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authorHemanth V <hemanthv@ti.com>2010-05-20 20:18:17 +0530
committerSantosh Shilimkar <santosh.shilimkar@ti.com>2010-05-21 11:42:15 +0530
commit76335689e7554e4f19544c246db0dbf77554fa11 (patch)
treedebcdf504b069e21dac3c88c8f78b39d314fe4a1 /Documentation
parent939b459dce259bdce82f0eb3e1c190960ca648c3 (diff)
input: CMA3000 Accelerometer Driver
This patch adds support for CMA3000 Tri-axis accelerometer, which supports Motion detect, Measurement and Free fall modes. CMA3000 supports both I2C/SPI bus for communication, currently the driver supports I2C based communication. Driver reports acceleration data through input subsystem and supports sysfs for configuration changes. This is V2 of patch, which fixes open source review comments Signed-off-by: Hemanth V <hemanthv@ti.com>
Diffstat (limited to 'Documentation')
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diff --git a/Documentation/input/cma3000_d0x.txt b/Documentation/input/cma3000_d0x.txt
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+Kernel driver for CMA3000-D0x
+============================
+
+Supported chips:
+* VTI CMA3000-D0x
+Datasheet:
+ CMA3000-D0X Product Family Specification 8281000A.02.pdf
+
+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 intented 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 supports both I2C/SPI bus for communication, currently the driver
+supports I2C based communication.
+
+Driver reports acceleration data through input subsystem and supports sysfs
+for configuration changes. 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 threshold value
+
+mdfftmr: Motion detect and free fall time value
+
+ffthr: Free fall 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-acclerometer"
+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)
+
+Sysfs entries
+-------------
+
+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)