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Commit | Line | Data |
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e5970223 AJ |
1 | Supported chips: |
2 | * Dialog Semiconductors DA9055 PMIC | |
3 | Prefix: 'da9055' | |
4 | Datasheet: Datasheet is not publicly available. | |
5 | ||
6 | Authors: David Dajun Chen <dchen@diasemi.com> | |
7 | ||
8 | Description | |
9 | ----------- | |
10 | ||
11 | The DA9055 provides an Analogue to Digital Converter (ADC) with 10 bits | |
12 | resolution and track and hold circuitry combined with an analogue input | |
13 | multiplexer. The analogue input multiplexer will allow conversion of up to 5 | |
14 | different inputs. The track and hold circuit ensures stable input voltages at | |
15 | the input of the ADC during the conversion. | |
16 | ||
17 | The ADC is used to measure the following inputs: | |
18 | Channel 0: VDDOUT - measurement of the system voltage | |
19 | Channel 1: ADC_IN1 - high impedance input (0 - 2.5V) | |
20 | Channel 2: ADC_IN2 - high impedance input (0 - 2.5V) | |
21 | Channel 3: ADC_IN3 - high impedance input (0 - 2.5V) | |
22 | Channel 4: Internal Tjunc. - sense (internal temp. sensor) | |
23 | ||
24 | By using sysfs attributes we can measure the system voltage VDDOUT, | |
25 | chip junction temperature and auxiliary channels voltages. | |
26 | ||
27 | Voltage Monitoring | |
28 | ------------------ | |
29 | ||
30 | Voltages are sampled in a AUTO mode it can be manually sampled too and results | |
31 | are stored in a 10 bit ADC. | |
32 | ||
33 | The system voltage is calculated as: | |
34 | Milli volt = ((ADC value * 1000) / 85) + 2500 | |
35 | ||
36 | The voltages on ADC channels 1, 2 and 3 are calculated as: | |
37 | Milli volt = (ADC value * 1000) / 102 | |
38 | ||
39 | Temperature Monitoring | |
40 | ---------------------- | |
41 | ||
42 | Temperatures are sampled by a 10 bit ADC. Junction temperatures | |
43 | are monitored by the ADC channels. | |
44 | ||
45 | The junction temperature is calculated: | |
46 | Degrees celsius = -0.4084 * (ADC_RES - T_OFFSET) + 307.6332 | |
47 | The junction temperature attribute is supported by the driver. |