projects / linux-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 5812f928 SH |
1 | Kernel driver ads7828 |
| 2 | ===================== | |
| 3 | ||
| 4 | Supported chips: | |
| b04f2f7d | 5 | |
| 5812f928 | 6 | * Texas Instruments/Burr-Brown ADS7828 |
| b04f2f7d | 7 | |
| 5812f928 | 8 | Prefix: 'ads7828' |
| b04f2f7d | 9 | |
| 46d78462 | 10 | Datasheet: Publicly available at the Texas Instruments website: |
| b04f2f7d MCC |
11 | |
| 12 | http://focus.ti.com/lit/ds/symlink/ads7828.pdf | |
| 5812f928 | 13 | |
| 0962e0f1 | 14 | * Texas Instruments ADS7830 |
| b04f2f7d | 15 | |
| 0962e0f1 | 16 | Prefix: 'ads7830' |
| b04f2f7d | 17 | |
| 0962e0f1 | 18 | Datasheet: Publicly available at the Texas Instruments website: |
| b04f2f7d MCC |
19 | |
| 20 | http://focus.ti.com/lit/ds/symlink/ads7830.pdf | |
| 0962e0f1 | 21 | |
| 5812f928 | 22 | Authors: |
| b04f2f7d MCC |
23 | - Steve Hardy <shardy@redhat.com> |
| 24 | - Vivien Didelot <vivien.didelot@savoirfairelinux.com> | |
| 25 | - Guillaume Roguez <guillaume.roguez@savoirfairelinux.com> | |
| 5812f928 | 26 | |
| 46d78462 VD |
27 | Platform data |
| 28 | ------------- | |
| 5812f928 | 29 | |
| 46d78462 VD |
30 | The ads7828 driver accepts an optional ads7828_platform_data structure (defined |
| 31 | in include/linux/platform_data/ads7828.h). The structure fields are: | |
| 32 | ||
| 33 | * diff_input: (bool) Differential operation | |
| b04f2f7d | 34 | set to true for differential mode, false for default single ended mode. |
| 46d78462 VD |
35 | |
| 36 | * ext_vref: (bool) External reference | |
| b04f2f7d MCC |
37 | set to true if it operates with an external reference, false for default |
| 38 | internal reference. | |
| 46d78462 VD |
39 | |
| 40 | * vref_mv: (unsigned int) Voltage reference | |
| b04f2f7d MCC |
41 | if using an external reference, set this to the reference voltage in mV, |
| 42 | otherwise it will default to the internal value (2500mV). This value will be | |
| 43 | bounded with limits accepted by the chip, described in the datasheet. | |
| 46d78462 VD |
44 | |
| 45 | If no structure is provided, the configuration defaults to single ended | |
| 46 | operation and internal voltage reference (2.5V). | |
| 5812f928 SH |
47 | |
| 48 | Description | |
| 49 | ----------- | |
| 50 | ||
| 0962e0f1 | 51 | This driver implements support for the Texas Instruments ADS7828 and ADS7830. |
| 5812f928 | 52 | |
| 0962e0f1 GR |
53 | The ADS7828 device is a 12-bit 8-channel A/D converter, while the ADS7830 does |
| 54 | 8-bit sampling. | |
| 5812f928 SH |
55 | |
| 56 | It can operate in single ended mode (8 +ve inputs) or in differential mode, | |
| 57 | where 4 differential pairs can be measured. | |
| 58 | ||
| 59 | The chip also has the facility to use an external voltage reference. This | |
| 60 | may be required if your hardware supplies the ADS7828 from a 5V supply, see | |
| 61 | the datasheet for more details. | |
| 46d78462 VD |
62 | |
| 63 | There is no reliable way to identify this chip, so the driver will not scan | |
| 64 | some addresses to try to auto-detect it. That means that you will have to | |
| 65 | statically declare the device in the platform support code. |