# st-mems-android-linux-drivers-input

**Repository Path**: erinfeng/st-mems-android-linux-drivers-input

## Basic Information

- **Project Name**: st-mems-android-linux-drivers-input
- **Description**: No description available
- **Primary Language**: Unknown
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 2
- **Created**: 2022-08-18
- **Last Updated**: 2022-08-18

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

Index
=======
	* Introduction
	* Integration details
	* More information
	* Copyright


Introduction
==============
This repository contains STMicroelectronics MEMS sensors for Linux/Android kernels leveraging on **Input framework**. STM sensor drivers are located under the directory [drivers/input/misc/st](https://github.com/STMicroelectronics/st-mems-android-linux-drivers-input/tree/master/drivers/input/misc/st) organized in folders by sensor type:

### Inertial Module Unit (IMU):

> LSM330, LSM330DLC, LSM6DS0,
> LSM6DS3, LSM6DSL, LSM6DSM, LSM9DS0, LSM9DS1, ISM330DLC,
> ASM330LHH, LSM6DSO, LSM6DSO32, LSM6DSOX, LSM6DSO32X, LSM6DSR,
> ISM330DHCX

### eCompass:

> LSM303AGR, LSM303AH, LSM303C, LSM303D, LSM303DLHC, ISM303DAC

### Accelerometer:

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

### Gyroscope:

> A3G4250D, L3G4200D, L3GD20, L3GD20H

### Magnetometer:

> LIS3MDL, LIS2MDL, IIS2MDC

### Humidity:

> HTS221

### Pressure:

> LPS22CH, LPS22HB, LPS22HD, LPS22HH, LPS22DF, LPS25H, LPS25HB,
> LPS27HHW, LPS27HHTW, LPS33HW, LPS35HW

### Ultraviolet:

> UVIS25

### Temperature:

> STTS751, STTS22H


Data collected by STM sensors are pushed from kernel-space to user-space 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][1] for more information.

All STM MEMS sensors support *I2C/SPI* digital interface. Please refer to [I2C][2] and [SPI][3] for detailed documentation.


Integration details
=====================

## Source code integration
From your kernel source code root directory add the git remote (i.e. stmems_input_github) for this repository:
```bash
git remote add stmems_input_github \
               https://github.com/STMicroelectronics/st-mems-android-linux-drivers-input.git
```

Fetch the just added remote:
```bash
git fetch stmems_input_github
```

There are now two ways you may choose for integrating the drivers code into your kernel target branch:
* merge (**suggested strategy**)
* rebase

### merge
Merge the remote branch stmems_input_github/master with your target kernel source branch (i.e branch linux-4.19.y):

```bash
git merge --no-fork-point \
          linux-4.19.y \
          stmems_input_github/master
```

### rebase
Rebase the remote branch stmems_input_github/master on top of your target kernel source branch (i.e branch linux-4.19.y):

```bash
git rebase -Xno-renames \
           --no-fork-point \
           linux-4.19.y \
           stmems_input_github/master
```

## Apply patches
Now that drivers code has been added to the target kernel branch, few patches needs to be added in order to add STM drivers into Kconfig & Makefile systems

Apply the patches available in the just added repository selecting the proper kernel release directory (i.e for branch linux-4.19.y):

```bash
git am stm_input_patches/4.19.y/*-stm-*.patch
```

## Configuration
A folder named ``stm_input_configs`` is provided containing the default configs for the supported drivers. Following are two proposed alternative ways (beside the traditional ones) for enabling configurations.
``common_defconfig`` is mandatory for enabling STM MEMS Sensors drivers' configuration.

### Modify target defconfig
Sensors defconfig can be appended to the board defconfig (i.e. if your current configuration file is arch/arm/configs/stm32_defconfig):

```bash
cat stm_input_configs/common_defconfig >> all_sensors_defconfig
cat stm_input_configs/accel_defconfig >> all_sensors_defconfig
cat all_sensors_defconfig >> arch/arm/configs/stm32_defconfig
```

Alternatively, it can be done at build time without altering the board config file, as follow.

### Merge configuration
Driver config can be merged into current target pre-configured kernel using a script available in the kernel itself:

```bash
export ARCH=arm
export CROSS_COMPILE=arm-linux-gnu-
cat stm_input_configs/common_defconfig >> ./all_sensors_defconfig
cat stm_input_configs/imus_defconfig >> ./all_sensors_defconfig
scripts/kconfig/merge_config.sh -n .config ./all_sensors_defconfig
```

### Traditional Kernel configuration

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

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

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


### 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][4]

> *- interrupts*: interrupt mapping for IRQ as documented in [interrupts][4]

>
>**Recommended properties for SPI bus usage:**

> *- spi-max-frequency*: maximum SPI bus frequency as documented in [SPI][3]
>
> **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>;
>			};

More Information
=================
[http://st.com](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/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/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/spi)

[https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bings/interrupt-controller/interrupts.txt](https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/interrupt-controller/interrupts.txt)


Copyright
===========
Copyright (C) 2022 STMicroelectronics

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

[1]: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/input "Input"
[2]: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/i2c "I2C"
[3]: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/spi "SPI"
[4]: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/interrupt-controller/interrupts.txt "interrupts"