projects / GitHub / mt8127 / android_kernel_alcatel_ttab.git / blame
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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: |
| 5812f928 SH |
8 | http://focus.ti.com/lit/ds/symlink/ads7828.pdf |
| 9 | ||
| 0962e0f1 GR |
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 | |
| 46d78462 VD |
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). | |
| 5812f928 SH |
40 | |
| 41 | Description | |
| 42 | ----------- | |
| 43 | ||
| 0962e0f1 | 44 | This driver implements support for the Texas Instruments ADS7828 and ADS7830. |
| 5812f928 | 45 | |
| 0962e0f1 GR |
46 | The ADS7828 device is a 12-bit 8-channel A/D converter, while the ADS7830 does |
| 47 | 8-bit sampling. | |
| 5812f928 SH |
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. | |
| 46d78462 VD |
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. |