Pavel Machek | 455fbdd | 2008-11-12 13:27:02 -0800 | [diff] [blame] | 1 | Kernel driver lis3lv02d |
| 2 | ================== |
| 3 | |
| 4 | Supported chips: |
| 5 | |
| 6 | * STMicroelectronics LIS3LV02DL and LIS3LV02DQ |
| 7 | |
| 8 | Author: |
| 9 | Yan Burman <burman.yan@gmail.com> |
| 10 | Eric Piel <eric.piel@tremplin-utc.net> |
| 11 | |
| 12 | |
| 13 | Description |
| 14 | ----------- |
| 15 | |
Pavel Machek | 219beb2 | 2009-01-15 13:51:24 -0800 | [diff] [blame] | 16 | This driver provides support for the accelerometer found in various HP |
| 17 | laptops sporting the feature officially called "HP Mobile Data |
| 18 | Protection System 3D" or "HP 3D DriveGuard". It detect automatically |
| 19 | laptops with this sensor. Known models (for now the HP 2133, nc6420, |
| 20 | nc2510, nc8510, nc84x0, nw9440 and nx9420) will have their axis |
| 21 | automatically oriented on standard way (eg: you can directly play |
| 22 | neverball). The accelerometer data is readable via |
Pavel Machek | 455fbdd | 2008-11-12 13:27:02 -0800 | [diff] [blame] | 23 | /sys/devices/platform/lis3lv02d. |
| 24 | |
| 25 | Sysfs attributes under /sys/devices/platform/lis3lv02d/: |
| 26 | position - 3D position that the accelerometer reports. Format: "(x,y,z)" |
Pavel Machek | 219beb2 | 2009-01-15 13:51:24 -0800 | [diff] [blame] | 27 | calibrate - read: values (x, y, z) that are used as the base for input |
| 28 | class device operation. |
| 29 | write: forces the base to be recalibrated with the current |
| 30 | position. |
Pavel Machek | 455fbdd | 2008-11-12 13:27:02 -0800 | [diff] [blame] | 31 | rate - reports the sampling rate of the accelerometer device in HZ |
| 32 | |
| 33 | This driver also provides an absolute input class device, allowing |
| 34 | the laptop to act as a pinball machine-esque joystick. |
| 35 | |
Pavel Machek | ef2cfc7 | 2009-02-18 14:48:23 -0800 | [diff] [blame] | 36 | Another feature of the driver is misc device called "freefall" that |
| 37 | acts similar to /dev/rtc and reacts on free-fall interrupts received |
| 38 | from the device. It supports blocking operations, poll/select and |
| 39 | fasync operation modes. You must read 1 bytes from the device. The |
| 40 | result is number of free-fall interrupts since the last successful |
| 41 | read (or 255 if number of interrupts would not fit). |
| 42 | |
| 43 | |
Pavel Machek | 455fbdd | 2008-11-12 13:27:02 -0800 | [diff] [blame] | 44 | Axes orientation |
| 45 | ---------------- |
| 46 | |
| 47 | For better compatibility between the various laptops. The values reported by |
| 48 | the accelerometer are converted into a "standard" organisation of the axes |
| 49 | (aka "can play neverball out of the box"): |
| 50 | * When the laptop is horizontal the position reported is about 0 for X and Y |
| 51 | and a positive value for Z |
| 52 | * If the left side is elevated, X increases (becomes positive) |
Pavel Machek | 219beb2 | 2009-01-15 13:51:24 -0800 | [diff] [blame] | 53 | * If the front side (where the touchpad is) is elevated, Y decreases |
| 54 | (becomes negative) |
Pavel Machek | 455fbdd | 2008-11-12 13:27:02 -0800 | [diff] [blame] | 55 | * If the laptop is put upside-down, Z becomes negative |
| 56 | |
Pavel Machek | 219beb2 | 2009-01-15 13:51:24 -0800 | [diff] [blame] | 57 | If your laptop model is not recognized (cf "dmesg"), you can send an |
| 58 | email to the authors to add it to the database. When reporting a new |
| 59 | laptop, please include the output of "dmidecode" plus the value of |
| 60 | /sys/devices/platform/lis3lv02d/position in these four cases. |
Pavel Machek | 455fbdd | 2008-11-12 13:27:02 -0800 | [diff] [blame] | 61 | |