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![Pavel Machek](/assets/img/avatar_default.png)
This adds freefall handling to hp_accel driver. According to HP, it should just work, without us having to set the chip up by hand. hpfall.c is example .c program that parks the disk when accelerometer detects free fall. It should work; for now, it uses fixed 20seconds protection period. Signed-off-by: Pavel Machek <pavel@suse.cz> Cc: Thomas Renninger <trenn@suse.de> Cc: Éric Piel <eric.piel@tremplin-utc.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
61 lines
2.4 KiB
Text
61 lines
2.4 KiB
Text
Kernel driver lis3lv02d
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==================
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Supported chips:
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* STMicroelectronics LIS3LV02DL and LIS3LV02DQ
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Author:
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Yan Burman <burman.yan@gmail.com>
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Eric Piel <eric.piel@tremplin-utc.net>
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Description
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-----------
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This driver provides support for the accelerometer found in various HP
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laptops sporting the feature officially called "HP Mobile Data
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Protection System 3D" or "HP 3D DriveGuard". It detect automatically
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laptops with this sensor. Known models (for now the HP 2133, nc6420,
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nc2510, nc8510, nc84x0, nw9440 and nx9420) will have their axis
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automatically oriented on standard way (eg: you can directly play
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neverball). The accelerometer data is readable via
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/sys/devices/platform/lis3lv02d.
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Sysfs attributes under /sys/devices/platform/lis3lv02d/:
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position - 3D position that the accelerometer reports. Format: "(x,y,z)"
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calibrate - read: values (x, y, z) that are used as the base for input
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class device operation.
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write: forces the base to be recalibrated with the current
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position.
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rate - reports the sampling rate of the accelerometer device in HZ
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This driver also provides an absolute input class device, allowing
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the laptop to act as a pinball machine-esque joystick.
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Another feature of the driver is misc device called "freefall" that
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acts similar to /dev/rtc and reacts on free-fall interrupts received
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from the device. It supports blocking operations, poll/select and
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fasync operation modes. You must read 1 bytes from the device. The
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result is number of free-fall interrupts since the last successful
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read (or 255 if number of interrupts would not fit).
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Axes orientation
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----------------
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For better compatibility between the various laptops. The values reported by
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the accelerometer are converted into a "standard" organisation of the axes
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(aka "can play neverball out of the box"):
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* When the laptop is horizontal the position reported is about 0 for X and Y
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and a positive value for Z
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* If the left side is elevated, X increases (becomes positive)
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* If the front side (where the touchpad is) is elevated, Y decreases
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(becomes negative)
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* If the laptop is put upside-down, Z becomes negative
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If your laptop model is not recognized (cf "dmesg"), you can send an
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email to the authors to add it to the database. When reporting a new
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laptop, please include the output of "dmidecode" plus the value of
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/sys/devices/platform/lis3lv02d/position in these four cases.
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