1Kernel driver toshiba_haps
2Toshiba HDD Active Protection Sensor
3====================================
4
5Author: Azael Avalos <coproscefalo@gmail.com>
6
7
80. Contents
9-----------
10
111. Description
122. Interface
133. Accelerometer axes
144. Supported devices
155. Usage
16
17
181. Description
19--------------
20
21This driver provides support for the accelerometer found in various Toshiba
22laptops, being called "Toshiba HDD Protection - Shock Sensor" officialy,
23and detects laptops automatically with this device.
24On Windows, Toshiba provided software monitors this device and provides
25automatic HDD protection (head unload) on sudden moves or harsh vibrations,
26however, this driver only provides a notification via a sysfs file to let
27userspace tools or daemons act accordingly, as well as providing a sysfs
28file to set the desired protection level or sensor sensibility.
29
30
312. Interface
32------------
33
34This device comes with 3 methods:
35_STA -  Checks existence of the device, returning Zero if the device does not
36	exists or is not supported.
37PTLV -  Sets the desired protection level.
38RSSS -  Shuts down the HDD protection interface for a few seconds,
39	then restores normal operation.
40
41Note:
42The presence of Solid State Drives (SSD) can make this driver to fail loading,
43given the fact that such drives have no movable parts, and thus, not requiring
44any "protection" as well as failing during the evaluation of the _STA method
45found under this device.
46
47
483. Accelerometer axes
49---------------------
50
51This device does not report any axes, however, to query the sensor position
52a couple HCI (Hardware Configuration Interface) calls (0x6D and 0xA6) are
53provided to query such information, handled by the kernel module toshiba_acpi
54since kernel version 3.15.
55
56
574. Supported devices
58--------------------
59
60This driver binds itself to the ACPI device TOS620A, and any Toshiba laptop
61with this device is supported, given the fact that they have the presence of
62conventional HDD and not only SSD, or a combination of both HDD and SSD.
63
64
655. Usage
66--------
67
68The sysfs files under /sys/devices/LNXSYSTM:00/LNXSYBUS:00/TOS620A:00/ are:
69protection_level - The protection_level is readable and writeable, and
70		   provides a way to let userspace query the current protection
71		   level, as well as set the desired protection level, the
72		   available protection levels are:
73		   0 - Disabled | 1 - Low | 2 - Medium | 3 - High
74reset_protection - The reset_protection entry is writeable only, being "1"
75		   the only parameter it accepts, it is used to trigger
76		   a reset of the protection interface.
77