projects / deliverable / linux.git / blame
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|---|---|---|
| 455fbdd3 PM |
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 | ||
| 219beb29 PM |
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 | |
| 455fbdd3 PM |
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)" | |
| 219beb29 PM |
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. | |
| 455fbdd3 PM |
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 | ||
| ef2cfc79 PM |
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 | ||
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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) | |
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53 | * If the front side (where the touchpad is) is elevated, Y decreases |
| 54 | (becomes negative) | |
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55 | * If the laptop is put upside-down, Z becomes negative |
| 56 | ||
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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. | |
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