 ------ standby Mode Default : 5 |
| Value | Get sensor x, y, z axis valus | R | Read return x, y, z axis values |
| Delay | Set and get delay time for delay task | RW | value Range (0- 200) ms Default : 200 |
| Enable | Enable or disable sensor work task | RW | Write : 0 ------ disable sensor 1 ------ enable sensor Read : 0 ------ disable sensor 1 ------ enable sensor Default : 0 |
| sleepdur | Set and get sleep phase duration in Low Power mode |
RW | Write : 5 ------ 0.5ms 6 ------ 1ms 7 ------ 2ms 8 ------ 4ms 9 ------ 6ms 10 ------ 10ms 11 ------ 25ms 12 ------ 50ms 13 ------ 100ms 14 ------ 500ms 15 ------ 1s Read : 5 ------ 0.5ms 6 ------ 1ms 7 ------ 2ms 8 ------ 4ms 9 ------ 6ms 10 ------ 10ms 11 ------ 25ms 12 ------ 50ms 13 ------ 100ms 14 ------ 500ms 15 ------ 1s Default : 0 |
| reg | Set value to specific register and get whole register value |
RW | Write : para1 para2 Para1: register address Para2: value to be set Read: whole register and value |
| fast_calibration_x | Set and get fast calibration configure value for x axis |
RW | Write : 0 ------ 0 g 1 ------ 1 g 2 ------ -1 g 3 ------ 0 g Read : 0 ------ 0 g 1 ------ 1 g 2 ------ -1 g 3 ------ 0 g Default : 0 |
| fast_calibration_y | Set and get fast calibration configure value for y axis |
RW | Write : 0 ------ 0 g 1 ------ 1 g 2 ------ -1 g 3 ------ 0 g Read : 0 ------ 0 g 1 ------ 1 g 2 ------ -1 g 3 ------ 0 g Default : 0 |
| fast_calibration_z | Set and get fast calibration configure value for z axis |
RW | Write : 0 ------ 0 g 1 ------ 1 g 2 ------ -1 g 3 ------ 0 g Read : 0 ------ 0 g 1 ------ 1 g 2 ------ -1 g 3 ------ 0 g Default : 0 |
| Chip_id | Get sensor chip id | R | 0xFA |
| offset_x | Set and get offset x register | RW | value Range (0- 255) |
| offset_y | Set and get offset y register | RW | value Range (0- 255) |
| offset_z | Set and get offset z register | RW | value Range (0- 255) |
| enable_int | Enable or disable sensor interrupt | W | Write : para1 para2 Para1: 4 ------ Data Ready Interrupt 5 ------ Slope X Interrupt 6 ------ Slope Y Interrupt 7 ------ Slope Z Interrupt Para2: 0 ------ disable interrupt 1 ------ enable interrupt |
| int_mode | Set and get interrupt latched time | RW | Write : 0 ------ non-latched 1 ------ temporary, 250 ms 2 ------ temporary, 500 ms 3 ------ temporary, 1 s 4 ------ temporary, 2 s 5 ------ temporary, 4 s 6 ------ temporary, 8 s 7 ------ latched 8 ------ non-latched 9 ------ temporary, 500 us 10 ------ temporary, 500 us 11 ------ temporary, 1 ms 12 ------ temporary, 12.5 ms 13 ------ temporary, 25 ms 14 ------ temporary, 50 ms 15 ------ latched Read : 0 ------ non-latched 1 ------ temporary, 250 ms 2 ------ temporary, 500 ms 3 ------ temporary, 1 s 4 ------ temporary, 2 s 5 ------ temporary, 4 s 6 ------ temporary, 8 s 7 ------ latched 8 ------ non-latched 9 ------ temporary, 250 us 10 ------ temporary, 500 us 11 ------ temporary, 1 ms 12 ------ temporary, 12.5 ms 13 ------ temporary, 25 ms 14 ------ temporary, 50 ms 15 ------ latched Default : 1 |
| slope_duration | Set and get slope interrupt duration | RW | value Range (0- 3) Default : 0 |
| slope_threshold | Set and get slope interrupt threshold | RW | value Range (0- 255) Default : 0 |
| en_sig_motion | enable and disable slope function | RW | Write : 0 ------ disable 1 ------ enable Read : 0 ------ disable 1 ------ enable Default : 0 |
| selftest | Set selftest and get result | RW | Write: 1 ------ start self-test Read: 0 ------ success 1 ------ x axis failed 2 ------ y axis failed 3 ------ x and y axis failed 4 ------ z axis failed 5 ------ x and z axis failed 6 ------ y and z axis failed 7 ------ x, y and z axis failed |
| softreset | set soft reset | W | Write: 1 ------ start soft reset |
| temperature | Read temperature in LSB | R | value Range (-127- 127) |
SMI130_GYRO driver is registered as input class. In /sys/devices/virtual/input/inputX(X indicates the sensor number) on sysfs, the registered name is “smi130_gyro”.
The gyro sysfs interfaces are shown below.
| Name | Descriptions | RW | Usage |
|---|---|---|---|
| chip_id | Get sensor chip id | R | 0x0F |
| name | Get sensor name | R | smi130_gyro |
| range | Set and get sensor range | RW | Write: 0 ------ +/- 2000 º/s 1 ------ +/- 1000 º/s 2 ------ +/- 500 º/s 3 ------ +/- 250 º/s 4 ------ +/- 125 º/s Read: 0 ------ +/- 2000 º/s 1 ------ +/- 1000 º/s 2 ------ +/- 500 º/s 3 ------ +/- 250 º/s 4 ------ +/- 125 º/s Default : 0 |
| bandwidth | set and get sensor bandwidth | RW | Write: 0 ------ 523 Hz 1 ------ 230 Hz 2 ------ 116 Hz 3 ------ 47 Hz 4 ------ 23 Hz 5 ------ 12 Hz 6 ------ 64 Hz 7 ------ 32 Hz Read: 0 ------ 523 Hz 1 ------ 230 Hz 2 ------ 116 Hz 3 ------ 47 Hz 4 ------ 23 Hz 5 ------ 12 Hz 6 ------ 64 Hz 7 ------ 32 Hz Default : 7 |
| op_mode | Set and get sensor mode | RW | Read : 0 ------ Normal Mode 1 ------ Deep suspend Mode Write : 0 ------ normal Mode 1 ------ Deep suspend Mode Default : 0 |
| value | Get sensor x, y, z axis values | R | Read return LSB values of x, y, z axis |
| reg | Set value to specific register and get whole register value |
RW | Write : para1 para2 Para1: register address Para2: value to be set Read: whole register and value |
| selftest | Perform a selftest for sensor | R | Read : 0 ------ selftest passed 1 ------ selftest failed |
| delay | Set and get delay time for delay task | RW | value Range (0- 200) ms |
| enable | Enable or disable sensor work task | RW | Write : 0 ------ disable sensor 1 ------ enable sensor Read : 0 ------ disable sensor 1 ------ enable sensor Default : 0 |
Application should read input event for the sensor value and interrupt report. The input event descriptions are shown below. Table 4: Input event
| Type | Code | Description | Value |
|---|---|---|---|
| EV_MSC | MSC_GESTURE | Event for x axis | LSB Value of X axis |
| EV_MSC | MSC_RAW | Event for x axis | LSB Value of X axis |
| EV_MSC | MSC_SCAN | Event for x axis | LSB Value of X axis |
| EV_MSC | MSC_TIMESTAMP | Event for Time Stamp | Timestamp value |
| EV_REL | REL_DIAL | slope/any motion interrupt | Interrupt notification 7-12 |
Set SENSORS_SMI130_ENABLE_INTERRUPT to 'yes' in Kconfig file is prerequisite before using other interrupt features
Set SENSORS_SMI130_ACC_ENABLE_NEWDATA_INT to ‘yes’ in Kconfig file
Set SENSORS_SMI130_ACC_ENABLE_MOTION to ‘yes’ in Kconfig file
Set SENSORS_SMI130_GYRO_ENABLE_NEWDATA_INT to ‘yes’ in Kconfig file
To enable driver probing, add the smi130_acc and smi130_gyro node to the platform device tree as described below.
Required properties:
- compatible: "bosch,smi130_acc"
- compatible: "bosch,smi130_gyro"
- reg: the I2C address or SPI chip select the device will respond to
- interrupt-parent: phandle to the parent interrupt controller as documented in interrupts
- interrupts: interrupt mapping for IRQ as documented in interrupts
I2C example (Qualcomm DragonBoard 410c):
status = "okay"; smi130_acc@19{ compatible = "smi130_acc"; reg = <0x19>; interrupt-parent = <&msmgpio>; interrupts = <115 0>; smi130_acc,gpio_irq = <&msmgpio 115 0>; }; smi130_gyro@69{ compatible = "smi130_gyro"; reg = <0x69>; interrupt-parent = <&msmgpio>; interrupts = <13 0>; smi130_gyro,gpio_irq = <&msmgpio 13 0>; };
SPI example (Qualcomm DragonBoard 410c):
status = "okay"; cs-gpios = <&msmgpio 18 0>,<&msmgpio 110 0>; spi-cpol = <0>; spi-cpha = <0>; smi130_acc@0{ spi-max-frequency = <500000>; compatible = "smi130_acc"; reg = <0>; interrupt-parent = <&msmgpio>; interrupts = <115 0>; smi130_acc,gpio_irq = <&msmgpio 115 0>; }; smi130_gyro@1{ spi-max-frequency = <500000>; compatible = "smi130_gyro"; reg = <1>; interrupt-parent = <&msmgpio>; interrupts = <13 0>; smi130_gyro,gpio_irq = <&msmgpio 13 0>; };
Configure kernel with make menuconfig
Device Drivers ---> Input device support ---> [*] Enable Bosch SMI130 IMU sensor ---> Select communication interface (Enable I2C connection) ---> ( ) Enable SPI connection (X) Enable I2C connection <*> Bosch Sensor driver smart log function support <*> SMI130 sensor support <*> SMI130_ACC acceleration sensor interrupt INT2 support <*> enable acc data ready interrupt <*> support sensor slope/any motion function <*> enable gyro data ready interrupt
- Copy driver source code into the target directory (e.g. drivers/input/sensors/smi130)
- Edit related Kconfig to include smi130 support:
source "drivers/input/sensors/smi130/Kconfig"
- Edit related Makefile adding the following line:
obj-$(CONFIG_INPUT_SMI130) += sensors/smi130/