aboutsummaryrefslogtreecommitdiffstats
path: root/Documentation/hwmon/lis3lv02d
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/hwmon/lis3lv02d')
-rw-r--r--Documentation/hwmon/lis3lv02d55
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
3 3
4Supported chips: 4Supported chips:
5 5
6 * STMicroelectronics LIS3LV02DL and LIS3LV02DQ 6 * STMicroelectronics LIS3LV02DL, LIS3LV02DQ (12 bits precision)
7 * STMicroelectronics LIS302DL, LIS3L02DQ, LIS331DL (8 bits)
7 8
8Authors: 9Authors:
9 Yan Burman <burman.yan@gmail.com> 10 Yan Burman <burman.yan@gmail.com>
@@ -13,32 +14,52 @@ Authors:
13Description 14Description
14----------- 15-----------
15 16
16This driver provides support for the accelerometer found in various HP 17This driver provides support for the accelerometer found in various HP laptops
17laptops sporting the feature officially called "HP Mobile Data 18sporting the feature officially called "HP Mobile Data Protection System 3D" or
18Protection System 3D" or "HP 3D DriveGuard". It detects automatically 19"HP 3D DriveGuard". It detects automatically laptops with this sensor. Known
19laptops with this sensor. Known models (for now the HP 2133, nc6420, 20models (full list can be found in drivers/hwmon/hp_accel.c) will have their
20nc2510, nc8510, nc84x0, nw9440 and nx9420) will have their axis 21axis automatically oriented on standard way (eg: you can directly play
21automatically oriented on standard way (eg: you can directly play 22neverball). The accelerometer data is readable via
22neverball). The accelerometer data is readable via 23/sys/devices/platform/lis3lv02d. Reported values are scaled
23/sys/devices/platform/lis3lv02d. 24to mg values (1/1000th of earth gravity).
24 25
25Sysfs attributes under /sys/devices/platform/lis3lv02d/: 26Sysfs attributes under /sys/devices/platform/lis3lv02d/:
26position - 3D position that the accelerometer reports. Format: "(x,y,z)" 27position - 3D position that the accelerometer reports. Format: "(x,y,z)"
27calibrate - read: values (x, y, z) that are used as the base for input 28rate - read reports the sampling rate of the accelerometer device in HZ.
28 class device operation. 29 write changes sampling rate of the accelerometer device.
29 write: forces the base to be recalibrated with the current 30 Only values which are supported by HW are accepted.
30 position. 31selftest - performs selftest for the chip as specified by chip manufacturer.
31rate - reports the sampling rate of the accelerometer device in HZ
32 32
33This driver also provides an absolute input class device, allowing 33This driver also provides an absolute input class device, allowing
34the laptop to act as a pinball machine-esque joystick. 34the laptop to act as a pinball machine-esque joystick. Joystick device can be
35calibrated. Joystick device can be in two different modes.
36By default output values are scaled between -32768 .. 32767. In joystick raw
37mode, joystick and sysfs position entry have the same scale. There can be
38small difference due to input system fuzziness feature.
39Events are also available as input event device.
40
41Selftest is meant only for hardware diagnostic purposes. It is not meant to be
42used during normal operations. Position data is not corrupted during selftest
43but interrupt behaviour is not guaranteed to work reliably. In test mode, the
44sensing element is internally moved little bit. Selftest measures difference
45between normal mode and test mode. Chip specifications tell the acceptance
46limit for each type of the chip. Limits are provided via platform data
47to allow adjustment of the limits without a change to the actual driver.
48Seltest returns either "OK x y z" or "FAIL x y z" where x, y and z are
49measured difference between modes. Axes are not remapped in selftest mode.
50Measurement values are provided to help HW diagnostic applications to make
51final decision.
52
53On HP laptops, if the led infrastructure is activated, support for a led
54indicating disk protection will be provided as /sys/class/leds/hp::hddprotect.
35 55
36Another feature of the driver is misc device called "freefall" that 56Another feature of the driver is misc device called "freefall" that
37acts similar to /dev/rtc and reacts on free-fall interrupts received 57acts similar to /dev/rtc and reacts on free-fall interrupts received
38from the device. It supports blocking operations, poll/select and 58from the device. It supports blocking operations, poll/select and
39fasync operation modes. You must read 1 bytes from the device. The 59fasync operation modes. You must read 1 bytes from the device. The
40result is number of free-fall interrupts since the last successful 60result is number of free-fall interrupts since the last successful
41read (or 255 if number of interrupts would not fit). 61read (or 255 if number of interrupts would not fit). See the hpfall.c
62file for an example on using the device.
42 63
43 64
44Axes orientation 65Axes orientation
@@ -55,7 +76,7 @@ the accelerometer are converted into a "standard" organisation of the axes
55 * If the laptop is put upside-down, Z becomes negative 76 * If the laptop is put upside-down, Z becomes negative
56 77
57If your laptop model is not recognized (cf "dmesg"), you can send an 78If your laptop model is not recognized (cf "dmesg"), you can send an
58email to the authors to add it to the database. When reporting a new 79email to the maintainer to add it to the database. When reporting a new
59laptop, please include the output of "dmidecode" plus the value of 80laptop, please include the output of "dmidecode" plus the value of
60/sys/devices/platform/lis3lv02d/position in these four cases. 81/sys/devices/platform/lis3lv02d/position in these four cases.
61 82