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Documentation / input / cma3000_d0x.txt




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Based on kernel version 3.13. Page generated on 2014-01-20 22:03 EST.

1	Kernel driver for CMA3000-D0x
2	============================
3	
4	Supported chips:
5	* VTI CMA3000-D0x
6	Datasheet:
7	  CMA3000-D0X Product Family Specification 8281000A.02.pdf
8	  <http://www.vti.fi/en/>
9	
10	Author: Hemanth V <hemanthv@ti.com>
11	
12	
13	Description
14	-----------
15	CMA3000 Tri-axis accelerometer supports Motion detect, Measurement and
16	Free fall modes.
17	
18	Motion Detect Mode: Its the low power mode where interrupts are generated only
19	when motion exceeds the defined thresholds.
20	
21	Measurement Mode: This mode is used to read the acceleration data on X,Y,Z
22	axis and supports 400, 100, 40 Hz sample frequency.
23	
24	Free fall Mode: This mode is intended to save system resources.
25	
26	Threshold values: Chip supports defining threshold values for above modes
27	which includes time and g value. Refer product specifications for more details.
28	
29	CMA3000 chip supports mutually exclusive I2C and SPI interfaces for
30	communication, currently the driver supports I2C based communication only.
31	Initial configuration for bus mode is set in non volatile memory and can later
32	be modified through bus interface command.
33	
34	Driver reports acceleration data through input subsystem. It generates ABS_MISC
35	event with value 1 when free fall is detected.
36	
37	Platform data need to be configured for initial default values.
38	
39	Platform Data
40	-------------
41	fuzz_x: Noise on X Axis
42	
43	fuzz_y: Noise on Y Axis
44	
45	fuzz_z: Noise on Z Axis
46	
47	g_range: G range in milli g i.e 2000 or 8000
48	
49	mode: Default Operating mode
50	
51	mdthr: Motion detect g range threshold value
52	
53	mdfftmr: Motion detect and free fall time threshold value
54	
55	ffthr: Free fall g range threshold value
56	
57	Input Interface
58	--------------
59	Input driver version is 1.0.0
60	Input device ID: bus 0x18 vendor 0x0 product 0x0 version 0x0
61	Input device name: "cma3000-accelerometer"
62	Supported events:
63	  Event type 0 (Sync)
64	  Event type 3 (Absolute)
65	    Event code 0 (X)
66	      Value     47
67	      Min    -8000
68	      Max     8000
69	      Fuzz     200
70	    Event code 1 (Y)
71	      Value    -28
72	      Min    -8000
73	      Max     8000
74	      Fuzz     200
75	    Event code 2 (Z)
76	      Value    905
77	      Min    -8000
78	      Max     8000
79	      Fuzz     200
80	    Event code 40 (Misc)
81	      Value      0
82	      Min        0
83	      Max        1
84	  Event type 4 (Misc)
85	
86	
87	Register/Platform parameters Description
88	----------------------------------------
89	
90	mode:
91		0: power down mode
92		1: 100 Hz Measurement mode
93		2: 400 Hz Measurement mode
94		3: 40 Hz Measurement mode
95		4: Motion Detect mode (default)
96		5: 100 Hz Free fall mode
97		6: 40 Hz Free fall mode
98		7: Power off mode
99	
100	grange:
101		2000: 2000 mg or 2G Range
102		8000: 8000 mg or 8G Range
103	
104	mdthr:
105		X: X * 71mg (8G Range)
106		X: X * 18mg (2G Range)
107	
108	mdfftmr:
109		X: (X & 0x70) * 100 ms (MDTMR)
110		   (X & 0x0F) * 2.5 ms (FFTMR 400 Hz)
111		   (X & 0x0F) * 10 ms  (FFTMR 100 Hz)
112	
113	ffthr:
114	       X: (X >> 2) * 18mg (2G Range)
115	       X: (X & 0x0F) * 71 mg (8G Range)
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