projects / linux.git / blame
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|---|---|---|
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1 | Kernel driver max197 |
| 2 | ==================== | |
| 6c1fe725 VD |
3 | |
| 4 | Author: | |
| b04f2f7d | 5 | |
| 6c1fe725 VD |
6 | * Vivien Didelot <[email protected]> |
| 7 | ||
| 8 | Supported chips: | |
| b04f2f7d | 9 | |
| 6c1fe725 | 10 | * Maxim MAX197 |
| b04f2f7d | 11 | |
| 6c1fe725 | 12 | Prefix: 'max197' |
| b04f2f7d | 13 | |
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14 | Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX197.pdf |
| 15 | ||
| 16 | * Maxim MAX199 | |
| b04f2f7d | 17 | |
| 6c1fe725 | 18 | Prefix: 'max199' |
| b04f2f7d | 19 | |
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20 | Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX199.pdf |
| 21 | ||
| 22 | Description | |
| 23 | ----------- | |
| 24 | ||
| 25 | The A/D converters MAX197, and MAX199 are both 8-Channel, Multi-Range, 5V, | |
| 26 | 12-Bit DAS with 8+4 Bus Interface and Fault Protection. | |
| 27 | ||
| 28 | The available ranges for the MAX197 are {0,-5V} to 5V, and {0,-10V} to 10V, | |
| 29 | while they are {0,-2V} to 2V, and {0,-4V} to 4V on the MAX199. | |
| 30 | ||
| 31 | Platform data | |
| 32 | ------------- | |
| 33 | ||
| 34 | The MAX197 platform data (defined in linux/platform_data/max197.h) should be | |
| b04f2f7d | 35 | filled with a pointer to a conversion function, defined like:: |
| 6c1fe725 VD |
36 | |
| 37 | int convert(u8 ctrl); | |
| 38 | ||
| 39 | ctrl is the control byte to write to start a new conversion. | |
| 40 | On success, the function must return the 12-bit raw value read from the chip, | |
| 41 | or a negative error code otherwise. | |
| 42 | ||
| 43 | Control byte format: | |
| 44 | ||
| b04f2f7d | 45 | ======= ========== ============================================ |
| 6c1fe725 VD |
46 | Bit Name Description |
| 47 | 7,6 PD1,PD0 Clock and Power-Down modes | |
| 48 | 5 ACQMOD Internal or External Controlled Acquisition | |
| 49 | 4 RNG Full-scale voltage magnitude at the input | |
| 50 | 3 BIP Unipolar or Bipolar conversion mode | |
| 51 | 2,1,0 A2,A1,A0 Channel | |
| b04f2f7d | 52 | ======= ========== ============================================ |
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53 | |
| 54 | Sysfs interface | |
| 55 | --------------- | |
| 56 | ||
| b04f2f7d MCC |
57 | ============== ============================================================== |
| 58 | in[0-7]_input The conversion value for the corresponding channel. | |
| 59 | RO | |
| 6c1fe725 | 60 | |
| b04f2f7d MCC |
61 | in[0-7]_min The lower limit (in mV) for the corresponding channel. |
| 62 | For the MAX197, it will be adjusted to -10000, -5000, or 0. | |
| 63 | For the MAX199, it will be adjusted to -4000, -2000, or 0. | |
| 64 | RW | |
| 6c1fe725 | 65 | |
| b04f2f7d MCC |
66 | in[0-7]_max The higher limit (in mV) for the corresponding channel. |
| 67 | For the MAX197, it will be adjusted to 0, 5000, or 10000. | |
| 68 | For the MAX199, it will be adjusted to 0, 2000, or 4000. | |
| 69 | RW | |
| 70 | ============== ============================================================== |