Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  1) =======================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  2) Kernel driver lis3lv02d
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  3) =======================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  4) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  5) Supported chips:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  6) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  7)   * STMicroelectronics LIS3LV02DL, LIS3LV02DQ (12 bits precision)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  8)   * STMicroelectronics LIS302DL, LIS3L02DQ, LIS331DL (8 bits) and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  9)     LIS331DLH (16 bits)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) Authors:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12)         - Yan Burman <burman.yan@gmail.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) 	- Eric Piel <eric.piel@tremplin-utc.net>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) Description
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) -----------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) This driver provides support for the accelerometer found in various HP laptops
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) sporting the feature officially called "HP Mobile Data Protection System 3D" or
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) "HP 3D DriveGuard". It detects automatically laptops with this sensor. Known
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) models (full list can be found in drivers/platform/x86/hp_accel.c) will have
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) their axis automatically oriented on standard way (eg: you can directly play
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) neverball). The accelerometer data is readable via
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) /sys/devices/platform/lis3lv02d. Reported values are scaled
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) to mg values (1/1000th of earth gravity).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) Sysfs attributes under /sys/devices/platform/lis3lv02d/:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) position
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31)       - 3D position that the accelerometer reports. Format: "(x,y,z)"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) rate
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33)       - read reports the sampling rate of the accelerometer device in HZ.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) 	write changes sampling rate of the accelerometer device.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) 	Only values which are supported by HW are accepted.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) selftest
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37)       - performs selftest for the chip as specified by chip manufacturer.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) This driver also provides an absolute input class device, allowing
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) the laptop to act as a pinball machine-esque joystick. Joystick device can be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) calibrated. Joystick device can be in two different modes.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) By default output values are scaled between -32768 .. 32767. In joystick raw
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) mode, joystick and sysfs position entry have the same scale. There can be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) small difference due to input system fuzziness feature.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) Events are also available as input event device.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) Selftest is meant only for hardware diagnostic purposes. It is not meant to be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) used during normal operations. Position data is not corrupted during selftest
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) but interrupt behaviour is not guaranteed to work reliably. In test mode, the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) sensing element is internally moved little bit. Selftest measures difference
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) between normal mode and test mode. Chip specifications tell the acceptance
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) limit for each type of the chip. Limits are provided via platform data
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) to allow adjustment of the limits without a change to the actual driver.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) Seltest returns either "OK x y z" or "FAIL x y z" where x, y and z are
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) measured difference between modes. Axes are not remapped in selftest mode.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) Measurement values are provided to help HW diagnostic applications to make
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) final decision.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) On HP laptops, if the led infrastructure is activated, support for a led
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) indicating disk protection will be provided as /sys/class/leds/hp::hddprotect.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) Another feature of the driver is misc device called "freefall" that
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) acts similar to /dev/rtc and reacts on free-fall interrupts received
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) from the device. It supports blocking operations, poll/select and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) fasync operation modes. You must read 1 bytes from the device.  The
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) result is number of free-fall interrupts since the last successful
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) read (or 255 if number of interrupts would not fit). See the freefall.c
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) file for an example on using the device.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) Axes orientation
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) ----------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) For better compatibility between the various laptops. The values reported by
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) the accelerometer are converted into a "standard" organisation of the axes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) (aka "can play neverball out of the box"):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78)  * When the laptop is horizontal the position reported is about 0 for X and Y
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79)    and a positive value for Z
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80)  * If the left side is elevated, X increases (becomes positive)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81)  * If the front side (where the touchpad is) is elevated, Y decreases
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82)    (becomes negative)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83)  * If the laptop is put upside-down, Z becomes negative
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) If your laptop model is not recognized (cf "dmesg"), you can send an
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) email to the maintainer to add it to the database.  When reporting a new
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) laptop, please include the output of "dmidecode" plus the value of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) /sys/devices/platform/lis3lv02d/position in these four cases.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) Q&A
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) ---
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) Q: How do I safely simulate freefall? I have an HP "portable
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) workstation" which has about 3.5kg and a plastic case, so letting it
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) fall to the ground is out of question...
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) A: The sensor is pretty sensitive, so your hands can do it. Lift it
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) into free space, follow the fall with your hands for like 10
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) centimeters. That should be enough to trigger the detection.