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diff --git a/Documentation/hwmon/ds1621 b/Documentation/hwmon/ds1621 deleted file mode 100644 index fa3407997795..000000000000 --- a/Documentation/hwmon/ds1621 +++ /dev/null @@ -1,187 +0,0 @@ -Kernel driver ds1621 -==================== - -Supported chips: - * Dallas Semiconductor / Maxim Integrated DS1621 - Prefix: 'ds1621' - Addresses scanned: none - Datasheet: Publicly available from www.maximintegrated.com - - * Dallas Semiconductor DS1625 - Prefix: 'ds1625' - Addresses scanned: none - Datasheet: Publicly available from www.datasheetarchive.com - - * Maxim Integrated DS1631 - Prefix: 'ds1631' - Addresses scanned: none - Datasheet: Publicly available from www.maximintegrated.com - - * Maxim Integrated DS1721 - Prefix: 'ds1721' - Addresses scanned: none - Datasheet: Publicly available from www.maximintegrated.com - - * Maxim Integrated DS1731 - Prefix: 'ds1731' - Addresses scanned: none - Datasheet: Publicly available from www.maximintegrated.com - -Authors: - Christian W. Zuckschwerdt <zany@triq.net> - valuable contributions by Jan M. Sendler <sendler@sendler.de> - ported to 2.6 by Aurelien Jarno <aurelien@aurel32.net> - with the help of Jean Delvare <jdelvare@suse.de> - -Module Parameters ------------------- - -* polarity int - Output's polarity: 0 = active high, 1 = active low - -Description ------------ - -The DS1621 is a (one instance) digital thermometer and thermostat. It has -both high and low temperature limits which can be user defined (i.e. -programmed into non-volatile on-chip registers). Temperature range is -55 -degree Celsius to +125 in 0.5 increments. You may convert this into a -Fahrenheit range of -67 to +257 degrees with 0.9 steps. If polarity -parameter is not provided, original value is used. - -As for the thermostat, behavior can also be programmed using the polarity -toggle. On the one hand ("heater"), the thermostat output of the chip, -Tout, will trigger when the low limit temperature is met or underrun and -stays high until the high limit is met or exceeded. On the other hand -("cooler"), vice versa. That way "heater" equals "active low", whereas -"conditioner" equals "active high". Please note that the DS1621 data sheet -is somewhat misleading in this point since setting the polarity bit does -not simply invert Tout. - -A second thing is that, during extensive testing, Tout showed a tolerance -of up to +/- 0.5 degrees even when compared against precise temperature -readings. Be sure to have a high vs. low temperature limit gap of al least -1.0 degree Celsius to avoid Tout "bouncing", though! - -The alarm bits are set when the high or low limits are met or exceeded and -are reset by the module as soon as the respective temperature ranges are -left. - -The alarm registers are in no way suitable to find out about the actual -status of Tout. They will only tell you about its history, whether or not -any of the limits have ever been met or exceeded since last power-up or -reset. Be aware: When testing, it showed that the status of Tout can change -with neither of the alarms set. - -Since there is no version or vendor identification register, there is -no unique identification for these devices. Therefore, explicit device -instantiation is required for correct device identification and functionality -(one device per address in this address range: 0x48..0x4f). - -The DS1625 is pin compatible and functionally equivalent with the DS1621, -but the DS1621 is meant to replace it. The DS1631, DS1721, and DS1731 are -also pin compatible with the DS1621 and provide multi-resolution support. - -Additionally, the DS1721 data sheet says the temperature flags (THF and TLF) -are used internally, however, these flags do get set and cleared as the actual -temperature crosses the min or max settings (which by default are set to 75 -and 80 degrees respectively). - -Temperature Conversion: ------------------------ -DS1621 - 750ms (older devices may take up to 1000ms) -DS1625 - 500ms -DS1631 - 93ms..750ms for 9..12 bits resolution, respectively. -DS1721 - 93ms..750ms for 9..12 bits resolution, respectively. -DS1731 - 93ms..750ms for 9..12 bits resolution, respectively. - -Note: -On the DS1621, internal access to non-volatile registers may last for 10ms -or less (unverified on the other devices). - -Temperature Accuracy: ---------------------- -DS1621: +/- 0.5 degree Celsius (from 0 to +70 degrees) -DS1625: +/- 0.5 degree Celsius (from 0 to +70 degrees) -DS1631: +/- 0.5 degree Celsius (from 0 to +70 degrees) -DS1721: +/- 1.0 degree Celsius (from -10 to +85 degrees) -DS1731: +/- 1.0 degree Celsius (from -10 to +85 degrees) - -Note: -Please refer to the device datasheets for accuracy at other temperatures. - -Temperature Resolution: ------------------------ -As mentioned above, the DS1631, DS1721, and DS1731 provide multi-resolution -support, which is achieved via the R0 and R1 config register bits, where: - -R0..R1 ------- - 0 0 => 9 bits, 0.5 degrees Celsius - 1 0 => 10 bits, 0.25 degrees Celsius - 0 1 => 11 bits, 0.125 degrees Celsius - 1 1 => 12 bits, 0.0625 degrees Celsius - -Note: -At initial device power-on, the default resolution is set to 12-bits. - -The resolution mode for the DS1631, DS1721, or DS1731 can be changed from -userspace, via the device 'update_interval' sysfs attribute. This attribute -will normalize the range of input values to the device maximum resolution -values defined in the datasheet as follows: - -Resolution Conversion Time Input Range - (C/LSB) (msec) (msec) ------------------------------------------------- -0.5 93.75 0....94 -0.25 187.5 95...187 -0.125 375 188..375 -0.0625 750 376..infinity ------------------------------------------------- - -The following examples show how the 'update_interval' attribute can be -used to change the conversion time: - -$ cat update_interval -750 -$ cat temp1_input -22062 -$ -$ echo 300 > update_interval -$ cat update_interval -375 -$ cat temp1_input -22125 -$ -$ echo 150 > update_interval -$ cat update_interval -188 -$ cat temp1_input -22250 -$ -$ echo 1 > update_interval -$ cat update_interval -94 -$ cat temp1_input -22000 -$ -$ echo 1000 > update_interval -$ cat update_interval -750 -$ cat temp1_input -22062 -$ - -As shown, the ds1621 driver automatically adjusts the 'update_interval' -user input, via a step function. Reading back the 'update_interval' value -after a write operation provides the conversion time used by the device. - -Mathematically, the resolution can be derived from the conversion time -via the following function: - - g(x) = 0.5 * [minimum_conversion_time/x] - -where: - -> 'x' = the output from 'update_interval' - -> 'g(x)' = the resolution in degrees C per LSB. - -> 93.75ms = minimum conversion time |