varzhou / stmems_linux_input_drivers

This repository contains Linux kernel (v3.10, v3.4) with STMicroelectronics MEMS Input sensor support

Index

* Introduction
* Integration details
* More information
* Copyright

Introduction

This repository contains Linux kernel (v3.10, v3.4) with STMicroelectronics MEMS sensor support. STM sensor drivers are located under the directory drivers/input/misc/st organized by sensor type:

Inertial Module Unit (IMU):

ASM330LXH, LSM330, LSM330DLC, LSM6DL0, LSM6DS0, LSM6DS3, LSM6DSL, LSM6DSM, LSM9DS0, LSM9DS1, ISM330DLC

eCompass:

LSM303AGR, LSM303AH, LSM303C, LSM303D, LSM303DLHC, ISM303DAC

Accelerometer:

AIS328DQ, AIS3624DQ, H3LIS100DL, H3LIS331DL, LIS2DE, LIS2DE12, LIS2DH, LIS2DH12, LIS2DS12, LIS2HH12, LIS331DLH, LIS331HH, LIS3DE, LIS3DH, LIS3DSH, N2DM, LIS2DW12, LIS3DHH, IIS3DHHC, IIS2DH

Gyroscope:

A3G4250D, L3G4200D, L3GD20, L3GD20H

Magnetometer:

LIS3MDL, LIS2MDL, IIS2MDC

Humidity:

HTS221

Pressure:

LPS22HB, LPS22HD, LPS25H, LPS25HB, LPS33HW, LPS35HW

Ultraviolet:

UVIS25

Data collected by STM sensors are pushed to userland through the Linux kernel Input framework using EV_MSC events. User space applications can get sensor events by reading the related input device created in the /dev directory. Please see Input for more information.

All STM MEMS sensors support I2C/SPI digital interface. Please refer to I2C and SPI for detailed documentation.

Integration details

In order to explain how to integrate STM sensors in a different kernel, please consider the following LSM6DSM IMU example

Source code integration

• Copy driver source code into the target directory (e.g. drivers/input/misc)
• Edit related Kconfig (e.g. drivers/input/misc/Kconfig) to include LSM6DSM support:

    source "drivers/input/misc/lsm6dsm/Kconfig"

• Edit related Makefile (e.g. drivers/input/misc/Makefile) adding the following line:

    obj-y += lsm6dsm/

Device Tree configuration

To enable driver probing, add the lsm6dsm node to the platform device tree as described below.

Required properties:

- compatible: "st,lsm6dsm"

- 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

Recommended properties for SPI bus usage:

- spi-max-frequency: maximum SPI bus frequency as documented in SPI

Optional properties:

- st,drdy-int-pin: MEMS sensor interrupt line to use (default 1)

I2C example (based on Raspberry PI 3):

  &i2c0 {
  	status = "ok";
  	#address-cells = <0x1>;
  	#size-cells = <0x0>;
  	lsm6dsm@6b {
  		compatible = "st,lsm6dsm";
  		reg = <0x6b>;
  		interrupt-parent = <&gpio>;
  		interrupts = <26 IRQ_TYPE_EDGE_RISING>;
  };

SPI example (based on Raspberry PI 3):

  &spi0 {
  	status = "ok";
  	#address-cells = <0x1>;
  	#size-cells = <0x0>;
  	lsm6dsm@0 {
  		spi-max-frequency = <500000>;
  		compatible = "st,lsm6dsm";
  		reg = <0>;
  		interrupt-parent = <&gpio>;
  		interrupts = <26 IRQ_TYPE_EDGE_RISING>;
  	};

Kernel configuration

Configure kernel with make menuconfig (alternatively use make xconfig or make qconfig)

  Device Drivers  --->
  	Input device support  --->
  	[*]   Miscellaneous devices  --->
  		<*>   STM MEMs Device Drivers  --->
  			<M>   Inertial motion unit  --->
  				<M>   STMicroelectronics LSM6DSM sensor

More Information

http://st.com

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/input

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/i2c

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/spi

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bings/interrupt-controller/interrupts.txt

Copyright

Copyright (C) 2016 STMicroelectronics

This software is distributed under the GNU General Public License - see the accompanying COPYING file for more details.