| Maxim MAX197 driver |
| =================== |
| |
| Author: |
| * Vivien Didelot <vivien.didelot@savoirfairelinux.com> |
| |
| Supported chips: |
| * Maxim MAX197 |
| Prefix: 'max197' |
| Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX197.pdf |
| |
| * Maxim MAX199 |
| Prefix: 'max199' |
| Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX199.pdf |
| |
| Description |
| ----------- |
| |
| The A/D converters MAX197, and MAX199 are both 8-Channel, Multi-Range, 5V, |
| 12-Bit DAS with 8+4 Bus Interface and Fault Protection. |
| |
| The available ranges for the MAX197 are {0,-5V} to 5V, and {0,-10V} to 10V, |
| while they are {0,-2V} to 2V, and {0,-4V} to 4V on the MAX199. |
| |
| Platform data |
| ------------- |
| |
| The MAX197 platform data (defined in linux/platform_data/max197.h) should be |
| filled with a pointer to a conversion function, defined like: |
| |
| int convert(u8 ctrl); |
| |
| ctrl is the control byte to write to start a new conversion. |
| On success, the function must return the 12-bit raw value read from the chip, |
| or a negative error code otherwise. |
| |
| Control byte format: |
| |
| Bit Name Description |
| 7,6 PD1,PD0 Clock and Power-Down modes |
| 5 ACQMOD Internal or External Controlled Acquisition |
| 4 RNG Full-scale voltage magnitude at the input |
| 3 BIP Unipolar or Bipolar conversion mode |
| 2,1,0 A2,A1,A0 Channel |
| |
| Sysfs interface |
| --------------- |
| |
| * in[0-7]_input: The conversion value for the corresponding channel. |
| RO |
| |
| * in[0-7]_min: The lower limit (in mV) for the corresponding channel. |
| For the MAX197, it will be adjusted to -10000, -5000, or 0. |
| For the MAX199, it will be adjusted to -4000, -2000, or 0. |
| RW |
| |
| * in[0-7]_max: The higher limit (in mV) for the corresponding channel. |
| For the MAX197, it will be adjusted to 0, 5000, or 10000. |
| For the MAX199, it will be adjusted to 0, 2000, or 4000. |
| RW |