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5812f928 SH |
1 | Kernel driver ads7828 |
2 | ===================== | |
3 | ||
4 | Supported chips: | |
5 | * Texas Instruments/Burr-Brown ADS7828 | |
6 | Prefix: 'ads7828' | |
46d78462 | 7 | Datasheet: Publicly available at the Texas Instruments website: |
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8 | http://focus.ti.com/lit/ds/symlink/ads7828.pdf |
9 | ||
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10 | * Texas Instruments ADS7830 |
11 | Prefix: 'ads7830' | |
12 | Datasheet: Publicly available at the Texas Instruments website: | |
13 | http://focus.ti.com/lit/ds/symlink/ads7830.pdf | |
14 | ||
5812f928 | 15 | Authors: |
5d84291d | 16 | Steve Hardy <shardy@redhat.com> |
46d78462 | 17 | Vivien Didelot <vivien.didelot@savoirfairelinux.com> |
0962e0f1 | 18 | Guillaume Roguez <guillaume.roguez@savoirfairelinux.com> |
5812f928 | 19 | |
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20 | Platform data |
21 | ------------- | |
5812f928 | 22 | |
46d78462 VD |
23 | The ads7828 driver accepts an optional ads7828_platform_data structure (defined |
24 | in include/linux/platform_data/ads7828.h). The structure fields are: | |
25 | ||
26 | * diff_input: (bool) Differential operation | |
27 | set to true for differential mode, false for default single ended mode. | |
28 | ||
29 | * ext_vref: (bool) External reference | |
30 | set to true if it operates with an external reference, false for default | |
31 | internal reference. | |
32 | ||
33 | * vref_mv: (unsigned int) Voltage reference | |
34 | if using an external reference, set this to the reference voltage in mV, | |
35 | otherwise it will default to the internal value (2500mV). This value will be | |
36 | bounded with limits accepted by the chip, described in the datasheet. | |
37 | ||
38 | If no structure is provided, the configuration defaults to single ended | |
39 | operation and internal voltage reference (2.5V). | |
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40 | |
41 | Description | |
42 | ----------- | |
43 | ||
0962e0f1 | 44 | This driver implements support for the Texas Instruments ADS7828 and ADS7830. |
5812f928 | 45 | |
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46 | The ADS7828 device is a 12-bit 8-channel A/D converter, while the ADS7830 does |
47 | 8-bit sampling. | |
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48 | |
49 | It can operate in single ended mode (8 +ve inputs) or in differential mode, | |
50 | where 4 differential pairs can be measured. | |
51 | ||
52 | The chip also has the facility to use an external voltage reference. This | |
53 | may be required if your hardware supplies the ADS7828 from a 5V supply, see | |
54 | the datasheet for more details. | |
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55 | |
56 | There is no reliable way to identify this chip, so the driver will not scan | |
57 | some addresses to try to auto-detect it. That means that you will have to | |
58 | statically declare the device in the platform support code. |