71 lines
2.1 KiB
ReStructuredText
71 lines
2.1 KiB
ReStructuredText
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Kernel driver max197
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====================
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Author:
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* Vivien Didelot <vivien.didelot@savoirfairelinux.com>
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Supported chips:
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* Maxim MAX197
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Prefix: 'max197'
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Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX197.pdf
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* Maxim MAX199
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Prefix: 'max199'
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Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX199.pdf
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Description
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-----------
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The A/D converters MAX197, and MAX199 are both 8-Channel, Multi-Range, 5V,
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12-Bit DAS with 8+4 Bus Interface and Fault Protection.
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The available ranges for the MAX197 are {0,-5V} to 5V, and {0,-10V} to 10V,
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while they are {0,-2V} to 2V, and {0,-4V} to 4V on the MAX199.
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Platform data
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-------------
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The MAX197 platform data (defined in linux/platform_data/max197.h) should be
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filled with a pointer to a conversion function, defined like::
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int convert(u8 ctrl);
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ctrl is the control byte to write to start a new conversion.
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On success, the function must return the 12-bit raw value read from the chip,
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or a negative error code otherwise.
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Control byte format:
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======= ========== ============================================
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Bit Name Description
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7,6 PD1,PD0 Clock and Power-Down modes
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5 ACQMOD Internal or External Controlled Acquisition
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4 RNG Full-scale voltage magnitude at the input
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3 BIP Unipolar or Bipolar conversion mode
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2,1,0 A2,A1,A0 Channel
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======= ========== ============================================
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Sysfs interface
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---------------
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============== ==============================================================
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in[0-7]_input The conversion value for the corresponding channel.
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RO
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in[0-7]_min The lower limit (in mV) for the corresponding channel.
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For the MAX197, it will be adjusted to -10000, -5000, or 0.
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For the MAX199, it will be adjusted to -4000, -2000, or 0.
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RW
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in[0-7]_max The higher limit (in mV) for the corresponding channel.
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For the MAX197, it will be adjusted to 0, 5000, or 10000.
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For the MAX199, it will be adjusted to 0, 2000, or 4000.
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RW
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============== ==============================================================
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