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----------------------------------
- AD525x Digital Potentiometers
----------------------------------
-
-The ad525x_dpot driver exports a simple sysfs interface. This allows you to
-work with the immediate resistance settings as well as update the saved startup
-settings. Access to the factory programmed tolerance is also provided, but
-interpretation of this settings is required by the end application according to
-the specific part in use.
-
----------
- Files
----------
-
-Each dpot device will have a set of eeprom, rdac, and tolerance files. How
-many depends on the actual part you have, as will the range of allowed values.
-
-The eeprom files are used to program the startup value of the device.
-
-The rdac files are used to program the immediate value of the device.
-
-The tolerance files are the read-only factory programmed tolerance settings
-and may vary greatly on a part-by-part basis. For exact interpretation of
-this field, please consult the datasheet for your part. This is presented
-as a hex file for easier parsing.
-
------------
- Example
------------
-
-Locate the device in your sysfs tree. This is probably easiest by going into
-the common i2c directory and locating the device by the i2c slave address.
-
- # ls /sys/bus/i2c/devices/
- 0-0022 0-0027 0-002f
-
-So assuming the device in question is on the first i2c bus and has the slave
-address of 0x2f, we descend (unrelated sysfs entries have been trimmed).
-
- # ls /sys/bus/i2c/devices/0-002f/
- eeprom0 rdac0 tolerance0
-
-You can use simple reads/writes to access these files:
-
- # cd /sys/bus/i2c/devices/0-002f/
-
- # cat eeprom0
- 0
- # echo 10 > eeprom0
- # cat eeprom0
- 10
-
- # cat rdac0
- 5
- # echo 3 > rdac0
- # cat rdac0
- 3