diff options
Diffstat (limited to 'Documentation/hwmon/lis3lv02d')
| -rw-r--r-- | Documentation/hwmon/lis3lv02d | 55 |
1 files changed, 38 insertions, 17 deletions
diff --git a/Documentation/hwmon/lis3lv02d b/Documentation/hwmon/lis3lv02d index effe949a728..06534f25e64 100644 --- a/Documentation/hwmon/lis3lv02d +++ b/Documentation/hwmon/lis3lv02d @@ -3,7 +3,8 @@ Kernel driver lis3lv02d Supported chips: - * STMicroelectronics LIS3LV02DL and LIS3LV02DQ + * STMicroelectronics LIS3LV02DL, LIS3LV02DQ (12 bits precision) + * STMicroelectronics LIS302DL, LIS3L02DQ, LIS331DL (8 bits) Authors: Yan Burman <burman.yan@gmail.com> @@ -13,32 +14,52 @@ Authors: Description ----------- -This driver provides support for the accelerometer found in various HP -laptops sporting the feature officially called "HP Mobile Data -Protection System 3D" or "HP 3D DriveGuard". It detects automatically -laptops with this sensor. Known models (for now the HP 2133, nc6420, -nc2510, nc8510, nc84x0, nw9440 and nx9420) will have their axis -automatically oriented on standard way (eg: you can directly play -neverball). The accelerometer data is readable via -/sys/devices/platform/lis3lv02d. +This driver provides support for the accelerometer found in various HP laptops +sporting the feature officially called "HP Mobile Data Protection System 3D" or +"HP 3D DriveGuard". It detects automatically laptops with this sensor. Known +models (full list can be found in drivers/hwmon/hp_accel.c) will have their +axis automatically oriented on standard way (eg: you can directly play +neverball). The accelerometer data is readable via +/sys/devices/platform/lis3lv02d. Reported values are scaled +to mg values (1/1000th of earth gravity). Sysfs attributes under /sys/devices/platform/lis3lv02d/: position - 3D position that the accelerometer reports. Format: "(x,y,z)" -calibrate - read: values (x, y, z) that are used as the base for input - class device operation. - write: forces the base to be recalibrated with the current - position. -rate - reports the sampling rate of the accelerometer device in HZ +rate - read reports the sampling rate of the accelerometer device in HZ. + write changes sampling rate of the accelerometer device. + Only values which are supported by HW are accepted. +selftest - performs selftest for the chip as specified by chip manufacturer. This driver also provides an absolute input class device, allowing -the laptop to act as a pinball machine-esque joystick. +the laptop to act as a pinball machine-esque joystick. Joystick device can be +calibrated. Joystick device can be in two different modes. +By default output values are scaled between -32768 .. 32767. In joystick raw +mode, joystick and sysfs position entry have the same scale. There can be +small difference due to input system fuzziness feature. +Events are also available as input event device. + +Selftest is meant only for hardware diagnostic purposes. It is not meant to be +used during normal operations. Position data is not corrupted during selftest +but interrupt behaviour is not guaranteed to work reliably. In test mode, the +sensing element is internally moved little bit. Selftest measures difference +between normal mode and test mode. Chip specifications tell the acceptance +limit for each type of the chip. Limits are provided via platform data +to allow adjustment of the limits without a change to the actual driver. +Seltest returns either "OK x y z" or "FAIL x y z" where x, y and z are +measured difference between modes. Axes are not remapped in selftest mode. +Measurement values are provided to help HW diagnostic applications to make +final decision. + +On HP laptops, if the led infrastructure is activated, support for a led +indicating disk protection will be provided as /sys/class/leds/hp::hddprotect. Another feature of the driver is misc device called "freefall" that acts similar to /dev/rtc and reacts on free-fall interrupts received from the device. It supports blocking operations, poll/select and fasync operation modes. You must read 1 bytes from the device. The result is number of free-fall interrupts since the last successful -read (or 255 if number of interrupts would not fit). +read (or 255 if number of interrupts would not fit). See the hpfall.c +file for an example on using the device. Axes orientation @@ -55,7 +76,7 @@ the accelerometer are converted into a "standard" organisation of the axes * If the laptop is put upside-down, Z becomes negative If your laptop model is not recognized (cf "dmesg"), you can send an -email to the authors to add it to the database. When reporting a new +email to the maintainer to add it to the database. When reporting a new laptop, please include the output of "dmidecode" plus the value of /sys/devices/platform/lis3lv02d/position in these four cases. |