Date: Sat, 25 Aug 2007 10:25:13 +0000
From: Pavel Machek <pavel@ucw.cz>
To: Yan Burman <burman.yan@gmail.com>
Cc: linux-kernel@vger.kernel.org, khali@linux-fr.org
Subject: Re: [PATCH 2.6.23-rc2]  hwmon: HP Mobile Data Protection System 3D ACPI driver (resend)
Message-ID: <20070825102512.GA5850@ucw.cz>
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On Sat 2007-08-11 14:26:02, Yan Burman wrote:
> HP Mobile Data Protection System 3D ACPI driver. Similar to hdaps in functionality.
> This driver provides 4 kinds of functionality:
> 1) Creates a misc device /dev/accel that acts similar to /dev/rtc and unblocks
> the process reading from it when the device detects free-fall interrupt
> 2) Functions as an input class device to provide similar functionality to
> hdaps, in order to be able to use the laptop as a joystick
> 3) Provides an interface similar to hdaps, so that hdapsd could work with it
> 4) Makes it possible to power the device off.

I assume this means 'power the sensor down'? What is interface for
that?

Aha, /sys. Could we simply power off the device when its input device
is not opened?

> +Description
> +-----------
> +
> +This driver provides support for the HP Mobile Data Protection
> +System 3D (mdps), which is an accelerometer. HP nc6420, nw9440 and nx9420
> +are supported right now, but it may work on other models as well. The
> +accelerometer data is readable via /sys/devices/platform/mdps.
> +
> +Sysfs attributes under /sys/devices/platform/mdps/:
> +position - 2D position that the accelerometer reports. Format: "(x,y)"
> +position3d - 3D position that the accelerometer reports. Format: "(x,y,z)"
> +calibrate - read: values (x, y) that are used as the base for input class device operation.
> +            write: forces the base to be recalibrated.
> +rate - reports the sampling rate of the accelerometer device in HZ
> +state - read: the current power state of the accelerometer device
> +        write: "0" or "1" to power on/off the device
> +joystick - read: whether the input class device is active or not
> +           write: "0" or "1" to enable/disable the input device
> +
> +Load time parameters:
> +bool joystick - whether to enable the input class device or not (default 1)
> +bool power_off - whether to power off the device on module load (default 0)
> +bool hdaps_compat - Make the driver export same interfaces as hdaps,
> +	so that apps like hdaps-gl will work the same as with hdaps (default 0)
> +	The effect of this is:
> +	1) Instead of /sys/devices/platform/mdps/, /sys/devices/platform/hdaps/ is created
> +	2) Sensitivity is adjusted to match that of hdaps
> +bool input_3d - Whether to operate as a 3D input device. (default 0)
> +		BIG FAT WARNING: Do not enable this mode unless you are sure
> +		that you want it, since it eats more CPU
> +
> +This driver also provides an absolute input class device, allowing
> +the laptop to act as a pinball machine-esque joystick.
> +

							Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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