| Hemanth V | b029ffa | 2010-11-30 23:03:54 -0800 | [diff] [blame] | 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) |