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70 lines
2.1 KiB
70 lines
2.1 KiB
Kernel driver max197 |
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==================== |
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Author: |
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* Vivien Didelot <[email protected]> |
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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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