0001 Kernel driver da9055
0002 ====================
0003
0004 Supported chips:
0005 * Dialog Semiconductors DA9055 PMIC
0006
0007 Prefix: 'da9055'
0008
0009 Datasheet: Datasheet is not publicly available.
0010
0011 Authors: David Dajun Chen <dchen@diasemi.com>
0012
0013 Description
0014 -----------
0015
0016 The DA9055 provides an Analogue to Digital Converter (ADC) with 10 bits
0017 resolution and track and hold circuitry combined with an analogue input
0018 multiplexer. The analogue input multiplexer will allow conversion of up to 5
0019 different inputs. The track and hold circuit ensures stable input voltages at
0020 the input of the ADC during the conversion.
0021
0022 The ADC is used to measure the following inputs:
0023
0024 - Channel 0: VDDOUT - measurement of the system voltage
0025 - Channel 1: ADC_IN1 - high impedance input (0 - 2.5V)
0026 - Channel 2: ADC_IN2 - high impedance input (0 - 2.5V)
0027 - Channel 3: ADC_IN3 - high impedance input (0 - 2.5V)
0028 - Channel 4: Internal Tjunc. - sense (internal temp. sensor)
0029
0030 By using sysfs attributes we can measure the system voltage VDDOUT,
0031 chip junction temperature and auxiliary channels voltages.
0032
0033 Voltage Monitoring
0034 ------------------
0035
0036 Voltages are sampled in a AUTO mode it can be manually sampled too and results
0037 are stored in a 10 bit ADC.
0038
0039 The system voltage is calculated as:
0040
0041 Milli volt = ((ADC value * 1000) / 85) + 2500
0042
0043 The voltages on ADC channels 1, 2 and 3 are calculated as:
0044
0045 Milli volt = (ADC value * 1000) / 102
0046
0047 Temperature Monitoring
0048 ----------------------
0049
0050 Temperatures are sampled by a 10 bit ADC. Junction temperatures
0051 are monitored by the ADC channels.
0052
0053 The junction temperature is calculated:
0054
0055 Degrees celsius = -0.4084 * (ADC_RES - T_OFFSET) + 307.6332
0056
0057 The junction temperature attribute is supported by the driver.
