Kernel driver for CMA3000-D0x
Supported chips:
- VTI CMA3000-D0x
Datasheet:
CMA3000-D0X Product Family Specification 8281000A.02.pdf
http://www.vti.fi/en/
Author: Hemanth V hemanthv@ti.com
Description
CMA3000 Tri-axis accelerometer supports Motion detect, Measurement and
Free fall modes.
Motion Detect Mode: Its the low power mode where interrupts are generated only
when motion exceeds the defined thresholds.
Measurement Mode: This mode is used to read the acceleration data on X,Y,Z
axis and supports 400, 100, 40 Hz sample frequency.
Free fall Mode: This mode is intended to save system resources.
Threshold values: Chip supports defining threshold values for above modes
which includes time and g value. Refer product specifications for more details.
CMA3000 chip supports mutually exclusive I2C and SPI interfaces for
communication, currently the driver supports I2C based communication only.
Initial configuration for bus mode is set in non volatile memory and can later
be modified through bus interface command.
Driver reports acceleration data through input subsystem. It generates ABS_MISC
event with value 1 when free fall is detected.
Platform data need to be configured for initial default values.
Platform Data
fuzz_x: Noise on X Axis
fuzz_y: Noise on Y Axis
fuzz_z: Noise on Z Axis
g_range: G range in milli g i.e 2000 or 8000
mode: Default Operating mode
mdthr: Motion detect g range threshold value
mdfftmr: Motion detect and free fall time threshold value
ffthr: Free fall g range threshold value
Input Interface
Input driver version is 1.0.0
Input device ID: bus 0x18 vendor 0x0 product 0x0 version 0x0
Input device name: “cma3000-accelerometer”
Supported events:
Event type 0 (Sync)
Event type 3 (Absolute)
Event code 0 (X)
Value 47
Min -8000
Max 8000
Fuzz 200
Event code 1 (Y)
Value -28
Min -8000
Max 8000
Fuzz 200
Event code 2 (Z)
Value 905
Min -8000
Max 8000
Fuzz 200
Event code 40 (Misc)
Value 0
Min 0
Max 1
Event type 4 (Misc)
Register/Platform parameters Description
mode:
0: power down mode
1: 100 Hz Measurement mode
2: 400 Hz Measurement mode
3: 40 Hz Measurement mode
4: Motion Detect mode (default)
5: 100 Hz Free fall mode
6: 40 Hz Free fall mode
7: Power off mode
grange:
2000: 2000 mg or 2G Range
8000: 8000 mg or 8G Range
mdthr:
X: X * 71mg (8G Range)
X: X * 18mg (2G Range)
mdfftmr:
X: (X & 0x70) * 100 ms (MDTMR)
(X & 0x0F) * 2.5 ms (FFTMR 400 Hz)
(X & 0x0F) * 10 ms (FFTMR 100 Hz)
ffthr:
X: (X >> 2) * 18mg (2G Range)
X: (X & 0x0F) * 71 mg (8G Range)
