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lis3: update documentation and comments
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Most of the documentation and comments were written when the driver was
only supporting one type of chip, only via ACPI/HP. Update the info to
the much clearer understanding that we have now.

Signed-off-by: Éric Piel <[email protected]>
Signed-off-by: Samu Onkalo <[email protected]>
Cc: Pavel Machek <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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pieleric authored and torvalds committed Dec 15, 2009
1 parent 66c8569 commit bc62c14
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24 changes: 14 additions & 10 deletions Documentation/hwmon/lis3lv02d
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Original file line number Diff line number Diff line change
Expand Up @@ -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 <[email protected]>
Expand All @@ -13,13 +14,12 @@ 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
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.

Sysfs attributes under /sys/devices/platform/lis3lv02d/:
Expand All @@ -33,12 +33,16 @@ rate - reports the sampling rate of the accelerometer device in HZ
This driver also provides an absolute input class device, allowing
the laptop to act as a pinball machine-esque joystick.

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
Expand All @@ -55,7 +59,7 @@ 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.

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22 changes: 12 additions & 10 deletions drivers/hwmon/Kconfig
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Expand Up @@ -1046,25 +1046,27 @@ config SENSORS_ATK0110
will be called asus_atk0110.

config SENSORS_LIS3LV02D
tristate "STMicroeletronics LIS3LV02Dx three-axis digital accelerometer"
tristate "STMicroeletronics LIS3* three-axis digital accelerometer"
depends on INPUT
select INPUT_POLLDEV
select NEW_LEDS
select LEDS_CLASS
default n
help
This driver provides support for the LIS3LV02Dx accelerometer. In
particular, it can be found in a number of HP laptops, which have the
"Mobile Data Protection System 3D" or "3D DriveGuard" feature. On such
systems the driver should load automatically (via ACPI). The
accelerometer might also be found in other systems, connected via SPI
or I2C. The accelerometer data is readable via
/sys/devices/platform/lis3lv02d.
This driver provides support for the LIS3* accelerometers, such as the
LIS3LV02DL or the LIS331DL. In particular, it can be found in a number
of HP laptops, which have the "Mobile Data Protection System 3D" or
"3D DriveGuard" feature. On such systems the driver should load
automatically (via ACPI alias). The accelerometer might also be found
in other systems, connected via SPI or I2C. The accelerometer data is
readable via /sys/devices/platform/lis3lv02d.

This driver also provides an absolute input class device, allowing
the laptop to act as a pinball machine-esque joystick. On HP laptops,
a laptop to act as a pinball machine-esque joystick. It provides also
a misc device which can be used to detect free-fall. On HP laptops,
if the led infrastructure is activated, support for a led indicating
disk protection will be provided as hp:red:hddprotection.
disk protection will be provided as hp::hddprotect. For more
information on the feature, refer to Documentation/hwmon/lis3lv02d.

This driver can also be built as modules. If so, the core module
will be called lis3lv02d and a specific module for HP laptops will be
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20 changes: 10 additions & 10 deletions drivers/hwmon/lis3lv02d.c
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Expand Up @@ -43,7 +43,7 @@
#define MDPS_POLL_INTERVAL 50
/*
* The sensor can also generate interrupts (DRDY) but it's pretty pointless
* because their are generated even if the data do not change. So it's better
* because they are generated even if the data do not change. So it's better
* to keep the interrupt for the free-fall event. The values are updated at
* 40Hz (at the lowest frequency), but as it can be pretty time consuming on
* some low processor, we poll the sensor only at 20Hz... enough for the
Expand All @@ -65,7 +65,7 @@ static s16 lis3lv02d_read_8(struct lis3lv02d *lis3, int reg)
return lo;
}

static s16 lis3lv02d_read_16(struct lis3lv02d *lis3, int reg)
static s16 lis3lv02d_read_12(struct lis3lv02d *lis3, int reg)
{
u8 lo, hi;

Expand Down Expand Up @@ -411,20 +411,20 @@ EXPORT_SYMBOL_GPL(lis3lv02d_remove_fs);

/*
* Initialise the accelerometer and the various subsystems.
* Should be rather independant of the bus system.
* Should be rather independent of the bus system.
*/
int lis3lv02d_init_device(struct lis3lv02d *dev)
{
dev->whoami = lis3lv02d_read_8(dev, WHO_AM_I);

switch (dev->whoami) {
case LIS_DOUBLE_ID:
printk(KERN_INFO DRIVER_NAME ": 2-byte sensor found\n");
dev->read_data = lis3lv02d_read_16;
case WAI_12B:
printk(KERN_INFO DRIVER_NAME ": 12 bits sensor found\n");
dev->read_data = lis3lv02d_read_12;
dev->mdps_max_val = 2048;
break;
case LIS_SINGLE_ID:
printk(KERN_INFO DRIVER_NAME ": 1-byte sensor found\n");
case WAI_8B:
printk(KERN_INFO DRIVER_NAME ": 8 bits sensor found\n");
dev->read_data = lis3lv02d_read_8;
dev->mdps_max_val = 128;
break;
Expand All @@ -445,7 +445,7 @@ int lis3lv02d_init_device(struct lis3lv02d *dev)
if (dev->pdata) {
struct lis3lv02d_platform_data *p = dev->pdata;

if (p->click_flags && (dev->whoami == LIS_SINGLE_ID)) {
if (p->click_flags && (dev->whoami == WAI_8B)) {
dev->write(dev, CLICK_CFG, p->click_flags);
dev->write(dev, CLICK_TIMELIMIT, p->click_time_limit);
dev->write(dev, CLICK_LATENCY, p->click_latency);
Expand All @@ -456,7 +456,7 @@ int lis3lv02d_init_device(struct lis3lv02d *dev)
(p->click_thresh_y << 4));
}

if (p->wakeup_flags && (dev->whoami == LIS_SINGLE_ID)) {
if (p->wakeup_flags && (dev->whoami == WAI_8B)) {
dev->write(dev, FF_WU_CFG_1, p->wakeup_flags);
dev->write(dev, FF_WU_THS_1, p->wakeup_thresh & 0x7f);
/* default to 2.5ms for now */
Expand Down
28 changes: 16 additions & 12 deletions drivers/hwmon/lis3lv02d.h
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@
* lis3lv02d.h - ST LIS3LV02DL accelerometer driver
*
* Copyright (C) 2007-2008 Yan Burman
* Copyright (C) 2008 Eric Piel
* Copyright (C) 2008-2009 Eric Piel
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
Expand All @@ -22,20 +22,18 @@
#include <linux/input-polldev.h>

/*
* The actual chip is STMicroelectronics LIS3LV02DL or LIS3LV02DQ that seems to
* be connected via SPI. There exists also several similar chips (such as LIS302DL or
* LIS3L02DQ) and they have slightly different registers, but we can provide a
* common interface for all of them.
* They can also be connected via I²C.
* This driver tries to support the "digital" accelerometer chips from
* STMicroelectronics such as LIS3LV02DL, LIS302DL, LIS3L02DQ, LIS331DL,
* LIS35DE, or LIS202DL. They are very similar in terms of programming, with
* almost the same registers. In addition to differing on physical properties,
* they differ on the number of axes (2/3), precision (8/12 bits), and special
* features (freefall detection, click...). Unfortunately, not all the
* differences can be probed via a register.
* They can be connected either via I²C or SPI.
*/

#include <linux/lis3lv02d.h>

/* 2-byte registers */
#define LIS_DOUBLE_ID 0x3A /* LIS3LV02D[LQ] */
/* 1-byte registers */
#define LIS_SINGLE_ID 0x3B /* LIS[32]02DL and others */

enum lis3_reg {
WHO_AM_I = 0x0F,
OFFSET_X = 0x16,
Expand Down Expand Up @@ -94,6 +92,12 @@ enum lis3lv02d_reg {
DD_THSE_H = 0x3F,
};

enum lis3_who_am_i {
WAI_12B = 0x3A, /* 12 bits: LIS3LV02D[LQ]... */
WAI_8B = 0x3B, /* 8 bits: LIS[23]02D[LQ]... */
WAI_6B = 0x52, /* 6 bits: LIS331DLF - not supported */
};

enum lis3lv02d_ctrl1 {
CTRL1_Xen = 0x01,
CTRL1_Yen = 0x02,
Expand Down Expand Up @@ -194,7 +198,7 @@ struct lis3lv02d {
int (*write) (struct lis3lv02d *lis3, int reg, u8 val);
int (*read) (struct lis3lv02d *lis3, int reg, u8 *ret);

u8 whoami; /* 3Ah: 2-byte registries, 3Bh: 1-byte registries */
u8 whoami; /* indicates measurement precision */
s16 (*read_data) (struct lis3lv02d *lis3, int reg);
int mdps_max_val;

Expand Down

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