linux/Documentation/hwmon/da9055
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   1Supported chips:
   2  * Dialog Semiconductors DA9055 PMIC
   3    Prefix: 'da9055'
   4    Datasheet: Datasheet is not publicly available.
   5
   6Authors: David Dajun Chen <dchen@diasemi.com>
   7
   8Description
   9-----------
  10
  11The DA9055 provides an Analogue to Digital Converter (ADC) with 10 bits
  12resolution and track and hold circuitry combined with an analogue input
  13multiplexer. The analogue input multiplexer will allow conversion of up to 5
  14different inputs. The track and hold circuit ensures stable input voltages at
  15the input of the ADC during the conversion.
  16
  17The ADC is used to measure the following inputs:
  18Channel 0: VDDOUT - measurement of the system voltage
  19Channel 1: ADC_IN1 - high impedance input (0 - 2.5V)
  20Channel 2: ADC_IN2 - high impedance input (0 - 2.5V)
  21Channel 3: ADC_IN3 - high impedance input (0 - 2.5V)
  22Channel 4: Internal Tjunc. - sense (internal temp. sensor)
  23
  24By using sysfs attributes we can measure the system voltage VDDOUT,
  25chip junction temperature and auxiliary channels voltages.
  26
  27Voltage Monitoring
  28------------------
  29
  30Voltages are sampled in a AUTO mode it can be manually sampled too and results
  31are stored in a 10 bit ADC.
  32
  33The system voltage is calculated as:
  34        Milli volt = ((ADC value * 1000) / 85) + 2500
  35
  36The voltages on ADC channels 1, 2 and 3 are calculated as:
  37        Milli volt = (ADC value * 1000) / 102
  38
  39Temperature Monitoring
  40----------------------
  41
  42Temperatures are sampled by a 10 bit ADC.  Junction temperatures
  43are monitored by the ADC channels.
  44
  45The junction temperature is calculated:
  46        Degrees celsius = -0.4084 * (ADC_RES - T_OFFSET) + 307.6332
  47The junction temperature attribute is supported by the driver.
  48