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