1 Kernel driver max197
2 ====================
3
4 Author:
5
6 * Vivien Didelot <vivien.didelot@savoirfairelinux.com>
7
8 Supported chips:
9
10 * Maxim MAX197
11
12 Prefix: 'max197'
13
14 Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX197.pdf
15
16 * Maxim MAX199
17
18 Prefix: 'max199'
19
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
35 filled with a pointer to a conversion function, defined like::
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
45 ======= ========== ============================================
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
52 ======= ========== ============================================
53
54 Sysfs interface
55 ---------------
56
57 ============== ==============================================================
58 in[0-7]_input The conversion value for the corresponding channel.
59 RO
60
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
65
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 ============== ==============================================================
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